M30B35 aftermarket cam timing questions

[tfritz]

I have a '90 e34 M30B35 that I have recently taken apart to fix a bad head gasket. Now it is time to put everything back together and I have some questions on cam timing.

I purchaced a Korman adjustable cam gear initially planning on having it to advance timing back to factory specs after decking the head but after only having a small amount removed I find it unnecessary. Therefore I am wondering about the advantages it can give me by advancing vs. retarding the cam timing.

What is the proper way to set camshaft timing? -degree the cam? What all is needed and involved?

Will there be any gains from advancing/retarding the cam from factory specs?

Given my set up (below) would you reccomend changing the timing out of factory specs? -to benefit the upper rpm range or the lower rpm range?

For some back ground I have done/have the following:

Resurfaced head (not a significant amount removed, you can still vaugely see the old gasket outline)
Reground valves
new valve seals (guides checked out within specs)
port matched
Ireland Engineering Dual Race valve springs
IE race rocker arms
IE 292 reground cam
oversized eccentrics
Korman adjustable cam gear
Factory Head gasket
ARP studs
Miller MAF
Miller WAR chip
water pump
and a slew of other odd and ends.

I can turn wrenches but when it comes to this technical stuff I am counting on you guys. Any information or suggestions are much appreciated!

[thesixerkid]

With a 292 and some beefy rockers you can spin that motor per high. You are going to want to retard the timing for high RPM use to optimize combustion chamber filling at high rpm. Throw a short diff in the back and it will be a rocket.

The only way to set cam timing is to do on a dyno. I wouldn't do it any other way.

Cam timing just affects where the motor will make power. Proper cam timing in addition to modified duration cams can big differences in power (both in loss and gain).


A word of the wise, one of my sixer buddies has the 284 regrind on his M90. The engine lost a lot of low end grunt with the new regrind, but make damn good power above 5000rpm. Just something to think about.

[paul burke]

Can you post the spec. sheet on the cam? I am curious about the lobe displacement angle (centers). After I know more about it I may have some suggestions on how to install it.

Paul

[tfritz]

I received a spec sheet from IE but I can't seem to post it up

[tfritz]

here we go.

[paul burke]

tfritz, you have a PM

Paul