Oil pressure fluctuation

[Kllongbrake]

It's a Twin Cam 124" in a Touring. I've had some....issues this year and I've ended up with a Dan Thayer 3 stage pump and R&R plate. Now the pressure drops under acceleration from 38psi sometimes down to 15psi then pulls back to 38psi. I changed the oil pressure sender as it was weeping anyway and has 60k on it. No change. I've got a 60psi mechanical gauge on it also to verify that it's really happening.
Anybody seen this before or have any ideas? Thanks for your time. 

[Admiral Akbar]

You have an EVO oil pan gasket in your twincam.

[Kllongbrake]

You have an EVO oil pan gasket in your twincam.

No sir.

[smoserx1]

The cam support plate has a bypass valve in it operated by a spring and I wonder if your spring is too weak.  this is what some folks would replace with a Baisley spring.  The oil filter itself also has a bypass valve that opens if there is too much pressure drop across the media (usually dirty media or very cold temps).  I doubt that is the issue but you could put on a different filter and see if it makes any difference.  You are not running an odd viscosity oil are you?

[BVHOG]

It's a Twin Cam 124" in a Touring. I've had some....issues this year and I've ended up with a Dan Thayer 3 stage pump and R&R plate. Now the pressure drops under acceleration from 38psi sometimes down to 15psi then pulls back to 38psi. I changed the oil pressure sender as it was weeping anyway and has 60k on it. No change. I've got a 60psi mechanical gauge on it also to verify that it's really happening.
Anybody seen this before or have any ideas? Thanks for your time.

Any chance it has an Axtel bypass spring in the plate?

[Kllongbrake]

The cam support plate has a bypass valve in it operated by a spring and I wonder if your spring is too weak.  this is what some folks would replace with a Baisley spring.  The oil filter itself also has a bypass valve that opens if there is too much pressure drop across the media (usually dirty media or very cold temps).  I doubt that is the issue but you could put on a different filter and see if it makes any difference.  You are not running an odd viscosity oil are you?

Redline 20-60 oil
Don't know about the spring or bypass. It's just a new R&R plate with 75 miles on it. I don't have a pop off gauge to check the plate. Is it a problem for the pressure to dip?

[Kllongbrake]

It's a Twin Cam 124" in a Touring. I've had some....issues this year and I've ended up with a Dan Thayer 3 stage pump and R&R plate. Now the pressure drops under acceleration from 38psi sometimes down to 15psi then pulls back to 38psi. I changed the oil pressure sender as it was weeping anyway and has 60k on it. No change. I've got a 60psi mechanical gauge on it also to verify that it's really happening.
Anybody seen this before or have any ideas? Thanks for your time.

Any chance it has an Axtel bypass spring in the plate?

If it does it came straight from Thayer like that. I'll call Randy @ Hyperformance Monday and see what he says about the bypass.
Does the axtell bypass cause a dip in pressure?

[Deye76]

Was the oil pan removed, re-installed? If so, the symptoms are like the wrong gasket that akbar referred to.

[Kllongbrake]

Was the oil pan removed, re-installed? If so, the symptoms are like the wrong gasket that akbar referred to.

No it wasn't. It is vented at the fill tube however it has seen an S&S 3 stage and plate and a Screamin eagle orange plate with high flow pump since vented and there wasn't any issues.

[Admiral Akbar]

Was the oil pan removed, re-installed? If so, the symptoms are like the wrong gasket that akbar referred to.

No it wasn't. It is vented at the fill tube however it has seen an S&S 3 stage and plate and a Screamin eagle orange plate with high flow pump since vented and there wasn't any issues.

Sounds like you fixed it til it was broke. Go back to where you where before.

[Nastytls]

Sounds like you've spent a boatload on them.... Why so many different oil pumps? If it was fine before put it back that way as Akbar alluded to.

[les]

I've got a 124" with the S&S plate and pump.  I've got an Arlen Ness oil pressure gauge.  Oil pressure is wacky.  If I'm out riding and pull over, the time it takes to drink down exactly one beer, when I get back on the bike and start it, the pressure is around zero.  It gradually gets it's way back up to around 40.  If I take my time and slowly have two beers, when I start it the pressure is about 20, and again works it's way back up.  If I start it cold, the pressure is immediately at 40.

If I start it cold and then idle warm up normally, when it gets hot for my first run them it's around 35 - 38.  If I ride it, then stop for a while and the engine is still a bit warm, then pressure works it way up past 40 to the 42 and sometimes 45 range.

