I have enough blow-by that I've noticed it pushes the dip stick out everytime I take the car for a spin.

Could this be a bad PCV valve? If not, then what could it be?

Do a compression test, better yet a leakdown test to determine where the blowby is going.
A PCV thats not sealing can pressurize the crank case and blow the dipstick out as well under boost

Marchev said:

Do a compression test, better yet a leakdown test to determine where the blowby is going.
A PCV thats not sealing can pressurize the crank case and blow the dipstick out as well under boost

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Thanks, but N/T 420a

Oh didn't realize. In that case, definitely do a compression and leakdown test. You probably have blown rings

Marchev said:

Oh didn't realize. In that case, definitely do a compression and leakdown test. You probably have blown rings

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Thanks, I will try that. Oh no

Is the breather on the driver side of the valve cover still going to the intake tube? It's not blocked off or anything right?

silvreclips said:

Is the breather on the driver side of the valve cover still going to the intake tube? It's not blocked off or anything right?

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Yes, with new hose and a new intake pipe. It is not blocked off.

Is there suction on one side of that tube going to the intake? their needs to be, check it running with your finger, the side coming from the valve cover needs to have oil mist/smoke/pressure from the valve cover coming from it, check it with the engine running.

motomattx said:

Is there suction on one side of that tube going to the intake? their needs to be, check it running with your finger, the side coming from the valve cover needs to have oil mist/smoke/pressure from the valve cover coming from it, check it with the engine running.

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I'll look this evening. I also just ordered a new PCV valve since mine was stock.

My next vacation from work I'll be pulling the car in the garage to replace the head gasket, since I've heard that can cause some blow by if it is bad. And I know it's bad because it leaks oil

Head gaskets rarely leak any oil, its probably your valve cover gasket leaking, not your head gasket.

motomattx said:

Head gaskets rarely leak any oil, its probably your valve cover gasket leaking, not your head gasket.

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I'm confused, how do you think a leaking VC gasket can cause a dipstick to pop out on a N/T? genuinely wondering if I'm missing something.

I'm doubtful it's a hg myself, leaning on rings not seating properly. A leakdown test would be the proper diagnostic step instead of replacing the hg willy-nilly.

ThunderChild said:

I'm confused, how do you think a leaking VC gasket can cause a dipstick to pop out on a N/T? genuinely wondering if I'm missing something.

I'm doubtful it's a hg myself, leaning on rings not seating properly. A leakdown test would be the proper diagnostic step instead of replacing the hg willy-nilly.

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I don't think that's what he meant. He was just stating that a HG doesn't normally leak oil and the oil is probably coming from the VC. But the oil leak doesn't have anything to do with the blow by issue.

I agree with what was said above. Compression test and then leak down. Don't waste your time guessing.

Ah, missed the hg-leaking-oil post... Haha

motomattx said:

Head gaskets rarely leak any oil, its probably your valve cover gasket leaking, not your head gasket.

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I fixed the VC gasket leak. 99% sure that the HG is leaking oil. I can look again but I do know that it is not the VC gasket.

Compression test results:



I have no idea why cylinder 4 is so much higher. What do you guys think of these numbers?

BLACK'98DSM said:

Compression test results:

I have no idea why cylinder 4 is so much higher. What do you guys think of these numbers?

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I'd re-check it as a first step.

VelocitàPaola said:

I'd re-check it as a first step.

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Those results are accurate +/- 2 psi.

VelocitàPaola said:

I'd re-check it as a first step.

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Is that considered good compression for a 420a?

I know that's exceptional for a lawn mower

Good. Was the engine cold or warm?

Cylinder 4 could have oil leaking into it causing a higher reading. Try to look down in there Iand see if it's wet. You could also add a cap full of oil and repeat the test in that cylinder and see if it goes up. If it doesn't then there's probably oil sitting in it from bad valve seals or something.

jakk220 said:

Cylinder 4 could have oil leaking into it causing a higher reading. Try to look down in there Iand see if it's wet. You could also add a cap full of oil and repeat the test in that cylinder and see if it goes up. If it doesn't then there's probably oil sitting in it from bad valve seals or something.

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It's dry. I think the rings are just doing a better job in there.

VelocitàPaola said:

Good. Was the engine cold or warm?

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Warm but not hot. It ran like an hour before the test.

I was able to get cylinder 1 up to 161 psi.