I still haven't adjusted the timing curve on the non-computer controlled (canadian car) HEI that came with the LG4 since I dropped in the 350. Under my xmas tree sits a new module and coil, (that i dont know about, hee hee) but I grabbed a set of springs to recurve the timing as well. Question: Which should I use? It comes with "light, medium, heavy" springs with "stock being closer to medium". The tech article posted here used a medium and a heavy spring, but isn't that going backwards? Don't you want to use a lighter spring for a quicker advance?

I'm running ~9:1 compression with a stock set of 882 casting heads, flattops pistons, decked block, yadda yadda. 94 octane gasoline is readily available in my area, albeit at a ridiculous price.

I can advance my base timing to ridiculous levels without getting a hint of any audible detonation (but, I have no knock sensor either, so...) so I would have to assume I'm not getting enough timing in as soon as I could.

If stock springs are "closer to medium" as this great package is telling me, I was thinking of trying a medium and a light spring, but I thought I'd stop by here first in order to prevent any "3 rocks in a coffee can" type of detonation I may cause with my bumbling.

Thanks guys, Merry Christmas.
Hype.

 

back to the top.....

im in the same situation

 

It sounds like you have the Mr. Gasket spring set? The tech article uses the Crane kit, which uses entirely different springs. One "heavy" and one "medium" spring in the Crane kit are still much lighter than the stock springs. In your case I'd try the light Mr. Gasket springs first.

 

Start with medium/medium. If you don't get any pinging..try light/light. If still no pinging..then wonderful.

Be sure you have yout total timing set first tho, or you'll just have to play with the springs again when you do.

 

Wahooo! Somebody replied!

Actually, its the Moroso set. The light springs are rated as such:

1500 RPM - 6 deg.
2000 RPM - 8 deg.
2500 RPM - 14 deg
3000 RPM - 16 deg
3500 RPM - 18 deg
4000 RPM - 20 deg.
4500 RPM - 22 deg
5000+ - 24 deg.

Where as the medium springs go like this...

1500 RPM - 0 deg.
2000 RPM - 2 deg.
2500 RPM - 4 deg.
3000 RPM - 8 deg.
3500 RPM - 10 deg.
4000 RPM - 12 deg.


Anyway you get the idea. If that is stock, it seems a little too sluggish for max. performance. I bumped base timing from the stock LG4 4 deg (non-comp) to 8 degrees and there was a noted SOTP improvement.

I will try the light springs tomorrow with a tank 'o 94 octane just to be safe. For 15 bucks, I can't believe I didn't do this sooner.

Later,
Hype.

 

Here is the best way that I know. Get a timing light with the adjustable **** and check the timing at idle and at 3k rpm's. Set the base timing to 10 to 12 degrees. (which ever your car still starts right up) Next make the timing reach 36 degrees by 3k rpm's by changing the springs to stiffer or looser. Looser for more advance and tighter for less advance. If you can get it to 36 degrees by 3k and rev it even higher and doesn't go over 36 your good to go. It'll take a few tries to get this right but is well worth it. Also, if you have a vacuum advance on the distributor you can adjust that with an allen wrench. You can set the advance to come in fast or slow. Disconnect the vacuum hose and stick the allen wrench in the hole of the distributor. Turn clockwise for quicker advance and counter clockwise for slower. Coming in too fast will cause detonation. You can get one of these timing lights at Sears or at a parts store. Good luck!

 

Ugh... even the "light" springs in the Moroso set don't sound all that great.

 

Apieron is right. All the advance should be in by somewhere in the 3,000's.

 

The Moroso kit sucks. That's why I talk about the Crane kit in the tech article. The Moroso springs are designed only to work with the Moroso advance weights and centerplate. If you use them with the stock weights and centerplate I don't know what kinda curve you'll get.

The stock weights and centerplate work fine for performance (assumign they'r in good shape and not worn out), it's just he springs you will want to upgrade.

 

After comparing the Moroso kit to the Crane kit, the timing curve on even the most aggressive set of springs is definitely tamer than Crane's.

As for having your timing all in, are you not supposed to shoot for 20 degrees centrifugal advance at ~3,000RPM or so? The kit I have here will give me 16 degrees, which apparently is better than stock at around 8 degrees.

Since I have this package lying around the house now I might as well chuck it in, it does come with weights and a center plate, BTW.

As it stands now the timing curve must be pythetic, (actually it FEELS pythetic) as I can advance the base timing to the point where the car has trouble turning over, yet will not ping on 87 octane with 9:1 compression using crappy 882 heads with supposedly equally crappy combustion chambers. I should also note that my EGR has been removed, and I am using the stock vaccum advance canister.

Timing is something that I have never really ****ed around with myself, any light would be appreciated, of course. =)

Later,
Hype.

 

The stock weights and centerplate should give you ~20* of centrifugal advance with no modification. Not sure what the Moroso kit will give you.

If your stock stuff isn't giving you about 20* then either the centrifugal advance is gummed up (the article talks about how to fix this) or there is something worn/bent/broken/wedged in there.