Piston rings not sealing?

[MicroMachinery]

I didn't go nuts on honing; I just went enough to break the glaze.. maybe a little more, just to make sure that I got full coverage. All ring gap measurements were taken after the hone.

 

A dry block soaking up oil.. very interesting point. I didn't think of that... more good knowledge for my records :)

 

 

 

I did just drop out the old oil today; it was black as soot. I know that when the SU's were flooding off and on, I had been running way overrich(I was way up in the mountains, so I had to drive it back that way). I know that fuel contaminated oil thins out and will be more prone to burning, so that's why I dropped it out. There was nothing unusual in the oil, except for the color. No flakes, nothing like that. I changed the filter as well.

 

I only ran it for a little bit, but I noticed a bit of a change in the amount of blue smoke that was present when I jazzed the throttle. There was very little, if any that I could see. Tomorrow I'm going to take it for a long drive and see what happens. I've been running it a little extra hard to try and get those rings seated in(between 3000-4500 then letting the engine slow the truck back down, while running the transmission a gear lower than I would normally).

[banzai510(hainz)]

MY block builder says dont soak the pistons in oil. On new motor he say run them dry on intial startup says rings seat faster. Its only aboyt 20sec before the oil pump kicks in anyways.

Maybe chrome rings are different. I have cast.

 

at least you gapped the rings , alot of people just put them in!

[MicroMachinery]

I didn't soak the rings or pistons in oil. I haven't done it before this time, but I also put the rings in dry. As for the pistons, I put a small amount of engine assembly grease on the outside to keep them from scuffing. It hasn't affected ring break-in in a bad way for me before.

[datzenmike]

If you were to start with a fresh clean engine with oil on the full line it stands to reason that a big chunk of oil will be spread over all internal surfaces. That's a lot of square yards!!! Think about it. But once it is wet it shouldn't need more oil.

 

 

Are the plugs dirty??? If that much oil is burning it should show on the plugs.

[MicroMachinery]

#2 and #3 look like brand new. Running very clean. There is, however, some ash deposit on #1 and #4. They're not oily or black, but they do have grey ash.

 

The dry block explanation does make alot of sense.. perhaps I'm not burning as much as I thought? But I did just do my 3rd oil change.. I would think that the block would be saturated by the 1st change @ 20miles... I could be wrong, though. :unsure:

[hogboy52]

The compression numbers you have for oiled cylinders would indicate leaking valves on #'s 1 and 4, which may be too tight lash adjustment, but probably not.

 

I have seen that reference to breaking in engines many times, but he clearly says he uses it on brand new modern racing motorcycles (and others) "that use a much finer honing pattern". If a ring gets too hot it can lose tension and be inclined to stick in the piston groove permanently.

[datzenmike]

#2 and #3 look like brand new. Running very clean. There is, however, some ash deposit on #1 and #4. They're not oily or black, but they do have grey ash.

 

The dry block explanation does make alot of sense.. perhaps I'm not burning as much as I thought? But I did just do my 3rd oil change.. I would think that the block would be saturated by the 1st change @ 20miles... I could be wrong, though. :unsure:

 

Oh yeah I would expect full coverage in a few hundred klicks.

 

Looks like #1 and #4 are 'burning'oil. If you squirt oil in those cylinders, does the compression go up? I had a quick look but didn't see if you did. If so the rings aren't sealing.

[thisismatt]

Oh yeah I would expect full coverage in a few hundred klicks.

 

Looks like #1 and #4 are 'burning'oil. If you squirt oil in those cylinders, does the compression go up? I had a quick look but didn't see if you did. If so the rings aren't sealing.

 

 

Did a wet/dry compression test today, with the engine hot. 10cc of oil was added for wet readings.

 

Dry/Wet-

1)140/192

2)210/260

3)215/275

4)155/200

 

I do see that the readings went up almost exactly 50psi for both wet and dry, so that doesn't necessarily tell me that the rings are not seated. It just tells me that 10cc of oil will increase compression by 50psi :rolleyes:

 

The cylinders do hold their pressures, wet and dry. The compression reading doesn't dissipate after I'm done cranking, so I know that they are capable of sealing.

 

Here to help ;)

[datzenmike]

Ahh there it is.

 

10cc is quite a bit and skews the answer. What about a couple of teaspoons just to seal and not add compression?

[MicroMachinery]

I just got back from a long drive. In 145 miles, I burned just over a qt

 

This is bullshit. :angry:

[DanielC]

I kinda think you know what you gotta do. It really sucks, but you know.

 

There is a lot of good advise in this thread.

[MicroMachinery]

Yeah. I'm coming to grips with that reality. FML

[Sealik]

How's the engine doing?

