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Hi all!
New here. Got a problem. When ever I accelerate hard I’m pushing oil out of the dip stick hole. PCV new. New motor, did the same on old motor. No dip tick tube. I’ve seen some with a dip stick tube. Is this common? Will a dip stick tube cure this? Thanks for the help in advance!,
Quote:
Originally Posted by Specialklj
I would say you have the PCV hooked up wrong. The PCV should have a very strong suction on the end of it with the engine running. Crank case pressure is building up and pushing oil out of the motor, a tube isn't going to fix that. Are you running a non stock carburetor? Normally, I'd say you have a worn engine with too much blow by, but you mentioned the new motor doing the same as the old one.
Checked the Pcv it’s correct. It is a edelbrock carb with a 3/4 inch riser on the car when I got it. Seems to be a lot of vacuum. I did notice vacuum to distributor is zero till accelerating. Also seems vacuum gets weaker at pcv when I rev up motor. Suggestions?
Edelbrock Carburetors have 2 large connections, one is for a charcoal canister, the other has vacuum for a PCV. Just wanted to make sure you didn't mix them up. A 3/4" spacer shouldn't affect the vacuum, but it might decrease the signal to the carburetor. If you have no vacuum to the distributor until you open the throttle, that is normal for a ported vacuum connection. A manifold connection will hiss at idle when you uncover it. If you want vacuum advance at idle, try another connection at the carburetor. It is normal for vacuum to drop when you abruptly open the throttle. At wide open, it will be near 0. The PCV system should keep the crankcase from pressurizing which is what is happening. If you have too much blow by, it can overwhelm the system and push oil out of the gaskets and openings.Quote:
Originally Posted by Specialklj
I defiantly have too much blow by but how do i decrease it? pcv is working, do I need a vent on the driver side? I'm using the vacuum port on the back of the carb.
Too much blow by is from worn rings. The engine needs to be rebuilt. The engine is usually vented at one of the valve covers. The amount of blow by is overwhelming the PCV system.
This is a rebuilt motor with less than 250 miles! I didn’t mean blow by I just meant to much crankcase pressure.
I am with Larry. I see no way for crankcase pressure to be excessive except gasses getting by the rings. With only 250 miles they may not be broken in yet. Perhaps drive a few hundred miles , at various speeds, and see what happens. Even with too much crankcase pressure, I can't see pushing oil out the dipstick hole. Too full? Ben
Lots of Buick engines in the mid-60s were built without a dipstick tube. The 340 did not have one unless it was a California car with an AIR pump. An original tube and associated dipstick will be very hard to locate as the part numbers were only used on '66-67 340 AIR cars.
The dipstick which plugs directly into the block for the non-AIR 340 is a Buick part no 1375251 (which is printed on the stick). There is a rubber plug or stopper on the stick that should prevent minor leaking out the hole in the block. Owners who have found this piece missing have added a 1/2" piece of fuel line or a rubber grommet as a replacement.
Another item to check for is the internal oil pan baffle which bolts to the bottom of the block. If this piece is missing or mispositioned, crankshaft turbulence at high speeds may be forcing the oil out. The baffle is part no 1379743 which was used on '64-67 225 - 300 - 340 engines. See attached cross-section side view of engine from the '67 shop manual. Hopefully the engine rebuilder can confirm this item is in place.
One engine rebuilder association reported a weird cause of oil leakage out the dipstick tube on much later Buick-designed 3.8L engines. In that instance the dipstick would hit the baffle and bow out horizontally. This would throw off the position of the stick so that owners had to overfill the crankcase to hit the full mark.
Dipstick should show full when changing oil and filter after adding 5 quarts, running the engine for bit, and allowing some time for draining back. Foaming in the oil would be a sign of overfilling.
There should be a vented oil filler cap containing metal mesh in the left rocker arm cover unless it's a California car. The PCV valve in the right cover pulls fresh air in through the filler cap then through the crankcase while also vacuuming out the blowby gases and vapors that get past the pistons. See attached front cross-section view. When blowby becomes more than the PCV valve can handle, the vapors exhaust out the filler cap. Fumes coming out the filler cap and oil stains nearby would be indicators the PCV valve is not keeping up.
Thank you all that replied! I know itÂ’s tough not being able to see, touch, or hear whatÂ’s going on.
Todd thank you very much you nailed it! Not only did you clear up for me,and probably many others, that didnÂ’t know why there were some 340s with and some without dip stick tubes. The problem that I had was someone before me must not have like the looks of the vented oil filler, so they replaced it with a non vented chrome cap! I got a vented cap and problem solved!! :hurray: Thank you! This is a great forum and IÂ’m very happy to be part of it!,