S&S Cylinder Dowels and O-rings

[Ohio HD]

Guys, I'm working on final assembly of my 124, and have a question pertaining to the cylinder dowels and o-rings S&S supplies. I did the mock up and claying with standard HD pins, and am now wanting to use what came in the S&S cylinder kit to finish assembly. I'm going to attach three pictures, one of what I have, one of what I thing I should have, and one of the S&S instructions.

The instructions shows the upper dowels as having a grove on both ends of the dowel, and shows o-rings for the groves. The lower dowel shows one grove, for one o-ring, that goes in the cylinder.
[attach=0]


This is a photo of what I received in the kit, the lower dowel is not grooved, and there are only enough o-rings for the upper dowel.
[attach=1]


This is a photo from an HTT post that shows the lower dowel as having a grove, and o-rings supplied.
[attachimg=3]


So, what is correct? I have to believe that having the o-ring on the lower dowel is going to be better. Trouble is I'm screwed for the weekend now, as this holds me up.

[No Cents]

  did you try to mock it up with the S&S dowels?
I've been told the S&S dowels are too long and you either have to grind some of the length off them...or drill the dowel holes deeper into the heads.    This is what I was told by a fellow member on here last week when he contacted S&S about his dowels not fitting properly on the 124 he is building.

[jimlibo]

the last few cylinder kits I've gotten from S&S were packaged as yours, solid dowels for top of cylinders at intake sides, double o ringed top of cylinders at exhaust sides and no dowels for the base were included. so oem solid ones were used.

Yes verify the double o-ringed length do not bottom in the head counterbore on install, I've hat to trim them too w/CVO heads and S&S eith very little decked of the head (like .020ish) the ones in your picture look a little shorter though

[Ohio HD]

Thanks for the heads up on length Jim, and Ray. I just measured the MVA heads, they have a depth of 0.426" of clean bore length for the dowel, and the S&S cylinders measure 0.371" of clean bore depth. The dowel from S&S measures 0.790" long. So I figure 0.426" + 0.371" + 0.036"(head gasket) gives me 0.833", so I'm good with the length. I'm not certain the amount of material that Larry removed on these heads, the final chamber is 93cc, but valve sink and shape effects that as well. I guess I could measure the thickness.

I was guessing that since there's a base gasket for these cylinders the lower is ok, just would have preferred an o-ring at the cylinder side against the base gasket.

[jimlibo]

You're welcome and a follow up, I just measured the length of a couple of the double o ringed ones that have been hanging over my assembly bench since they came out with them and they are .815" long so S&S apparently shortened them a little. That explains that

[Ohio HD]

Good info to have as well.   

[Ohio HD]

More info, just as a reference, the front head measures 3.699" thick, and the rear head 3.710" thick. So that would suggest a approximate of 0.051" and 0.040" was removed from the heads.

[Ohio HD]

OK, so we have a lesson in perceived clearance, and actual clearance. What I perceived as usable bore for the dowel, is my perception, and what the dowel said it can use when inserted, is the dowels reality. So, I have actual dimensions to discuss.

Dowel measures 0.785" out of the plastic bag. I realized about 0.003" per side of plastic, but that wasn't a critical dimension last night, +/- 0.006". As you should have about 0.030" more room than the dowels length to use.

When the dowel is inserted in the head as far as it will go, there is 0.432" of the dowel protruding. When the same dowel is pressed int the cylinder as far as it will go, there is 0.420" of the dowel protruding. Subtract these numbers from the dowel length, and you will have the value inserted into the head and cylinder. Head has 0.353" of the dowels length, the cylinder has 0.365" of the dowels length. Add them together to get 0.718". Subtract that from the dowel length of 0.785" you get 0.067". This is the amount that the dowel should be shorter for my situation. Even with the head gasket taking 0.036", the dowel will be too long. So I need to have the heads bored at the dowel hole about 0.070" more depth, or run the standard HD dowel pins.

I've used MLS head gaskets in the past on Twin Cams without anything to seal the oil return, other than the head gasket embossment. So I did the adult thing, I put the cylinders on, washed my hands, made a phone call, and we went riding! 

So now I need to ask, what has anyone used to aid in sealing the MLS head gaskets? As I said I haven't used anything in the past, and had no leaks, but they were always factory Twin Cam cylinders. I just want to insure this larger 4.125" bore doesn't leak oil at the oil return.
 

[FSG]

So I need to have the heads bored at the dowel hole about 0.070" more depth, or run the standard HD dowel pins.

Can you not just take 35 thou off the ends of the dowel pins?

[FXDBI]

So I need to have the heads bored at the dowel hole about 0.070" more depth, or run the standard HD dowel pins.

