I recently picked up a 54 235 engine w/a known problem, cyl #1 low to no compression, all other cyl's are supposed to be OK and the engine ran on 5 cyls. Today I finally got a chance to troubleshoot it before teardown.
The engine block# indicates it's a 54 235 and the head# indicates it's an 848. It came out of a truck so the front mount is a direct boltup to my 49 3100.
My long range plan is to rebuild this engine and squeeze as much streetable perfomance out of it that can be somewhat easily done. I have no interest in going w/an open drivetrain and all that that encompasses. I'm wanting to stay somewhat period correct as well as being a direct boltup. $$$'s are a major consideration. So with the exception of perhaps changing the rear gears to 3.55 the engine will bolt to the existing drivetrain.
On to the troubleshooting.
I rigged up a temporary
test stand to test it. The engine came w/a good starter so I rigged up a 12v battery for testing. I hooked up an oil test gauge to the oil gauge port to also test for oil pressure while cranking.
I removed the carb so the intake was wide open.
Here are the results of the compression test.
#1 dry - 0 psi. Wet - 0 psi.
#2 dry - 120 pso, Wet 130 psi.
#3 dry 100 psi, Wet - 110 psi.
#4 dry 115 psi, Wet - 120 psi.
#5 dry 130 psi, Wet - 135 psi.
#6 dry 115 psi, Wet - 120 psi.
Oil pressure at cranking speed varied between 10 - 15 psi.
I pulled the head and
this is what I found on #1.
#1
cylinderlooked good considering. There was no gouges or deep scratches so the cylinder can be bored if needed.
The rest of the
cylinders also looked good. The is a barely discernable rough at the top of each cylinder so a hone could clean it up. But those compression #'s seem to indicate an oversize bore is needed.
The
head looks good to my naked eye. No visable cracks or obvious burnt valve problems. A
closeup of #1. The oily film is probably from me squirting oil in the cyl for the wet compression test.
There were no piston parts floating around in #1 so the debris either shgot out the exhaust or dropped down into the pan. I ran out of time so I didn't get that far.
Wonder what damaged the piston? It's not directly under either valve. The cyl area doesn't seem to show any signs of overheating. Ingested something hard like a screw or nut perhaps?
Dave
