Smoking 300/350....not good
I think I know the answer to this, but I'm gonna ask anyway. After a particularly long and hard full-throttle blast during Bloomington Gold, I parked my '70 300 hp 350 and I noticed (smelled) the starter, the exhaust pipes and the trans were covered in oil. After a cooldown period, the dipstick showed a quart of freshly changed 15W40 Rotella oil had been expelled. Today, I started the car back up and it idled rough, and I noticed smoke coming from the air cleaner. I pulled the breather tube and the PVC valve out of the valve covers, and the idle came right around but there was exhaust smoke pulsing out both valve cover holes. So.....time to yank the 186's and have a valve job done, I assume? I'm still not sure where the oil came from, but I suspect the rear main.....can that be changed by taking off the oil pan with the motor still in the car? Or should I just get ambitious and pull the motor? Thanks in advance!!!
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Re: Smoking 300/350....not good
Sorry to say I don't think that a valve job is the answer. If the guides and seals were shot you would be getting oil drawn down the guides under heavy vacuum conditions such as deceleration. That oil would be burned in the combustion and showing up as tail pipe smoke. This would be much less evident at idle. On the other hand severely worn or cracked rings, scored piston or cylinder, cracked piston or similar bad things can cause blow by to get past the rings and pressurize the crank case. That blow by shows up in the valve covers and any other place it can find its way out of the motor. With enough blow by it is possible to pressurize the case enough to actually push oil through gaskets and seals. The first thing to do is perform a cylinder leak down test and see how much loss of compression you have and where exactly you are loosing it from. I suspect you will be doing a motor rebuild very soon. If that is the case be very careful of who you take it to so that you preserve the motor and its markings.
Regards Kenny
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