Can you not just take 35 thou off the ends of the dowel pins?

[No Cents]

   Brian...your 117 using S&S cylinders doesn't have anything between the cylinders and heads beside the factory dowels and the MLS head gaskets.
I built my 124 the same way as I did the 117. I never had a leak on either engine. For the base gaskets I used aviation sealant on both sides of them...with the factory dowels in place in the cases with no O-rings...and I've never had a base gasket weep or seep down there either. I still don't see any gain by using the S&S dowels...but maybe I'm missing something. 

[319fatboy]

I have the same issue with the dowels being too long on my 124 with 110 heads. I am just going to use oem dowels. Hopefully it works out.

[turboprop]

My TC124 uses the Zippers dowels, which are very similar to the S&S o-ring dowels. Used a MLS head gasket and these o-ringed dowels from S&S, no leaks. They fit pretty snug. Used a bit of lube as per the instructions from Zippers and everything went together without issue.

[Ohio HD]

So I need to have the heads bored at the dowel hole about 0.070" more depth, or run the standard HD dowel pins.

Can you not just take 35 thou off the ends of the dowel pins?

Yes, sometimes a ride and then a cold beer, or two and cooler thoughts prevail. I think I can get by with taking 0.030" from both ends. That will give me 0.029" "float" for the dowel. That leaves a lip of  0.059" on both ends for the o-ring.


[attach=0]  

[Ohio HD]

My TC124 uses the Zippers dowels, which are very similar to the S&S o-ring dowels. Used a MLS head gasket and these o-ringed dowels from S&S, no leaks. They fit pretty snug. Used a bit of lube as per the instructions from Zippers and everything went together without issue.

Ed, I think the situation for me is the heads have been milled approximately 0.045" to 0.050", so the dowel is too long. If I shorten them a bit as FSG suggest above, I should be ok.

I guess I just wanted to ride today, now I feel better.   

[Ohio HD]

   Brian...your 117 using S&S cylinders doesn't have anything between the cylinders and heads beside the factory dowels and the MLS head gaskets.
I built my 124 the same way as I did the 117. I never had a leak on either engine. For the base gaskets I used aviation sealant on both sides of them...with the factory dowels in place in the cases with no O-rings...and I've never had a base gasket weep or seep down there either. I still don't see any gain by using the S&S dowels...but maybe I'm missing something. 

I don't think you're missing anything Ray, and I'm sure if I don't use them, I'd be OK. I just would rather use them as an added measure of oil sealing at the return port down the cylinders. If I shorten them a bit on both ends, I'm good to use them.

I stopped to see Bill on the ride home, he smacked me and said shorten them. So he gets to do it for me.   

[Ohio HD]

I have the same issue with the dowels being too long on my 124 with 110 heads. I am just going to use oem dowels. Hopefully it works out.

You probably could use them if you have the ends machined down. That's my plan.

[turboprop]

   Brian...your 117 using S&S cylinders doesn't have anything between the cylinders and heads beside the factory dowels and the MLS head gaskets.
I built my 124 the same way as I did the 117. I never had a leak on either engine. For the base gaskets I used aviation sealant on both sides of them...with the factory dowels in place in the cases with no O-rings...and I've never had a base gasket weep or seep down there either. I still don't see any gain by using the S&S dowels...but maybe I'm missing something. 

I don't think you're missing anything Ray, and I'm sure if I don't use them, I'd be OK. I just would rather use them as an added measure of oil sealing at the return port down the cylinders. If I shorten them a bit on both ends, I'm good to use them.

I stopped to see Bill on the ride home, he smacked me and said shorten them. So he gets to do it for me.   

I gotcha. FWIW, I think these o-ringed dowel pins are a pretty good idea.

[Ohio HD]

I gotcha. FWIW, I think these o-ringed dowel pins are a pretty good idea.

I figure it cant hurt, and can only help.   

[Azgunner]

I just got done re-building the top end on my S&S 124" crate motor which would make that the 3rd top end rebuild on this motor. Prior to that S&S replaced my motor under warranty 3 times due to recurring head gasket leaks near the oil return dowels. S&S made a cyl. design change in 2014 that had some unintended consequences such as oil leaking around the oil return dowels hence the new style oring'd dowels. This was explained to me by 2 S&S techs that I dealt with, not some internet hearsay. This was also later confirmed to me by another member that was told the same thing by S&S. It is interesting that you can't find this info on any of the H-D discussion forums. I do think there are a lot of shops that move a lot of S&S product that are aware of this, but they keep their mouths shut about it.