The oil pumping system is about as precise as a yard stick.  All over the place.

[koko3052]

les...I would say that it's your gauge...would drive me bonkers!

[les]

les...I would say that it's your gauge...would drive me bonkers!

I thought of that.  But I'd say the gauge is not really operating erratic, or I just think it's not.  It used to drive me crazy, but I've learned to just ignore the weird readings and focus on what it's generally trying to tell me.

My current assessment is that the H-D oil pump architecture is somewhat of an imprecise POS.

[PoorUB]

My current assessment is that the H-D oil pump architecture is somewhat of an imprecise POS.

Only the oil pump?

[Y2KRKNG]

It's a Twin Cam 124" in a Touring. I've had some....issues this year and I've ended up with a Dan Thayer 3 stage pump and R&R plate. Now the pressure drops under acceleration from 38psi sometimes down to 15psi then pulls back to 38psi. I changed the oil pressure sender as it was weeping anyway and has 60k on it. No change. I've got a 60psi mechanical gauge on it also to verify that it's really happening.
Anybody seen this before or have any ideas? Thanks for your time.

Does it do the same thing after the oil is up to normal temp?

[Kllongbrake]

Yes it did. But I only tested that once. An unnamed person, who should know something about this, stated that the only time he'd seen this is in drag racing when the oil goes to the back of the pan and starves the pump. That everything else he hears says the pump and plate are working.
I usually run about halfway up the stick. I filled it and rode it to work. Still did it in the morning. On the way home it was hot out and it quit diving but did start lightly bouncing a few PSI and then would intermittently drop to 20-25ish for a few minutes then would come back up to 35 with no change in load.
Just haven't had the chance to put the SE stuff in. Should be able to do it tomorrow and try it this weekend.

[kd]

I'm thinkin it could be a loose oil intake line at a fitting drawing air but I suspect it would drip when the oil was hot and thin.  Does your oil look foamy or creamy with air?  Another thought not mentioned is the bypass spool in the cam plate. It might be hanging up when hot only from a tight fit and expansion. Or even the spring.

[smoserx1]

An unnamed person, who should know something about this, stated that the only time he'd seen this is in drag racing when the oil goes to the back of the pan and starves the pump.

The only way I could imagine that happening on a Harley touring bike is if someone removed the oil pan and fail to install the baffle.  I would still be suspecting the bypass valve in the cam plate, it sounds like it is opening too soon but I am having trouble understanding how it would happen.

[Hossamania]

Does the sound of the motor change at all when it happens?

[capn]

If the gauge is in the fairing could be the pressure sending unit.

[Kllongbrake]

Does the sound of the motor change at all when it happens?

No it doesn't change. No change in performance either. I'm almost done putting the SE stuff in. I'll ride it tomorrow but I'm sure the SE stuff will work fine again.

[Kllongbrake]

If the gauge is in the fairing could be the pressure sending unit.

I've installed a mechanical gauge to verify issue. It's really doing it. I thought the same though and changed the sending first anyway since it was weeping very lightly.

[pwmorris]

Wasn't there a post about someone having issues with the Thayer pump?
I've never run one, and I never speak of something I personally haven't tested or ran.

I had a several psi oil fluctuation (maybe 5-10) before I vented my tank, and eliminated my crossover line. Now, it's rock solid.

How are you venting this 124"?
Tank?
Case?
Heads?
Cam chest?
Rocker boxes?
Nothing? Just leaving stock, like a 60 HP set up?
This issue just happening now on hot summer days, and not before?
Make sure you are getting advice from owners of 124" and bigger on the street. That regularly run their bikes during hot, 90-100 degree summer days? Are running hard (like I just did today as it's 100 degrees in the SF Valley today and came back from a nice couple hour putt in LA Friday traffic on my hi compression 126"),
in stop and go, big traffic, high speeds, low speeds, freeway jams, etc. as a daily driver, not a "Sunday Starbucks and back to the house to cool off bike"? Or a "I take it out in the AM when it's cool, then it's back to the garage before it gets too hot!"
Or, even worse, "I've got several bikes, and my hot rod 124" only goes out once in a while, or when it's nice and cool outside, and no traffic...."


The 124" is a different animal than a stock HD Twin Cam, and thus requires a different approach to your oil system requirements. Just as your clutch, and other areas need different solutions that have nothing to do with stock set ups.
Also, I run Liqui-Moly, and got rid of by Redline for my street bike oil due to heat related thinning/tapping issues. Still run Redline in my trans, and 10 wt in race bike.

