While researching for a shop to do a PPI I came across this info from Exotech in NH. It describes their process for valve guide replacement and grinding.

http://www.exotechpower.com/36401.html

I would be interested to hear Steve W.'s take on this.

 

Isn't Exotech the home of the $3500 valve job? I have heard great things about them.

 

It is indeed. I had mine done there. Mark has his act together. He was once described as a smart guy with a box of wrenches which I think is apropos. His facility won't roll your socks up and down but who cares, he does the job and does it well. My car was done at 95k miles and is at 115k now and hasn't drunk a (noticable) drop of oil.

 

3500 including R&R the engine or do you have to send him your heads and it's $3500?

 

Personally I don't see why a Porsche valve job would be more costly than any other engine except for guides that might be a few more dollars and set-up of 6 heads instead of 1 or 2.(R&R not considered)

 

Once you've done a set of 911 heads v. some cast iron V-8 or generic Asian 4 cylinder, you'll know.

I get why this guy does it that way; and I also get why other machinists do them on their production machines.

 

Educate me then What extra work is required?

 

Time. Setting up six heads v. a single blob that you can plop down and slam through 4 cylinders in a few minutes. Not to mention on most water cooled heads you're not replacing guides. (And no, I'm not going to get into a discussion of 911 v. Type 1 or Type 4 engines; I've never done machine work on a VW, and in any case outside of very, very, very highly developed race engines I can't imagine the tolerances on the VW stuff is anywhere near what we do on Porsches.)

Personally, the few that I've done I was not using a machine optimized for 911 heads (BMW machinist's stuff); the odd angles of a 911 head meant that I took great care in setting stuff up.

 

Matt -

I think you have basically answered part of your own question. Having 6 individual heads requires multiple setups with equals a lot of labor time. Most machine shop bills I have paid were 80-90% labor and the rest was parts.

The last non-Porsche head that I had done was a 16 valve 4 cylinder Mazda head done to a race spec but with minimal porting and paid about $300. My last Porsche heads were about $450 IIRC. So, a $150 premium for the additional setups seems reasonable to me.

I'd like to here Race911s opinion though as I think he has much more experience than I.

Oops - looks like Race911 is a faster typer!

 

Yep. Or thereabouts. I'd have no reservations driving the Dung Beetle up there for top-end work. Mark is all set up with jigs, etc.


Andreas

 

.005" concentricity sounds a little high. Is that really the Porsche spec? Some of it sounds like propaganda....

"By the way it should be noted that Teflon seals are NOT the hot setup, ultimately they will in fact wear your valve stems prematurely. Another thing often found is incorrect valve springs. Sometimes referred to as "saftey" springs they usualy have far too much seat pressure, resulting in premature valve and cam drive wear."

Do many shops really do this?? I wouldn't think so.

 

I still don't see the price being multiples of a pair of V8 aluminum heads. I wonder if the muscle car machine work is just a lot more competitive bringing the price down. We still didn't hear if the $3500 included r&r. That would be a heck of a deal. Either way, I'll be shipping my heads somewhere when the day comes.

 

I believe you mis-read, here's the text:
"It should be noted that concentricity should be held to .002" per Porsches specs, which is, of course, correct.Typical seats done on a Serdi or the like are generally around .005" non-concentric which at first will be fine but will not last as long as they would were they held to a tighter tolerance."

At $3500, seems like a great deal. Don't most shops charge double or more?

 

My previous dealings with machining 3.2/3.6L heads come to about $600-750 depending on how much work is done...for all 6.

That was with me delivering the heads to the local machine shop.

The $3500 includes the R&R, I just called...of course the price goes up with more stuff that is needed (split case, oil leaks everywhere, etc).

The individual head price compares with what others have paid previously, if you deliver the heads for machining.

I must say one thing, the guy I talked to (Mark's partner) is great and he didn't rush me off the phone.

 

Sounds pretty reasonable to me.