OK so for a performance build how bad are these stock rods. What are you guys seeing in actual use in the field?
Are you referring to the taper-top, OE T/C connecting rods?
That has been used in the diesel industry for years now.
Scott
Of course and that is tough service for sure.
Your opinion then?
And that said why bother then with "H beam" rods? Who makes those anyway?
The tapered top is done to reduce the overall weight and move the strength in the rod to where it's needed. Think about what part of the pin area is used for what and it makes perfect sense. The top of the pin area is only used to pull the piston down the bore on the intake stroke. So by removing the metal from up top and adding it back on the bottom where all the load is makes the pin area stronger for what it's used for. It also allows the piston to give more surface area on the pin during the power stroke if made properly with no increase in weight. As said before it's been around for some 30 years in the diesel industry and is well proven.
Just thinking out loud. When these are used in a Diesel the clearances are more than likley much closer as far as cylinder/piston which reduces lateral movement of the piston in the cylinder (Makes sence?). With Forged pistons in an air cooled Harley the clearance is a bit looser. This one would think could/will cause more stress on the top piston pin area due to more movement of the piston in the cylinder. I would prefer having more material on the small end end of the rod likke the "H" beam uses.
As Scott and Steve stated, these rods have been used in diesel applications and other applications for years without issue. Although as a T/C Crankshaft rebuilder we have not experienced any issues with these rods (Bushed or Non-Bushed) when using stock length skirted pistons, but have experineced issues of small end wear on the front rod because of piston rock with "Slipper Skirt" pistons. We rebuild hundreds of T/C crankshafts each year and these are our findings.
Our suggestion to our customers is if you are using stock length skirted pistons, re-use the stock rods, if you are going to use "Slipper Skirt" pistons replace the rods with either the earlier style rods or the H-Beam rods. We have found that the front rod is always the one that has the wear and have found that this is attributed to the severe rod angle on the front cylinder. Also in rebuilding crankshafts we also find that the front rod big end, cages and bearings are always the loosest and need resized. In severe applications, we turn the rods around and run the female rod in the front and this virtually stops the rocking and wearing.
Hope this information is helpful.
Quote from: Deweysheads on January 07, 2012, 09:38:51 AM
And that said why bother then with "H beam" rods? Who makes those anyway?
More to the rod than just the tapered wrist pin area. Never had a problem with the design myself but there have been reports of the bushing rotating and jamming the pistons tapered area where the rod sits. Probably from less bushing area press fit. I think the design is best suited for a no bushing rod. Rigididity and anti stretch would be more inline for H beams. I have these same rods in the crank I have for sale in this forum. Very stout.
Ron
What make the front rod angle more severe? From what I see the bore is centered to the crank for both the front ant rear cylinder. Geometry is the same for both.
Max
Quote from: Hot-Shot Motorworks on January 07, 2012, 11:55:23 AM
As Scott and Steve stated, these rods have been used in diesel applications and other applications for years without issue. Although as a T/C Crankshaft rebuilder we have not experienced any issues with these rods (Bushed or Non-Bushed) when using stock length skirted pistons, but have experineced issues of small end wear on the front rod because of piston rock with "Slipper Skirt" pistons. We rebuild hundreds of T/C crankshafts each year and these are our findings.
Our suggestion to our customers is if you are using stock length skirted pistons, re-use the stock rods, if you are going to use "Slipper Skirt" pistons replace the rods with either the earlier style rods or the H-Beam rods. We have found that the front rod is always the one that has the wear and have found that this is attributed to the severe rod angle on the front cylinder. Also in rebuilding crankshafts we also find that the front rod big end, cages and bearings are always the loosest and need resized. In severe applications, we turn the rods around and run the female rod in the front and this virtually stops the rocking and wearing.
Hope this information is helpful.
Hmm: I always thought the front wore more because of the odd firing and degrees the front did a bit more work than the rear under load?
Ron
Quote from: Deweysheads on January 07, 2012, 09:38:51 AM
And that said why bother then with "H beam" rods? Who makes those anyway?
Eagle was manufacturing(importing) Evo rods at one time, that looked extremely similar, but as far as the T/C counterpart, I do not know for sure. Ultima?
One thing, I'll bet dollar to donuts, that the T/C H-beam rods, ARE NOT, made here.
Hoban Bros. prefers the H-beams for better wrist pin support, as was told to us. :smile:
Scott
So what, my Hyundai got me to the dealer and back today. :hyst:
Ron
Never herd the term "slipper skirt pistons" ???? .... Can somebody give me a description. Thanks.
