Re: Running very hot

Posted by Jim Kavanagh On 2018/9/10 11:24:30

Owen D - your observation on exhaust restriction is interesting, and not in a good way. When rebuilding the heat riser, I was unable to get the weight for the heat riser to be at 6 o'clock when opened. Best I could do was about 11 0'clock closed (or diverted to the intake) and about 7/8 o'clock opened, or undiverted. I posted a subject on that a few weeks ago. It is now exactly as the one in my '41 (which is to say that undiverted is around 7/8 o'clock), which seems to work. There are a few pictures, but I don't know how to cross reference them here. When this (overheating) started, I removed the spring from the post, allowing the weight to fall to full open at all times. I don't see how this is restrictive, but it is an area that I believe is different from before. I think the shaft is slighty different in the rebuild kit, but maybe I put the flap in totally wrong. Can you look at that post and see if it looks OK to your eye? I show pix of both diverted and undiverted.

If anyone has a good picture or diagram of how this (heat riser) goes together, I would really appreciate it.

Arthur C - I am not sure I follow your comment here. Are you thinking the water pump is pulling hard enough to collapse the intake hose? I will look at this when hot, but the system is a 7 lb system and generally the hoses are under pressure when everything gets hot. The bottom hose is new (actually all are) . The only sign I get of collapse is when the car cools down, the top hose shows a small amount of contraction, i think from the displacement as the water contracts to normal temp. This was also the case before the rebuild.

PTV - The engine is timed at 6 BTC, per the manual, and I can see a good amount of additional advance when I accelerate. Also, the timing is confirmed by my vacuum gauge and i have good power throughout the driving curve, so I believe it is right on. It is a great suggestion, I have a Plymouth flathead that is very sensitive to timing and will run hot when it is off, so this is an area I have looked at closely. The vacuum unit is the same as when I began.

Jim - yes, I am assuming that I did something wrong or caused an issue, so I am trying to think through what the potential causes are. I can eventually get all the way back to the head gasket, but I don't think that is where the issue is. I'll try to easy stuff first - flushing the system, thermostat and then I'll put the old water pump back on. I was not aware it was going bad until I removed it and saw traces of rust from the weep hole and on the balancer. But you are right - I need to think through everything I did as the problem did not exist before. BTW - this is my '52 I am working on - no louvers.

This gives me a few new tings to look at. Thanks to all for taking the time to help.