Re-torquing 308 QV heads

I have isolated a teeny tiny oil leak @ the intake/flywheel corner of the front head on my 85 Euro 308 QV (supercharged BTW). I used UV dye and ultraviolet penlight to isolate it, trying to confirm a cam/distributor seal leak. No compression or performance loss or other signs of head gasket failure. I'm thinking that the PO's mechanic neglected the head re-torque @ the 30,000 mile major (not mentioned in the service records)? or at least the heads need to be re-torqued period, especially since I'm now supercharged. (Swiss spec Euro, 8.8:1 compression ratio w/ a max 9-10 psi boost.) I read that there is a "special tool" req for the 4V head re-torque to avoid cam removal.

Input and comment requested....

 

I think the retorque will do it. The leak is tiny, and actually stops when the motor is warmed up fully. Thats one reason it has been so hard for me to pinpoint. It took pulling everything out from under the intake runners, cleaning to surgical spotless, putting UV dye in the oil and inspecting with a ultraviolet penlight.

Tool and camcover gaskets ordered, thanks for your input.

-Lou

 

Well,

I retorqued the heads, reassembled using all the tricks learned on this forum RE: cam cover gasket dressing and trimming @ the cam seal O ring etc. etc. It all went very smooth, and all my work is leak free and tidy. The head nuts were found to be pretty darn tight, at or close to spec. I backed them off a teeny bit to break, and brought them into spec one at a time per the proper sequence. I'm very confident that they are torqued down properley.

But..... the S.O.B. still leaks oil @ that same place, maybe even a little worse when dead cold. Once it's up to temp, the leak all but stops (maybe just a little teeny tiny "weep" @ the dizzy corner of the front bank head. I'm unhappy.

So, what do I do.

A) Live with it. Clean the engine up a little more often, buy a drip pan.

B) Attempt a topical fix, apply that red RTV used in emergency refinery/industrial repairs $$$$$ (I have access to some, but this smacks of Jethro Clampet backyard bandaid)

C) attempt an engine in the car head pull of the front head and change the headgasket. (nightmare ?!)

D) Be a man. Pull the motor and change both head gaskets. And while It's out..........(maybe next winter ?)


?

 

Carl,

I bought the genuine Ferrari tool, and the heads are retorqued (it was easy) but that did not fix the oil leak. Must be a scratch on the mating surface or break in the head gasket at the oil passage feeding up to the intake cam bearings. There is only about 6mm or so of gasket outside that hole right at the corner of the head. The leak is about the size of a pin prick, and it bleeds like one, I'm talking teeny tiny ( . ) that period there is 10 times as large as the leak, but it is under full oil pressure. The most maddening part is that it leaks less when the engine is warm, and not at all when its good and hot at the track. It has leaked as long as I have owned the car, but I just recently finally located it. It leaks more of course with the 5w40 redline synthetic than the 20w50 dino oil the PO's mechanic had in it.

The thought of pulling the front head in the car is daunting. Pulling the whole lump would probably take less time, but for a teeny tiny leak, .....I don't think so. I need a space age fix I think.

 

Yeah, yeah .....I know. The definition of insanity. My thinking was the fact that the leak stops when the engine warms up pointed to a possible torque issue. But NOOOOOOO....

 

Yes, I am thinking topical fix at this point, Jethro Clampet bandaid as it may be, but I aint' pulling the motor for a pin prick size leak. I'm also not willing to have an oil drip and a dirty sump and bell housing. This is the ONLY leak on my car at this point (I chased and fixed all others) This "patch" would be at the head/block gasket line, and have to hold oil pressure as well as head temperature. Would have to be very high bond strength to both aluminum and gasket material, be slightly flexible to remain intact with heat/expansion/contraction cycles, withstand high heat (300f min), and be oil and solvent proof.

Any Ideas ?

 

OK. Brand part # ? (blue RTV already failed the test, though) Thanx for the input.



1 vote for grey RTV

 

I appreciate and understand your advice and experience, thank you. That is the procedure I used (or close to it, I backed them off to confirm a smooth no bind or chatter pull to torque) after reading everything I could find on a search of this forum, including the rest and second pass loosen/retorque. I am 110 % sure the heads are torqued properley. The leak is not torque/clamping force related, AFAIK. It is not between head studs or "along the gasket line", its a tiny (.002 ?) single point @ the corner oil passage area. It may well have been there since new or a scratch or damaged gasket done by a PO mechanic (Although my service records show no history of heads off,.. 30k valve adj & belt major only).

End of awl in picture is the needle point leak location. I almost wish I had other signs of head gasket failure, It would be less of a mystery and frustration. I may disassemble and retorque the front head again just as a sanity check,...what fun!
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Yeah, I know its a long shot, at best, but it is so effing tiny I may still try it. I will probably have to pull the front head eventually. (darn, I just did timing belts a couple months ago. My understanding is never re-tension a timing belt, so theres that also.) You think it might be do-able engine in?