The original name,slipper skirt, came from the 60s. It was a drag racing piston with tephlon buttons installed in the skirts (not the pin holes). In this context I expect it refers to narrow skirt pistons like Wisecos.
max
When I spoke with Hoban about my build they were more concerned about the rods than the possible crank issues.Ended up doing both and had them install "their own"h beams as opposed to the import option.Not sure who actually made them though.
Hotshot
"We have found that the front rod is always the one that has the wear and have found that this is attributed to the severe rod angle on the front cylinder".
Having some trouble digesting that.So the rear cylinder has less of a "rod angle" than the front?
I'd sure like to hear that expounded-upon, too. I could see where on average the front cylinder is trying to accelerate the crank harder than the rear because it'd been 90° crank rotation longer since the last power stroke compared to what the rear cylinder sees in that respect. But without seeing the actual drawings or carefully measuring things, I can't envision the rod angles being any different front-to-rear.
:agree:
Also, the length of the piston skirt on a Diesel is conciderably longer than any Gas powered vehicle i've seen. This IMO aides to the stability of the piston within the cylinder of a diesel. Durring the power stroke a diesel will direct it's energy more precicly thru the rod. In some of these high power Harleys with short skirt forged pistons they fit much more loosly and IMO will cause additional strain on the small end due to more movement of the piston within the cylinder. Maybe i'm wrong but from this view it makes sence. As far as diff. angle front to rear on a Harley I have never heard of that... Love to hear the explination.
Are you guys being kind since it's Hot Sh*t's first post?
You get more second posts with honey than with vinegar, right?
Quote from: glens on January 07, 2012, 03:17:03 PM
You get more second posts with honey than with vinegar, right?
:hyst: :hyst:
Ron
The 110" we did that was 133/127tq sae 5th gear had a stock crank in it. No issues so far. Beginning to think that the stock crank may not be the end of the world afterall. It may not be to the strict standards of HTT ;) but i think it will suffice in most builds
Quote from: machinist on January 07, 2012, 03:10:56 PM
Are you guys being kind since it's Hot Sh*t's first post?
[/quote i
he is somebody we want posting. They have a great reputation and a lot to share.
I mean no harm.
Hoban offers h-beam rods from across the pond as well as from the USA. I run the H beam in my 113", the SE rods in that 4.375" assy. had noticable movement in 10,000 hard miles. The Hoban H-beams have been good through 42,000 miles (some abusive) so far.
Isn't the firing order harder on the equipment in a V-Twin than a diesel?
Quote from: Deye76 on January 07, 2012, 04:47:56 PM
Hoban offers h-beam rods from across the pond as well as from the USA. I run the H beam in my 113", the SE rods in that 4.375" assy. had noticable movement in 10,000 hard miles. The Hoban H-beams have been good through 42,000 miles (some abusive) so far.
Isn't the firing order harder on the equipment in a V-Twin than a diesel?
I noticed my Hbeam Darkhorse the same. 13k when I pulled it and not change one bit since install.
Ron
I think my concern was more of a tolerance issue, bushing press fit, not a statement about the tapered rod design. I haven't seen any of these rods let go but I have seen bushings spin. It wouldn't be hard to bush and ream them with a little more press and premium material even with the crank in the bike on a top end.
Quote from: Jaycee1964 on January 07, 2012, 03:07:47 PM
Also, the length of the piston skirt on a Diesel is conciderably longer than any Gas powered vehicle i've seen. This IMO aides to the stability of the piston within the cylinder of a diesel. Durring the power stroke a diesel will direct it's energy more precicly thru the rod. In some of these high power Harleys with short skirt forged pistons they fit much more loosly and IMO will cause additional strain on the small end due to more movement of the piston within the cylinder. Maybe i'm wrong but from this view it makes sence. As far as diff. angle front to rear on a Harley I have never heard of that... Love to hear the explination.
Well the amount of power produced by a HD is no where close to what many diesels produce today and the pistons are much shorter than you think. Just to give you a little idea a few of our diesel race engines produce over 3.5Hp per cu. in.! Using this rod design there are no failures at these power levels so I doubt it will be an issue in a HD. As for how well HD installs bushings and controls the clearances, that's anyones best guess.
Water cooled engine clearances Verses Air cooled. Also, a Diesel doesn't rev as much. There are differences.
Quote from: Steve Cole on January 07, 2012, 06:54:01 PM
Quote from: Jaycee1964 on January 07, 2012, 03:07:47 PM
Also, the length of the piston skirt on a Diesel is conciderably longer than any Gas powered vehicle i've seen. This IMO aides to the stability of the piston within the cylinder of a diesel. Durring the power stroke a diesel will direct it's energy more precicly thru the rod. In some of these high power Harleys with short skirt forged pistons they fit much more loosly and IMO will cause additional strain on the small end due to more movement of the piston within the cylinder. Maybe i'm wrong but from this view it makes sence. As far as diff. angle front to rear on a Harley I have never heard of that... Love to hear the explination.
