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Head Rebuild
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koolkarateguy  



Joined: 16 Dec 2005
Posts: 108
Location: Nova Scotia ,Canada

PostPosted: Sat Apr 28, 2007 11:26 am    Post subject: Head Rebuild Reply with quote

Hey everyone, I think the time has come to seriously consider a cylinder head rebuild. Anyone have any suggestions regarding performance parts such as cams, headers and such and some sources ?
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Chrenan  



Joined: 15 Jan 2003
Posts: 3903
Location: Canada

PostPosted: Sat Apr 28, 2007 2:13 pm    Post subject: Reply with quote

Send it to European Motorworks in California, get the Big Valve work done, comes with cam of your choice, total head rebuild, bigger valves, stiffer springs, porting, the list goes on. Best $1100 I have spent on the car.
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462avi  



Joined: 15 Sep 2006
Posts: 149
Location: Hollister, California

PostPosted: Sat Apr 28, 2007 2:54 pm    Post subject: Reply with quote

Chrenan

Does this do any good for the 931? Sorry for the string highjack

Geoff
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gohim  



Joined: 02 Nov 2002
Posts: 4459
Location: Rialto, CA

PostPosted: Sat Apr 28, 2007 5:22 pm    Post subject: Reply with quote

If you are going to pour money into the cylinder head, start with one of the better ones.

Use either the early Euro Engine cylinder head with the "D" shaped ports, or the later 80 or 81 cylinder head. The intermediate model year cars that came with smog pumps had a head design that tends to crack between the middle cylinders.
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2745
Location: Sydney, Australia

PostPosted: Sat Apr 28, 2007 7:55 pm    Post subject: Reply with quote

If you compare the NA intake ports with the 931 intake ports you see what a total disaster the NA head is. If you show the NA head to any specialist he will suggest doing what Porsche did with the 931 intake ports; fill in that huge lip at the opening, lift the roof and generally tidy it up.
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Chrenan  



Joined: 15 Jan 2003
Posts: 3903
Location: Canada

PostPosted: Sat Apr 28, 2007 11:30 pm    Post subject: Reply with quote

462avi wrote:
Chrenan

Does this do any good for the 931? Sorry for the string highjack

Geoff


I've heard no, the 931 head is very well designed apparently. The 924 head on the other hand is purposely designed to cripple the car.
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koolkarateguy  



Joined: 16 Dec 2005
Posts: 108
Location: Nova Scotia ,Canada

PostPosted: Sun Apr 29, 2007 12:59 am    Post subject: Reply with quote

Hi thanks for the input. I live in Nova Scotia, Canada. The head will not be leaving the city nor will I be changing the head. What I was wondering is keeping the fact that the head will not be switched nor will it be shipped out of town, are there any parts in it like cams and such or anything else that is worthwhile upgrading while it is out of the vehicle.
Actually Chrenan , did that $1100 you paid include round trip shipping to Alberta ?
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Chrenan  



Joined: 15 Jan 2003
Posts: 3903
Location: Canada

PostPosted: Sun Apr 29, 2007 1:39 am    Post subject: Reply with quote

No, that was extra, can't remember the total for shipping, but it wasn't as much as you'd think.
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11733
Location: PacNW

PostPosted: Sun Apr 29, 2007 2:01 am    Post subject: Reply with quote

931 head can benefit from porting/polishing.
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  • WeiBe (1987 924S 2.5t) - 931 S3
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koolkarateguy  



Joined: 16 Dec 2005
Posts: 108
Location: Nova Scotia ,Canada

PostPosted: Sun Apr 29, 2007 2:40 am    Post subject: Reply with quote

Thanks but I don't have a 931 head. So again, anything that'll benefit a 924 N/A head specifically ?
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NEMESIS  



Joined: 29 Jul 2006
Posts: 296
Location: BamaLamaDingGone, of course!

PostPosted: Sun Apr 29, 2007 4:39 am    Post subject: Reply with quote

Upgrades? Not many.

Hotter cam profile? Yes. Integral, Webcams, Piper, Schneider, European Motorworks, Elgin, and others.

Stainless steel valves? Yes. SI Valves

Adjustable cam gear? Yes. Too many to list.

Other than that, just your basic rebuild will do. Check all the tappets for wear, replace guides, seals, 3 angle seat, and do not port and polish the intakes, only clean up the rough edges and smooth it out. DO NOT attempt to port it or you run the risk of loosing much needed velocity by opening it up too much.

Headers? MSDS, Stahl, Bursch and maybe some others.

By the way, all of this information can be found by using the SEARCH function at the top of the page, that's how I did it.
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Tigger937  



Joined: 11 Apr 2004
Posts: 919
Location: PCA Milwaukee Region

PostPosted: Sun Apr 29, 2007 5:04 am    Post subject: Reply with quote

I've heard good things about ExtrudeHone for the head, intake & exhaust manifolds. Anyone have experience with this? Cost?

NEMESIS wrote:
DO NOT attempt to port it or you run the risk of loosing much needed velocity by opening it up too much.

Does this also apply to the 931?
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11733
Location: PacNW

PostPosted: Sun Apr 29, 2007 5:23 am    Post subject: Reply with quote

Tigger937 wrote:
NEMESIS wrote:
DO NOT attempt to port it or you run the risk of loosing much needed velocity by opening it up too much.

Does this also apply to the 931?


Not according to Peter. See his two cents HERE.
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NEMESIS  



Joined: 29 Jul 2006
Posts: 296
Location: BamaLamaDingGone, of course!

PostPosted: Sun Apr 29, 2007 6:02 am    Post subject: Reply with quote

Tigger937 wrote:
I've heard good things about ExtrudeHone for the head, intake & exhaust manifolds. Anyone have experience with this? Cost?

NEMESIS wrote:
DO NOT attempt to port it or you run the risk of loosing much needed velocity by opening it up too much.

Does this also apply to the 931?


My understanding is no it is not the same since the turbo is producing all the velocity so bigger is better but matching is key. Whether or not off boost performance suffers is another question, and I don't have the answer to that.

As far as extrude hone goes, I have yet to read of anyone doing this to a 931 intake. BUT, since all it does is smooth the intake track by romving imperfections in the casting, judging by the castings on the 931, it can't hurt. Same goes for exhast manifold I guess but less important in my opinion.
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koolkarateguy  



Joined: 16 Dec 2005
Posts: 108
Location: Nova Scotia ,Canada

PostPosted: Sun Apr 29, 2007 9:22 am    Post subject: Reply with quote

Thanks Nemesis, I appreciate the info it was very helpful. And I did do a search, but it doesn't hurt to ask a question to get some opinions.
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