Whats the best Cam timing for the 964 cams in a 3.0

[pcar9119]

I'm timing my cams tonight and want to know the best timing for them. I'm running carbs and headers. I have installed a COP ignition system too. Can you guys help?

[Flat6pac]

1.26 is spec. You can go to 1.40
Bruce

[boyt911sc]

Originally Posted by Flat6pac

1.26 is spec. You can go to 1.40
Bruce

Bruce,

What would be the differences between these two (2) settings. For example an engine set @ 1.2 mm compared to another with the higher lift of 1.4 mm. What power band characteristics each of these settings exhibit? Thanks.

Tony

[Flat6pac]

When the number is lower, 1.26, the engine produces power at higher RPM and the 1.40 would be more power in the lower RPM.
You can see this more readily in the SC engines. The 78/79 8.5 compression, off my memory, the euro sets at .9 to 1.1 and the same cam sets for USA 1.5 to 1.7. The USA car needs performance to 100 mph while the euro needs power to redline.
Bruce

[pcar9119]

Thanks! But that isn't how was thinking thr number would be. I was expecting a different measurement. So 1.26, what is that measurement? What would I measure it off of? Thanks guys!

[Gary.H]

I have a 3.0 Euro engine ('82 SC) with 964 cams that makes 232bhp right at the redline (6700). My engine rebuilder set it to the 'factory' 964 setting (only a single value for 964 cams I was told, not a band of values like 3.0 cams).

How can we be sure that the higher number, 1.4 (ie additional 'lift' ?) isn't going to cause valve/piston clearance issues !?

[rgoodrich]

Gary H, what other mod's does your Euro 3.0 have besides the 964 cams?

[Gary.H]

Originally Posted by rgoodrich

Gary H, what other mod's does your Euro 3.0 have besides the 964 cams?

Most of the mods were reliability, safety related tbh. 993T headstuds, Ti-retainers and race springs. Heads were lightly ported and the car has SSI's with a stock 2-in, 1 out Dansk backbox.

[kiwiokie]

^ Still running CIS with the 964 cams?

[Gary.H]

Originally Posted by kiwiokie

^ Still running CIS with the 964 cams?

Yes, you can't go 'much' more aggressive on the cams than 964 if you stick with CIS because of the reversion issues.

A couple of mates have rebuilt 3.0 engines with different cams (they both twin plugged theirs), both still with CIS and the power ceiling for 3.0 engines on CIS seems to be about 235bhp.

Another mate went Jenvey ITB's and EFI on his 3.0 and he's putting out 285bhp (IIRC)
Ditching CIS allows you to run much more aggressive cams and removes that ~235bhp ceiling.

[kiwiokie]

Wow, 285 even with the CIS pistons? That is impressive and certainly food for thought.

[Gary.H]

Originally Posted by kiwiokie

Wow, 285 even with the CIS pistons? That is impressive and certainly food for thought.

Nope, IIRC he's using 95mm JE's, 10.5:1 c/r, OMEX EFI

[ChrisBennet]

Gary-H,
How were those HP numbers measured? Engine dyno or ?
thanks

[Gary.H]

Mine or theirs ? All using respected wheel roller dyno's.

We've done the whole 'Who trusts dynos ?' thread.

The dyno's have consistantly provided reproduceable results and are used as 'Control' dyno's by several British Racing teams (in case that's where you're headed with this )

[ChrisBennet]

Originally Posted by Gary.H

Mine or theirs ? All using respected wheel roller dyno's.

We've done the whole 'Who trusts dynos ?' thread.

The dyno's have consistantly provided reproduceable results and are used as 'Control' dyno's by several British Racing teams (in case that's where you're headed with this )

Not trying to be argumentative, it's just that (flywheel) hp numbers derived from wheel dyno numbers are just estimates. They are fine for comparing things or tuning but (as we both know) the wheel dyno numbers are only a very rough approximation of actual hp so my question is something along the line of "what units are we using?".

To clarify, are we talking rear wheel horsepower or estimated flywheel horsepower?

thanks!

[Gary.H]

Originally Posted by ChrisBennet

To clarify, are we talking rear wheel horsepower or estimated flywheel horsepower?

thanks!

No worries Chris, engine horsepower.

Anyone got the answer about possible valve and piston interferance at the higher cam lift values ?