need help with oil blowby
Thread Starter
Racer
Joined: Sep 2002
Posts: 402
Likes: 0
From: Kingsport TN
need help with oil blowby
hey guys, i have been on here before, but its been a long time, forgot name and pass, but i didnt really like it anyway, and i didnt have a lot of posts.
anyways
i have a new, well its got about 3000 miles on it, 350, with a 327/350 horse cam and i think they are comp roller tip rockers, that have the oil hole at an angle instead of straight like most of the others ive seen.
i have a high pressure (50-75 lbs) oil pump
the problem is at moderate rpms, 25-3500, oil starts to spray out of the breather hole on the valve cover, its not really exhaust blowby either, it looks like the motor has been turned upside down and a quart or two of oil has been poured out the breather hole. what could cause this? i even made a homemade baffle for the cover and it still does it, sort of like the drainback holes are plugged, but everything is clean on the inside.
also, i cant seem to get the rockers adjusted on this motor, they are good till i rev the motor, and then it sounds like oil pressure just drops, but it doesnt, they just rattle really bad. is this the rockers or is it me?
thanks
anyways
i have a new, well its got about 3000 miles on it, 350, with a 327/350 horse cam and i think they are comp roller tip rockers, that have the oil hole at an angle instead of straight like most of the others ive seen.
i have a high pressure (50-75 lbs) oil pump
the problem is at moderate rpms, 25-3500, oil starts to spray out of the breather hole on the valve cover, its not really exhaust blowby either, it looks like the motor has been turned upside down and a quart or two of oil has been poured out the breather hole. what could cause this? i even made a homemade baffle for the cover and it still does it, sort of like the drainback holes are plugged, but everything is clean on the inside.
also, i cant seem to get the rockers adjusted on this motor, they are good till i rev the motor, and then it sounds like oil pressure just drops, but it doesnt, they just rattle really bad. is this the rockers or is it me?
thanks
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: need help with oil blowby (SharkBit)
Roller tip rockers have that distince clicky clicky sound....but not a CLANK!!!
so I think from tone of your note here, it's normal....
the oiling thing is a sort of join the club type event....I find that my engine does the same, just be sure your PCV valve is working....usually on one valve cover with 3/8 hose to the intake manifold full vacuum source....
and the other cover is vented into the intake air passages above the throttle blades....it's a 3/4 inch pipe....typically....to the air cleaner assy....where it's usually oily....
causes is blowby, but that can be from a LONG list of faults...and frankly my engine got a LOT better after a year's operation, forged pistons...don't know about clearances.....still oily on the valve covers, but not so bad I can't keep it clean easily.....
GENE
so I think from tone of your note here, it's normal....
the oiling thing is a sort of join the club type event....I find that my engine does the same, just be sure your PCV valve is working....usually on one valve cover with 3/8 hose to the intake manifold full vacuum source....
and the other cover is vented into the intake air passages above the throttle blades....it's a 3/4 inch pipe....typically....to the air cleaner assy....where it's usually oily....
causes is blowby, but that can be from a LONG list of faults...and frankly my engine got a LOT better after a year's operation, forged pistons...don't know about clearances.....still oily on the valve covers, but not so bad I can't keep it clean easily.....
GENE
Race Director
Joined: Aug 2000
Posts: 10,854
Likes: 3
From: HONOLULU HAWAII
Re: need help with oil blowby (mrvette)
The New Bill Mitchell is doing this too.....It appears these high performance engines will have some blow by due to the high performance oil pump sending more oil to the top than the drains can draw down.....The Beck Racing 383 did the same thing....I find myself always wiping up the oil smear around the breather holes on the valve covers after a hard run....even on the PVC side valve cover oil will blow by....Any body know how to stop this is a genius :seeya Cappy
Safety Car
Joined: Apr 2001
Posts: 4,795
Likes: 1
From: Regina Saskatchewan, Canada.
Re: need help with oil blowby (8T1-7T9 BIONIC VETTE)
The New Bill Mitchell is doing this too.....It appears these high performance engines will have some blow by due to the high performance oil pump sending more oil to the top than the drains can draw down.....The Beck Racing 383 did the same thing....I find myself always wiping up the oil smear around the breather holes on the valve covers after a hard run....even on the PVC side valve cover oil will blow by....Any body know how to stop this is a genius :seeya Cappy
[Modified by Stingy74, 12:21 AM 9/23/2002]
Melting Slicks
Joined: Feb 2002
Posts: 2,298
Likes: 1
From: Sodertalje/Sweden
Re: need help with oil blowby (Stingy74)
I had thet problem but i built two catchcans to take the oil spitting out.Built em from SS and the look really :cool:
ran a 3/4 braided hose from the breather to the cans..
ran a 3/4 braided hose from the breather to the cans..
Melting Slicks
Joined: Apr 2000
Posts: 3,341
Likes: 6
Re: need help with oil blowby (SharkBit)
i have a high pressure (50-75 lbs) oil pump
Le Mans Master
Joined: Feb 1999
Posts: 6,807
Likes: 0
From: Hoosier
Cruise-In III Veteran
Re: need help with oil blowby (45ACP)
Another way...a PIA for sure...is to pull the heads and champhor into the oil drain holes and enlarge the holes as much as you can. A lot of guys do that along with a port job when the heads are off.
Thread Starter
Racer
Joined: Sep 2002
Posts: 402
Likes: 0
From: Kingsport TN
Re: need help with oil blowby (AlwaysWave)
dont wanna take the heads off the car, thanks for the info guys, im going to look at them sometime this week to see if i can do anything to them
thanks again
45acp, i had the engine built, i spun a bearing in the old motor, and it was cheaper, ya i know, i really wanted to build it myself, to go this route, strong tho that was the pump that came with the engine its about 40 at idle
[Modified by SharkBit, 5:21 AM 9/24/2002]
thanks again
45acp, i had the engine built, i spun a bearing in the old motor, and it was cheaper, ya i know, i really wanted to build it myself, to go this route, strong tho that was the pump that came with the engine its about 40 at idle
[Modified by SharkBit, 5:21 AM 9/24/2002]
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Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Re: need help with oil blowby (SharkBit)
You do have baffles on the valve covers under the breather and PCV holes?
If crankcase pressure is blowing oil out, it seems to me that you have too much blowby. If things are working correctly, with everything hooked up - PCV, etc., you should have a slight vacuum at the valve cover breather inlet. You can check by placing a piece of thin paper over the valve cover breather hole. If you get pressure rather than vacuum, there is a problem
If crankcase pressure is blowing oil out, it seems to me that you have too much blowby. If things are working correctly, with everything hooked up - PCV, etc., you should have a slight vacuum at the valve cover breather inlet. You can check by placing a piece of thin paper over the valve cover breather hole. If you get pressure rather than vacuum, there is a problem