NineMeister

A 964 came into the shop recently for some bodywork which necessitated an engine removal, prompting a little "whilst it's out" response from the owner in relation to minor oil leaks and tinware refurbishment. The oil leaks turned out to be the original camshaft cover paint flaking off and the oil leaking under the flakes, but whilst the covers were off Richard spotted a possible problem with one of the camshaft lobes. Given the choice of refitting as-is or stripping the engine to fix the problem, thankfully the customer chose the latter.

This is what we found.

NineMeister

The cause of the problem are blocked oil spraybar oil holes in the cam carriers, looks like residue of Loctite 574 from what we can see. The engine definitely needs new cams and rockers, our next job is to inspect the pistons and cylinders as this is an early engine with the spigot cylinder tops/rebated heads and there is already evidence of cylinder leakage from the joints less than 3000 miles from the build.

Suffice to say that the customer is not happy because one of the reasons he bought this car was because it had had a recent top end rebuild at a well known Porsche specialists just prior to his purchase. You have been warned!

ALEX P

Uuurgghh, what do you think caused them to get so bad, lack of oil, wrong oil, no oil???

Edit, you can type quicker than me!!

I found very similar when I tore my engine down i.e. bit's of sealant and silicone in places they shouldn't be - The question is now how far to go!!

I wasn't happy until all the core plugs were out and all the galleys were properly cleaned out.

Vandit

Seems like a common problem on these cars. Wasn't FP's C4 engine rebuild initiated by similar problems too?

luckyJ

apologies for reviving an old thread but just looked at a 1989 C4 where the PO had taken out his cams and grinded/resurfaced one of the lobes...car had little over 60k miles when serviced at dealer...

from what year did Porsche fix this problem or are all the 964s prone please?...

thank you

Steve Weiner-Rennsport Systems

LuckyJ,

I used to have boxes full of ruined cams like that and finally threw them all out into the metal recycling as I ran out of room to store them. Now, I keep one pair just to show people what happens when they make the wrong decision about engine oils.

The majority of the damaged ones I saw here were due to people using the wrong oils (insufficient ZDDP in the oil), compared to spray bar obstructions.

IMHO, its not a factory defect, based on my observations since 2003 when this really started in earnest. From 1969 to 2002 or so, we never saw any cams that suffered such damage unless the spray bars were blocked with dirt of some kind and that was rare. Once the EPA mandated reductions in ZDDP, this problem became more frequent.

Goughary

Steve...every time someone posts something to a "what's the best oil thread",,,,copy and paste what you just wrote. Such a simple explanation. Thanks. The zddp thing is such a short sighted tragedy for vintage cars.

JB 911

^Agreed. But in this particular case Colin pointed out the spraybar holes were blocked with what looked to be Loctite 574 seemed to be the problem. I'm curious to know where the 574 was used on this 964 and if in Colin (and Steve's) thoughts if this is the wrong product for these engines or if was maybe used too sloppily is this case.

NineMeister

Loctite 574 is the correct choice for 911 engine case joints, we use it on all Metzger engine builds.

I can't remember the details of this engine build now, so I guess the only reason why I thought it was 574 would have been down to the orange colour of the particles blocking the spray bars. The only way for cured 574 to arrive in the oil gallery would be from sloppy use or more likely a dirty part engine rebuild.

KaiB

Both Steve and Colin have often mentioned misuse of sealants and less than absolutely sanitary rebuilding.

Evidently this occurs FAR too often.

BLACK-BETTY

Yup exactly that - blocked spray tube... damaged rockers etc.

JasonAndreas

I have seen a few cases when shops/dealerships have used it (incorrectly) as extra insurance to seal a valve cover.

-nick

Here is mine at 85k miles. I don't know what the oil history was before me but PO mainly used the dealer, so likely mobil1 products. Of course, their zddp contents vary quite a lot depending on the weight.

The oil galleys in the cam towers were all clean. I only found one lobe with a pit. Tappets were all clean. I would suspect my short trips / oil+condensation = acid combo as another factor. My 70's 400cc motorcycle cam also had some pitting when I tore it down ~7 years ago. The modern oil reformulation appears to be a pretty well documented culprit at this point. Would love to see some kind of info on just how quickly a low-zddp oil can start causing issues. With 80k miles, and assuming at least half of those have been with good oil, that's a pretty quick road to destruction!

perelet

Here's mine at 78K:



They all do that. New one on order. I guess it is matter of luck which one is bad - left cost $600K right $1200.

I think most of 964 owners reading this thread have similar inside their engines, good practice is - do not open your engine and you'll never know

Goughary

+1