Hot, Hot, Hot

[Jim Downard]

O.K. everyone. Here's the situation. My headers are running rather hot. Last spring I installed a 393 stroker. As per Don Scott's reccomendation, I installed a comp cams camshaft of his spec, and I'm running a performer RPM manifold with an Edelbrock 750 cfm carb. I just recently converted the old Duraspark II iginition to an MSD 6AL with MSD billet distributor. Timing is between 5-8 degrees at idle, and 30 degrees total. I do not have vacume advance. I've been told that most Edelbrocks come out of the box with nearly perfect A/F ratio. I've gone 16-20% richer in cruise and power modes and have plugs with a chocolate brown to little lighter than chocolate brown. Headers are Jet Hot coated and have been hot enough to cause the coated surface to roughen up. All valves had been adjusted as follows. I tightened rockers down until slop was out of rocker. Then went 1/2 turn more for preload. Engine has a 165 degree thermostat but has been running around 195-200 with fan on all the time. Air temps in upper 80's. At highway speeds water temps still around 180-185. Still, heat from headers makes me not want to drive the car until winter. My next step is to wrap headers with insulating wrap. Oh yea. Has a brand new double roller timing chain and the cam had been degreed. Maybe this is the way it's supposed to be. O.K. guys, give my your input.

Jim Downard

[Hotfingrs]

It's the MSD box that's doing it....Last spring I put an msd box on, and within 15 mins of idling in the garage trying to get things right..my chrome sidepipes were purple...the headers were already wrapped. The system is burning more effect because of the multiple sparks at low rpms...I found that I had to go up 2 jet sizes on my holley type carb..You should put in a new set of plug, so that you can tell what your engine is doing..

[Jack21]

Gut tells me retarded timing. Fuel charge being ignited too late producing more heat, but less power. To compensate, you're adding more fuel (which makes it worse) when you should be advancing the timing. Initial should be 12 - 14 deg, with 20 deg centrifugal all in by 2300 - 2500 RPM.

If you're using a hydraulic roller, look for 15 - 16" vacuum at idle.

You should be able to hold your hand an inch or two from the coated header with the engine idling, and it should feel warm, but not hot so you'd have to pull your hand away.

[dscott]

Jim, I would put the timing at about 35 degrees @ 3000 rpm. Don't worry about the timing at idle. You didn't say if the car is running poorly or if you are just getting heat inside the cockpit. Normally I use a heat insulation under the carpet to keep the engine heat at bay. It will get hot on your feet otherwise. It's very common to have interior heat on these cars. That's where the insulation works great. The problem is probably more in the timing area though. High heat at the headers is usually a sign of the timing being off. If the carb was lean you don't normally see a problem until higher rpm.
Don