Topic: Burning oil, need assistance

[wohali]

Hi there - need some assistance on my project thread. On a newly rebuilt engine, I seem to be burning a lot of oil. A "poor woman's" compression test is showing leakage of air back into the crankcase. More information starting on this post and continuing down: http://forums.sohc4.net/index.php?topic=80554.msg1007027#msg1007027

Should I be pulling the cylinders now, or is this to be expected on a new rebuild? How long will it take for the rings to set themselves?

I double-checked ring orientation when I installed the rings, but these rings don't have a step on the 2nd one, so there really isn't a clear top and bottom on them. There's no mark or indication from Total Seal (who made the replacements) as to the correct orientation, and as far as I can tell, the cross-section is symmetrical.

[Bodi]

The second ring will have a slight "taper" I think. Every scraper ring I've ever seen has this. The top compression ring is flat faced and the second scraper ring is tapered so it scrapes oil down and slips over it going up. The oil ring lets this oil flow back via the holes through the piston skirt.

[wrenchmuch]

I looked at your other thread . 1 liter in 10 mins is excessive . I didn't look far enough into the thread to see what pistons you are using / re using . Are you sure the expander in the 3 piece oil ring was installed correctly (ends butted together not overlapped )? I live in Oakville and travel to T.O. almost daily . I'll send a PO with my phone number . Let me know if I can help .
Mike

[wohali]

@Bodi: The first and second rings are identical. Total Seal confirmed they did not cut a notch into the second ring.

@wrenchmuch: The oil ring is a one-piece, not a 3-piece. I could put the original Honda 3-piece rings back in if I had to, but I would think these one-piece ones would be fine.

[dave500]

compression checks should really be done with the engine hot,ignition off and the throttle held wide open,id run it for a while ,even ride it if you can then recheck it,carefull with the plugs going in and out over and over,if your sure you didnt snag any rings on assembly and the valves are adjusted correctly was the bore taper and out of round measured?this can cause low compression till the rings seat if its minimal,if its out of spec badly it can easily break a ring,we hope this isnt the case,dont baby the motor either just ride it normally more or less with a few short seconds lugging SLIGHTLY in too tall a gear three or four times,id recheck it after that.

[wohali]

Thanks guys - I am going to try your suggestions. I did run the compression test with the throttle full open, ignition off, but it was a cold engine - I've already burned myself too many times to want to put the adapter into a hot block on #s 2 and 3. Still I will try and re-do the test on 1 and 4 once she's hot again.

@dave500: I did check out of round with an ID gauge and a mic and it was < 0.01mm on all 4 cylinders.

The full update for today is below

OK - today I had a chance to refill the oil, put Hondaman's ignition back in the circuit, wheel her outside and adjust the timing dynamically. She was very close but needed a little tweak (was slightly retarded). A small rotation and another check with the strobe and she's spot on, maybe 1 degree off, max.

A plug for the Hondaman Ignition: after adding it in, she started on the first push of the starter. No teasing required.

After about 10 minutes of running the engine and testing it, she doesn't seem to have dropped the oil level in the tank, though the level is a bit higher than I would like right now (even with the oil temp about 80F, ambient is 70F).

She's still blowing blue smoke at a steady pace, increasing in volume with more throttle applied. However upon first startup, there was no oil at all - it took about 30-60s before blue smoke started coming out.

I'm also getting a little smoking from the manifold, but this is my own fault: it smells like burnt paint. I used a heat resistant primer and middle coat, but I risked applying a silver top coat that wasn't heat resistant. And surprise! Guess I know how that work out now  My one place to skimp, I couldn't see ceramic coating a header in this condition for more than it'd cost to get a brand new header.

Ran out of time due to work running over, so tomorrow I'll rider her around the neighborhood at reasonable speed and low RPMs and see what happens. I'm hoping that 10-100 miles of riding will sort her out, even if I go through a quart or two of oil. If she's still burning oil after that, guess I'll pull the cylinders.

One last thing: she decided to start running a bit rough towards the end of the test. I'm going to assume this is due to oil in the cylinders, since the smoke didn't decrease with time. I'll be sure to take a mobile phone with me while on these test runs

More tomorrow. Feeling a bit more upbeat.

[Hush]

I'm sure if oil was washing the cylinders the spark plugs would be fouling up and even with the HM ignition you would be dead in the water.
Could it be the valves/seats instead of the rings? Letting oil run down into the top end and being burned off almost straight away by the running engine!

[scottly]

You pumped oil into the cylinders during the compression test; a fair amount of that oil is now coating the insides of your exhaust pipes, and will take heat and time to burn off. Don't bother with more compression tests at this point, as you don't seem to have a compression problem.
You may have oil-fouled a spark-plug or 2, causing the rough running?
Also, 1+ to Dave's comment about accelerating in too low of a gear to help seat compression rings, and will also generate the heat needed to burn-off the oil. Short bursts, followed by cooling periods is the way I learned to break-in motors.