Question for Wayne

JB · 05-19-2003, 09:48 PM

Wayne, I am building a 2.2S Motor and have several questions from your book which I am following on this rebuild.

1) Regarding the O'ring around #8 nose bearing. Your pictures show installing this dry and you mention a concern about oil contamination from O'rings on the oil pump to the case seam. Can you comment a little more on this? I think this is a critical area regarding oil leakage and want to do it right. What is the best practice for this O'ring and the oil pump seals? I am wondering why you recommend Curil-T for the nose bearing seal and the flywheel seal and not the #8 o'ring, through bolt O'rings or the oil pump seals.

2) Regarding case sealants: There are several very well respected Porsche engine builders around here that refuse to use Loctite 574 from bad past experience. I also have had very poor luck using Loctite 574 in the three prior engines I have built, all resulting in oil leaks at the case seam. Loctite 574 is also very difficult to clean off after it has cured or if an engine has to be rebuilt. I have been recommended a case sealant called Drie-Bond that I'm told, Porsche recommends for the Boxter engine case seam. It is available from my local Porsche dealership for $20 per tube which is enough to do one rebuild. Have you heard of it? Any comments?

3) In figure 3-23, you mention that Loctite 574 will wash itself from the circular oil pressure relief groove noted in fig 3-22, or anywhere there is not a metal to metal bond. On a recent tear down (I suffered the infamous Mag case crack behind the flywheel, left case half) the circular oil pressure relief grove was totally blocked with hardened Loctite 574. Is this a critical thing, keeping this oil pressure relief groove clear of sealant?

4) the factory manual recommends assembling the oil pump and intermediate shaft into the right case half before you drop in the crank assembly. Why is it better to do it the other way around as you recommend in your book?

Thanks, and by the way, I think you have done an excellent job on your book! In our world of high priced Porsche parts, it is an incredible bargain!

JB

ChrisBennet · ChrisBennet's Garage

Bump.
Inquiring minds want to know...

JB · 06-02-2003, 08:14 AM

I am bumping this in hopes Wayne will comment.

JB

PS: The engine is built and just set G and F class lap records at the Texas Motor Speedway PCA club race over Memorial Day weekend with Weber tuning help from Eric Geores of Valkyrie Racing.

snowman · 06-02-2003, 08:56 PM

Bump.
Inquiring minds want to know...

Wayne 962 · Wayne 962's Garage

1- On these particular issues, it's basically a matter of preference. When you are putting the engine together, it's important not to contaminate the engine case sealant (574) with any motor oil or any other debris (watch out for bristles from your acid brush). So, not using any oil on the o-rings is fine. The number eight o-ring doesn't have a tendency to leak very often on a new rebuild - the flywheel and pulley seals can suffer from scratches in the inside of the case. You can put Curil-T on the o-ring if you'd like for extra assurance. The oil pump seals are all internal to the engine and don't need any sealant, as they will not leak. I recommend the black silicone for the through-bolt o-rings because it blends in well with the case, and doesn't look sloppy.

2- People have had good luck and bad luck with 574. I would guess that 99% of the time, it's not the 574, but the case that has a scratch, or is slightly deformed. You can't just bolt together a 2.7 (for example) that has been warped and expect it to be leak-free. It must have the proper machine work done to it. I know many, many people who have had good luck with the 574 (including the factory). It's a matter of preference as to what you use, but I don't know any one who has used this Boxster stuff...

3- That doesn't sound right to me. Everyone I know (including the guys at Loctite that I spoke with) confirm that it only cures in metal-to-metal contact. Without looking at your case, I would guess that maybe the material used in that particular rebuild wasn't Loctite 574? Also, the 574 is really easy to get off, compared to the Dow Corning stuff.

4- I did have this argument with my technical editor. It doesn't really matter, but it's slightly easier if you drop the crank in first. It's a bit difficult to put the crank in , with the rods all lined up, *and* have it mesh properly with the intermediate shaft.

Sorry for the delay, didn't see this post until now...

-Wayne

Wayne 962 · Wayne 962's Garage

Oh, one more comment. The contamination problem and concern is mostly with motor oil leaking onto the case halves - not from the Curil-T...

-Wayne

ChrisBennet · ChrisBennet's Garage

Thanks Wayne!

JB · 06-03-2003, 04:54 PM

Wayne, thanks for the reply! But you left one question unanswered.

Regarding the oil pressure relief groove: How critical is it that this groove be left free of sealing material?

And, what exactly, is this groove supposed to do?

Thanks, JB

P.S. Regarding locktite 574 and clean up: The heads I just used on this rebuild were from the previous Mag case motor that I sealed with LT 574. The LT 574 material that extruded out around the cam housing openings and studs (and not sealed metal to metal) hardened into a tough rubber like material that has been impossibled to remove from the heads. My head rebuilder dissassembled the heads, put them through a vibration type parts cleaner (using naptha) and then bead blasted them. The LT 574 was not effected. The glass beads just bounced off the rubberized Locktite 574 material. I had to use a razor blade to cut the material from around each stud to insure I had a good seal when the cam housings were attached. Any comments on this? Is there a solvent that will dissolve this stuff?

snowman · 06-03-2003, 06:12 PM

I would suggest removing the studs. I know its a lot of work, but greatly simplifies the clean up. Worked well for me.

john walker's workshop · 06-03-2003, 06:26 PM

the gobs need the old buck knife routine. around the studs too. the glass bead normally removes the thin skin remaining between the heads and cam towers, unless it's not a thin skin, in which case, too much was applied, and it didn't squeeze out well before hardening, which is the general complaint about 574. it really needs to go on THIN. i don't care if the #8 o ring is supposed to go on dry. one leaking engine is too much, so i always put a little dirko, or other soft sealer on the o ring just to be sure.

Wayne 962 · Wayne 962's Garage

Yes, keep the oil relief area generally free of 574, however, it shouldn't harden without metal to metal contact. Sounds like you might have had a bad batch of 574 (or maybe it was really old?). It hardens in the absence of air...

-Wayne

JB · 06-03-2003, 09:17 PM

so what does the F------ oil relief ring do???? (pardon my french)!

JB

Wayne 962 · Wayne 962's Garage

Hmm, I used to know, but I forget. It's not in that Engine Book either...

-Wayne

MotoSook · 06-05-2003, 03:02 PM

Someone post a picture of the oil relief groove...

I think this was a groove we ran into when we were putting Chris Streit's motor together. If I recall correctly, and if the groove is the one we were looking at; then it is a path of least resistance for the oil to return to the case instead of being pushed out the case seam in that region. There is no stud at the corner, and it is what I suspect to be a weak region along the case seam, so the groove allows the pressure relief in a designed manner. Does that make sense? Post a picture Wayne..I don't have my book with me...