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Best cam grind for a 931
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Rick MacLaren  
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PostPosted: Thu Aug 30, 2001 1:28 am    Post subject: Reply with quote

Hi,
I'm gonna grind my cam down to a Stage 1 level - can anyone recommend the best grind for the 1980 931 with around 15 PSI boost?

Thanks very much.

Rick
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larso  
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PostPosted: Thu Aug 30, 2001 12:21 pm    Post subject: Reply with quote

don't do it the same as an NA, i'd read up on it but I beleive you want not so much duration like the NA cars, but u still want a steep one, just pointier like a triangle.

duration=lag
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Rick MacLaren  
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PostPosted: Thu Aug 30, 2001 12:25 pm    Post subject: Reply with quote

Thanks Lars. I need a good grind for the 931...I've heard it should be made specifically for the car...not a general purpose grind. Do you know anyone that has one?
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Patrick  
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PostPosted: Thu Aug 30, 2001 6:26 pm    Post subject: Reply with quote

N/A and turbo use the same oem cam.


I have had a cam made for my car. Specs: 268 degrees duration, 12.25 mm lift, and 112 degree "nockvinkel" (don't know the name for it in eng.).

Very powerful, pulls strongly to 7500.

L8ta
Patrick
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Rick MacLaren  
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PostPosted: Thu Aug 30, 2001 11:01 pm    Post subject: Reply with quote

EXCELLENT! Thanks Patrick.

When does the pull start?

Whoa! Isn't redline 6400?

_________________
1980 Porsche 931 C2H5OH/H2O injected 15 PSI
1979 Porsche 924

[ This Message was edited by: Rick MacLaren on 2001-08-30 23:07 ]
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Patrick  
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PostPosted: Fri Aug 31, 2001 3:34 am    Post subject: Reply with quote

"EXCELLENT! Thanks Patrick."

My pleasure! Observe that my cam has 1 mm smaller base circle. Therefore it is not a "plug and play" cam, you have to do a valve and seat job.

"When does the pull start?"

A little after 3500.


"Whoa! Isn't redline 6400?"

It used to be 6600 on my car. Just change the rotor to an n/a...

My block is balanced, weighed rods/pistons. Ported head, calibrated double valve springs, etc.. etc..

Should be dynoed in about 1 month. Hopefully on the right side of 300 hp...

Hehe!

L8ta
Patrick
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Rick MacLaren  
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PostPosted: Fri Aug 31, 2001 3:46 am    Post subject: Reply with quote

I just can't do that much work on it presently. I'm looking for a bolt on.
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larso  
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PostPosted: Fri Aug 31, 2001 10:00 am    Post subject: Reply with quote

with almost all cam grinds you need lash pads, expensive stuff...
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Rick MacLaren  
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PostPosted: Sat Sep 01, 2001 12:24 am    Post subject: Reply with quote

FOUND ONE! Cut from a fresh billet.

Stage 2: $300 USD, no lash pads or anything required.
Stage 1 268º .500"

http://www.integralcams.com/background.htm
http://www.integralcams.com/catalog%20cams.htm

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ricomartinez  
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PostPosted: Sat Sep 01, 2001 1:40 am    Post subject: Reply with quote

How much are the lash pads? I was getting ready to do a head rebuild and figuring about a $100 for regrind plus a few bucks for a few small pieces of metal (8 lashpads).
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Rick MacLaren  
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PostPosted: Sat Sep 01, 2001 3:54 am    Post subject: Reply with quote

Check out Integral's links Lars, no lash pads required for the Stage 2 grind.
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larso  
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PostPosted: Sat Sep 01, 2001 3:57 am    Post subject: Reply with quote

ok good, I was talking about grinding your current cam... I never knew there were companies that made new cams for the 924.

Lash pads are expensive, and are neccessary if you are not getting a new custom cam ground, they are like 250 for a set of lash pads at tweeks or something.


[ This Message was edited by: larso on 2001-09-01 04:11 ]
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Rick MacLaren  
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PostPosted: Sun Sep 02, 2001 6:03 am    Post subject: Reply with quote

I had no idea that lash pads could be so expensive.

Yeah, they'll use a FRESH BILLET for the cam at Integral, and did you check out the guys resume and background? He's pretty sharp.

He has the cam made for me already! Hoo ha.

I'm just ITCHING to hear that 'balump, balump' rumble of the cam at a stop light...I think it's giving me a stiffy...
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larso  
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PostPosted: Sun Sep 02, 2001 2:27 pm    Post subject: Reply with quote

actaully lash pads aren't expensive it's just tweeks thats screwed up, sorry about that.

Schneider cams still does cams for cheap, if you do wanna get lash pads and a grind on your cam u have now.

If a guy has a "mechanical engineering" degree, I don't take that into much consideration though $330 compared to 220 at Elgin or even cheaper at schneider, but then again it's not a billet.
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Patrick  
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PostPosted: Sun Sep 02, 2001 9:01 pm    Post subject: Reply with quote

Correction: Lash pads are not necessary unless you leave the rest of the head oem.

To gain the max performance from the cam one should "grind" the valve seats (to a radius-shape) and give the valves a few angles.

When doing this the valve automatically comes higher, therefore no need for lash caps.

L8ta
Patrick

The $300 for a brand new cam seems to be a very good deal!
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