Well the amount of power produced by a HD is no where close to what many diesels produce today and the pistons are much shorter than you think. Just to give you a little idea a few of our diesel race engines produce over 3.5Hp per cu. in.! Using this rod design there are no failures at these power levels so I doubt it will be an issue in a HD. As for how well HD installs bushings and controls the clearances, that's anyones best guess.
Agreed with the above. But I also agree just because other industries run these with great results doesnt mean HD didnt do a piss poor rip off of the design. Have had many failures come through our shop. Metallurgical issues with the integrated hardened race they use at the crank pin imo. Also seen alot of the spun bushings issues as well, correctable though. What kind of cylinder temps are these diesels seeing?
Quote from: Deweysheads on January 07, 2012, 05:16:37 PM
I think my concern was more of a tolerance issue, bushing press fit, not a statement about the tapered rod design. I haven't seen any of these rods let go but I have seen bushings spin. It wouldn't be hard to bush and ream them with a little more press and premium material even with the crank in the bike on a top end.
You just nailed the big issue. Top of bushing is too thin to offer a good compression on the press fit. Lose that and the load at the bottom of the bushing could cause it to rotate. The more the power and operational rpms the engine sees the more the risk. You don't see these things in the 120r because they know better.
Ron
Quote from: jimlibo on January 07, 2012, 02:07:17 PM
Hotshot
"We have found that the front rod is always the one that has the wear and have found that this is attributed to the severe rod angle on the front cylinder".
Having some trouble digesting that.So the rear cylinder has less of a "rod angle" than the front?
We all understand that the stroke vs rod length causes the connecting rods to run at an undesirable angle in a 45* engine. Over the years of building harley engines it is always found that the front cylinder always has more wear on the minor thrust side of the cylinder than the rear cylinder does and it also runs the hottest because of the additional friction created.
In researching the reasoning behind this, it has shown that both cylinders do run with abnormal rod angles compared to any other engines. If you were to look at the rotation of the crankshaft when the piston is at bottom dead center on the rear cylinder and is rotating up on compression you will see that the rod angle is more in-line with the the angle of the rear cylinder. Now look at the front cylinder and look at the angle of the rod compared to the angle of the front cylinder when it is rotating up from bottom dead center on compression. What you are going to witness is the rod angle on the front cylinder is trying to push the piston thru the front of the front cylinder. With this happening, it causes severe loads on the front connecting rod and failures on the front rod is more prevalent than the rear rod. This is just the nature of the beast that we have to deal with.
If any of you have ever have the opportunity to witness a engine being run on a engine dyno you would be astounded at the amount of frictional horsepower/torque loss there is in a H-D engine. Frictional horsepower loss in a stock engine can average around 40-50% and will increase as the cubic inches increase. Don't get me wrong there are many other things in an engine that creates frictional horsepower/torque loss other than the pistons and cylinders, but the pistons and cylinders are where the majority of the loss is created, especially the front cylinder.
I will pull some dyno sheets and get some exact amounts of frictional horsepower/torque losses. I will also show what g's the piston generates as it rotates directions.
Hope this helps you understand.....
Todays OEM diesels are running ~1425 peak EGT's. Our race engines can handle 1800 with short peaks to 2000! Would I recommend that to anyone for a street vehicle..... no way, but when you set a land speed record at 341 mph you push things a little.............. OK maybe a lot! One full size drag truck we have runs 5.8x in the 1/8 at 5800 lbs with 1.38 60 ft times. Not your grampa's diesel! It's fun to be at the track and the vette's, mustangs and camaro's laugh at you until you blow them off the track in a pickup truck.
As far as HD screwing up the design, well all we have to do is look at the crankshafts but it's what they can get away with.
Hot shots been around for more than a day or 2. I remember looking at their head work years ago if they are the same people. Those rods appeared shortly after the primary side bearing change in the case where the crank had enough end play that the front rods were being lost. My best guess is that it allows the wristpin end of the rod to walk easier putting less strain on the big end. Strange things happen to rods as they are running.
Just a FYI, as an example Volvos 13 liter truck engine (also used in Mack) has slipper skirt pistons, made of steel,
and using the tapered small end concept.
One can just start to guess how tight they can fit a steel piston to a steel bore, all water cooled.
Some diesels have a two piece piston. For example the dt530. It has a steel piston that contains the rings and wrist pins, then has a separate crown made of aluminum that slides under the piston. The wrist pin holds things together.
This reply is to deathwish's comment....
