Tim Berframe
Bronze Member
It has been 2 years since this machine broke as discussed in a previous thread : Jinma 354 white smoke no power won't rev past 800rpm
Recap: Cam thrust plate bolt came out and went through the timing gears, busting case and hydraulic driver. Repaired but did not change cam bearings. Decided to do the head bolt torque and valve lash adjustment. These were all over the map with #3 cylinder valves never having ever closed (been running on 3 cylinders ever since I bought it new). Engine power band characteristics changed dramatically but it was running hot with exhaust from the crank case vent - now know that means head gasket leak or head crack. With only maybe 10 hours run time since these changes, the cam shaft broke. I think the front bearing was damaged in the first episode and it wallowed out allowing enough flex to break it.
I couldn't get rings for the 3 ring pistons it came with so I did a complete rebuild. New 4 ring pistons, rods, liners, bearings, seals, clutches, pilot bearing, throwout bearing. Had the block hot tanked and painted. Cleaned and painted everything I touched. Hand lapped several valves that weren't holding liquid. Block deck and head were perfectly flat and smooth. Made sure all was meticulously clean and placed head gasket in same orientation as the old one. All holes and passages seemed to be aligned correctly. Torqued it down carefully in three stages with new head bolts after thread chasing all holes. Threads clean and dry torqued to 115 ft lbs.
I had fuel difficulties and hydraulic leaks on first start up. Engine ran a total of maybe 15 minutes over 4 or five tries to get the fuel delivery correct and the hydraulics sorted out. It still starts hard but is strong and smooth when it catches. I ran it another 20 minutes to verify the clutches were set up right before covering up with the loader. I had been concerned this whole time that it had a slight grey smoke that didn't clear with temperature rise.
Then the head gasket blew. Antifreeze out the overflow with gusto and exhaust from the crankcase vent. There is no water in the oil or oil in the water - just compression where it shouldn't be.
So, two years later and 100 hours into a major rebuild and I'm back to where I started. Is it possible to pressure test the head myself somehow?
Recap: Cam thrust plate bolt came out and went through the timing gears, busting case and hydraulic driver. Repaired but did not change cam bearings. Decided to do the head bolt torque and valve lash adjustment. These were all over the map with #3 cylinder valves never having ever closed (been running on 3 cylinders ever since I bought it new). Engine power band characteristics changed dramatically but it was running hot with exhaust from the crank case vent - now know that means head gasket leak or head crack. With only maybe 10 hours run time since these changes, the cam shaft broke. I think the front bearing was damaged in the first episode and it wallowed out allowing enough flex to break it.
I couldn't get rings for the 3 ring pistons it came with so I did a complete rebuild. New 4 ring pistons, rods, liners, bearings, seals, clutches, pilot bearing, throwout bearing. Had the block hot tanked and painted. Cleaned and painted everything I touched. Hand lapped several valves that weren't holding liquid. Block deck and head were perfectly flat and smooth. Made sure all was meticulously clean and placed head gasket in same orientation as the old one. All holes and passages seemed to be aligned correctly. Torqued it down carefully in three stages with new head bolts after thread chasing all holes. Threads clean and dry torqued to 115 ft lbs.
I had fuel difficulties and hydraulic leaks on first start up. Engine ran a total of maybe 15 minutes over 4 or five tries to get the fuel delivery correct and the hydraulics sorted out. It still starts hard but is strong and smooth when it catches. I ran it another 20 minutes to verify the clutches were set up right before covering up with the loader. I had been concerned this whole time that it had a slight grey smoke that didn't clear with temperature rise.
Then the head gasket blew. Antifreeze out the overflow with gusto and exhaust from the crankcase vent. There is no water in the oil or oil in the water - just compression where it shouldn't be.
So, two years later and 100 hours into a major rebuild and I'm back to where I started. Is it possible to pressure test the head myself somehow?