Blowby

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Cougar281

Well-known member
Sep 11, 2006
1,834
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St Louis, MO
My LLY has a lot of blowby. With the PCV re-routed to atmosphere, if I have the oil cap off, I get quite a bit of it out the oil cap AND from the PCV hose, and have a lot of oil on my frame rail by the hose, and small puddles of oil end up under the hose periodically. My guess is it's rings, since it runs fine and balance rates are normal and if it was a hole or crack in a piston, it would probably run rough.

Would it be possible to replace the rings without honing the bores, or is honing absolutely required? I don't expect much more than 50k to be put on the block. If replacing the rings without honing is nothing but trouble, then I'll just leave it as is and not worry about it until my shortblock is built (which will be a while yet).
 
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Cougar281

Well-known member
Sep 11, 2006
1,834
276
83
St Louis, MO
wdino73 said:
I would do a compression check on that cylinder first,
Good Luck,
Click to expand...

The problem is I can't do a compression test. I tried about a year ago and couldn't get the #5 glow plug to budge. Bent it trying to remove it and if I kept trying, I'm pretty sure I would have snapped it off and had bigger problems (I've been running since then with it disconnected and the code turned off). I did test all the other cylinders, but while I got readings (I don't recall what they where), they weren't accurate due to the stuck glow plug. Hopefully, when I get it out and pull the heads, I'll be able to determine which one was causing it.
 
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wdino73

wdino73

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Sep 25, 2009
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Versailles, Ky
I would strongly suggest trying anything u can to get it out an do a compression test, that would take quess work out of it, hell if it brakes you'll going to have the head off anyway machine it out then. IMO
Here's what happened to mine,:(
 

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C

Cougar281

Well-known member
Sep 11, 2006
1,834
276
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St Louis, MO
Maybe what I'll do is when I'm lining up for the swap, I'll give it a last ditch effort to get the plug out and do a compression test. If it breaks, well, the motor's coming out anyway. If I get it out, then I should have a clearer idea of which cylinder is the culprit. Then I can see if I can fix the problem or not.
 
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C

Cougar281

Well-known member
Sep 11, 2006
1,834
276
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St Louis, MO
LarryJewell said:
any updates
Click to expand...

Not yet. I started tearing down the LLY on Saturday, but only got as far as the turbo, intake bridge, coolant bridge and some of the fuel sytem. Like a tard, I forgot to try to pull the plug when I parked the truck. Got all carried away tearing it apart and realised I was going to try to pull the plug and do a compression test when it was too late. I'll have to do a visual once I have the heads and oil pans off.

Interestingly, the LBZ has a similar amount of blowby, but it only had about 10k less than the LLY had. A 60K LBZ I looked at a few weeks ago had pretty much zero blowby (or at least appeared to).
 
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