Yes we are the same company as years past. Although on your statement "Strange things happen to rods as they are running". Please review our article on T/C Crankshaft Shifting at the link below. It tells what happens to a crankshaft while it is running and with this big mass moving and doing what it does, it makes a person wonder what the connecting rods and pistons are doing. :scratch:
www.hotshotmotorworks.com/didja_know.htm (http://www.hotshotmotorworks.com/didja_know.htm)
The dt466 and the dt530 used regular connecting rods. The replacement for them are the powdered metal tappered wrist pin rod.
Lots of engines use the powdered rods. They are fine and work well. BUT what doesn't work well is the fact that HD uses the rod as a bearing surface. They should have put races on the connecting rods.
QuoteSome diesels have a two piece piston.
Yes, I recognise this as well.
Our products at work used that concept on our 11 litre engines.
Quote from: Hot-Shot Motorworks on January 07, 2012, 08:23:10 PM
If you were to look at the rotation of the crankshaft when the piston is at bottom dead center on the rear cylinder and is rotating up on compression you will see that the rod angle is more in-line with the the angle of the rear cylinder. Now look at the front cylinder and look at the angle of the rod compared to the angle of the front cylinder when it is rotating up from bottom dead center on compression. What you are going to witness is the rod angle on the front cylinder is trying to push the piston thru the front of the front cylinder.
...
Hope this helps you understand.....
I'm sorry, but that really doesn't help me see what you're trying to say, which you've basically said twice the same now. There are only three ways I can envision a functional difference between the two cylinders such as you're trying to describe:
1. The cylinder bore centerlines both pass through and intersect at and perpendicular to the crankshaft rotational centerline, both rods are the same length with wrist pins set at same height and with same offset in pistons (same working length), but gravity appreciably pulls the pistons/rods toward the ground, through the rear of the rear cylinder and the front of the front cylinder.
2. The cylinder bore centerlines both pass through the crankshaft centerline, the effects of gravity on the pistons/rods is inconsequential, but the rods have different working lengths and/or wrist pins are set differently in the two pistons.
3. Both rods have the same working length/etc., gravity difference is inconsequential, but the intersection of the cylinder bore centerlines is not located at the crankshaft rotational centerline.
At any rate, so long as the connecting rod centers are the same measurement front/rear and the cylinder bores' centers both intersect at the crankshaft rotational center (at 90° to the bore centerlines) and both pistons have the same pin locations, I don't see how the "rod angle" is going to be any different between the two cylinders. Please try to explain things a little better/differently for me. Thanks.
I understand the MOCO has gone to no bushing, isn't that true? During what MY did that happen? What are your opinions on that setup VS the version with the bronze bushing.
I bring no bias to the table and I am trending toward thinking the new rods are not as bad as they are said to be.
Harley did go to a bushing less rod a couple years ago. It was discussed on here. Someone here posted the dealer handouts from the annual meeting that showed all of the changes for that year.
I was chatting with Reggie @ R&R and he mentioned the non- bushing rod change happened late 2006.
From an engineering point of view a tapered rod is probably an advance over a standard rod. My VW diesel is 1900 cc. Over 275 pounds of torque, 400 lbs ccp, and tapered rods. I regularily turn it to 5500 rpm and no problems in over 150 thou miles. On the other hand my SE Jims 4 3/8 crank has I beams, was loosey,goosey right out of the package,and has stood up to severe abuse for quite a few years now. Rocket science technology is great, but when translated into our beloved big twins not sure how much practical advantage we see. Going to put a bigger turbo,run an additional 8 lbs boost on the VW and see how those rods like that.
Joel 2001 FLHT
Just annectdotal but, my diesel pick up(02 Ford 7.3) has the tapered end powdered metal rods, it's pushing 500hp/900ft.lbs. and has held together for 10 years. But I'm about at the limit for pm rods, over 500 hp and they come apart. Seen this personally several times.
Glens....It is difficult to describe without having illustrations of how the rod angles are in an engine. The next time you have an opportunity to examine a disassembled engine watch the rod angles in relationship to each cylinder and you should be able to understand what I am saying. The highest load on the front cylinder happens on the compression stroke and the highest load on the rear cylinder happens on the power stroke. Hope this helps....
How many degrees difference is there?
Its ok to have 500 plus horse and 900 ft pounds with a stout connecting rod. The problem is when you have a twig of a connecting rod with 140 horse and 160 ft pounds.
BTW I have a 2009 and my connecting rod is bushed.
"always found that the front cylinder always has more wear on the minor thrust side of the cylinder than the rear cylinder does and it also runs the hottest because of the additional friction created."
I've always maintained the front cyl. runs hotter than the rear, but many here disagreed with me when I stated it a few years ago. Their thinking is it gets more air than the rear. Hotshots explanation of the rotation of the crankshaft when the piston is at BDC makes a lot of sense to me.
Also, that same rotation pulls oil to the rear..does it not?
