Post by javtwotone on Jul 11, 2023 4:14:35 GMT -8
OK, so the Jeep that I did a shit load of work on, and SC397 built the engine for, is back.. We fought an oil leak and thought we had won, but of course it started leaking again. ANYHOW, the guy said it just didn't run like a 401 should and is getting too hot, so it's back. 401 with a 270H cam and Edelbrock Pro Flo 4 injection. Tuning the fuel injection has been frustrating at best, but the guy is right, it's a slug.. Trouble is, when it gets too hot, runs even worse so first things first, need to figure out what's going on with the cooling system (or engine).
Big ass aluminum radiator from BJ's off road and big ass electric fan with a shroud. 93 degree humid ass day, I pull it outside stone cold and let it idle with the cap off. Appears that it would do this all day long if I let it. Stayed at 176 degrees (by the Edelbrock tablet reading) and didn't go higher. throttle it up and the coolant level drops and you can see it flowing fine. different RPM, different flow rate so far so good. I put the cap on for a bit, and no change. Pull it back off and it hadn't built any pressure. Bring it up to 2500ish RPM and hold it while watching the flow. level dropped at first, then started to climb back up. Adding more throttle at this point didn't help, still going up and about to gush out when I got the cap back on while still holding the throttle. Went in the cab to read the gauge, and it had jumped 16 degrees in less than a minute. I let it idle while checking other readings, and it sat there at 189 for a few minutes. I couldn't keep the test going to see if it go all way back down to 176 cuz of a stupid storm front that came out of nowhere..
Pulled the plugs. 7 were identical, and looked just fine. 1 plug slightly different with some white ash on it. Minor, but a visible difference from the others. Tried a compression check with my 35 yr old Sears tester. Cold 150 psi on the cyl with the different plug. 155 on a cyl on the other side of the engine. At 190 degrees, it was up to 155 on the suspect cyl. Not sure about my ancient tester..
Any ideas out there? engine is coming out for the oil leak, and will get torn down to see if there is any sign of a head gasket issue, but trying see if anybody was run into a similar issue. Jeep will heat up at highway speeds with the A/C running and get to 225-230 on a hot-ass day, but go no further. Once it's that hot though, it struggles to cool back down even at less speed. Not going to work in Kentucky where the guy lives.
Thought about asking Gaymc (not really), but the 100's of idiot responses isn't worth the 10 guys that do have clue.. are the belts tight? back in '37 my model-T was overheating..
Big ass aluminum radiator from BJ's off road and big ass electric fan with a shroud. 93 degree humid ass day, I pull it outside stone cold and let it idle with the cap off. Appears that it would do this all day long if I let it. Stayed at 176 degrees (by the Edelbrock tablet reading) and didn't go higher. throttle it up and the coolant level drops and you can see it flowing fine. different RPM, different flow rate so far so good. I put the cap on for a bit, and no change. Pull it back off and it hadn't built any pressure. Bring it up to 2500ish RPM and hold it while watching the flow. level dropped at first, then started to climb back up. Adding more throttle at this point didn't help, still going up and about to gush out when I got the cap back on while still holding the throttle. Went in the cab to read the gauge, and it had jumped 16 degrees in less than a minute. I let it idle while checking other readings, and it sat there at 189 for a few minutes. I couldn't keep the test going to see if it go all way back down to 176 cuz of a stupid storm front that came out of nowhere..
Pulled the plugs. 7 were identical, and looked just fine. 1 plug slightly different with some white ash on it. Minor, but a visible difference from the others. Tried a compression check with my 35 yr old Sears tester. Cold 150 psi on the cyl with the different plug. 155 on a cyl on the other side of the engine. At 190 degrees, it was up to 155 on the suspect cyl. Not sure about my ancient tester..
Any ideas out there? engine is coming out for the oil leak, and will get torn down to see if there is any sign of a head gasket issue, but trying see if anybody was run into a similar issue. Jeep will heat up at highway speeds with the A/C running and get to 225-230 on a hot-ass day, but go no further. Once it's that hot though, it struggles to cool back down even at less speed. Not going to work in Kentucky where the guy lives.
Thought about asking Gaymc (not really), but the 100's of idiot responses isn't worth the 10 guys that do have clue.. are the belts tight? back in '37 my model-T was overheating..