hi guys, I was wondering if anyone knew what the compression should be for a stock 71 200 inline 6? thanks, jakob
8.7 to 1 .... otherwise known as "not enough" .... If you are rebuilding, I would like to see that close to 10 to 1.
Yep.. that sure would be good. IIRC.. 125'ish was about the best I could get from a fresh "stock rebuild" motor. If I were not planning on a refresh.. I would generally only buy an engine like these that puts out between 85-90 psi MINIMUM and must be within about 5-7% of each other. Otherwise the rings and valve-guide wear issues will make tuning a chore and you'll never get what you want out of it after all the tune-up parts and tuning in the world are thrown at it. It would be an extremely safe bet that the motor already has loose guides and most definitely stem seal issues as it is anyways since that's a major weak point even when they were brand spanking new. That little puff of white smoke on startup is usually the telltale sign(under heavy deceleration too). If it keeps on puffing in between those scenario's?.. the oil rings are shot and second rings are marginal at best regardless of what the compression test says. If that's the case?.. run heavier synthetic oil to reduce burn off and go 2 steps hotter on the plugs heat range to help matters.