Sorry for taking this a bit off "track"
Quote from: Deye76 on January 08, 2012, 03:52:04 PM
"always found that the front cylinder always has more wear on the minor thrust side of the cylinder than the rear cylinder does and it also runs the hottest because of the additional friction created."
I've always maintained the front cyl. runs hotter than the rear, but many here disagreed with me when I stated it a few years ago. Their thinking is it gets more air than the rear. Hotshots explanation of the rotation of the crankshaft when the piston is at BDC makes a lot of sense to me.
Also, that same rotation pulls oil to the rear..does it not?
Sorry for taking this a bit off "track"
I think it runs hotter if the cooling air was removed because it works harder to maintain a fixed rpm than the rear. Add load, this is amplified. Cooler air hitting the front masks what's really going on with temps. I still claim it's from the uneven firing degrees between the front and rear placing more heat and wear on the fronts components. I believe the front is also prone to more oiling since back in the earlier days the front cyl case bores actually had block offs to reduce the amount of oil force up the front cyl from crank rotation.
Ron
Quote from: Jaycee1964 on January 08, 2012, 10:07:04 AM
I was chatting with Reggie @ R&R and he mentioned the non- bushing rod change happened late 2006.
The one's we work on, are bushed........... :scratch:
Scott
Quote from: Hillsidecyclecom on January 08, 2012, 04:17:39 PM
Quote from: Jaycee1964 on January 08, 2012, 10:07:04 AM
I was chatting with Reggie @ R&R and he mentioned the non- bushing rod change happened late 2006.
The one's we work on, are bushed........... :scratch:
Scott
Years back we used to have S&S make some special 7.440" rods with .927 pins and they were not bushed. We had very good success with them. We are now seeing those engines returning for rebuilds and with anywhere from 50,000 - 75,000 miles on them they look and feel like they did when we installed them. If any rod was to fail on the small end these would have. The application was in the early Evo 117" with 4 5/8" stroke X 4" bore using a short 7.440" rod and these things produced anywhaere from 160 -180 hp depending on what version you had.
Harley made the change to bushing-less rods (small end) in late 2010.
Quote from: turboprop on January 08, 2012, 04:32:59 PM
Harley made the change to bushing-less rods (small end) in late 2010.
That's what I remember as well. Same time parent metal pinion hole in cam plate. I don't have a problem with either one, myself.
Ron
Have not heard of a single issue with the new bushing-less connecting rods. Maybe because they have only been out for a year and a half or so. I guess any issues will come out as the warranty runs out on these bikes and people start to hot rod them.
The bushing less/tapered rods should weigh a bunch less than a traditional square-end connecting rod. Would certainly make for a faster revving motor.
I wonder if these rods are able to be retrofitted to earlier cranks?
Yes they can be installed on the early model T/C's. Have many sets in stock if you need any.
I saw the HD bulletin with rods minus the bushings.Now..who has seen one in a production bike?I have yet to hear of a firsthand experience or image of an actual production rod without the bushing.
Not doubting,but have yet to see or hear about one.
Thanks for the offer Hot-Shot, at this point I am just thinking out loud. I will need a TC crank in the future but have not nailed down the specs. My buddy Dan Baisley thinks I should run 8" rods. Thinking right now is 4.250" bore by 4" stroke with 8" rods. The hard part is making this fit into an un-cut OEM FXR frame. Any insight?
Quote from: autoworker on January 08, 2012, 05:01:05 PM
I saw the HD bulletin with rods minus the bushings.Now..who has seen one in a production bike?I have yet to hear of a firsthand experience or image of an actual production rod without the bushing.
Not doubting,but have yet to see or hear about one.
I did see a photo of a slipped bushing in a 2011 bike.
Quote from: turboprop on January 08, 2012, 05:04:43 PM
Thanks for the offer Hot-Shot, at this point I am just thinking out loud. I will need a TC crank in the future but have not nailed down the specs. My buddy Dan Baisley thinks I should run 8" rods. Thinking right now is 4.250" bore by 4" stroke with 8" rods. The hard part is making this fit into an un-cut OEM FXR frame. Any insight?
There isn't much clearance on that frame and it might be difficult to accomplish. Dan is very intelligent and he is correct in using an 8" rod which will greatly reduce the rod angle and make for a happier engine. My calculation says that the cylinder height is going to raise .330 if you use a piston for a 4" stroke engine. If you were to use a piston for a 4 3/8" stroke engine ( which has a smaller ring pack to allow a shorter compression height) this would increase the cylinder height only .1425". You might be able to accomplish that without modifying the frame.
I'll apologize upfront to everyone else that is following this thread for going off subject here.
