PCV size/oil usage
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PCV size/oil usage
Could the PCV size be an issue? please read. I have a 383 stroker built by ARracing that has used oil since day one. I've had it about 2 years now but about a year ago I took the heads to have them looked at due to occassional light blue smoke and using oil. I was told the valve seals were crushed due to the valve springs not set correctly? They fixed that problem but since I had the heads off I pulled the oil pan to replace the rear main seal (2 piece) which has also leaked. Looking up at pistons I see they are stamped 60 yet ARracing said it was going to be 30 over. Many have said since it is 60 over tha is probably your oil problem BUT there is no oil on spark plugs. They are clean. Getting to the PCV valve. A friend down the street just got his big block running and I noticed he didn't have a PCV valve. He said you don't need one? I went home and did a little reading on the PCV valve to understand it's purpose. It says you have to make sure you have the correct size for your engine. I am using a PCV valve that was for the original 76 vette engine. My PCV valve has always had a little oil on it. Is there a difference size PCV valve for the 350 and 383? The valve cover does have the baffels. I'm not happy with ARracing but I will say the engine does get up and go.
Melting Slicks
Joined: Nov 2001
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From: Katy (Houston) TX
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I can't answer the PCV question but I do have experience with AR (not good experience). I've had 2 383's from them. The first one burned oil like crazy and never built much oil pressure. After exploding a piston after only a few months I sent the engine back and they completely rebuilt it. In the end I actually ended up getting a complete new engine. The second one was much better but it still burnt a little oil.
Have you made a few good hard runs to make sure the rings have fully seated? How many miles do you have on it?
Have you made a few good hard runs to make sure the rings have fully seated? How many miles do you have on it?
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I was curious to see how many "ARracing" replies I would get. I'm about as positive as I can be that it not the PCV valve but was curious if there is a size difference required between the 350 and 383engines and if you need PCV valve. I didn't go into as much detail earlier but I did pull the pistons out when I had the heads off. Keith Black recommended rehoning the cyclinders and trying new rings which I did. No change. Runs good but light smoke. The engine has 8,000 miles on it. It has had numerous hard runs also. Seems everyone wants to see what you can do. I've always wondered where the oil goes since I don't see it on my spark plugs. Unless it's so little that it is getting burned away?? I've just about given up and just deal with it smoking for now. I can say AR racing is not one of my recommendations.
Last edited by 7t6vette; Sep 25, 2007 at 11:19 AM. Reason: update
Race Director
Joined: Mar 2006
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From: Florida
You can do a leakdown test for the rings.
To test the pcv, remove the dipstick and adapt a vacuum/pressure gauge to the dipstick tube, drive the car and record the readings. At anything below approx 4000 rpm, you should have a slight negative pressure not positive.
Pcv valves are available with different flow rates, but a quality one with the internal spring for a 350 or 400 should work.
No direct experience with the ar engines, so I guess anything is possible with them.
To test the pcv, remove the dipstick and adapt a vacuum/pressure gauge to the dipstick tube, drive the car and record the readings. At anything below approx 4000 rpm, you should have a slight negative pressure not positive.
Pcv valves are available with different flow rates, but a quality one with the internal spring for a 350 or 400 should work.
No direct experience with the ar engines, so I guess anything is possible with them.
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Do a leakdown test on the engine - all the AR engines I've re-done have had out-of-round cylinder bores, making it impossible for the rings to seal even with a new hone job. The leak-down test will reveal the problem. 
