Mopar Action On-line – Tech Questions
Gino Faini, Framingham, MA, 1970 Plymouth Cuda 426
I have a 1966 426 Hemi engine in a 1970 ‘Cuda. The enginewas just redone, new rings, bearings, guides, seals. My problem is, after ashort time of driving the oil pressure goes down to about 15 to 20 from 60PSI, and when you let off the throttle it starts to smoke. I have about 575miles on the engine and it seems to be burning oil. Any help would begreatly appriciated.
Gino – There’s no magic. It sure sounds like two serious problems. If theoil pressure drops that low, unless you’ve done something stupid (like 0W20oil…), either then engine was built with too much clearance somewhere, orthere’s tons of friction that’s heating the oil. I doubt it’s a pump-relatedproblem, since that typically shows up even when cold. But if the pressurecomes up when the revs increase, that might almost be livable, though notdesirable.
But the oil burning, while there are a few possibilities, sure sounds likerings that never seated (rings in upside-down, poor cylinder wall surfacefinish, taper, out-of-round, etc.) This is very bad, no way to candy-coatit.
You didn’t say who assembled the engine, whether it was professionallybored, honed with a deck plate, clearances all checked, etc. Sometimes adriveway, 50-cent rebuild works out OK, sometimes…