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Which Cams? Original or not?

H

h_____

New member
Folks,

So my engine is in peices with the good guys at RPM. Been to see it this am, and there are a few things that need sorting. Not least of which is that I need at least one new cam (possibly 2 when they strip the other side). So I have a choice put original parts back in, or tune slightly for top end power (its a track car!).

I *think* I've decided on original, but please debate my logic. I plan to keep the car the car pretty much standard for everything on it. That means no throttle body conversions etc. I also plan to race it one day (i.e. at some point in the future) when it is eligible for something interesting and a bit more gentlemanly than say the AMOC series. Clearly I dont know when or what is coming, but I'm guessing it is likely that regs will require standard cams? What are peoples views on whether that is right? How much do people know about what is allowed in appendix K for example? I've probably got some leg work to do on the FIA site I suppose, but thought that this group of highly informed people might have a view! [:)]

Cheers

hugh
(missing his car!)

 
Broken piston rings on 2 cylinders - correctly diagnosed I might add.

No gravel found. Always better to find gravel than bits of Armco I say!
 
h_____ , a few "while you're in there" bits...... you may as well take the opportunity to change the rod bolts for ARP and upgrade to titanium springs and lifters. Whilst not adding anything directly, upgrading these bits gives you a bit more head room on the rev limit. With those bits done you can safely rev to over 7k, which might allow a "save" on a missed shift, and to my mind just buys you a bit of peace of mind. A bit of porting and polishing of the heads can liberate a few more ponies. Send it over to Wayne Schoffield at Chip Wizards for a remap (which you can always get put back to standard if you decide to go racing). Without too much effort or anything difficult to reverse you can get to 300bhp (I am discounting MoTeC emgine management at this point).

If you are looking at enigne "trinkets" you could do a lot worse than talk to Colin at 9m, who can replace just about any engine component with an upgraded equivalent. Budget is your only constraint here !

Jamie
 
Jamie thanks for the advice. Anyone have any idea if FIA regs get interested in things like titanium springs and lifters, its a bit of guess at this point, as I dont really have a class I'm aiming at, just think about the types of things the current historics get regulated on. Head work may be a good idea. Budget is indeed a big constraint!

So current view is keep the cams standard.
 
h_______, I think you are only likely to get the best out of changing the cams if you remap to suit (and upgrade some of the valve train parts). So unless you intend to go the "whole hog" I would be inclined to go for stock cams. With MoTeC on my car and the Ti bits I mentioned above, my car is running 335bhp. Cams on top of that might get me to 350bhp (I have a friend with a very similarly specced engine with cams that is putting out 350bhp on MoTeC). I decided to stick with the stock cams as my car is used on road as well as track, so a tractable engine was more important to me than outright top-end perfromance.
Colin is now getting comfortably over 400bhp out of a 964 engine, but the costs increase exponentially to get there from where I am currently.
No idea what the regs might be on springs and lifters etc, but they are not directly "performance enhancing", so might be ok. At the end of the day who would ever know, though I accept that's not in the "spirit" of the rules !

Jamie

 
mine has those titanium valve springs,dont think it would be a problem,doesnt increase power just makes it safer to rev
 
Hugh

The one thing you must do is replace the cams, not just one of them. It would be an error to replace one only and would probably lead to an uneven,unsmooth engine. My RS runs non-standard cams and it is quicker at the top end but only a bit. Standard cams are fine and I wouldn't advise changing. Your money would be better spent on making sure care and attention is taken in putting everything back together carefully (you might find that the standard cams are more expensive than more aggressive but non-Porsche parts).

Damen
 
Sorry, yes should have been clear, if I replace one cam only it will be stock, so matched to the other side. I actually think that more agressive cams are pretty much the same price as standard cams.

Damen, what cams did you go with?
 
Hugh

I still think you need to replace them both at the same time, even if you only need one. Same age, wear, similar balance, manufacture etc, will make for a better engine.

Mine were fitted by 9m and the invoice states "Race Cams" but does not state the type. My car was the first MoTec +1 they did, and with these cams fitted has been dyno'd at just over 350 bhp (both at 9m and elsewhere), not that the figures matter at all to me (but it gives an idea of what's achievable). The engine being smooth and reliable as well as fast is just as important as big bhp figures. I also have all of the various titanium bits and pieces, which make a quick engine a bit safer too.

Damen
 
Thanks Damen, interesting advice. I am now torn on what to do. Spoke to a friend with a '65 2L car that is Appendix K compliant, it makes about 190bhp from a 2.0, so clearly not orignial internals. That potentially leaves some options open, who else has had engine work, what did you have done?
 
h
The fia are fine with any cams,i would stick with standard for reliability.
But if you want to hot it up a bit,9m did do a good mild version,i forget which now.But i went out in Russell Grice old yellow 964 rs,it was dam quick around 340bhp with a cam change ecu remap etc
 

ORIGINAL: paul howells

h
The fia are fine with any cams,i would stick with standard for reliability.
But if you want to hot it up a bit,9m did do a good mild version,i forget which now.But i went out in Russell Grice old yellow 964 rs,it was dam quick around 340bhp with a cam change ecu remap etc
Click to expand...

Was that the yellow car with the black wheels Paul?

ps.. would love some pics of your RSR please.[:)] Tim says hello!
 
A lot of torque here, but how much ?

With Motec and a Wills Tip, Wayne gave me 317bhp and 307 Lb Ft of torque --- 6500 and 4800rpm respectively, and 103.7dB at Olton last.


 
Paul, many thanks for the advice. It looks like original is the way to go. I want the reliability, but I'll look into the titanium springs/lifters for a safetly net. I think gaining 20bhp, isnt going to significantly help in the grand scheme of things.
 
Mat yes it was the yellow rs with black wheels,a dam good car.
I will send you some photos of the rsr
H i agree on power gains vs reliability etc Titanium retainers and fresh springs etc are a good idea,along with a crack test of rockers if they have done a few miles/high revs.
 
Going to replace rockers, the bushes looked a little worn, so new rockers and springs all around. Funny isnt it, rockers arent that expensive, but all soon starts adding up.
 
You must be itching to get her back h___ ,especially now the evenings are long and the weather is good!
 
[:eek:] indeed I am, I was supposed to be going to the goodwood breaky club on sunday to meet some mates in it. They were looking forward to seeing it. Now, I've had to drag the Morris Minor out of the garage to be MOT'd instead. [:)] Two cars couldnt be quite so different.
 
But you also couldn't have chosen a more enigmatic alternative --- other than (possibly) a 2cv !
 
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