PCar SBA

I am contemplating to upgrade my cams a little bit "while I am in there". I have the engine apart and am doing a top end rebuilt (heads, cylinders, head gaskets, rod bearings, ARP rod bolts). I also need to have at least one cam repaired (exessive wear on a couple of lobes)

The engine is a stock 91 964 with 993 heat exchangers and a chip feeding into a 915 transmission with 7/31 R/P in a 74 Targa. Yeah baby!!

I was wondering what cam profile you guys would recomend for the stock fuel injection. I don't want to go too crazy or end up having problems with valve to piston clearance. I am using the car for track events once in a while but mostly as daily driver. So it needs to be streetable. I would prefer a profile that can be done by regrinding as opposed to welding up the cams.

I am thinking of going to send the cams to Elgin tomorrow.

Thanks,
Ingo

NineMeister

I suggest that you reprofile the cam to stock specification.

Our experience of welded cams is not good, I would never buy one again since the ones we had wore out and destroyed two sets of new followers in less than 2500 miles. In my opinion, if you can find a suitable cam have it made on a new chilled iron billet only.

Also understand that with stock rods & pistons the bottom end is only good for 7000rpm maximum (even with rod bolts), so there is a limit to what you can achieve with a cam change. We have seen 320bhp from a stock 964 cam, so I would save my money and spend it elsewhere, like on a good valve seat / porting job (but without increasing the port size).

Steve Weiner-Rennsport Systems

Hi Colin:

FWIW,...we've had excellent results for the past 18 years with Webcam's regrinding services. After well over 300 race engines, only one set went bad on us.

Indeed, Ingo should install better rods (Pauter or Carrillo) or at least ARP rod bolts to be safe.

With RS cams, RS intake valves, a high-quality valve job, and a decent heat exchanger/muffler system, that 3.6 will make over 300 HP.

Aftermarket valve springs & retainers are a given, too.

pzull

Steve,
Why is it that the 964RS with the above mentioned parts and a blue printed engine could only muster 260 bhp?

Is it porsche marketing dept at play again, given that the 964 3.3 turbo only pumped out 330bhp then and with the extra weight would have been slower 0-60mph if the 964RS was any more powerful. So was the RS purposely detuned? If so, would this be via the chip or somewhere else which could easily be liberated.

I ask this because my brother just bought the new Mini One base model which has been purposely detuned. It is identical to the cooper model (except for cometics) and he can upload a new MAP onto his ECU and get the same power curve. Done and dynoed.

J.PELLEGRINO

Ingo,fwiw....I have used camshafts from various suppliers.I have had good and not so good results from most.I have been using camshafts from Elgin Cam.I deal with John and he is always helpfull and responsive.As for 964 engines,they have a couple of grinds that work well.I have used their "super c2 grind and most recently ther "c2 sport" both with excellent results.Good luck,have fun,Jerry

PCar SBA

Steve, smog compliance is not an issue for me. The 74 cars are excempt in CA.

Jerry, that is the information I am looking for. Walt Watson who did my machine work also spoke highly of Elgin. I'll call them up later today.

All, I understand that the sky is the limit when it comes to hotrodding the 964 (Pauter, porting, polishing, titanium retainers, etc) but that isn't my goal here. I don't want to raise the rev limit. The reason I went with ARP rod bolts is that the engine might have seen previous high revs events that could have caused permant damage to the stock bolts. Who knows. I simply didn't want to take chances of a bolts giving in six month from now.

Cheers,
Ingo

Bill Verburg

The cams I am familiar w/ are the 993RS for hydraulic applications and 993ss for mechanical, both are slightlt hotter than stock yet stil compatible w/ Motronic. Both are nice street cams, some of the GE cams 60 and maybe 80 have been purported to wrok well also.

The problem w/ comparing cams is the dufferent methods for measuring them, some use seat to seat others use .1mm lift to .1mm lift and the mech vs hyd. issue throws another curve into the picture. I bought Webcam but Elgins were also recommended. The bigger sport valves and port clean up will also help a lot.

schubee

Ingo,

I was suggested to go with 993ss cams. I'll be going through a source who uses WebCams. They are not regrinds and will be made from a new billet.

NineMeister

Steve,
I am interested in your comments regarding your experience of various cams & manufacturers, please understand that I know Dema Elgin and I like the quality of the work he does, he did us a superb grind on a welded 964 cam that made 360bhp in lightly modified 3.6 964RS engine with standard rods and pistons. We were absolutely delighted with the results.

Unfortunately, some factor (oil?) caused premature wear of the new lightened followers within 2500 miles. So, Dema re-licked the cam for us and in they went with another set of new followers. A thicker 20/50 semi synthetic oil was used for break-in plus the usual graphite paste etc., fired it up and held it at 2000-3000 for 20 minutes, set idle to 1250 for the first 1000 miles. The result was dead followers again after 2000 miles. Since no-one I could find at the time (1999) could tell me what I had done wrong (Dema included) we eventually rebuilt the engine with someone elses billet cams. These are still in after 15,000 miles running on the same Jerry Woods springs.

As for the 964 engine, we get 295lbft & 320bhp from a standard (totally stock) RS engine on Motec, so why go to the expense of cams etc. for less power than this when the parts are not being fully utilised?

revolution993

Any suggestion guys i am thinking of going 993SS mechanical webcams 296/296 grind for my 964 3.8 build.
Anyone recommend these? And would it be worth it for the money?

Thanks