Dan is smart, maybe too smart sometimes. But his concerns of ring seal and chasing the tune are valid. We have looked at pistons with shorter compression heights. Also looking at other areas like rocker boxes. The Delkron website claims their rocker boxes save almost .500" compared to oem rocker boxes. I have a set of the Delkron boxes, .500" is an exaggeration, my side by side measurements show them as being .200" less than stock. Every little bit helps. I wrestle with this every day, 8" rod all bore 114" vs a cookie cutter 124". The rod to stroke ratio of the 124 is horrible and the larger bore of the 114" allows for a larger valve and less shrouding, the 4" crank is readily available and will allow higher rpms while maintaining a reasonable piston speed. Decisions, decisions.
I am currently in possession of an S&S TC case for evo frames. This case has the S&S spread pattern, makes head selection a challenge. If I were to do an off the shelf 124", then S&S heads are available for less than $500 but flow like crap and would require an expensive 4.625" crank.
If I go the 114" route, Axtell could make a set of ductile cylinders with the S&S base pattern and the oem harley top pattern. This setup allows allot more choices for heads. A set of MVA or Hurricanes are less than $1,400. More decisions.
Good Luck !!!!
Like I said, I wrestle with this daily but will probably not spend a dime on it until the Taj-Mah-Motor is back in the bike. Then I will shift attention to the Smack-A-Hoe engine. Right now it is just an abstract.
I have done several upgrades to late model bushing-less bikes, They look fine to me........
2012 CVO 110" has bushings. :up:
Scott
The first tapered rods I saw here were on an 06 cvo 103, even with my small hobby here I have seen a VERY egg shaped rear rod on an 08 Road Glide and a pair of slipped pin bushings on a 117 built over a stock welded crank. As for the non bushed rods it seems hit and miss, a friend pulled down a 2012 Saturday and it still has bushings, fuel moto has previously mentioned non bushed rods here. As for the rods themselves, my limit here other than the cvo bikes is a 107.
No way in hell am I taking the chance on those in a built 113-up.
As for the Diesel comparison even with the relatively low rpm of the V-twin it is still a high rev motor compared to most diesels.
I have built a few diesel industrial motors and some had tapered rods some didn't. Keep in mind tapered rods would also increase the ability for oiling in comparison to the small oil hole at the top of full bushed rods.
As for opinion I think it was a really bad idea(tapered rods) in an area that was previously working just fine and I don't see benefits in this application only downsides.
Yep, i know the factory said 11 models are supposed to be bushing-less (which i am in favor of) but ive pulled apart several 12 models yet and had bushings in them :scratch:
Non-bushed rods are not new.. I've yet to see any kind of bronze rod pin bushing on a Japanese bike..
As far as the fronts burning up the bushing, I seriously doubt that it's differences in the amount of work done buy the front cylinder. It is definitely not a difference in rod angularity between front and back cuz there ain't any difference. I'm sure longer skirts and rod to stroke ratios help with thrust on the cylinders and ring seal fer sure.. I'd be more inclined to believe that the layout of the motor gives the front rod a bit less oil then an the back. Also explains why slipper skirts have more of a problem.. Harder target for the oilier to hit.. Also explains why reversing the rods helped..
Max
Quote from: Hot-Shot Motorworks on January 08, 2012, 11:02:42 AM
Glens....It is difficult to describe without having illustrations of how the rod angles are in an engine. The next time you have an opportunity to examine a disassembled engine watch the rod angles in relationship to each cylinder and you should be able to understand what I am saying. The highest load on the front cylinder happens on the compression stroke and the highest load on the rear cylinder happens on the power stroke. Hope this helps....
I certainly appreciate your taking the time with this for me.
Based on what you've consistently said about this in the present thread, if one were to have at their disposal an actual (official) sectional side view "drawing" of the engine assembly, the bore centerlines would be seen to intersect below the center of the crank circle and/or the wrist pins would be located symmetrically offset away from the center of the vee. Interesting...
I don't doubt for a moment that you're seeing the wear patterns you describe. However my real-drawing-uninformed gut wants to say factors other than system geometry must be at play here; that it would be more of a dynamic phenomenon.
To the other aspect of this thread, I've isolated and attached pages 4 and 6 of Harley's "2011_MY_Technical_Forum.pdf".
[attachment removed after 60 days by system]
Do you think "running change" may mean as stock depletes?
HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?
Quote from: Deweysheads on January 09, 2012, 03:29:37 PM
Do you think "running change" may mean as stock depletes?
I bet that is correct but is strange that some 2011's have the bushings and some 10's don't.
Maybe they found an old crate of them?
Quote from: Deweysheads on January 09, 2012, 03:29:37 PM
HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?
