Overheating after Distributor swap

mustang_12

New member
Hello all, after the past months i have been working on some small engine updates. Those updates include a full exhaust from header to knockoff flowmaster muffler, new timing chain, new HEI style distributor. I swapped the LOM due to the advance not working at all after several tests and the timing would flicker from the mark bad. I put in the hei and my 200 was completely different, better acceleration and driveable. I was able to go 70-75 easy with alot left on the freeway. Since making the switch ive used my car maybe 7 times, 2 car shows and several easy country road runs. On all occasions the temp has gone up to overheated and the radiator boiling over....had to stop serveral times to check it out and the oil pressure would come down...guess from the engine being too hot. Also one night at 12am coming from a show had the car shudder until it couldnt drive anymore. Not sure if the carb vapor locked of the plugs got to hot to fire. I know it has to do with the distributor for sure. I have it set between 10-12 degree and its solid....great advance. Do you think the timing is to hot and i should back down? To what? I feel like just going back to the broke LOM just to be able to drive.
 
Typically overheating due to timing would be retarded timing. It sounds like you are in a reasonable range @ 12 deg advanced. Might be time to do a head gasket leak test on the radiator.
 
seems like an innumerable amount of things could B goin on (or not). Not sure how long it sat B4 U began these changes. Can U fill us in on that? what was the use/running like B4 the changes?

A (triple, real good) flush may help. Re-fill w/the correct 50 50%.

Also reading the 6 plugs can help w/several 'mis-functions'.

I didn't C any components listed in sig or post (but a 200'n DUI). What carb do U have?

"...on the radiator..."
pump her up!
 
mustang_12":3fi5jqb1 said:
Hello all, after the past months i have been working on some small engine updates. Those updates include a full exhaust from header to knockoff flowmaster muffler, new timing chain, new HEI style distributor. I swapped the LOM due to the advance not working at all after several tests and the timing would flicker from the mark bad. I put in the hei and my 200 was completely different, better acceleration and driveable. I was able to go 70-75 easy with alot left on the freeway. Since making the switch ive used my car maybe 7 times, 2 car shows and several easy country road runs. On all occasions the temp has gone up to overheated and the radiator boiling over....had to stop serveral times to check it out and the oil pressure would come down...guess from the engine being too hot. Also one night at 12am coming from a show had the car shudder until it couldnt drive anymore. Not sure if the carb vapor locked of the plugs got to hot to fire. I know it has to do with the distributor for sure. I have it set between 10-12 degree and its solid....great advance. Do you think the timing is to hot and i should back down? To what? I feel like just going back to the broke LOM just to be able to drive.
12 degrees initial is not enough advance, but in your case the distributor was not recurved so you will have to live with it.
As Chad said time to flush out the entire cooling system. Take the radiator to a shop & have them back-flush it to make sure the tubes are not clogged.
Hope you didn't blow a head gasket or warp the head from over heating. Wish you the best.
 
before the changes it would run like a hog , no acceleration due to no timing advance, raw fuel smell and the last 3 plugs were always fouling out with oil. it would REV great, the temp gauge would never move far from the coolest temp reading, i always thought the gauge wasn't working until now. the radiator would never bubble from the heat. the radiator is a new 3 row and i have flushed the system a few times with the engine on and a water hose down its mouth, i took the thermostat out to try it out and replace with a lower radiator pressure cap and large overflow tank. since i put the new HEI in the plugs have clean but some read lean, but what can you do with a 1bbl on a log. I did a new oil change 3 weeks ago with some thicker weight to see if it hold oil pressure more after getting hot and it does. the old oil was clear as can be but did smell like fuel. i am running a 1bbl carter
 
What PSI is your cap? If you have a new 3 row I would use a 16lb. Try bumping up the timing a little.
 
Had a 16 psi on it then went down to a 13 psi to see if it relieved the pressure but doesn't. Ill try moving the timing around a bit or richen the carb up.
 
Just something simple. But, did you burp the cooling system to get the air out? Run the engine with the radiator cap off. But have the front of the car raised. Either on a sloped driveway or with a jack. Also have the heater on in the heat position.

Lastly. Does it only get hot when you drive? Does you lower radiator have a spring in it? What type of lower hose?
 
Imo there's never a need to run a 16# cap, straight water won't boil until 245*F with a 13# cap. Running a higher cap pressure is like asking for a gasket leak. The only time I use a 16# cap is at work when a boats water heater is above the engine and we have to install a "surge"(more like "fill") tank above that point. I'll replace the engine's heat exchanger cap with a 16# and move the 13# cap to the surge tank. Iow, the 16# cap is just to ensure the upper one opens first. The stock cap is 13#.

To parrot what 65coupei6 said, any air in the system will ensure an overheating situation and a boil over at the cap. I like the thermostats that have the air bleed hole in them. And parking facing uphill will definitely help with some car's depending on the height of the heater core and it's hoses.
 
we fill em w/the closetite funnel. None gets in.
May B nxt time, eh?
 
Well... great news...ill get to that in a bit. Yeah when i got the car it had that cap on the original radiator. As for the hoses they are the original style spring inside on the lower, still in great condition. They might be old stock ones even with original gates clamps that have a tapered screw. Ill get some photos. I had switched the water pump when i did the timing chain.

Now the news. Just got in right now after a few long test runs. I bumped the timing down from 12° to somewhere around 6° moved to carb idle and mix screw and bamm , smooth as silk, left it on for 20 minutes in the same spot of my garage where it boiled and now we are good. I could even put my hand a few secs on the radiator. I went for 2 40 minute runs... first one easy, last one stood on it and the gauge moved just a small tad if any from the C. Finally, guess it was just to much power out of that distributor or coil. The engine runs great where its at ...75mph easy and smooth, not sure what the deal is with that, i know the balancer is spot on. Tomorrow will be the test in 100° weather. It would boil at 45° weather, lol. I hope this is it so i can get my A/c update project going.
 
"... to much power out of that distributor or coil...."
swaped out the DUI?
Good on ya mate!
 
If I had to guess, I'd bet you had air in the system. There's no way tuning it to 6 btdc from 12 and adjusting the carb is going to make a damn bit of difference to the radiator or the temp. It may idle better the way it is tuned, today. And it may run better, today and on. But it's not the cause of your overheating problem. Atmospheric pressure, the temperature, the humidity, elevation, they all play a role in tuning a carb and the timing at any given moment. There is no set and forget. Its a compromise. You tune it so it will run ok in all conditions. Or you dick with it all the time. That's why we developed computers to do it for us. Anyone who tries to sell you on some perfect carburetor is ignorant, a liar or a fool. Some are better than others, but they're all static and set in their adjustment. The only changes or adjustments that happen automatically are controlled by the weather.
 
Hey,I LIKE dicking with it all the time.Keeps me out of the lazyboy,watching sportsball.At least I'm moving.I've got old Triumphs for same reason,oil puddle is a design feature.
Anyone north of Lamesa,Tx has no idea of the heat or lack of humidity.
To the OP,it'll be fine after it burps a couple times.But before it does,might want to do that Areostar(?) heater valve thing to keep that heater core from heating up the interior.I like it.
Rio Grande City be all hot,yo...
 
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