[Kllongbrake]

Wasn't there a post about someone having issues with the Thayer pump?
I've never run one, and I never speak of something I personally haven't tested or ran.

I had a several psi oil fluctuation (maybe 5-10) before I vented my tank, and eliminated my crossover line. Now, it's rock solid.

How are you venting this 124"?
Tank?
Case?
Heads?
Cam chest?
Rocker boxes?
Nothing? Just leaving stock, like a 60 HP set up?
This issue just happening now on hot summer days, and not before?
Make sure you are getting advice from owners of 124" and bigger on the street. That regularly run their bikes during hot, 90-100 degree summer days? Are running hard (like I just did today as it's 100 degrees in the SF Valley today and came back from a nice couple hour putt in LA Friday traffic on my hi compression 126"),
in stop and go, big traffic, high speeds, low speeds, freeway jams, etc. as a daily driver, not a "Sunday Starbucks and back to the house to cool off bike"? Or a "I take it out in the AM when it's cool, then it's back to the garage before it gets too hot!"
Or, even worse, "I've got several bikes, and my hot rod 124" only goes out once in a while, or when it's nice and cool outside, and no traffic...."


The 124" is a different animal than a stock HD Twin Cam, and thus requires a different approach to your oil system requirements. Just as your clutch, and other areas need different solutions that have nothing to do with stock set ups.
Also, I run Liqui-Moly, and got rid of by Redline for my street bike oil due to heat related thinning/tapping issues. Still run Redline in my trans, and 10 wt in race bike.

What do you run? Liqui-moly 10-60?
It was doing it cold and hot.
I've put SE plate and "high flow" pump in and it now works as should again. Builds to 40 at operating rpm and doesn't drop one psi.
I'm convinced there's a problem with the plate. Likely the bypass plunger.  I've got drilled heads behind the AC mounts with 90 degree 3/8" fittings and 3/8" hose going over the rear rocker box and venting to the ground. And the oil tank is vented at the fill neck with a -4 AN fittings and hose to the rear fender with a filter and one way valve.
Can feel the head vents working but they don't drip. I don't flog it very often though. Typically keep it under 5K. Run higher speeds on the freeway for extended periods and everything seems to be working.

[pwmorris]

Yup, LM 10-60.
Glad you figured it out. Put some real, hard miles on it and recheck.
Also check oil level, as I run a quart low.
Your heads need a one way check valve and all your lines back there to a catch can, with the can vertically vented to atmosphere. With smart planning and efficient layout, you should be able to keep the lines almost unnoticed and clean-and still functional and safe (should you have catastrophic engine failure and a sudden oil dump-which would be devastating to lines running to ground anywhere near rear tire).

[Kllongbrake]

Yup, LM 10-60.
Glad you figured it out. Put some real, hard miles on it and recheck.
Also check oil level, as I run a quart low.
Your heads need a one way check valve and all your lines back there to a catch can, with the can vertically vented to atmosphere. With smart planning and efficient layout, you should be able to keep the lines almost unnoticed and clean-and still functional and safe (should you have catastrophic engine failure and a sudden oil dump-which would be devastating to lines running to ground anywhere near rear tire).

I'll look for some check valves and a catch can. Any advice as far as good brands or specific product?
What's the purpose of the check valve? Does the umbrella valve not keep it from huffing in air?
I know another guy here personally and he uses that 10-60 too. Maybe I'll give it a shot. Been using redline 20-60 for a couple years but I'm open to trying something different if it'll quiet this pig down just a smidge.
Thanks for the knowledge. Appreciate it.

[pwmorris]

I run a Pingel as they also sell a nice bracket that bolts solid to our Harley frames.
No need to spend big bucks on the one way check valves. I've run them from a variety of sources, including off a Mitsubishi Raider, Auto Zone, S&S, ACS https://www.aircraftspruce.com/catalog/appages/acscheckvalve.php (if you are running AN stuff) Jegs, and other sources. To save real estate, you can "T" the heads and check valve after the "T", and other tricks I use to clean up the final product. A bagger should have all kinds of pockets, gaps, and nooks and crannies to tuck stuff away and end up with a super sano look. Stare at it, step back and find areas to run this stuff. Take your time as function first, last, and always in my book.
I did recently add a second catch can dedicated to just my oil tank, but that is due to having extra hidden space now and not needing to "T" my head, case and tank vents into one line going to the catch can. See my recent, last page posts on my 126" rebuild on this topic.
Again, my system is a bit complicated and maybe overkill for a mild 130 HP 124" touring bike that seldom sees above 5 grand on a regular basis.
http://www.pingelonline.com/pc_combined_results.asp
You need to plan, design, and think of covering everything in a clean, efficient way. Pluming these bigger engines can be as efficient as you dream it to be....or a tangled mess of lines, clamps, hoses, lines running the wrong way, and zip ties.
Think, efficient, clean, and effective. This takes work and planning.
Would love you to post how you designed yours, when all done.