[MicroMachinery]

Funny you should ask, I just did another compression test today. Turns out the schrader valve in my compression gauge was not sealing correctly. I replaced it with a newer one.

 

Dry/Wet

1)100/110

2)175/198

3)185/203

4)135/155

 

It looks like #4 has come up, but #1 is still low. I hooked up the air to #1, and it's definitely blowing down into the crankcase, and up out of the breather... hmm... :hmm:

[I'm BLUE]

hhhhmmmmm ,,,Staggering of the piston rings ,,, away from the piston pin ( no gaps above piston pin ) correct ?

 

Sucks Man :(

[MicroMachinery]

Yeah, they're all staggered 45 degrees from the piston pins

[Sealik]

Any improvements with the compression...????

[MicroMachinery]

I've just stopped driving it. It only gets about 16mpg and burns about a quart every fill up.. can't really afford to keep driving it just to see if things get better. I bought a ka24e and when I get time, I'll just yard the LZ22 out and either put it on an engine stand until I have the motivation to tear into it, or I'll just sell it. I'm leaning towards selling it at this point. I may end up just selling the entire pickup. Haven't quite made up my mind yet.

 

I bought the parts a year ago in May, so it's pretty much useless to try and take it out and tear it down in order to try to get the rings warrantied(1-year), even if they are garbage. I wouldn't want them to warranty the rings anyway; all they'll do is send me another set of that American made junk.

[izzo]

I've just stopped driving it. It only gets about 16mpg and burns about a quart every fill up.. can't really afford to keep driving it just to see if things get better. I bought a ka24e and when I get time, I'll just yard the LZ22 out and either put it on an engine stand until I have the motivation to tear into it, or I'll just sell it. I'm leaning towards selling it at this point. I may end up just selling the entire pickup. Haven't quite made up my mind yet.

 

 

What???

[Sealik]

That sucks.....

[MicroMachinery]

What???

 

Yeah, I love the 720, it's awesome. But I just get pissed every time I get in it and remember that I just went through the engine, did everything right, and it's running the way it is. It's frustrating. I've never had this happen, and I've built many engines successfully, all of which are still on the road today.

I spent a lot of time documenting and recording my progress, step by step, instead of zipping right through. As always, I took my time and did it right. Then this.. .. and this isn't just some hobby that I have. It's my life. I pay my bills, eat, sleep, and live by the wrench. If I could afford to tear it all back down, hot tank it, buy ALL new parts again, I would. But I can't. I don't know what went wrong, but all I can assume is that the rings were faulty. They were gapped, staggered, measured, and installed to spec. All facing correctly, oil controls butted, exactly as they were supposed to be. The compression readings haven't changed, something's wrong, and I know it wasn't the installation. Cylinders were honed perfectly, and were checked over by 2 professional machinists. Bores were straight, no taper, not oblong.

[izzo]

Yeah, I love the 720, it's awesome. But I just get pissed every time I get in it and remember that I just went through the engine, did everything right, and it's running the way it is. It's frustrating. I've never had this happen, and I've built many engines successfully, all of which are still on the road today.

I spent a lot of time documenting and recording my progress, step by step, instead of zipping right through. As always, I took my time and did it right. Then this.. .. and this isn't just some hobby that I have. It's my life. I pay my bills, eat, sleep, and live by the wrench. If I could afford to tear it all back down, hot tank it, buy ALL new parts again, I would. But I can't. I don't know what went wrong, but all I can assume is that the rings were faulty. They were gapped, staggered, measured, and installed to spec. All facing correctly, oil controls butted, exactly as they were supposed to be. The compression readings haven't changed, something's wrong, and I know it wasn't the installation. Cylinders were honed perfectly, and were checked over by 2 professional machinists. Bores were straight, no taper, not oblong.

 

 

Totally understand man. Sucks if you sold the truck over the motor tho :\ If it comes to that, i may be interested in buying it back off you (just the truck, not the motor)

[banzai510(hainz)]

Nothing wrong with USA made rings. Thats what I use.

 

maybe they werent gapped correctly.

 

I would just drive it. if chrome rings they take longer to seat but a quart of oil is too much.

 

16mpg out of a 4x4 720 I think is about right,dont you think?

 

SELL IT!!!!!!! You wont misss it. You have to many rigs to keep up anyways if your worried about money issues

[MicroMachinery]

So today I drove the truck up to Battle Ground. I was shocked that for driving up there pulling a dolly, and coming back with a car in tow, I am now getting 17.3mpg! That's a good sign, as I was barely getting 16mpg previously.

[datzenmike]

Drive harder, move faster!