LFA

I need a set of clean camshafts for a 1991 928

BC

I have some good S4 cams. Where are you?

Randy V

Please read thru the NEW VISITOR FAQ thread posted at the top.

ROG100

1991 S4 or GT?

ROG100

GT from your other thread - GT cams are like hens teeth or rocking horse **** to find.
Talk to Colin Jensen "LIZARD" as he has some nice aftermarket sets.

Rob Edwards

Guessing GT, based on his other thread.

LFA, some of the individual GT cams are NLA, and those that aren't, are hideously expensive. You'll be money and hp ahead by ordering a set of cams from Colin (AKA Lizard931).

GregBBRD

Rocking horse ****.......how funny is that?

SeanR

One evening and two bottles of wine with him will get you speaking another language.

To the OP, I also recommend going with the cams that Colin (Lizard931) offers, good stuff.

LFA

I am not expert at all on 928s but, when I look at the parts catalogue it seem like S4 and GT have the same cam shafts from 1988 to 1991. Is this wrong? ( 928 105 274 01 fits both 88- M28.41 nand 89- M28.47)

ROG100

Wrong big time - 87 to 91 S4 5 speed and auto had one set of cams - 88 to 91 SE, CS and GT had another set of cams. Rob will be back in a few and give you all the detail.
You need GT cams my friend and by the way welcome to Rennlist you just found the source for more 928 information than you could ever wish for.

Rob Edwards

PET is misleading on the GT cams, as it lists M28.41/M637, which at first glance seems like S4 (since 'regular' S4 5-speeds have M28.41 engines) , but the M637 is referring specifically to CS and SE cars, which also have M28.41 engines.

Here's a table of 32V cam specs/lift/duration/etc and part numbers.

Mark Anderson

So Rob are you saying although the part numbers change they are really all the same?

928mac

It looks to me that the S3 cams are the same lift and duration as the GT

Rob Edwards

S3 vs. GT lift and duration are the same, LSA's and overlap are different.

Here are two tables shamelessly copied from work done by Dennis Kao (and possibly Jim Morton? apologies if the acknowledgements are incomplete.....)

Strosek Ultra

For you interested here are the camshaft data for a very high output stroker engine.

Intake lobe center (atdc) 111 dgs
Exhaust lobe center (btdc) 115 dgs
Intake duration @ 1mm 261 dgs
Exhaust duration @ 1mm 256 dgs
Intake lift 12,7 mm
Exhaust lift 12,7 mm
Overlap @ 1mm 32,5 dgs
Lobe separation angle 113 dgs

Ake