VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Overheating issue

I just replaced the top head on my 33 1.5 ton truck, after the last on broke a valve guide and bent a pushrod. The new head is from a parts truck, isn’t cracked- all good to go. I installed all new gaskets and a fresh set of rocker arms.

Upon starting it, it’s all of a sudden overheating. Where before, it would sit at 100-120 degrees on a 90 degree day, Now it boils over going down the block. The water pump is rebuilt and working, and it’s running at 160-180 idling. I flushed the block and radiator and some bits of material came out, then it made two trips around the block, didn’t boil over but was about about to, and still got up over 200.

I’m down to thinking it’s a radiator issue, and plan to flush the system again to see if anything comes of it. Any other suggestions? Nothing is leaking from the hose, head, or anywhere else.

Adam

Do you have a thermostat installed? Is it opening? Hendo

No thermostat- it’s all stock and doesn’t have one. We pulled back on the radiator to get the hood off, and I’m wondering if I cracked a seal- seems to be a radiator issue (best guess at the moment) Trying all options before shelling out radiator money.

Check the head for flow, it might have rust in it. These early engines only have 1/2 a water jacket, they run hot as it is. Hendo

Flow seemed to be good with the first flush. As I mentioned, the engine ran super cool before replacing the top head- so it running this hot is unusual.

If the engine ran real cool before head replacement... then the used head Has to have Rust clogging the small passages in it... a flush will NOT get those rust particles dislodged from the new(used) head..... you will have to remove the head and run wire through all the water channels.... flushing does not get the big, stuck rust out.....

I plan to let it run for a while and point a temp gun at parts of the head to see if it’s cooling evenly. Not sure if it will tell me much- but figure it is worth trying to confirm the issue before tearing it all down.

I may also just repair the old head and switch back- we replaced it so I could get around to repairing the other down the road and keep driving, but maybe that day has come sooner than expected.

Can anyone confirm what size intake valve a 1933 207 needs? Looks like my best place to find a valve and valve guide may be eBay.

If all that goes through, and the old head is on and it still overheats, O believe that will confirm that I have a radiator issue. Then, I’ll spend radiator money.

Adam,
It is not possible for your engine to run at 100-120 degrees regardless of the outside temperature. You might have a faulty gauge. 160-180 would be an excellent range for cruising or idling temperature. If your truck is puking at temps around 200, you have a circulation problem. Your "new, used" head might have released its rust into your radiator.
I might have new valves for your truck. If not, Bob Marx at Marxparts, in Wisconsin, will have them. Bob is a frequent contributor here.
Call me anytime at 573 864 6539. I am in Columbia, Missouri. My direct email is below.

Mike Russell

Thanks Mike- I'll assume a faulty gauge- showing temps, just not accurately. I'm assuming the same- loose rust from the used head has gotten into the radiator. It seems to be more of a radiator issue than a head issue at this point. Any tips on how to rid the radiator of any newly added gunk- just keep flushing with a hose until it seems nothing is coming out?

I've purchased items form Bob in the past, I'll reach out to either of you if I go the route of repairing the previous head and need valves.

Did you check the new head gasket to make sure it matched the holes pattern in the old one? Is it possible to install the head gasket "backwards" on this engine? That could block coolant passages.

I don’t believe I installed the gasket wrong, or backward- but now I’m second guessing everything!

Sorry that I am not familiar with the details of this particular engine and head. What I do know is that I have worked on a couple of engines where it is easy to installed the head gasket incorrectly. In one of them it blocked the oil passage to the overhead cam bearings. In another it blocked the cooling passages.

The fact that you did not have the overheating until you installed the different head is a factor to consider.

I just checked the old head and old gasket – doesn't appear that there's anyway we could have installed it upside down or backward. It's symmetrical, and there's only one way to install it to line up the bolt pattern. I was hoping that may be it.

And, I agree, the head is the main difference of before vs. after. I cleaned it out pretty well before install, but wondering if bits of rust still somehow mad it way into the radiator. At a loss currently.

After a solid flush using flushing component, I was able to find the source of what was blocking the head and radiator, thus leading to overheating.

Turns out when you have 7-8 cockleburrs in the system, they can clog things up pretty good! They must have clung in there tightly and after soaking for a week finally let go. I did one final flush to ensure everything came out, and it now appears to be running cooler. Went on a small 12 mile loop and no water leak and the temp never rose above 180. Temps were only in the high 70’s outside, so curious on how she does when it’s warmer.

Thanks for all of your tips.

Adam

Adam,
Glad to hear you are back on the road.

Mike