Originally posted by sixtyninegmc
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Concerning 75PSI, I've worked on many a 230. I've found the rule of thumb with compression is this in these engines. 100PSI is border line, 90 PSI may run, but will be weak, most likely at 90 you will at best get intermitent skipping on the affected cylinder, More likely than not, it will be a dead hole much below that. Anything below 90 surely will not make the cut. Other engines you speak of running 75 as new, well that is not these engines. I've done enough of these to have a hat and t-shirt at least. I'm just trying to offer assitance to the guy with the issue here, 75 psi reading is an issue of major concern. I certainly have no reason to throw him a curve, this is proven factual info that I'm offering. It's now up to him however he choses to proceed. One thing for sure though, if he finds that the coil is the knocking off issue and replaces that, he still will not have a decent engine with compression readings that low. It might be worth mentioning also to be sure the test is being done correctly so accurate results are certain as test results are only as good as the person performing the test with known reliable equipment.
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