overheating

[mike914]

Hello Everyone

Hope all is well with you.

I have been restoring a 71 swepty short bed and have developed an issue.

I recently adjusted timing and regapped plugs to .035 timing is 17 degrees advanced at 720 rpm

Distributor is stuck on a hard stop so not sure how to get it below 17

Anyway it starts and runs better than ever no bogging stumbling etcetera

However it overheated on a 7 mile run from my house
no obvious signs of where the coolant came from but it sprayed all over engine bay.

when I opened hood no signs of where leak was from,, restarted engine ran fine and put her away for the night.

I have read the advanced timing may be the issue as it was running poorly before the last adjustment.
Going out to buy tstat and radiator cap plus new coolant

Any ideas?

Thanks

[Wildergarten]

I'd look at the overflow system. Do you have a coolant reservoir on this truck? Is it a bag? Could be torn.

[mike914]

Thanks

Im not sure but will check tonight

Mike

[mike914]

Hello All

OK I swapped out the thermostat and radiator cap.

The overflow is simply a hose just below the radiator cap that is routed around radiator and empties onto pavement.

I overfilled radiator and it dispensed fluid on my garage floor so not clogged but needs a reservoir.

I did notice that when cold I started engine removed cap peered in no movement of fluid

Bad Water pump?

Any way to confirm?

Any advice is welcome

Thanks

Mike

[Wildergarten]

I did notice that when cold I started engine removed cap peered in no movement of fluid

It won't flow until the thermostat opens.

[mike914]

Thanks for the tip
I ran it in my driveway and i could put my hand on the radiator never got hot enough to open thermostat i guess.

Idled fine in driveway.

Will try to get her on the road this weekend

[Wildergarten]

Will try to get her on the road this weekend

Allow me to suggest that before you do that, take some cardboard and put it flat against the radiator on the outside. Start the motor and set the idle to about 1200 rpm. The fan draw should hold it there. It'll get hot soon enough. Once you see flow indicating that the thermostat has opened, replace the cap and let the pressure build to see what happens next. Watch that gauge that it doesn't get too hot! If you don't see anything, pull the cardboard, reset the idle, and then take it for a test run.

[mike914]

Great advice Ill try it tomorrow

So far swapped thermostat radiator cap and added coolant

idled in drive for 15 min no issues

took it for a short drive afterward go it up to 50 no issues so far

Ill try the cardboard idea to check for flow.

thank you

Mike

[Jims68]

After it has ran for awhile, FEEL the radiator hoses. BOTH should be HOT. If not... look at the thermostat. You can test it by placing in in a pan of boiling water. IF it is good, you can see it open. Make sure it opens all the way too.

[marklein]

On vehicles without an overflow tank, don't fill the rad to the top. Fill it just over the tubes and stop there. Will keep it from burping coolant.

[dynamutt]

Ummmm.... you mention you have the timing set at 17BTDC. thats pretty steep, i think. it would mean, maybe, at full advance you are WAY too advanced, which itself will get things hot.

[mike914]

I think you are correct'' about too much advance

I swapped thermostat and went for a ride no issues now seems to run without overheating.

still struggling with timing

I entered a new thread to ask for help

thanks