Carrera Valve Installation Question

[Determined]

Hello everyone,

Yesterday I reassembled my heads after having my valve seats cut and valves reground plus some I had some thermal barrier coatings applied. My question comes late but I reinstalled my valves without any lube, the moved freely up and down with no binding and I installed the white valve seals as well. These are the double spring type which I believe to be better than the OEM ones. The valve moved well with the valve seal in place also, do I need to disassemble to lube the valve stems? My Bentley manual made no mention to apply any lube nor did Wayne's Porsche rebuilding book. Opinions??? Pictures below:

Thanks,

Alex

[89turbocabmike]

No lube.

BTW, is that a coating on the springs, or spray paint? If it's paint, I'd be worried about it flaking off, not that it's super hard and would probably be filtered out, but why take a chance?

[Determined]

Hi Mike,

Thanks for your input, the valve move nicely up and down. My valve springs were professionally coated and cured to reduce temperature due to friction and they have oil release as well. My combustion chambers and valve faces where ceramic coated. I also had my piston domes ceramic coated and side skirts were treated with dry film lube. The bottom of my pistons have oil release to help the hot oil come off them. I know there are a lot of mix feelings on thermal barrier coatings but I see it as cheap insurance. I have a 3.2 Euro and I'm trying to minimize detonation, I also plan to retard the timing and go with a Steve Wong chip. Thanks again for your input, I greatly appreciate it.

Alex

[Eagledriver]

I haven't installed my own valves but I know the shop I use puts oil on the valve shafts when installing them. I can't imagine starting an engine with dry valve stems. I suspect but can't confirm that the book doesn't mention it because it's obvious.

-Andy

[89turbocabmike]

Bump for some of our resident experts

I can see using a bit of oil to lubricate the valve seal/valve installation, but I always assumed that, ideally, lubrication between the guide/stem interface came from the guides themselves. Being a turbo guy, I'm always worried about coked-up oil's abrasive nature and would think that oil baking in the guides would not be a good thing, but perhaps the combustion temps transfer fast enough to prevent reaching those temperatures.

Alex, I'm going to use some coatings in my engine also, though I haven't decided just how far I'll go, I'll have to see what fits the budget.

[Determined]

My understanding was that the Carrera's were known to fail at the valve guides because of oil getting past the valve seals then leaking into the combustion chamber. I could be wrong but I believe I read about it in one of my books and possibly in Pelican's forums or Wayne's book. I don't remember where I read something related to bad valve guides. Let's see if Henry or Wayne himself can help out here.

Best Regards,

Alex

[911pcars]

Parts that rub together without oil/lube create friction, heat and unnecessary wear - none of the 3 is desireable. The valve guide seals prevent excess oil from migrating into the guides. I suggest removing the retainers and apply some slippery stuff between guide and stem.

Whose product are the thermal barriers?

Sherwood

[cgarr]

you should be able to shoot some oil right thru the ports onto the stems and let it run down. That should do it if you need to get some oil thru it..

[Determined]

What type of oil is recommended and what about synthetics, I assume rubbing it on with the fingers on the valve stems is fine? More opinions please.

Thanks,

Alex

[911pcars]

Craig's suggestion about injecting oil onto the valve stems through the ports is more convenient than disassembly. I'd suggest synthetic oil since the viscosity is a lot lower (thinner) and because it has pretty good film strength. Mixing a small amount of synthetic with the dino-based break-in oil shouldn't be a problem.

Sherwood

[Determined]

Thank you Sherwood, I appreciate your time and advice as well as everyone elses.

Best Regards,

Alex

[Eagledriver]

Carreras are known for failures of valve guides. However the oil is a symptom not a cause of the failure. The failure is the guides wearing out and some of us believe that is caused by lack of oil getting past the seals. I think the white seals you are using are the best choice for allowing enough oil to pass to keep the guides lubricated. This doesn't mean you don't need to lube the valve stems/guides before the first start.

-Andy

[Determined]

Thanks eagledriver,

My heads are going to be sitting for a short while before I complete my reassembly, I think I'll teardown and put oil nearest the time for reassembly.

Thanks,

Alex

[hcoles]

I agree with Eagledriver....the seals were too good...is the most common story I heard... the machine shop I used who has done so many 911 heads over say 15 or more years... he dips the stem in clean oil before asm. I can't imagine not doing that or at least putting some amount of oil on the stem or guide

[john walker's workshop]

i've always oiled the guide as well as the valve stem on installation.

[ChrisBennet]

The guy who does my heads doesn't care for the teflon (white) valve stem seals. He says he sees more wear with them.
-Chris

[Jeff Alton]

Originally posted by ChrisBennet
The guy who does my heads doesn't care for the teflon (white) valve stem seals. He says he sees more wear with them.
-Chris

Same with the guy that does my heads....

Cheers

[john walker's workshop]

i like the 964 seals. the white ones seem to get hard and break after a while and sometimes they come off the guide and ride on the valve stem and act like a little oil pump.

[Determined]

Ouch! Do I have the wrong valve seals; it's not too late to remove them. I'm convinced about the oiling now but now I'm worried about the seal. John, I don't know what the 964 seals look like, does anyone have a pictures and pricing? Where can I get a set if needed or am I being too paranoid at this point?

Thanks everyone!
Alex

[Eagledriver]

I've heard the exact same story about the dark rubber ones. You pay your money and take your chances. I've used the white on my last 3 engines with no issues. Of course the longest I've had any of those engines is 5 years and 20k miles.

-Andy