sshaddow Posted August 27, 2021 Share Posted August 27, 2021 I have a 31 cg that quickly goes to 220 after a couple miles. Put in new rad core,pulled head cleaned out block,rebuilt pump and checked for correct fan and fan spacing. Are these a pressurized system? Is there a thermostat I can use.Car runs fine ,just too hot. Thank you from the newbie Link to comment Share on other sites More sharing options...
Peter Gariepy Posted August 27, 2021 Share Posted August 27, 2021 CG? Link to comment Share on other sites More sharing options...
61polara Posted August 27, 2021 Share Posted August 27, 2021 I assume it to be a 1931 Chrysler CG 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 27, 2021 Share Posted August 27, 2021 Not a pressurized system, Chrysler did not have that until the fifties. Get a laser thermometer and compare the temp of the front of the engine to the back, temp should be uniform all the way, if it is hotter at the back your water distribution tube is rusted away or missing. Without it the coolant streams up the front of the engine and does not reach the back of the engine, resulting in overheating of the rear cylinders. 3 Link to comment Share on other sites More sharing options...
sshaddow Posted August 27, 2021 Author Share Posted August 27, 2021 Yes all, it is a 1931 chrysler CG. Thank you Rusty, I will do as you recommend and post back. Link to comment Share on other sites More sharing options...
sshaddow Posted August 27, 2021 Author Share Posted August 27, 2021 This is embarrassing, as being a mechanic on 50's and 60's cars mostly for 40 years, I am out of my wheelhouse on this engine. Just setting the timing with a micrometer was a real adventure. My question is, where does the water distribution tube go? Are there any pictures available ? Where can I buy one? And yes, you are right, the rear cylinders are much hotter than the front cylinders. Your great advise has probably saved this engine, Thank you. Link to comment Share on other sites More sharing options...
TerryB Posted August 27, 2021 Share Posted August 27, 2021 Tube is in the block and I believe access is behind the water pump. Left side of engine as viewed from the front of the car. Link to comment Share on other sites More sharing options...
keiser31 Posted August 27, 2021 Share Posted August 27, 2021 (edited) 35 minutes ago, sshaddow said: This is embarrassing, as being a mechanic on 50's and 60's cars mostly for 40 years, I am out of my wheelhouse on this engine. Just setting the timing with a micrometer was a real adventure. My question is, where does the water distribution tube go? Are there any pictures available ? Where can I buy one? And yes, you are right, the rear cylinders are much hotter than the front cylinders. Your great advise has probably saved this engine, Thank you. There is no water distribution tube on the 1931 CG. The water pump is the smaller one that does not cover the front of the engine. Edited August 27, 2021 by keiser31 (see edit history) Link to comment Share on other sites More sharing options...
keiser31 Posted August 27, 2021 Share Posted August 27, 2021 2 hours ago, Rusty_OToole said: Not a pressurized system, Chrysler did not have that until the fifties. Get a laser thermometer and compare the temp of the front of the engine to the back, temp should be uniform all the way, if it is hotter at the back your water distribution tube is rusted away or missing. Without it the coolant streams up the front of the engine and does not reach the back of the engine, resulting in overheating of the rear cylinders. No water distribution tube in that engine. 1 Link to comment Share on other sites More sharing options...
TerryB Posted August 27, 2021 Share Posted August 27, 2021 Thanks for the clarification. I was basing my info on my 1937 Dodge ownership. Link to comment Share on other sites More sharing options...
sshaddow Posted August 27, 2021 Author Share Posted August 27, 2021 If there's no water tube on this engine, what can be done to cool the rear cylinders? Link to comment Share on other sites More sharing options...
keiser31 Posted August 27, 2021 Share Posted August 27, 2021 29 minutes ago, sshaddow said: If there's no water tube on this engine, what can be done to cool the rear cylinders? I believe there are water ports near the rear in order to cool the rear half of the block. Are you sure you got all of those cleared out? Also....it could be the timing. Sometimes the timing being slightly off will overheat the engine. 1 Link to comment Share on other sites More sharing options...
