Rebuilt 196 running hot.

[Michael Dimock]

I have a 1962 International Scout with a rebuilt ic 196 out of a Scout 2. It is running a 260 grind performance/towing cam, has a cast iron delco distributor with dwell set at 75*, new coil, plug wires, and points with about 1000 miles on them. The distributor has been shimmed to reduce the shaft endplay. I'm running a Holley 5200 carburetor that has been rebuilt by m mayben 9 or so months ago. The gas in the tanks is 6 months old, so I'm unsure of how good it is. I finished off one tank and it now has a gallon of new gas in it. I just switched the engine over to run off of that tank.

It seems to be running lean/hot as after about 5 minutes the exhaust pipe and manifold begin to start glowing. When I drove it down the highway a couple miles with the engine under load the manifold cooled down to a very dull red/barely visible glow.... Continuing on, I've tried multiple positions of the distributor and all result in the manifold glowing. Sometimes when I shut it off, the engine will run and fire a couple times and then run quickly backwards.... This is caused by retarded timing and excessive unburnt fuel correct? If that is the case, shouldn't my exhaust temps be low enough to not cause the manifold to heat up excessively?

Can this $#!%y ethanol gas degrade enough and absorb that much water that it will cause my engine to run excessively hot? I haven't run enough of the new gas through it to make a difference yet, as it was already glowing when I switched it over....

 

[Robert Kenney]

The glow is either retarded timing or super lean afr's. Retard style ignition timing is my first guess.

on an outside chance the cam timing can cause it eg way advanced so the exhaust valve opens up early. I really doubt that seeing as mm over saw the build.

 

[Michael Dimock]

I guess if I remembered all my schooling down at binder u. I wouldn't have to be going through all this..... well, I'll advance the timing and most likely see my glowing manifold go away! The new gas might help too!

 

[Michael Mayben]

Did you double check the cam timing/gear install???

Since I wasn't there when ya stuck the cam in the holes and installed the cam drive, I won't swear it's correct!

Fresh fuel will certainly help any engine perform, but that's not your problem if it starts and runs.

Need to read the manifold vacuum at idle measured right off the fitting on the side of the intake, no need to disconnect/bypass the wiper vacuum pump since ya ain't running that side mount fuel pump.

Idle rpm should be 550>600, a curb idle speed much greater than 650 rpm or so on these engines will create a "run-on" or dieseling condition.

Your ignition spec (dwell) will remain the same as oem, no need to change that. But set the base timing to 5*btdc on the light and try that. Use the light, do not perform the power timing deal at this point until we work through the issue.

What is the coolant (engine) temp reading when this occurs? Do you have an infrared thermometer to check temps at various points?

Since the motor now has a bit of time on it, I'd like for ya to post both cold and hot compression readings.

 

[Michael Dimock]

Well $#!% man, do think I have all that snazy stuff? I advanced the timing and all is well. I was running 190 before and now I'm running 180 like it's supposed to. Manifold and exhaust have ceased to glow. If I just thought about it, retarded timing = later in the time the plug fires I wouldn't have been second guessing myself. It now runs excellent with a nice throaty idle set at 750 rpms. Before it was definitely dieseling on and off if I dropped it below a fast idle. The dwell was also a little low at 68 before, so that probably also contributed. I made sure that my timing gears were set up right. I really need to make a trip to harbor freight to pick up a cheap compression tester and timing light. I forgot that my old, small engine analyzer had a dwell meter on it. It was well worth the $20. Thanks for all the help, and once I get more drive time on it I will post some more info.

 

[RobertC]

I am sure you remember from binder u that you set the dwell before you set the timing...

Glad you have the engine running cooler...

 

[Robert Kenney]

I advanced the timing and all is well. I was running 190 before and now I'm running 180 like it's supposed to. Manifold and exhaust have ceased to glow. If I just thought about it, retarded timing = later in the time the plug fires I wouldn't have been second guessing myself. .

Glad you got it fixed.

no snazy stuff needed, just a observation based on the facts you provided. You were probably 15-20 degrees redarded (no pun intended)

and the fact that egt's lowered under load was further evidence