My current , #4, S&S engine had the top end rebuilt last year due to another head gasket oil leak near the oil return dowel on the frt. head. I had a S&S authorized shop do the rebuild, which they decided to do both cyls., & the mechanic used a light coating of copper coat on the base & MLS HGs. I had no leaks for about 6 mos., the longest I'd ever gone without a HG leak. Unfortunately I did have excessive oil usage afterwards that required another top end rebuild. I took the bike to another S&S authorized shop because the previous mechanic was no longer there, only a temp mechanic. I insisted that shop also use a light coating of copper coat on the HG. No HG leaks on that one, however they did screw-up just about everything else they touched, that was in another thread.

I've got about 400 miles on the fresh top end rebuild & so far no leaks with the copper coated HGs.

I'm a big believer in following mfr. instructions since they hopefully know their product design & how to use it better than I do. I have found the copper coat to add an extra measure of insurance on my previous 117" as well.

[Ohio HD]

I appreciate the info about the issues that you unfortunately have had. So I wonder, could they have had issues with the dowel being too long? Just thinking out loud, if it kept the head from clamping against the head gasket as it should.

Copper coat is a good product, I remember we used to with the steel shim head gaskets on early small block Chevy motors. I always used it on Shovel and Evo oil pump gaskets, never a leak. I also agree that hopefully the OEM knows their products best. When I ordered my gaskets from Cometic, I ordered the Aramid Fiber material base gaskets. The guy I spoke with recommended that I use nothing on them as far as sealant. I know that several have used sealants on the base gaskets. I look at t like this, by the time you have the cylinder on, then the head, and torqued down, the sealant on the base gasket is probably either dry, or past it's tacky stage.

Hopefully your current assembly stays dry. As Ray stated above, the 117 I have, that I bought from him, it's been leak free for 40k now. It also has S&S 4.125" cylinders. They're a newer style cylinder, has the OEM look too them. I don't know if they also have any other changes that you mentioned S&S spoke of.

[Azgunner]

I appreciate the info about the issues that you unfortunately have had. So I wonder, could they have had issues with the dowel being too long? Just thinking out loud, if it kept the head from clamping against the head gasket as it should.

Copper coat is a good product, I remember we used to with the steel shim head gaskets on early small block Chevy motors. I always used it on Shovel and Evo oil pump gaskets, never a leak. I also agree that hopefully the OEM knows their products best. When I ordered my gaskets from Cometic, I ordered the Aramid Fiber material base gaskets. The guy I spoke with recommended that I use nothing on them as far as sealant. I know that several have used sealants on the base gaskets. I look at t like this, by the time you have the cylinder on, then the head, and torqued down, the sealant on the base gasket is probably either dry, or past it's tacky stage.

Hopefully your current assembly stays dry. As Ray stated above, the 117 I have, that I bought from him, it's been leak free for 40k now. It also has S&S 4.125" cylinders. They're a newer style cylinder, has the OEM look too them. I don't know if they also have any other changes that you mentioned S&S spoke of.

That's a good point about the dowel length on the later replacement engines I received. I had 3 complete S&S built engines that had the HG oil leak problem. The oring'd dowel was S&S fix for the cylinder issue that was causing the oil leak thru the HG of which I was told mine was one of the 1st engines that they started to see they had a problem. The problems with the redesign had to do specifically with changes to the outside dia. of the liner configuration & the addition of ridges to the liner O.D. that potentially encroached into the oil return passage. The ridges were introduced to prevent the possibility of up & down movement of the liners in the cast cyl.  I never had any issues with the HG oil leaks on subsequent rebuilds on my current motor, maybe they had reduced the OAL of the dowel by that time. It would be interesting to compare the depths of the dowel pin holes on various makes & models of heads to see if there is any variation.

It never occurred to me to have to check the cyl./ head bore depths for the dowels. I guess I assumed S&S parts would correctly fit their own parts. So far so good for now. If I ever have headwork done in the future I'll for sure be checking for the dowel assy. stack-up.

[Barrett]

How thick is the head gasket that comes with S&S kits?

[FSG]

Copper coat is a good product, I remember we used to with the steel shim head gaskets on early small block Chevy motors.

It sure is, we used it on HGs on 5 stage air compressors that ere pumping out 5000psi.

So I wonder, could they have had issues with the dowel being too long?

If they didn't I'll bet that someone else did.  Not me though, I'm like you and check all the irrelevant chit.

[Ohio HD]

Took a bit more that 0.035", took 0.0385" from each end. Could have gone more, the flange only exists to hold the o-ring on. Should be good to go with these now. Glad I was given the heads up on the length, makes it better when you know before hand.

A productive way to spend lunch break.


[attach=0]

[attach=1]