We install H-Beam Rods, in severe duty engines we turn the rods around for stability. Reassemble, true & weld. Pretty much a bullet proof crankshaft. Check out the link below and this will give you more details on what we do to regular cranks. If you have any questions, contact us.
http://www.hotshotmotorworks.com/didja_know.htm (http://www.hotshotmotorworks.com/didja_know.htm)
Quote from: Hot-Shot Motorworks on January 09, 2012, 07:28:56 PM
Quote from: Deweysheads on January 09, 2012, 03:29:37 PM
HotShot
You do crank work on the TC obviously. What do you do to upgrade the rods on a hard charger high compression late TC or do you?
We install H-Beam Rods, in severe duty engines we turn the rods around for stability. Reassemble, true & weld. Pretty much a bullet proof crankshaft. Check out the link below and this will give you more details on what we do to regular cranks. If you have any questions, contact us.
http://www.hotshotmotorworks.com/didja_know.htm (http://www.hotshotmotorworks.com/didja_know.htm)
When you say turn the rods around does the front rod become the rear rod?
How/why is this an improvement over the original orientation
Glens, I am trying to find, without much luck, a moving cutaway illustration that may help you understand what the rod angles look like in relationship to the cylinder. I will let you know when I do. I noticed one on a web site some time ago but can't remember who's it was.
Stability...
There's http://www.animatedpiston.com/New%20AP%20Site/Twin%20Cam%20Button.swf (http://www.animatedpiston.com/New%20AP%20Site/Twin%20Cam%20Button.swf) but it's not terribly detailed.
My first profession decades ago was as a pre-computer detail draftsman and I worked for a large machinery manufacturer. I have no problem visualizing this stuff. It would pretty much require an "official" set of prints (at least the pertinent ones) to convince me there's an asymmetry in the rod angles front-to-back between when the crank pin is on the cylinder side of center and when it's on the other side of center. But I look forward to anything you can find. I realize it's really just academic but I have that mindset :)
On a separate note, I've had to fetch your referenced web page in a text-mode browser to be able to read it. In both of the standards-compliant browsers I have/use, the images obscure the text quite inconveniently. Microsoft is not known for caring about standards anyway, and "Office" really is a poor way to create a public web page. Sadly, I primarily use MS Windows for interfacing with my TTS VCI. Certainly not for connection to any public networks. Please take this in the good spirit in which it was intended!
http://validator.w3.org/unicorn/check?ucn_uri=www.hotshotmotorworks.com%2Fdidja_know.htm&ucn_task=conformance (http://validator.w3.org/unicorn/check?ucn_uri=www.hotshotmotorworks.com%2Fdidja_know.htm&ucn_task=conformance)
Just a thought, based on engine rotation and firing order, doesn't the rear cylinder fire as the front is coming up on the compression stroke? If so then you've got the rear cylinder giving the crank and consequently the front rod a kick in the ass on its upstroke. This could cause a sudden shock load on the rod and piston driving it into the cylinder wall.
Quote from: ongrade on January 09, 2012, 08:22:53 PM
Just a thought, based on engine rotation and firing order, doesn't the rear cylinder fire as the front is coming up on the compression stroke? If so then you've got the rear cylinder giving the crank and consequently the front rod a kick in the ass on its upstroke. This could cause a sudden shock load on the rod and piston driving it into the cylinder wall.
nope, exhaust stroke..max
Okay, exhaust stroke, but the piston is still traveling upwards at a consistent speed when the rear cylinder fires and gives the front a sudden hit. Same effect some of the energy is expended pushing the rod forward instead of up due to the rod angle.
I do not yet have enough information to come to a definative conclusion here. I tend to agree with Glens at this point. I also want to add this is exactly why I think this forum is the best on the net. We have a collection of the real Myth Busters. It can be a thread like this or the one on the SE comp sprocket but at the end there is usually enough well researched fact to come to a conclusion.
I have been at the bike shop when they were boring cases for oversized cylinders and the fixture they use sets up on the main bearing, they bore the spigot hole then rotate the case 45 degs. then bore the other hole. After that they dust off the base surface with a fly cutter to make sure it is square to the crank mains and spigots. They did not offset the bore from the mains at all. The rod is a piece of metal with two holes in it, regardless of it’s shape the top will be located in the cylinder by the piston pin and in this case TDC will be when the main shaft, and both holes in the rod form a straight line. With the cylinders square and centered to this line every crankshaft degree before and after will create the same angle for both cylinders and rods regardless of direction of rotation.
I would like to see any drawings or math that can correct me on this, as I am always willing to learn something new and to my knowledge no one has ever brought any of this offset information up before.