ArticiferTom Posted August 27, 2021 Share Posted August 27, 2021 Maybe should post pic of engine . Maybe not be as thought . There should be letters and numbers on engine . 2 Link to comment Share on other sites More sharing options...
Bloo Posted August 27, 2021 Share Posted August 27, 2021 5 hours ago, Rusty_OToole said: Get a laser thermometer and compare the temp of the front of the engine to the back, temp should be uniform all the way How much difference would you consider acceptable? Link to comment Share on other sites More sharing options...
sshaddow Posted August 28, 2021 Author Share Posted August 28, 2021 Thank you much for the reply's, I will check those water ports and the timing. Thank's again to all. Link to comment Share on other sites More sharing options...
m-mman Posted August 28, 2021 Share Posted August 28, 2021 6 hours ago, sshaddow said: This is embarrassing, as being a mechanic on 50's and 60's cars mostly for 40 years, I am out of my wheelhouse on this engine. Just setting the timing with a micrometer was a real adventure. I'm with you here. It is a paradigm shift. I too have spent my life with 50s & 60s cars and I too thought I was a decent mechanic. For some unknown reason (boredom?) I got a 1920 Cadillac and a 1926 Lincoln. They have kicked my butt!! I have learned a whole lot (and I still have a whole lot to learn) but I will carry the scars of extreme frustration and the head banging scars the rest of my life . . . . Shifting eras in wrenching is NOT EASY. When moving from a 20s-30s car to a 60s car I have to stop and take a long break to reset my thinking. 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 28, 2021 Share Posted August 28, 2021 5 hours ago, Bloo said: How much difference would you consider acceptable? When I have checked later flathead six cylinder Chrysler products there was no difference. If there was 5 degrees I wouldn't worry about it but if the front of the engine is 160 and the back is 200 you have a problem. 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted August 28, 2021 Share Posted August 28, 2021 (edited) 7 hours ago, sshaddow said: If there's no water tube on this engine, what can be done to cool the rear cylinders? Later model Chrysler flatheads have a water distribution tube, those who are more familiar with the 31s say it never had one. If it never had one to begin with maybe there is some blockage from lime, rust etc stopping the water flow. I see by the picture there is a big thermostat on top of the engine that opens the radiator shutters. This is the old method of controlling engine temp, newer models control water flow. Are the shutters open? When you look in the rad with the engine running is coolant flowing? Edited August 28, 2021 by Rusty_OToole (see edit history) 2 Link to comment Share on other sites More sharing options...
OldsmoREO Posted November 12, 2022 Share Posted November 12, 2022 Did you ever cure your overheating issue? I working on a 1931 CD with the same problem. I will be removing the drivers side freeze plugs on Monday to check for a blockage. Link to comment Share on other sites More sharing options...
DFeeney Posted November 13, 2022 Share Posted November 13, 2022 I think removing the freeze out plugs for a block flush out will be well worth the money Also when you rebuilt your water pump did you look at how much fins were left on the impeller.. Link to comment Share on other sites More sharing options...
OldsmoREO Posted November 13, 2022 Share Posted November 13, 2022 Is there a high volume water pump? If so how many fins would it have? Link to comment Share on other sites More sharing options...
Bloo Posted November 13, 2022 Share Posted November 13, 2022 More important than the number of fins (although that can make a difference), are the internal clearances. I am no expert on this, but have been rebuilding some water pumps lately and know just enough to be dangerous. Neither of those things are probably your issue. Crud in the water jacket, a plugged radiator, or a leaky head gasket are more likely. Still, if you post a picture of your pump with the impeller showing I can probably point to which clearance matters the most. It is usually the face of the fins, but that can vary with impeller type. Link to comment Share on other sites More sharing options...
OldsmoREO Posted November 13, 2022 Share Posted November 13, 2022 When I remove it I will post a photo. Thank you Link to comment Share on other sites More sharing options...
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