Lock timing or no?

[MILD THUNDER]

When I pulled my caps and rotors today, i found the mechanical advance rusted to the point the weights were stuck in retard mode. Its been a while since i had the rotor off, i guess its safe to say that wasnt good for power. It would be cheap to just keep the current setup, but...

Anyhow, the setup is a 454, 236/246 roller cam, weiand 177, and dart aluminum heads. Compression around 8.4:1. I have the MSD marine boxes, and rev limiter, and pro-billet distributors.

Should i just go ahead and lock out the timing say at 30*? What about starting issues?

A buddy of mine has this similar setup, with locked timing. He has push buttons for the starters, and a separate toggle that powers his ignition up. He cranks the engines then flips the power on to light the motors.

 

[WETTE VETTE]

I've always run locked timing and never have had problem.

 

[Chris]

You have a maintenance issue. Clean it up, keep it maintained and run with it.

Bringing in full timing at low RPM on a heavily loaded engine can bring on detonation very easily. And when you're straining to get on plane, it's easy to not catch it. Having undersized blowers that spin really fast and add alot of heat to the intake charge definitely doesn't help.

 

[BUIZILLA]

+1

 

[WETTE VETTE]

You have a maintenance issue. Clean it up, keep it maintained and run with it.

Bringing in full timing at low RPM on a heavily loaded engine can bring on detonation very easily. And when you're straining to get on plane, it's easy to not catch it. Having undersized blowers that spin really fast and add alot of heat to the intake charge definitely doesn't help.

With that large of cam in a small CI low comp motor and a small blower I'm thinking that it would really like the extra timing down low. I've seen everything from NA 350's, NA 632, 598, 604, 8:71 roots 509, 565, 598 chilled and un chilled, blow thru 565, etc run with the timing locked and never once heard of issues with detonation per the description above.

I have seen some motors idle better with a curve, but most really like the timing at idle as well.

I do agree with Chris however regarding not changing something drastically just because its time for a little maintenance. If your only motivation is the corrosion factor get some new springs, clean it up and let her eat!

Craig

 

[Chris]

I mostly agree- it's borderline. But that 177 is tiny and to use it on a big block, you have to spin it fast. That means it's really warming up the intake charge.

 

[MILD THUNDER]

Think im just gonna keep the setup i have. Motors idled fine, no issues there. Just gonna clean it up and put some fresh springs in and call it a day.

 

[Airpacker]

There is no good reason to run locked timing and a few not to.

Idle quality and speed is easier to control with lower initial timing. Starting a hot motor with 30* of timing can wipoe starter motors out pretty quickly too. One good kick back and the drive end housing can crack. I tend to set the curve up to start advancing around 1800 and be all in by 2500 on a marine engine. Done hundreds of distributors that way for various engine and marine shops and never an issue.

 

[Chris]

The MSD's are known for this issue. When I use them, I pull the shafts and dry-film coat the tops of the shafts and the weights. If you have access to a hand-held sandblaster and an airbrush, it's easy and cheap.