Cometic Head Gasket Question

[HDCharger]

Still getting some water in the oil.  Ditching the FelPro 1009 gasket and taking Cryco's advice and ordering a set of Cometics.  I have Ross 99494 pistons 4.375 Bore.  My questions is do I use the 4.41 Bore Gasket or 4.380?  Thanks Dave    I know the 1009's were 4.41

[Challenger340]

4.41" Bore gaskets will work fine.

Question; are you going to re-surface the blocks and heads to the correct rms finish for the cometic gaskets ?

Might be an idea to Check their website, for reccomended surface finish requirements ?

Aluminum or cast iron heads ?

[HDCharger]

Aluminum (Eddy) Heads.  Didn't know they would have to be re-finished but I will get them done.  Gotta stop this leaking somehow, its giving me an ulcer.

[Challenger340]

The biggest advantage to going with a cometic or mls style gasket, is their ability to resisit the shearing effects of the dissimilar expansions rates, incurred between a cast iron block and aluminum cylinder head, during multiplty thermal cycles from engine cold to hot, and back to cold again, "over time".

Usually, even a standard composition style gasket like a Fel-Pro, is good for quite a while before they rip internally and leak. For actual "clampload" sealing, 1009 & cometic are about on par with each other.

I'm not understanding how your "leak", is being incurred relatively "very soon".

Just a thought, but, one more thing to check prior to going cometic, how much Piston to deck clearance do you have @ TDC ?

That's the only time I've seen a Fel-Pro failure so early in the thermal cylcling thing, was when the Pistons were "just touching" the heads. The guy had swapped to a closed chamber style head, from an open type 906 casting, then the Piston started 'touching" and the gaskets were failing really quick.
Just a thought, not trying to confuse you, good luck with it.

Bob out.

[HDCharger]

340, I don't know if you have read my other post about valve train noise but I still have some of that going on (Primarily on the drivers bank).  I did check the piston down the whole a while back and if I remember correctly they were .0015  (15 thousandeth).  Does that sound right?  Can't remember.  I do have the Closed Chamber 84cc Eddys.  Pistons are Forged Ross with valve reliefs.  I am thinking the same thing.  These heads should seal with the 1009s, after all that is the recommeded gasket by Edelbrock.  Sure making me tired though.  Dave

[firefighter3931]

Most people that i know running e-heads use the felpros with excellent results. I'm not sure what's going on with your's Dave ? 

The .015 deckheight means you've got plenty of clearnce between the piston and head...that is not an issue. It'll be interesting to see where the gaskets failed when the heads are pulled. 


Ron

[HDCharger]

I'll let you know and maybe snap a couple pics when I pull them.  May be a day or two.  Dave

[Challenger340]

I Ditto what Firefighter3931 said.

This seems to be a very premature failure of the FelPro 1009, if that is the case.
Which makes me curious as to other "mitigating" factors present, that if not found and cured, may cause the next set of gaskets, even cometic, to fail prematurely as well.

.015" Piston to deck clrc. is adequate.

Was the block decked ?

Are the block/head decks straight and flat with a good cutter pattern(rms finish) for "bite" ?

Just some more areas to check. No worries, I'm sure you'll find whatever problem is, upon teardown.

[HDCharger]

Well I took the heads off tonight and really didn't find any gasket failure that I could see.  Only qustionable place was the center head bolt on passenger side.  However, I think I may have found the source of the valve train noise.  The retainer on a couple lifters were bent, could this be the source of my noise. School me here fellas, should it be easy to depress the "plunger" on the lifters?  Thanks Dave

[firefighter3931]

Dave, those retainer rings look messed up. Could be caused by improper preload adjustment or valve float. They (lifters) definately need to be replaced. 

You should be able to compress the lifters somewhat.



Ron

[HDCharger]

Ron, I put a lifter on the table and stuck a pushron in it to try and depress it.  No budge.  None at all.  Solid.  I am ordering lifters but now I am wondering if I need 2 or 16.  David

[firefighter3931]

Dave, i would replace the entire set. Sounds like the lifter is pumped up and won't bleed down.


Ron