[1workinman]

Yup, LM 10-60.
Glad you figured it out. Put some real, hard miles on it and recheck.
Also check oil level, as I run a quart low.
Your heads need a one way check valve and all your lines back there to a catch can, with the can vertically vented to atmosphere. With smart planning and efficient layout, you should be able to keep the lines almost unnoticed and clean-and still functional and safe (should you have catastrophic engine failure and a sudden oil dump-which would be devastating to lines running to ground anywhere near rear tire).

Paul I appreciate all the advice here , I have used your advice on the breathers , check valves , venting the oil tank . When I was doing my breathers on my 124 I finally just built what I wanted by silver solder what I wanted in a fitting .   I lower my oil level a tad on the bikes as I was using the 4 dots low checked hot but lower is good . Not sure how much on the dip stick is the new measurement . I  started using the10-60 LQ when Ray posted the information . I yet to have the ticking of the lifters hot idle but I wondered if I would as the oil pressure drop at idle hot is significant . I don't know how low the pressure has to go at idle but it seem to be very close to the event.

[1workinman]

Paul I have wondered if the limiters would help in these instances where low oil pressure might help a lifter from collapsing . I assume there the growth of the cylinders but the limiters might help some since with a lot of lift and spring pressure may help the lifter bleed off with hot thin oil and oil pressure that is lower from idling

[pwmorris]

That's an interesting thought , and not sure.
Based on time lifters normally need to collapse in oil baths, and bleed down time needed to lock down pushrods when setting TDC settings (although with really hot oil going thru), I would love to see a test of this.....not sure how to do this test to verify results.
Limiters act similar to solids, and on race applications I've used with solids, I haven't seen this type of oil psi fluctuation on a gauge, but have seen oil pressure consistently dropping (hot, hotter, etc, and thinning occurs resulting in oil dropping pressure) over time. But have seen this with all lifters.
As far as pressure....
I don't really care, nor do I want, my parts, top to bottom, soaked in an oil bath (especially don't want my bottom end moving like stuck in a swimming pool-robbing HP).
With today's modern synthetics, if temps are consistent (I DO NOT run an oil cooler-I run a quart low), sufficiently lubricated parts can last many, many miles under normal street operating conditions.
As long as top to bottom is sufficiently and consistently fed a healthy supply of oil (you can test this), recycled, and returned under conditions how you normally ride (drive the highway, stop at Starbucks, meet buddies on the blvd vs, for example, my street bike that likes to spin it up regularly, a drag bike or Bonneville bike), bike cubes, lift and compression.................I'm good with it.

[1workinman]

Thanks I appreciate the reply .  I don't see a down side to limits and I think lifters are a maintenance item so I going to use them next time . 

[pwmorris]

Yup, thats exactly how I look at wear parts....they ain't a 5 grand Jewel Valvetrain, but simply like comps (I raised a stink here during the worn compensator debates a few years ago), saying "look, under any hard use or hi rpm application, replace the comp, like any other wear part"-when guys were saying "I only got 15K on my comp and it's wearing out and starting to make noise! Harley sucks!"
It's like a lifter, chain, tires, or other hard load part. No big deal.....just replace it.
Geez....
I do like my Premium S&S lifters with limiters though.......Remember, I have run for a few years now hard with .675 EZ's, 1.7's and healthy comp on my street 126". They get a workout on a regular basis and I love it-and my motor loves it.
Other than Jesel (not a street lifter)....best lifters I've ever run.
BTW, just for disclosure, I did blow apart a standard S&S lifter (non Premium-no limiters) on a Dyno at hard flogging a dozen years ago or so. Dumped and sprayed oil all over the dyno (another reason for guys not to run vent lines to the ground!). Lifter bearings destroyed......
These new Premiums with limiters are a huge upgrade everywhere.
After the stock S&S, I ran Jim's hydrosolids before these Premiums, and they worked well for me (although showed some wear).
Adding these new bad boys with limiters, and I don't even thing about this area of the valvetrain any more...just rip and ride.....
Street or strip.

