Hi Guy's

I just did a search, but didn't really get what I was looking for. My 454 has gotton really tempermental when I try to start it. I thought I was having problems with fouled plugs, but I just found that my distributer is a little loose and now I suspect that the timing has slipped. Once I get it started it seems to run fine which has me baffled a bit though. I hear you all talking about total timing around 36' Forgive my ignorance, but I don't understand what this means. I thougt that I would set it at 4 or 8 BTDC or so ? I don't have a vacuum advance. It has a MSD6AL, MSD Pro billit distributer. The Cam is an ISKY RR-620 solid roller and I'm running a holley 950 HP. Please post with your reccomendations for my timing, thanks much..

Garry

That MSD distributor comes with instuctions on how to set the advance curve depending on your application/power curve by changing springs and things. All the advance should be in by 3000 rpm. I think you need more initial advance, 12-14 degrees should be safe, I have set mine as high as 16 initial.

Mike

I put the timing light on it this afternoon and tried a few different settings. At 10,12.14 BTDC
it seemed to idle a little faster but when I shut it off it would detonate for a bit. I backet it off to 8' BTDC and it shut off nicely with no detonation, and started right away on the first crank. So, I have tightrned the distributer at 8' BTDC and it idles nicely, shuts off nicely with no detonation. I didn't take it down the road thouge due to a lake of time. I still don't understant what is meant by 36' total timing, other than I think it is where the timing is at a faster idle. The problem I have is my timing plate only shows 4',8',10,12 & 14' BTDC. How do you measure 36' aty a faster idle ? Can someone please help me understand ?

Also, does it sound like I have set my timing correctly at 8' BTDC at idle ?

Thanks,

Gaz

TTT, Anyone ????????

Gazzer

distributors have a mechanical advance mechanism that advances timing as rpms rise.

the initial timing (checked at idle) is the start of your advance curve. initial timing plus mechanical advance equals total timing. so if you had 12 initial and there is 20 degrees mechanical advance in the distributor you would have 32 degrees total timing.

you need either a timing tape installed on your harmonic balancer or a dial back timing light. there is also a formula you can use to mark the balancer at the 36 (or any for that matter) degree mark and so on.

to check for total timing you will have to raise the engine rpms until the distributor has reached full mechanical advance, which is usually around 3000rpms or so. while watching the timing marks with the light you will see when they stop advancing.

to get the initial timing and total correct you may end up having to limit or increase the amount of mechanical advance. for example, if you want 10 degrees initial timing and 38 total you need 28 degrees mechanical advance.

Brandon,

Thank you for the explanation. It sounds like a dial back timing light is the way to go. My engine starts,idles & shuts off best at 8' initial. If I find that I need to adjust the total timing for optimal performance without changing the initial, di I need to change something mechanical in the distributer ?
Unfortunately, I didn't purchase any of the ignition parts on the car or I would have kept the operating / tuning instructions.

Thanks for your help

Gaz

If you have an MSD system, call Autotronics (MSD) and I am sure they will send you the springs, stop button, etc and they probably will do it for FREE. They used to be good about honoring their products with good service. What MSD part number is it? I have the instructions for the 85551.

Mike

Gaz

here is the advance kit for msd distributors

http://store.summitracing.com/default.asp?target=partdetail.asp&part=MSD%2D8464&N=120+4294925143+4294925140+301084

here is the instructions for msd distributors from their website, check out pages 2 through 4.

http://www.msdignition.com/pdf/pn8360.pdf

to change the mechanical advance you will have to swap the advance stop bushings (included in the kit above) as shown in the instructions.

to change the rate (speed) at which the advance comes in you need to change the springs. you want timing "all in" by 3000 rpms.

glad i could help

Gaz

something i wanted to add, while i have never used a 6al box or one of msd's distributors i have heard that the 6al box will give you problems when using a dial back timing light. i believe msd actually makes their own timing light that is compatible with the 6al, not sure if its a dial back unit. before you buy one i suggest you do a search here or post a question regarding this since these lights are fairly expensive.

Brandon, Mike,

Thank you for the information, I will take what you have shared and proceed ahead.

Cheers, Gaz

Hey Gaz...
I'd just like to suggest that you "play" with your timing and take the car out for a spin. Set it at 8* and drive it around. Then advance it to 10*, drive it around, etc., on up to maybe 12-14* and see where your motor likes it best.

How do you know your motor was detonating? Did you hear any pinging while driving around? If the motor still "runs" when you turn the ignition off, turn it off in gear. My car does the same thing, and I was told just to turn it off in drive and I'd have nothing to worry about.

LSX,

I also plan to do what you suggest, It will help get to know my engine a bit better as well.

It has never pinged on acceleration, just spittered and sputtered when I shut if off, And that is anoying to me. I would shut it off in gear with the chutch depressed and let it out just as I turn the key off to avoid it. It really sucks when people see the Chevelle, make comments like "Sounds pretty healthy" etc. and then it does that spitter sputter fart burp thing :mad:

I'm sure there is a sweet spot in the timing, both initial and total that I just need to find with everyones input.

Cheers, Gaz

Outch!!! Yeah I hear ya! That spitter spatter part is annoying!!! I didn't know you had a man trans. I'd guess that you'd probably have to let the clutch out a bit with the trans in gear then turn the ignition off so that it won't continue to run after it was suppose to be off. I guess that's one of the advantages(?) of having an automatic tranny :confused:
Well I hope you get things figured out and fixed! Good luck and have fun playing with your car!!! :D graemlins/thumbsup.gif

...by the way...just wanted to add something....

When you advance your timing, the idle will always raise, as well as when you retard your timing, the idle will drop. When you advance timimg, just adjust the idle adjuster screw on your carb back to your desired idle speed/rpm smile.gif