Is this blow by?

[BigC3416]

I just found that my spark plug in my #5 cylinder was fouled up and was covered in black. I thought that all of my plugs were fouled because of my car running rich but when I replaced them the #5 plug was the only one that was bad. I also have a problem with oil shooting out of where my dipstick goes into the block and spraying on my headers and blowing tons of smoke everywhere.. The dipstick is kinda loose in the block but I dont see why there would be enough pressure in the oil pan to shoot the oil out of it that far. It has enough pressure to shoot the oil all the way up to my hood. What do yall think this could be? Thanks for any help.

Chris

 

[HISSIN50]

i would take a look at the PCV system. the valve and screen probably have seen better days. new grommet is always a good idea too.
to find out more with #4 i might do a dry and wet compression test.
good luck.

 

[PonyBoy90]

I'm pretty sure blow-by is diagnosed by looking at the oil. I think a sign of blow-by is tiny black particles present in the oil?

 

[ninety15.0]

Im not sure about this...and im sure someone can clarify this, but i thought that blow by was in reference to oil passing through the valves (because of poor valve seating) or blow by past the piston rings and either way it blows out the exhaust. I would also say that a leak down compression test might now be a bad idea. good luck man

 

[HISSIN50]

Im not sure about this...and im sure someone can clarify this, but i thought that blow by was in reference to oil passing through the valves (because of poor valve seating) or blow by past the piston rings and either way it blows out the exhaust. I would also say that a leak down compression test might now be a bad idea. good luck man

blow-by is the leakage of gasses out of the chambers. with EFI 5.0's, the normal culprit is the rings; low tension rings are used (economy and other reasons). they tend to allow some blow by.

the gasses are then vented into the crankcase. crankcase pressure is vented and redistributed via the PCV system. anyone notice oil in their intake? the blowby and PCV are a good reason why. it is a necessary evil.

a leakdown test is a good test, though it can be more involved than a dry and wet compression test. the point is to try to pinpoint the source of the leakage.

 

[BigC3416]

Can someone explain to me exactly how to do a leakdown test? I've never done one. Thanks.

Chris

 

[HISSIN50]

Can someone explain to me exactly how to do a leakdown test? I've never done one. Thanks.

Chris

do an internet search - many folks have written a write up. i know Jrichker has an article on how to make one on his site (here on Stangnet). as i recall, i think Tom (TMoss) also wrote an article.

 

[bhuff30]

Sounds like you have an internal problem on the #4. The dip stick tube will not blow oil unless pressure in getting into the crank case, and unless you have a blower or turbo, you arn't supplying pressure through a bad PCV valve. It is very likley that you have a major problem in #4.

 

[TheUser]

If you dipstick is loose, you might consider trying to get it tightened. Change your PCV Valve and screen if you haven't and see if that helps. I would also do a compression test or leakdown test and see which cyclinder is bad. You can also take your oil fil cap off and feel if there's any air pushing out...if it's enough to make your oil shoot like that, then it should be blowing air out the oil filler, I would think.

 

[BigC3416]

My dipstick is loose, and I have tried to tighten it down a few times but it just doesnt fit in there very well. So if what Hissin50 said is right then shouldnt the normal amount of blow by that our rings let by create pressure to blow out the oil? I guess the only way to really know is by a leakdown test?

Thanks,
Chris

 

[HISSIN50]

when the rest of the breathing set-up functions properly (PVC, etc), it accomodates blowby (assuming a normal amount of blowby). low tension rings are nothing new by any means - they help with economy (less friction, parasitic loss, etc).
if the PCV is compromised at all, problems surface. if too much blowby is an issue, some folks run a catch can and filter on the PCV line (there are articles on this floating around). some (esp forced induction applications) run a breathers in lieu of a PCV valve. you can also get a breather that replaces the oil fill cap. i will add that this allows unmetered air into the system, which can create problems (not as much of an issue on forced induction).

 

[BigC3416]

I just did a comression test on my motor, would have done a leak down test but I couldnt get my hands on a tester. But pretty much all my cylinders are at around 155 except for the one in question, #5, it is at 125. Is this a big enough difference that it indicates a bad problem? The TW heads did up the compression a little bit, so I dont know where the numbers are supposed to be due to the that. I also installed a breather to maybe relieve some of the pressure in the crankcase. Thanks.

Chris

 

[GT Trooper]

If you dipstick is loose, you might consider trying to get it tightened. Change your PCV Valve and screen if you haven't and see if that helps. I would also do a compression test or leakdown test and see which cyclinder is bad. You can also take your oil fil cap off and feel if there's any air pushing out...if it's enough to make your oil shoot like that, then it should be blowing air out the oil filler, I would think.

What tool do I need to use to get the screen out of the block. Also can you tell if it's bad by just looking at it?