I have yet to see the bushingless tapertop rod in any stock configuration, if someone else has I would like to see it (somewhat of an urban myth that HD corp initiated with their literature, I do not believe any of them actually hit the production line), been looking forward to it as when you spin a wristpin bushing nothing good happens and you certainly can not replace with out complete dis-assembly of your motor. I can not tell you honestly how many I have seen spun, but more than I would ever want in a product that came from our facility.
The stock taper-top rod works reasonably well in the stock application it was designed for, but I do not want to take ownership of it in a performance application. I always want to make sure people are aware of what we see, what they choose to do with this information is their business, but dont shoot the messanger.
The only method to replace a wristpin bushing in this application is with a tobin-arp pin boring machine with the rod out of the flywheel assembly. We have a pin-boring machine, but have yet to find anyone with enough stones to actually replace one when the 1st has failed them.
JMHO, Thanks, John
This is an Evo, but it may help to visualize what's going on and when ...
(http://bishopsperformance.com/images/MiscGifs/MOTORanimated.gif)
Quote from: ongrade on January 09, 2012, 09:28:45 PM
Okay, exhaust stroke, but the piston is still traveling upwards at a consistent speed when the rear cylinder fires and gives the front a sudden hit. Same effect some of the energy is expended pushing the rod forward instead of up due to the rod angle.
Doubt it's much of a force compared to the thrust of the rod pushing the piston down from the power stroke.. The rear cylinder also has to accelerate the flywheels so the forces is less than the power stroke.. The angle of the rod won't be that much either.. Peak pressure during combustion is what 10-15 deg ATDC so the front will be 30 to 35 BTDC.. Not much angle there,,
We can get back to my oil theory.. The extra pressure the rod sees helps to squeeze out the oil between the rod bearign and the pin. There is not enough oil to recover.. Should show up as a wear spot on the rod side of the pin hole..
Quote from: Darkhorse on January 10, 2012, 08:49:16 AM
I have yet to see the bushingless tapertop rod in any stock configuration, if someone else has I would like to see it (somewhat of an urban myth that HD corp initiated with their literature, I do not believe any of them actually hit the production line), been looking forward to it as when you spin a wristpin bushing nothing good happens and you certainly can not replace with out complete dis-assembly of your motor. I can not tell you honestly how many I have seen spun, but more than I would ever want in a product that came from our facility.
Maybe they got a really big box of left over rods.. They had more in inventory than they thought. Or the supplier had a ton of stock based on a bloated delivery schedule from HD?
Quote
The stock taper-top rod works reasonably well in the stock application it was designed for, but I do not want to take ownership of it in a performance application. I always want to make sure people are aware of what we see, what they choose to do with this information is their business, but dont shoot the messanger.
The only method to replace a wristpin bushing in this application is with a tobin-arp pin boring machine with the rod out of the flywheel assembly. We have a pin-boring machine, but have yet to find anyone with enough stones to actually replace one when the 1st has failed them.
JMHO, Thanks, John
I would think that the non bushed rod would be better in the case of the tapered rod.. No bushing to come loose..In a tapered rod bushing fit is probably only as good as the narrowest part of the rod.. Since you've seen a bunch come loose, do you see a trend more towards the front coming loose or the rear??
Thanks,
Bruce
a question for the fellows who have actually seen bushing failure in tapered rods... What type of motors are you seeing the failures in? 88", 96", 103", 107", 113",120", or maybe it would be easier to answer this question in terms of horse power and footpounds of torque..... Failure over 120HP?.... I know this is a difficult question to answer because of all the variables but do you see a pattern to the failures of any kind? Thanks.
Quote from: LilEvilAmy on January 10, 2012, 09:43:50 AM
This is an Evo, but it may help to visualize what's going on and when ...
(http://bishopsperformance.com/images/MiscGifs/MOTORanimated.gif)
That's useful. I yanked out some of the individual images and reassembled them forming two, attached below.
In the one called "front.gif" the crankpin is roughly 90° to the front bore axis and in the one called "rear.gif" the crankpin is roughly 90° to the rear bore axis. As nearly so in both cases as the images portray.
What has been suggested in this thread is that in those two positions (each cylinder) the angle of the connecting rod vs. the bore axis is different from front to back (of its bore axis). In order for this to happen, either (both) the bore axes do not pass through the center of the crankshaft, or one piston wristpin is offset forward of its bore axis and the other rearward of its bore axis.
It has also been suggested (countered) that both bore axes pass through the center of the crankpin and that if the piston wristpins do not lie directly on the bore axes that they are offset both the same, not opposite each other.
[attachment removed after 60 days by system]
Quote from: gabbyduffy on January 07, 2012, 01:36:20 PM
Never herd the term "slipper skirt pistons" ???? .... Can somebody give me a description. Thanks.
Slipper skirts http://www.patentstorm.us/patents/5058489/description.html (http://www.patentstorm.us/patents/5058489/description.html)