Porsche Enthusiasts Club Forum

Anybody know the specs for the stock NA cam for the 2.5 8v??? In particular the measurement from base to the tip of the lobe. I'm also after duration, Lift etc. If it's new cam time I need to know what the stock one should do first.
Or can anybody recommend a good cam grinder to check it out.

JJ I will have the specs somewhere here if you give me your engine type (Mxx/xx etc.)
As for cam grinders I always recommend David Newman in Farnborough, Kent. His knowledge is fantastic & in the past he's stuff has worked well for me & friends. He does a lot of development work for mainstream manufacturers as well as some of the other engine builders resale stuff.
http://www.newman-cams.com/history.html

The cam box & the cam came from the scrap yard of an early engine. Block is also off an early engine 1985 ish. Since the engines been rebuilt & is a mixture of parts from the early & late cars I can only say that it's a 2.5 8v for now. I will pull the old cam out of the box & get the id number off it. I was planning to check it for wear & then if it's ok swap it over. If there both goosed then I need a new one. Lift should be the same for them all & therefore the base circle to lobe tip measurement should be the same? Not much info in the Manual.

I have a 2.5 NA cam at the garage JJ, will get the numbers off it tomorrow for you,
Alasdair

That would be helpful Thanks.

I can ask Newman cams to check mine but it will cost lots & won't fix it. Just need the base circle to lobe tip measurement. Strangely missing from the manual. Just gives runout etc. Hint Hint

Don't you have a vernier calliper? Cheapy ones are around 20 quid or so these days. That'll measure that. Just checked the manual it only gives timing figures nowt else!

I have a good vernier caliper. But I don't know what the measurement should be. The tappets are large enough that there will be no ridge on the cam. But they will wear . I have one cam with 150K & the other over 200K. New cam is £500 & may not help at all. Probably I will have to ask Newman cams to check it! Thanks for looking!

JJ, cam specs are:
base circle to lobe - 49.6mm
base circle diameter - 36.04mm
Part number seems to be 944 105 155 05R but very difficult to read.
Alasdair

That would show a lift of 13.56mm or 0.542 which sounds about right. I read somewhere that later cams have different lift on in to ex?

My PET for an 88 8v car shows two cam part no's.
944 105 155 -09 for M44.05-10
944 105 155 -05 for M44 50/51/52 It sounds like this is your cam Alasdair.

Sorry gents, got the number mixed up, lift is 46.9mm and 47.8 so one side has greater lift! I also have a turbo cam so should really measure that as well!
Alasdair

Thanks very much for that. Now theres a thought. Could be I have a turbo cam in the car as due to a mix up the wrong one was fitted. It came with a new cam box that I got from the breakers. Not sure what engine it came off. Though wear may be a more likely explanation. Wear isn't easily noticeable on the 944 as the lifters are so big the lobe tips wear evenly & it's only possible to tell by measuring them. At least I can measure the original one & see how it compares.

My old one. (Not in the car.) was well worn. It made more power with this one as well! Looking at ordering a new cam & vernier wheel in the near future. Since it makes loads of torque & doesn't leak oil going to leave it for now & get the gearbox in & sort the suspension. No more dyno' time until winter now he's booked up!

Jj u got any figures u like 2 share?

140lbs at 2000rpm 160 at 3000rpm. Bit like a turbo deasel. Then 160 through to 5500rpm. Not right at all. But the wide power band makes it surprisingly quick. Should be hitting peak torque at 4000 to 4500 rpm. but a big improvement on the first run when I just got the car. Originally only made 110 at 2000rpm & peak torque just 135lbs at 4500 rpm which is why you can't just plug a chip in & expect it to work. Fairly typical figures from these cars as well. 25 years has taken it's toll. It is making progress but every time I think I've got there I discover another issue with the car. It needs to come to bits again but I need it on the road at the moment so it has to wait until winter. Sometimes wish I had another car as it would speed up the process. One day it will be right. Will probably have to sell it by then!