New engine, rings not sealing up..advice..

[streetknight]

Did some tests and have some info. Did compression and leak down.

cylinder compression leak down percentage

1 135 18%
3 130 13%
5 120 32%
2 130 22%
4 135 8%
6 130 20%

Looks like there's definately an issue with the #5 cylinder.

Another point is I noticed after letting the car run for about 1/2 hour. If I rev the engine up it blows water out the exhaust like condensation. But can that happen after the car is so warm.

I did pressure check the cooling system the other day and it was fine, but only did it cold. Was told I needed to do it at operating temperature also.

What do you think?

 

[84TXGN]

It took me between 300-500 miles to stop seeing smoke from my motor. Rings take a little time to seat. After I hit 300 miles I started getting on it a little more(part throttle/5psi). After a few weeks of that it stopped smoking.

 

[Benched]

How did you do the leak down test?

 

[streetknight]

I did what I was told by the mechanic that let me borrow the tool.

bring the cylinder to TDC, screw in the hose. Set the regulator for 100 lbs of air pressure. The first gauge should always read 100 lbs. the second gauge will be less.

He said if the second gauge showed 80lbs then that would mean I'm losing 20%.

Does this sound right using 100lbs as the common regulated pressure?

When I brought the cyl. to TDC and hooked everything up it would spin the engine over itself, then it would start to build and hold pressure.

 

[Benched]

You did well. 100 psi is good. A warm engine will give better readings than a cold one. If you can hold the piston at TDC, and then listen to where the air is coming out, it will pinpoint your area(s) of concern.
Sometimes by letting the piston drop a little, at least before the valves move off their seats, you can get a better idea what is going on.

Those numbers don't look healthy.

 

[streetknight]

I did the above tests with the engine cold. Should I redo them with it warmed up. Should the #'s get higher. I also heard if I squirt a little oil in the spark plug hole and retest if the # goes up it's a ring problem and if it stays the same it's a head gasket. Does this sound right?

Thanks again

 

[Benched]

Try it again when it is warm. Any unburnt fuel in the cyclinder will throw off the readings. Oil can be used when you suspect it is the rings.

Try going to the URL link in the first reply I made. That air has got to going somewhere. In a healthy engine the air is going past the gaps in the rings, which would equate to readings no greater than 5% leakdown.

 

[streetknight]

OK guys, got an update for you.

Friend's been driving the car and putting miles on for me. Got almost 500 on it now. He pulled it in his shop today and said the smoke is still there, but not worse, but IS noticeably Blue now.

Did a leakdown with engine hot and worst cyl. was 15% this go around.

Which leads me to believe it maybe the turbo seal. What do you think?
I pulled the down pipe off,but couldn't find an oil trail. I figure it would have to be a LOT of oil to do that. It's not really using oil anymore though. The down pipe does look very "sooty" and black.

Intercooler had no oil in it.

 

[JeffG]

With a 15% leakdown, you have got ring, valve, or headgasket issue that needs to be addressed. I would say it's not your turbo seals.

 

[streetknight]

Well the heads are new champion irons, and I had 30% leakdown on the cyl that is 15% now. It does have more ring gap than it needs at 23 on top and 20 on bottom.

How could I pick between ring and head gasket? I heard I could squirt oil thru the spark plug hole and then do the leak down, if the #'s get better it's a ring and if not its a head gasket. Does this sound right? If so, how much oil and do it hot or cold engine?

 

[JeffG]

I had new out of the box Champ irons on one of my new motors. The valve guide inserts they used lasted less the 2k miles before they were totally shot. Had to have the inserts removed and new guides put in. One more possiblity for you.........sorry, I know it's not what you want to hear. It is good to see that one cyl is improving assuming you used the exact same process the first time.

 

[87 turbo buggy]

cyl taper

Well the heads are new champion irons, and I had 30% leakdown on the cyl that is 15% now. It does have more ring gap than it needs at 23 on top and 20 on bottom.

How could I pick between ring and head gasket? I heard I could squirt oil thru the spark plug hole and then do the leak down, if the #'s get better it's a ring and if not its a head gasket. Does this sound right? If so, how much oil and do it hot or cold engine?

you hit it on the head. when the stated cyl taper do to ring change in top to bottom of bore.

did you bore this block. cyl clearance is .001 to.0017 to the piston. if you had .023 ring clearance at top and .020 of the botton. the rings must move in and out as it travles through the cyl. no matter what you do at that taper, the more you run it the more chance that the rings will shatter, bummer, also did you reuse the pistons, what was the clearance between the ring land and the ring. check it out cyl. taper more than .0005 will always blow oil even with 90 w.

 

[streetknight]

The block was already .030 over when I took it apart. The machine shop said it was dead on 3.830 and they just brush honed it to clean up the cyl that had water in it from the head gasket failure.

Used New Wiseco pistons and they have .005" clearance. I didn't check between the ring land and ring. Just assumed they were right since they came with the piston kit.

I did notice last night that I saw some oil on the passenger side header where the turbo bolts on. I think there's only one place that can come from. I had taken the down pipe loose and pulled it back to look for oil and didn't see any. I guess it could have trickled out without me noticing.

Thanks for the reply.

 

[VadersV6]

cyl. taper more than .0005 will always blow oil even with 90 w.

Not true. 5 tenths isnt much at all. Its actually very well within specs for cylinder taper. I always shot for .0002-.0005, but sometimes there were circumstances that forced me to go as much as .002 on the taper. Even the engines with .002 taper ran beautifully with no oil burning. Tapering half of 1 thousandth of an inch, from the top of the bore to the bottom of the bore is NOTHING. My old boss had a race boat with a 427 chevy in it. He was selling the boat and wanted to freshen the motor up. It was his company so why not. The cylinders had already been bored and honed to the limit, but he didnt want me to sleeve it. He said to just get the cylinders as good as I can. Those cylinders were terrible. They really needed to be sleeved. When I was finished, the best I could do was .006" oversized on the bore, .008" Taper and .005 out of round! I told him he was crazy and that it would never run right. Somehow it ran great and didnt suck oil...go figure.

 

[norbs]

what kind of rings are you using??????????????

 

[streetknight]

If you're talking about my motor. I'm not sure. I think they're Hastings. They came in the piston kit with the Wiseco's.