bunker

12370847 - Hydraulic Roller Cam - 234/242 duration - 539/558" lift

How many degrees advance is it? Like I know most of our LT1 cams come with 4* of advance ground into them what about this cam?

Injuneer

Why not put LT1 cam questions on "LT1 Tech"? Moving......

LJ93Z28GM

This is a really nice cam, buddy had it in his 95 Z with a set of heads and went real low twelves with no tuning at all except for a raised idle.

Not sure what your goals are but you might want to decide that before you go for such a large cam. It comes out to just under .600 lift with 1.6 rockers. It was still streetable but just barely.

You can set the cam at whatever degree you feel is needed for your setup when you install it. It takes a little work and knowledge.

Dr.Mudge

Since it wont work with the Optispark if you play with the advance/retard, then yeah it would take a "little work."

I forget what the advance ground in is, I'd call Jason and maybe you can find out from there?

LJ93Z28GM

I have seen setups to let you advance or retard cams on LT1's.

There was a GTP cam that was ground incorrectly so it was needed to obtain proper advance.

WS6 TA

Why do people say this?

All you need to do is advance/retard the ignition timing in the PCM program and all will be happy again...

anaik

What about the timing of the injector pulses. It's much more complicated than you think. I have been on this board for a few years and have seen discussions on this subject. Nobody, from what I've read has had satisfactory results from physically altering the cam to crank timing, and these are people that have knowledge that I envy. It is much easier to just have whatever timing you have in mind ground into the cam. But then I might have missed something.

96ltz

What about the timing of the fuel injectors? Can you advance/ retard them?

WS6 TA

Here's a dyno graph of one from yesterday (convinient timing, he just put it up this afternoon)

Quoting the owner:
"using a Cloyes Hex-A-Just timing set (where I have 5 degrees advance for the cam) require you to pull 5 degrees back out of the LT1 timing tables"

If you really think that changing injector pulses by a few degrees will make any difference, well... at WOT most of us are running 85-100% DC, in other words, each of the injectors are open for 612-720* of crank rotation, and if such a small change would make any significant change at idle wouldn't you expect a batch fire setup not to work at all, would it?

Kraest

If it's a 112 LSA, more than likely it'll be ground on a 108 intake centerline, giving it 4 degrees of advanced..... Not sure about that cam specifically, though.

You can run any cam in the LT1 as long as you install it straight-up (dot to dot), regardless of the advanced/retard ground into it.


Mike

bunker

Cool, just saw my own thread now LOL. I'm wondering how many ppl tried degreeing their 847's & what they came up with for ICL installing the cam straight up, or any cam for that matter on our LT1's, thanx guys. I want to degree mine & see where its at.

matt.

atljar

The ICL of the 847 is 107, so 5 degrees.

Anyways, as said if you are physically adjusting the cam, you play with the timing tables to compensate. The injector issues are pointless. At WOT, they are firing so fast, it doesnt matter "when" they fire.

As for proof.... my buddies 396, fastest m6 NA LT1 in country (10.7 something at 131+), has his cam 4º advanced using the cloyes chain.


~Jared

bunker

Yeah I understand the whole timing issues with ignition, & also I understand how injector pulsing really doesn't matter especially at WOT LOL

I just emailed you bro can you check your email ? I emailed you before even posting & guess who replies

yeah I just found out its on a 107 ICL, I pluged the numbers into desktop dyno 2000 & it said 107icl.

I'm thinking of retarding my valve timing to help power & move up the power band slightly.

Did you check what you were dialed in at when you put your cam in? & did you put it in straight up?

Check your email Atljar.

Thanx, Matt.

InjectedSS

You are WRONG... Valvetrain Timing and Ignition Timing are TWO COMPLETLY different thing's

bunker

TTT

hopeing for more of Atljar's insight.