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Old 09-22-2005, 07:43 PM
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Blowby Problem

I'm having a bad blowby problem with the motor in my T Bucket.

I took an EFI 302 from a van and freshened it up with rings and bearings and transplanted that into my T Bucket. The cylinders were in great shape with no noticable ridge. I have the el cheapo chrome valve covers and el cheapo chorme breather on the front of the drivers side cover. The PCV valve is on the back of the passenger side cover and connects to the stock fitting on the intake manifold, so I should have a good crossflow and good vacuum through the motor. This setup worked perfectly for about 3000 miles, nothing comming out of the breather and no oil dripping. All of a sudden I started getting oil mist from the breather. Of course the oil ends up on my windshild cause it's a T bucket. I've replaced the PCV valve three times and the vacuum hose to it with the same results. It's not bad under idle or low load, but going up hills, it's fuming and spitting oil out. Another 1500 miles and I'm still messing with it.

Now a couple things come to mind. Either all the PCV valves I'm using are junk, or my motor is all of a sudden blowingby excessive exhaust gas.

Now I have temporarily fixed the problem by eliminating the PCV valve and piping the vacuum directly to the valve cover. I put a small restriction in the hose as to not bleed off too much vacuum from the intake. This works great, but now all that exhaust gas is being sucked into the intake (which it probably was all along, I just didn't know it). How much blow by is normal anyway? I think I will do a compression test to see if I lost any cylinders. Should I get a breather that has a hose to the air cleaner? Will I just end up with oil in my air cleaner?

Any Input?
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