ON the exhuast of your in line 6... do you have a heat control valve the valve might be going in the open position when you are not going between 45-60 .. as you said it was fine at the higher speeds .. and,had touble with lower speeds. If you can use some mechinics wire and make sure the valve is in the closed position( not letting heat go up under the base of the carb...) good luck..
The engine is a full pressure and it has been drilled and tapped with an external oil filter so it is full flow too. The exhaust are two cherry bombs so they are pretty straight through. Will check the carb attachments, the manifold bolts, and a compression test. thanks for all the help.
One thing I always said: You learn how well tuned and leak-free your 235 really is, after you take her out on the freeways and do several good long runs. Once it's all in tune and tight, it will run for decades and outlast just about any other motor on the road during it's life. You mentioned several times you got 200 degrees even around town. That's way too hot for a 235, especially a fresh one ! These engines are cold-blooded and need a thermostat to get up to 180, if everything is right. Even out here in the desert at peak summer temps, you can go for hours and should not get higher than 190 degrees coolant temps. At first I suspected a too small water pump pulley, but now you are heating up even around town and in your drive way within just moments of starting up.... Start the engine and look at the flywheel marks with a timing light. Are the timing marks holding steady? Slowly increase throttle and go through the rpm range. Is the flywheel holding steady, if the rpm are steady? Back to idle, loosen the distributor clamp and rotate the distributer a little back and forth and again check for the flywheel to hold steady whenever you hold the dizzy steady. I once had a distributor which was lose somewhere inside and didn't hold timing well. Replaced it and all was well again. You can check the vacuum advance by ****ing on it and see if it holds and doesn't leak. It is only connected to one carb, while the other carb vacuum port is plugged.
Again, Do you have a spring installed in the lower radiator hose??? If not, at some point, the hose will colapse and prevent proper circulation of the coolant. Since it seems like its occuring when you go above a certain rpm, this could be one of the problems. I have run mine both with and without the vac advance connected, and there was no noticeable difference in how it ran. I did run more initial timing with it disconnected, because you still want to make sure you have the proper total timing. I have heard alot of horror stories about Langdons mini HEI. If you have something else you could install, I would try it just to rule out that possibility. Again, if the issue is not there all the time, then it can't be something like a plugged exhaust, for example... If it is now running like **** all the time, you may have done some more harm to it. Recheck the torque on the manifold and head bolts. Use some WD40 to check for vac leaks. Do the compression test. You do not need to hook up the advance to both carbs. When I put my 261 together, it would get hot pretty quick, I pegged the gauge at 240 once going into a show. But after about a 100 miles or so IIRC, it settled down. I run a 160 thermostat, and driving down the highway she runs around 180 degrees or so. stock 55-62 type pump with a 6" pulley.
Bill, compression testers are only about $30. They're worth having. FYI, the brakes on my 67 Volvo locked up on me once and I didn't smell it at all... until they started smoking, so you may not smell it... but that wouldn't cause the idling problems you're having now.
Do not have a spring installed. When we had it running and timed up it would keep the timing mark right on the pointer for a while and then it would bounce for a couple of beats and then hold steady again. It seemed to run fine at idle and at road speed.
Maybe it's the gas. My 59 acted in a similar way, and it was water in the gas. Perhaps try completely draining the tank an put some different gas in. Another possibility, is a fuel filter. Does your car have a factory filter inside the gas tank, (a sock type that slides on the end of the gas line), like 59's do? They tend to collapse, so it's a good idea to remove them, and run an inline one instead.
No. Thats why I said that he may now have other issues, and he should take a look at the dizzy, coil, vac leaks, compression test. Fix the stuff you know is wrong, then go from there. Not having a spring in the lower hose is definitely wrong, and is a known cause for overheating. I personnally don't trust those mini HEI's. One thing to consider is that under the ECM in the dizzy, there should be some goo. If there isn't, I have heard of guys having ignition troubles.
Another thing it may be is a bad or worn bushing in the dizzy. Timing will be right one second and way off the next.
Or any PC shop - it's the same stuff they use to affix heatsinks to CPU cores when building a computer.
its called dielectric grease. If you replace the ECM, the new one should have a small tube of it included.
The stuff I got has metallic silver in it (not anti sieze, but sorta looks like it, only thicker). Came with a warning to be extremly carfull not to leave any excess on anything, as it could cause a short if it were to migrate. Comes in a miniature syringe (no needle just easier to apply that way). I got it to put a MSD module into a large cap HEI (the box it came in was missing the packet with the screws and the heat sink compound and I didn't feel like waiting for the one MSD promised to send). Probably overkill, hope that helps.
NAPA had the radiator hose with the spring on the shelf so that is installed. I got a compression tester while there, so that will be the next thing. Should I unhook the fuel line to the fuel pump when doing the compression test to save all that $4.25 gas from being pumped when we crank the engine?
No. You don't touch the gas pedal. But you do want to pull all of the plugs out, not just one at a time. It will need to turn over several times in order to get a full reading...
You can turn the distributor so long as you move the plug wires to compensate for the rotation, for every 60 degrees you turn it move all the wires over by one terminal (might want to number them to be sure you keep them in order). Just for the heck of it if some of these other things don't cure the problem I would be tempted to pop the water pump off and have a look, maybe feed a wire with a bent end into the coolant p***ages, just to make sure there's nothing in there. There shouldn't be on a fresh rebuild, ***uming they hot tanked the block and all, but I have heard of guys finding things like wire from the sand cast plugs and other **** inside heads and parts that had already been rebuilt at least once - so it doesn't hurt to check. That wouldn't make it run funny but it could make it run hotter than normal.
I had a similar problem with my 54 chev sedan delivery. I replaced the vac*** advance and it was fine after that.
We finally got some time today to get the 49 running. Pulled the plugs and checked the gaps, pulled the HEI and reinstalled it to mike sure it was correctly working, put on a lower radiator hose with a spring in it (NAPA had it one the shelf!) and fired it up. After a few rough starts we got it running and then timed it up. It ran well, we checked for vac leaks around the carbs and intake and all seems fine, and we watched the coolant temps and then took it for a drive. So far, so good...it's not overheating and its running pretty well. The final test will be to get it on a longer run later in the week after we have had a chance to drive it around a bit to be certain it's not overheating etc. We also will do the compression test. What is normal or acceptable for a 235?
Excellent news. I was wondering how it all went. I'd like to know how this turns out after more driving. Late 235 shop manual says 130 lbs. compression for a new stock engine.
The Jalopy Journal
