924Board.org

[masterslamma]

Hi everybody,

i am currently rebuilding a na head. Its already skimmed, seats recut, valves optimized the lathe and has some mods to the ports done.

No i am thinking about what cam i want to use. Dbilas is a well known cam grinder here in Germany. And the do 2 different grinds (272° with 12,1mm lift and 276° with 12,4mm lift) from a standard 924 cam.
I would like to use the 276° one. Does anyone have some experience with those cam? Do they make a good grind? The car is manly driven on the road, only sometimes in the alps or slalom´s. But i want more top end power, but don´t really want to lose mid range torque.

I am also not sure if my cam can still be regrinded, as it has some pitting marks on the top of 3 cams. But i think they are not deeper than 3/10´s off a millimeter.
I already called the Dbilas service but they also couldn't´t help me.

My main question/worry is, that if i use the thickest adjusters screws for the lifters that you can buy at porsche, that those are still not thick enough and i can´t adjust the valve play.

Cheers

Chris
_________________
My other car is a Porsche,
but today i am in a hurry!

[Fifty50Plus]

It is possible that with the pitting on the lobes of your camshaft they might have to take a lot of material off the back side of the lobes to give you the grind you want. Then you might have a problem with the stock adjusters not being big enough. With this setup, to get the proper clearance using the stock adjusters you might have your valve seats cut a bit deeper and the valves cut to sink a bit more where they meet the valve seats.
A better option with the stock adjusters is to have a camshaft ground on a new billet and use all new Porsche parts.
Another option (and possibly even better), is to do away with the Porsche adjusters on your lifters and use shims to set your valve clearance. See Ideola's Garage web site for the lifters and shims. It's a bit more complicated to set up your initial clearances but works very well in the long run. This set up will work on a new billet camshaft grind as well as having it done on your original cam (if salvageable).
Regards,
Chuck
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

[Arvidw]

Or you could buy a newmans camshaft from the UK. They are billet ground cams for around 250euro, very cheap compared to pipercams or webcams camshafts.
_________________
Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

[Carrera RSR]

The lifter adjusting screws are NLA at Porsche.

I'm using a 278 Piper Cam in my turbo without ill effects at the moment. http://www.pipercams.co.uk/pipercams/www/product_nav.php?type=C&cat=CM&man=18&engine=2 claim is it adds 5-8bhp
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[masterslamma]

This newman cam looks like a fair deal. I once had an other engine witch had a newman camshaft, and this one did work well. So i think there´s nothing wrong with newman. 80 pounds for a set of cam followers is also cheap.

porsche still has some adjuster screws here in germany. But only the thickest ones are still available. But i don´t know how much thicker they are....does someone?
_________________
My other car is a Porsche,
but today i am in a hurry!

[daniel]

When I had my cam reground I put shims between the adjusting screw and the valve, works fine to 6500rpm
_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

[masterslamma]

that idea with the shims under the valve top went also threw my mind already.
But i am afraid that the shims can't stand the duty and my break ore have wear.
Were did you get your shims from? Have they been hardened? What sort of steel where they made from?

lots of question
_________________
My other car is a Porsche,
but today i am in a hurry!

[fiat22turbo]

They are valve stem shims and are commonly used in a number of applications and can work quite well. They have a cup machined on the bottom to fit the top of the valve stem and the tops are hardened I believe. I have a set I've set aside for use with my solid lifters and new valve springs that I might use someday.


_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[daniel]

They work, I race my car and after 5 meetings dont even have to adjust valves.

http://www.precisionshims.com.au/

The ones I use locate inside the follower between valve and the adjuster. no recess is required.
_________________
Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

[masterslamma]

I decided now to go the newman cam route. But here in Germany it is not possible to source a cam. Does someone know a good dealer in europe?

regards
_________________
My other car is a Porsche,
but today i am in a hurry!

[Arvidw]

Call Newman in the UK, they will certainly help you.
_________________
Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)