blow back/by

[capwred]

what cause this.

i can take the oil cap of and you can feel it hit your face.

[capowered240]

check pcv valve.

[capwred]

its fine

[240TweakerNewbee]

Turbo motors are notorious for blow by.

[float_6969]

Potentially, bad rings, but even a newly rebuilt motor will have blowby.

"Blowby" is actually compressed air that enters the crankcase by "blowing by" the piston rings. Some blowby is normal, when you start to get a lot of it, combined with oil and excessive fumes, it generally means that the rings are bad. A catchcan is the best way to determine if the amount of blowby is excessive or not. Before I rebuilt the motor I was emptying my catch can every couple of weeks (it held approx 1 pint). Since the rebuild, I've never emptied it and I've been driving it daily for months.

A compression test can give you an idea of the condition of the rings as well.

A leak down test is the best determination of the condition of the rings with out tearing the motor down.

[capwred]

im going to do a compersion test but i dont think the rings has had time to seat yet.the motor is rebuilt and started knocking today. and dont know why yet.its only got about 5 miles on it.

[float_6969]

If it's knocking, it'll prob be on the #3 rod. It's infamous for having oiling problems.

[Trigger]

to bad your not a little closer to me i would come up and give you and hand to see whats going on. my guess blow by from rings not seated and knock well not sure would have to hear it. if you have electric fans you can unhook them and let the engine run a little hot and that will help the rings seat...i have had to do that to a couple v8's i have rebuilt. just make sure the knock doesnt increase and you might see the knock go away after the rings seat...atleast you can hope for it.

Tim

[capwred]

i might try that trigger what else do i have to lose.

[dattodude]

I hope I read your post correctly. The knocking problems could be a problem to worry about..keep a close eye on that..

You say that you took the oil cap off the cam covers (probably while the engine was running) and you could feel oil spray in your face.. You should..what else do you expect cools and lubricates the cams?

Blowby is when the air in the sump pressurises and pushes a lot of oil up the oil galleries in the side of the block into the cam covers and out the breathers. It would be 'running out like a tap' from the oil cap hole if it were truely in a blowby situation, which only occurs from moderate to high revs..

If you have your pipes all connected correctly, the blowby will result in smokey exhaust for a little while, as the oil goes out the breather hoses and back into the intake tract. This is what makes the turbo get oily, and the insides of your intercooler and intercooler pipes get all oiled up.

Instead, if the pipes aren't fed directly into the intake, but are strained and filtered in a 'catch can' only hot air is sent back to the intake, and the oil remains in the catchcan.

Cheers,Chris

[capwred]

I hope I read your post correctly. The knocking problems could be a problem to worry about..keep a close eye on that..

You say that you took the oil cap off the cam covers (probably while the engine was running) and you could feel oil spray in your face.. You should..what else do you expect cools and lubricates the cams?

Blowby is when the air in the sump pressurises and pushes a lot of oil up the oil galleries in the side of the block into the cam covers and out the breathers. It would be 'running out like a tap' from the oil cap hole if it were truely in a blowby situation, which only occurs from moderate to high revs..

If you have your pipes all connected correctly, the blowby will result in smokey exhaust for a little while, as the oil goes out the breather hoses and back into the intake tract. This is what makes the turbo get oily, and the insides of your intercooler and intercooler pipes get all oiled up.

Instead, if the pipes aren't fed directly into the intake, but are strained and filtered in a 'catch can' only hot air is sent back to the intake, and the oil remains in the catchcan.

Cheers,Chris

i didnt say oil was hitting in my face i said the blowby was. i know how the oiling system works. i know everything you said.but thanks for the helpful info.