Moparts

Total timing. Need distributor advice.

Posted By: Magnum

Total timing. Need distributor advice. - 08/17/08 12:45 AM

Ran my pick up in time trials today. It's a 87 Ram with a 5.9L Magnum straight from a 2500 Van. 670 Holley, M1 dual plane, shortie headers. Behind that is a wide ratio 5 speed manual. 4:1 1st, 1:1 4rth.

It's 4000lbs, 3.55's with a 28" tire.

I've slowly advance the timing from a conservative 28 deg to 32. It went from 15.11 @ 90 to 14.80 @ 91.5 mph.

Here is where I need your help. It ran it's fastest and quickest time rattling in 4rth.

Backed it to a safer 30 deg but it slowed to 14.94 @ 91.5 and I want my tenth back.
Posted By: RapidRobert

Re: Total timing. Need distributor advice. - 08/17/08 03:57 AM

maybe richening it up a bit & colder plugs & see if that would let it tolerate that extra 2 degrees. You for sure don't want it to be pinging.
Posted By: Anonymous

Re: Total timing. Need distributor advice. - 08/18/08 12:15 PM

are you running premium?
Posted By: Magnum

Re: Total timing. Need distributor advice. - 08/18/08 04:31 PM

I've never opened the carb. So Rapid I do think some jetting is in order. The truck seems to run quicker when it's hot. Does this add up?

Cucu. The fuel is 87 octane. I thought about throwing in some booster or premium but I'm trying to set it up "as it's driven". Isn't 87 enough for a stock engine?
Posted By: Anonymous

Re: Total timing. Need distributor advice. - 08/18/08 05:00 PM

I would back down the timing or use premium.

If you have vacuum advance hooked up, that can increase your total timing way above what you think you have at part throttle cause the total mech adds to the vaccum.

You could try disconnecting the vacuum advance and trying it with the 87.

btw, a tankful of premium is about $3 more than a tank of 87
Posted By: RapidRobert

Re: Total timing. Need distributor advice. - 08/18/08 07:16 PM

Quote:

I've never opened the carb. So Rapid I do think some jetting is in order. The truck seems to run quicker when it's hot. Does this add up?


I cannot say for sure. Better gas would be the easy way out but where would the fun in that be.
Posted By: Paul_Fancsali

Re: Total timing. Need distributor advice. - 08/18/08 08:32 PM

I run my 360 at 200 degrees run best at that temp. However you must run premium 93 or they will ping By the way get the timing to close to 36-40 and that truck may click a 14.6
Posted By: Mobarge

Re: Total timing. Need distributor advice. - 08/18/08 11:33 PM

I'm running 38* total and have to run 101 octane - go with the premium gas, and try 34*
Posted By: dgc333

Re: Total timing. Need distributor advice. - 08/19/08 05:52 PM

Quote:

I would back down the timing or use premium.

If you have vacuum advance hooked up, that can increase your total timing way above what you think you have at part throttle cause the total mech adds to the vaccum.

You could try disconnecting the vacuum advance and trying it with the 87.

btw, a tankful of premium is about $3 more than a tank of 87



Vacuum advance won't have any impact on WOT throttle acceleration because the intake vacuum is close to zero well below the point at which the vacuum advance would add timing.

Magnum heads are much more efficient than open chamber LA heads so you won't need as much timing. I run my 360 with magnum heads with 33 degrees of total timing.

You never said at which rpm you are getting detonation. If it is in the lower rpm range going to a stiffer spring in the distributor will bring the timing in slower. If its above 3500 rpm then its likely to much timing for the combo.

I agree, in my area there is a $0.20 difference per gallon between 87 and 93 and I typically but 14 gallons in when I fill the car for a $2.80 difference.
Posted By: Anonymous

Re: Total timing. Need distributor advice. - 08/19/08 07:35 PM

Quote:



Vacuum advance won't have any impact on WOT throttle acceleration because the intake vacuum is close to zero well below the point at which the vacuum advance would add timing.





very true but at part throttle cruise it does.

I personally do not run vacuum advance
Posted By: dgc333

Re: Total timing. Need distributor advice. - 08/20/08 12:36 AM

Yep but the original poster is having detonation issues at the drags where I would assume he is running WOT.
Posted By: Anonymous

Re: Total timing. Need distributor advice. - 08/20/08 01:55 AM

then put some premium in it and be done with it
Posted By: RobX4406

Re: Total timing. Need distributor advice. - 08/20/08 02:31 AM

If it's rattling in high gear, I'll bet it's rattling in the others as well. You just can't hear it.
© 2024 Moparts Forums