Camshaft O-ring replacement ?

ischmitz · ischmitz's Garage

I need to replace the O-ring (22) and the gasket (23) between the cam housing and the cylinder head on a 964 engine.

Can I get to both by taking the cam sprocket off?

Is a way to do this without loosing the timing on the engine.

Maybe something like using a felt pen to mark the exact location of the chain on the sprocket and make sure the chain does not skip a tooth on the driving sprocket. Then mark the location that was used for the retaining pin. Any thoughts?

Ingo

Wayne 962 · Wayne 962's Garage

Nope, the 964 (late 3.6 engines) use a different method for setting the timing, what year is the engine.

The felt-tipped marker method is not a good way to go...

-Wayne

ischmitz · ischmitz's Garage

Wayne,

the engine is a 1991 3.6. I read the factory manual describing how to do the timing properly. It calls out for a special tool called auxiliary chain tensioner that I don't have.

Other than that it's pretty much the standard method: Do the rough timing by punching the cams at with #1 at TDC before disassembly, reassemble and do the fine adjustment with the feeler gauge method (that I don't have)

I just wanted to know if it is possible to do it with the felt marker pen. I know it's not the shop proper shop procedure.

The other question was if I would get to gasket 23 without having to remove the entire chain housing?

Ingo

cstreit · cstreit's Garage

Yes, you can get to the gasket without removing the housing. Beneath the sprocket and the flange (that the pin locks into) is an aluminum plate with a U shaped cut in the edge for the o-ring. Behind that is the gasket....

I would put a light coat of curil-T on both sides of the gasket to ensure proper sealing since there's very little torque on that aluminum plate and it's such a pain to get to.

Britwrench · 03-22-2003, 06:36 AM

With 964 engines you should always replace the chain housing to crankcase gasket as it usually leaks too.

All 911 engines up to the 993 engines use the same basic method of velve timing. The 964 tools can be made up fairly easily or or you can buy them (about $150, I think) If you don't have the tools, don't do it.

Wayne 962 · Wayne 962's Garage

I believe some of the late 964 engines used the newer 993 method of timing (not 100% sure).

It's not easy to replace the chain housing to crankcase gasket without messing with the chain...

-Wayne

Britwrench · 03-22-2003, 12:29 PM

All the 964 models use the dial gauge method of valve timing.
The 993 uses the tools that lock the camshafts. You can also use the dial gauge if you install a non-hydraulic rocker.
With the timing chain disconnected for the o-ring replacement the chain housing comes off fairly easily. Remember to change all the o-rings for the oil pipe on top of the housing.