Hello, I am 19 and am new to the world of vintage trucks and this forum. I am not totally new to engines, however, as I have rebuilt two older tractor engines. The vehicle in question is a 1951 (I believe it's a 3800) Chevy dually grain truck. It has the original 235 engine with the "JEA" code on the block. This truck is my grandpa's, and everything on it is original. It is in good shape for its age, but the engine is tired. It has 90,300 original miles, and the only major thing that has been done was a valve job at 85,000 miles. The engine has 110 # of compression in cylinder 1 & 6, but 2 through 5 are much lower- averaging out at about 50# each. I added some oil to the cylinders and performed another test, and a few cylinders went up in PSI by 2 or 3 pounds, but some stayed the same, indicating valve trouble. I am going to have the engine apart to replace the front and rear mains, so I was wondering if installing new piston rings and lapping the valves would be a good idea. I'm not sure of the bearing condition, as I've never had it apart, but it has decent oil pressure I think. 15 pounds when hot and cruising down the road. If it's hot and just idling it has about 7 or 8 pounds. Anyways....keeping in mind I won't be able to replace the bearings, do you experts think I will be okay just replacing the rings and lapping the valves? I'm on a college student budget, so a re-power is not an option. This truck doesn't see much use...just 3 or 4 times a year hauling grain to town. I only go about 45-50 mph when driving, because I've heard that's a good speed for these old tired engines. Also, the truck doesn't have the power to go any faster. Haha! I can get out on the road and hold the foot feed down to the floor for several miles straight and never make 55 mph. I've asked several of my trusted friends, and most say I will be fine. One guy said he used to put only new rings in old 216's and babbitt bearing 235's with 100,000+ miles and never had an issue (as long as the bearings looked good and the clearances weren't too large). However, other guys warn me if I re-ring the engine and lap the valves, the engine will end in catastrophic failure due to the increase in compression. What do you guys think? I don't have experience of my own, so I'm in the middle being pulled both ways, unsure what to do. Thanks!
