3.2 Valve guide work

[theiceman]

I have a friend who rebuilds a fair number of 911 engines , he usually does pre 3.0 litre stuff and has a fair bit of experience at it ... a mutual friend of ours talked him into doing his 3.2 which has excessive smoking.

He found leaking of oil actually between the valve guides and the head, so is sending them off to machine shop for repair ( also oil scraper rings are totally clogged on the ones where he spotted evidence of oil seepage at the guides. ). I hear a lot of issues with 3.2 valve guides, is this the normal failure mode on the exhaust guides ??

Also he told me it has lower black Dilivar head studs. I did my engine because of broken studs (3.0) but i was wondering with all the valve guide work done on 3.2s for valve guide work is it standard practice to replace these ? refresh with Dilivar , or just leave them alone if they are fine ?


Thanks Guys

[dtxscott]

I'm in the process of doing this now due to valve guide issues at 85k miles. My dilivars were in good shape but I replaced them with steel studs as a precaution.

As far as failure mode, I think most develop wear between the guide and valve.

Also, not to add to his repair tab, he may want to consider Titanium retainers.

[Flat6pac]

Black or silver, dilivar will break with the retorque.
In 1989 or 90 I torques a set of heads then went to bed.
Next morning, broken studs everywhere
Replace them with steel and cut the down time…
Bruce

[dannobee]

That failure isn't common. The guide to head is an interference fit, so if something leaks, it's because the guide hole in the head wasn't round or was galled or damaged. The guides wear out at the valve stem.

Replace the head studs while you have it apart.

[theiceman]

great info , thanks guys ...

i have passed the advice on. i thought so too about the dilivar , but wasnt sure about the valve guide stuff.. either way guides are getting replaced so machine shop should resolve any issues i would imagine.

[theiceman]

Passed along the advice and he is adding new studs to the order.. didnt bother with the retainers though.

Not my build so ..

[mepstein]

Originally Posted by Flat6pac

Black or silver, dilivar will break with the retorque.
In 1989 or 90 I torques a set of heads then went to bed.
Next morning, broken studs everywhere
Replace them with steel and cut the down time…
Bruce

I saw the same thing happen when I worked at the shop. Customer just wanted the one broken stud replaced. The next day there were 5 on the floor and one “pinged” while we were in the room. Went about a foot off the top of the engine and fell to the floor. I had seen them the previous day and they all looked fine. No corrosion.

[al lkosmal]

Dilivar bad...steel good.