unreal_news

well,
about a week ago i dropped off my head at a no name machine shop, and I cant tell for sure that i trust them. They seem honest enough, but what I've read here on rennlist conflicts with what they are telling me. So, here's what i know...

The pressure test came back good, so there are no leaks.

1 - They said they didnt feel comfortable grinding the intake valves because there wouldnt be much margin? I didnt think they had to grind them that much, just a hair to smooth the surface.

2 - they said the exhaust valves needed replaced, but I've read that only bent valves needed replaced?

At this point, I told them to go agaid and wrap up and Ill contact them at a later point (mabey)... Ill post pictures of the exhaust valves if that would help, Im sure that the head has never been touched before. Right now, i think i need a second opinion, cause if they had their way, they'ld replace all 8 valves. It just doesnt sound right.

thanks,
-john

Gator_86_951

How many miles are on your turbo. My head had like 180k miles on it. The picture below is of my exhaust valves. I would not be surprised if they recommended having some of the vavles replaced. They tend to crack over time.

luckett

I just got off the phone with German Precision (Sunnyvale, CA), who does machine work for Devek, concerning a head rebuild. He told me that he hardly ever has to rebuild the 16v heads. Of course, your 8v may differ.

Give Ted a call for advice at 408.747.0728. He seems to be a really nice guy.

unreal_news

My car currently has 82K on it. In fact, the guy said it was a blown head gasket, and the head was fine. So, I think I may just put the valves back in (mabey ill save to buy some intake valves) and ill do that work myself, nothing has to be recut to do that does it? Then I just need to get the bottom milled and I should be good to go.

-john

luckett

My 968 has almost 150k miles and I also blew the head gasket. The valves were in great shape and the valves were sealing perfectly.

Inspect your valves for damage. If there is no damage, put the valves in the head, put your plugs in and fill the combution chambers with water. You should then be able to identify any leakage by watching the water drain.

Just to be sure there are no particles holding the valve open, put something soft like a piece of wood or a screwdriver handle on the valve and smack it a few times with a hammer to dislodge the particles.

hoffman912

i would never take anything to a no name machine shop i would only take it to a shop that knows porsches.

Porsche-O-Phile

Sound advice.

unreal_news

Well, I think im in the green on this one, Im getting my head today, and Ill start looking for a performance machine shop so i can get my head milled. It's already been pressure tested and cleaned. So i think im good to go. Ill also inspect the valves and do the water leak test

thanks again,
-john

AznDrgn

John what shop are you using? I've used a couple of shops up in NOVA and have heard some stuff about other shops in the area as well. Off the top of my head I'd say stay away from Intersport, horrible experience with them when they had my 924 head, they know their stuff but they are slow and most of the times unresponsive to phone calls. Allied Machine shop in Falls Church is a favorite among a lot of NOVA guys including a lot of 911 guys and their prices are pretty good too. I've also heard good things about Curry's in Sterling but haven't used them personally.

While you have your head apart you should really have the valves cut and reseated and of course check the guides for wear and replace those as needed. At the very least lap the valves in yourself but the very best option with it already disassembled is to have them cut.

unreal_news

AznDrgn -> its kenson Automotive in fairfax,va.

The guy said that the exhaust valves all needed to be replaced ( which is weird since he said my compression test was good. And that the intake valves should also be replaced, but he could cut them, he just didnt feel comfortable with it, because it wouldnt leave much margin.

Ill feel better getting everything back and examining the valves myself.

Also, will cutting the valves weaken their ability to work propery? or should they be in perfect working order after being cut?

Ill give Allied a try, I looked them up and I came up with ...

Allied Industrial Machine Services Inc
1245 W Broad St Rear <---- this is them right?
Falls Church, VA 22046-2117
Phone: (703) 533-8355

thanks again,
-john

Matt H

Why do people both with the local yokel machine shops? If it isnt a Chevy 350 most machine shops are lost. Having done a ton of automotive work I can assure that most machine shops are just total crap. Every time you get a head back you have to wonder if it is a good one.

Send the thing off to a place like Scott Gomes at Under Pressure Performance (he is a member here) or since you are in California you could send it to one of the 9 million Porsche shops on that coast.
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unreal_news

nope, im on the east coast, not too much to work with over this way... but like i said, im gonna see how allied pars out. Itll be good to know that their comfortable working on a 951 head. Ill let e1 know how they work out.

-john

Matt H

Since you are on the east coast (I have no idea why I thought you were on the the "other" coast) Scott is your man, he is in Boston, if you prefer another lister, Vitesse is outside of Atlanta.
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jaje

have you tried contacting RPM Motorsports (Woodbridge, va) or AutoBahn (fairfax, va) as they are local shops that specialize in porsche (they might recommend someone else for machine work or know about the place you have your head at)...RPM also is a sponsor of the 44 cup series

AznDrgn

STAY AWAY FROM KENSON!!!! My buddy took his 951 block there for them to clean up and hone but instead of using the proper procedure to hone alusil bores they just stuck a regular hone down it and ruined the bores completely. Then to top it all off they argued that it wasn't their fault since he didn't specifically tell them that the block had alusil bores and needed a special process.

Just a side note, RPM uses Allied Machine Shop in Falls Church, not sure about Autobahn though.