[1workinman]

Ok I know when to take good advice I use them, the 675 with the 1.7 should be a good test especially at the 126 rpm range .  I don't mind replacing before failure lol lot cheaper.

[RoadKingKohn]

I'm thinkin it could be a loose oil intake line at a fitting drawing air but I suspect it would drip when the oil was hot and thin.  Does your oil look foamy or creamy with air?  Another thought not mentioned is the bypass spool in the cam plate. It might be hanging up when hot only from a tight fit and expansion. Or even the spring.

KD, Could you please explain what the foamy or creamy with air oil is a sign of?

Thank you

[kd]

I'm thinkin it could be a loose oil intake line at a fitting drawing air but I suspect it would drip when the oil was hot and thin.  Does your oil look foamy or creamy with air?  Another thought not mentioned is the bypass spool in the cam plate. It might be hanging up when hot only from a tight fit and expansion. Or even the spring.

KD, Could you please explain what the foamy or creamy with air oil is a sign of?

Thank you

I used to run clear reinforced oil lines and noticed some oils seemed to carry air bubbles when running.  I actually stopped using Castrol oil because it was so extreme.  The foaming can be just the way the oil reacts to the passing through the oil pump gears. Air bubbles in the oil reduce the application of lubricant between surfaces.

The foamy and creamy colored oil is usually related to short trips and not getting the oil up to temp long enough to remove the resulting condensation.  If for example you only ride to work and back, and the job is only a few minutes away, the engine oil gathers moisture.  That moisture mixes with air and the oil, resulting in a light tan (ish) color.  Kinda like coffee with cream in it instead of without.  It is most noticeable if you remove the oil filler / dipstick cap and if it is occurring you will see a buildup around the cooler spout area and underside of the oil cap.  It happens more in cooler weather.  The remedy is to take the scenic route and ride the bike longer    Get the oil temp up higher and longer to evaporate the moisture. The oil is still good but now mixed with moisture and needs time at higher temp to return to normal.  It is not a good idea to store the bike with this condition as the mix of condensation and oil additives produce acids.  These harsh chemicals can scar the bearing surfaces and places like the oil relief spool valve causing surface damage. 

[RoadKingKohn]

I'm thinkin it could be a loose oil intake line at a fitting drawing air but I suspect it would drip when the oil was hot and thin.  Does your oil look foamy or creamy with air?  Another thought not mentioned is the bypass spool in the cam plate. It might be hanging up when hot only from a tight fit and expansion. Or even the spring.

KD, Could you please explain what the foamy or creamy with air oil is a sign of?

Thank you

I used to run clear reinforced oil lines and noticed some oils seemed to carry air bubbles when running.  I actually stopped using Castrol oil because it was so extreme.  The foaming can be just the way the oil reacts to the passing through the oil pump gears. Air bubbles in the oil reduce the application of lubricant between surfaces.

The foamy and creamy colored oil is usually related to short trips and not getting the oil up to temp long enough to remove the resulting condensation.  If for example you only ride to work and back, and the job is only a few minutes away, the engine oil gathers moisture.  That moisture mixes with air and the oil, resulting in a light tan (ish) color.  Kinda like coffee with cream in it instead of without.  It is most noticeable if you remove the oil filler / dipstick cap and if it is occurring you will see a buildup around the cooler spout area and underside of the oil cap.  It happens more in cooler weather.  The remedy is to take the scenic route and ride the bike longer    Get the oil temp up higher and longer to evaporate the moisture. The oil is still good but now mixed with moisture and needs time at higher temp to return to normal.  It is not a good idea to store the bike with this condition as the mix of condensation and oil additives produce acids.  These harsh chemicals can scar the bearing surfaces and places like the oil relief spool valve causing surface damage.

Well that just described the situation I have been having and the conditions of my ride. This is one of the reasons why I use an oil with a TBN of 12 or higher.  That helps to control the acids.

On my 2005 95" Twin Cam about two years ago I started getting a lot of oil into my air cleaner.  I have been looking into adding a breather but in all of the reading I am doing I am starting to think that my stock oil pump started to die around 60,000 miles and I have 72,000 now.

So this is good information.

Thank you

[Norton Commando]

What's the purpose of the check valve? Does the umbrella valve not keep it from huffing in air?

The umbrella valves do keep the crankcase from inhaling air.  Some folks that by-pass the airfilter with their vent lines will install an additional check valve as a belt-and-suspenders approach to keeping the crankcase from sucking in air.

Jason