hksamc

Dear all,

I am having white smoke (oil burn smell) during idle of my 3.2 Carrera and I thought I need to replace the valve guides though 3.2 engines have an issue with soft valve guides. I am shopping around for valve guides. What does 1st replacement/2nd replacement mean? Do I need to replace cylinder heads studs as well? Do I need to replace both exhaust and intake valves and valve springs as a whole? I am thinking to replace piston rings as well given the fact that I am rebuilding the engine....What do you think?

Cheers, Eric

Mark Salvetti

hksamc

40,000 miles with excessive oil consumption.

Steve Weiner-Rennsport Systems

I would do a hot leakdown test to see how well your rings are sealing, but in general, these engines do not need rings at 40K.

I would replace the guides and head studs (don't use aftermarket) while dealing with any oil leaks. After that, your engine will last a very long time.

hksamc

Thanks for your reply. So what is 1st vs 2nd replacement valve guides? Should I take 1st replacement? (No restoration has been done to this engine since it was new).

For head studs, you mean I need to order the original ones?

Cheers, Eric

911Dave

White smoke is not oil burning, it is condensation. In other words, it's water. When oil burns, the smoke is BLUE. I think you should take your car to a professional mechanic for an assessment of the engine's health. Get leakdown and compression tests. Don't just start replacing parts based on assumptions. Find out, then do what's necessary.

hksamc

Thanks. It is confirmed that the smoke is blue and burning oil with pungent smell. So I consider it is a valve guide issue. It only happens when idling. When the engine speed raises to 1,500 rpm, blue smoke gone gradually and it comes back again when it sits for a while and idle again.

Steve Weiner-Rennsport Systems

We make our own guides since the factory ones are too soft. You don't need oversize ones unless the heads are damaged and this job must be left to experienced professionals who do 911 engines.

The only head studs we use in these engines are 993TT ones. Not cheap, however they are reliable and offer the expansion/contraction properties these engines need.

hksamc

Oversize valve guides u mean 1st replacement or 2nd replacement? Thanks

Steve Weiner-Rennsport Systems

OS guides are ONLY needed if the guide bores are damaged otherwise std guides are fine.

hksamc

sorry, so what is the part number I need for those valve guides? I can only see 1st and 2nd replacement valve guides from the PET catalog

Mark Salvetti

Are you planning to replace the valve guides yourself? That's not a typical DIY project. You need to send the heads to a reputable machine shop (ask here for recommendations - where are you located?) and get them reconditioned. The shop will know whether the valves can be reused and they will replace the guides with whatever size is needed. You need to put your trust in them.

Mark

hksamc

Thanks. Do you think I need to replace all cylinder head studs when the cylinder head is removed?

Mark Salvetti

Steve's recommendation is for the 993TT studs, I believe they are the latest iteration of the Dilivar stud but they cost about $60 each (part number 99310117053) and you need to replace at least the 12 exhaust studs. Plus you'll want new nuts and washers.

Others will use steel studs that only cost about $12 each. Probably OK for a non-race, normally aspirated car, but Steve is a highly respected engine builder here. He can't afford to have one of his motors fail due to studs, and I bet a lot of his motors are highly stressed.

I would be tempted to replace all 24. The top studs don't usually break, but until recently neither did the lower studs on the 3.2 engines. Maybe the uppers will start failing soon too.

I'm not an expert on these topics at all. Not sure which way I would go. Hopefully someone that knows better will chime in.

Mark

hksamc

Thanks Mark.

According to the PET catalogue, the upper studs part number is 91110117200 and the lower studs part number is 99310117053. The lower studs are from 993TT. The price difference is huge.