Compression results on rebuild @ 234miles

[Bullet3]

Just want to get some opinions. I know it's early, but im a worry wort.

1:155
2:165
3:165
4:165

Wiseco 9:1's. Its an evo 3, so I dunno how different it is from NA 2g's. The reason i did it so early is that I am burning oil. I put in about a quart in roughly 125miles. No other leaks.

edit: also, im using Motoman's break in. The only thing is when i first got it running it idled for about 20 mins as i bled the cooling system.

edit again: this is my build thread if you want to see anything else. http://www.dsmtuners.com/forums/newbie-forum/382211-my-canadian-evo-iii-build.html

Im also running very rich. low 10's at WOT. But my exhaust doesnt look black like it should be.

Also, it was done with a hot engine, but not WOT. Didn't know I had to.

 

[Bullet3]

No leakdown done yet, napa didn't have one in stock. Trying to find someone who has one. Its a brand new 68hta, and the head was fresh from rebuild as well. I went for a good rip today, will check my level in a bit. Found out the car weighs 2640lbs with roughly half a tank. Dry weight in the 25's . Still have abs as well.

So i probably did another 75-90km of some hard driving, and it burnt about .1-.2qts. it seems to be getting better. I will keep monitoring as i get more km's on it.

 

[jlr2196]

Waaay to early to start looking at compression numbers or start worrying about oil consumption, it can take some time for the rings to seat/bed in, which has alot to do with the finish & type of rings used as mentioned. My engine actually took about 3K miles before it was fully broke in. If you want to break your rings in quick use a chassis dyno with a load program around 50% load for 25-30 minutes. On many of the race engines I've built the only way to get the rings broke in properly is on a chassis dyno due to the loose piston to wall clearances & chrome faced rings (harder) vs moly rings. Your compression numbers sound good this early & the oil consumption should keep coming down.
Cams have an effect on compression testing as well, the more duration/overlap the cams have the more compression you will bleed off. The longer the exhaust valve is held open during the transition from compression stroke to exhaust stroke you will start bleeding off that compressed charge due to the earlier opening of the exhaust valve.
Bottom line...give it at least 1500 miles.

 

[phunny]

Waaay to early to start looking at compression numbers or start worrying about oil consumption, it can take some time for the rings to seat/bed in, which has alot to do with the finish & type of rings used as mentioned. My engine actually took about 3K miles before it was fully broke in. If you want to break your rings in quick use a chassis dyno with a load program around 50% load for 25-30 minutes. On many of the race engines I've built the only way to get the rings broke in properly is on a chassis dyno due to the loose piston to wall clearances & chrome faced rings (harder) vs moly rings. Your compression numbers sound good this early & the oil consumption should keep coming down.
Cams have an effect on compression testing as well, the more duration/overlap the cams have the more compression you will bleed off. The longer the exhaust valve is held open during the transition from compression stroke to exhaust stroke you will start bleeding off that compressed charge due to the earlier opening of the exhaust valve.
Bottom line...give it at least 1500 miles.

I would agree if we weren't talking about 4qts every 500 miles. Something is definitely wrong and it certainly isn't the turbo.

 

[PieEyedPiper]

I would agree if we weren't talking about 4qts every 500 miles. Something is definitely wrong and it certainly isn't the turbo.

I thought we were talking about .4qts.

Oil is down to about 1/8" over halfway on the dipstick. Roughly .4qts burned.

4qts over 500miles would leave only ~0.3qts!


Has the WOT compression test been performed? I'm still inclined to think things sounds perfectly normal to me. I'd not worry much until 1500 as mentioned.

 

[Bullet3]

I have not done another comp test yet. It's at 600km now. I have sorta diagnosed the problem, but don't know what it means.

What's happening is on cold start(sitting atleast 2 hours), my car starts to billow smoke from the exhaust at a somewhat high amount. This happens for the first 30 seconds of driving, and after that i can go through every gear at any rate with no excess smoke.

It's almost like there is oil collecting at idle that is being burnt off while idle/first 30sec of driving. Exactly what I am describing happened about a half hour ago. Lots of smoke on idle, through the first 30 seconds, and once i got to my destination maybe 2 miles away, I got out to chat with a friend and there was no excess smoke from the exhaust at all while idling.

 

[Palmetto_TSi]

I agree that it is too soon to really be worrying about checking compression. When you built the engine, did you check the ring to land clearance on your pistons? It is possible that you have a stuck ring on the one piston. There is also the possibility that the rings somehow ended up with the gaps aligned on the one piston.

I go back and forth on the motoman break in. I assume you did the most important part (the oil changes) already. Although, that should have nothing to do with your issues. How much time did you allow for cooling between the full throttle runs? I honestly believe the cylinders are still not polished enough to give a great seal with the rings. Give it a few more Km before doing anything drastic.

I know you would never speed on public highways, but have you perhaps taken the engine to redline and then allowed the car to coast back down to normal speed? When you do this, we need to know if it smokes then too? A dyno run will show these results. Not that you have access to a dyno for just any reason you would like.

 

[Bullet3]

I agree that it is too soon to really be worrying about checking compression. When you built the engine, did you check the ring to land clearance on your pistons? It is possible that you have a stuck ring on the one piston. There is also the possibility that the rings somehow ended up with the gaps aligned on the one piston.

I go back and forth on the motoman break in. I assume you did the most important part (the oil changes) already. Although, that should have nothing to do with your issues. How much time did you allow for cooling between the full throttle runs? I honestly believe the cylinders are still not polished enough to give a great seal with the rings. Give it a few more Km before doing anything drastic.

I know you would never speed on public highways, but have you perhaps taken the engine to redline and then allowed the car to coast back down to normal speed? When you do this, we need to know if it smokes then too? A dyno run will show these results. Not that you have access to a dyno for just any reason you would like.

The short block was assembled at a shop, so I have no idea on clearances. I have done 4 oil changes so far. As per his site, the first 50 miles put on the car were done on a strict routine. 3rd gear 3k-6k-3k, 4th 3k-6k-3k, 5th 3.5k-5.5k-3k. Then down to 4, 3, and so on. After this I wasn't so strict on my method, but never drove at constant rev's til atleast 200miles, and even now I still try and vary rpms whether it by 500 or 3000.

As i said, the only time i really see the smoke billow is idle and within those first 30 seconds. To the best of my knowledge, when letting the engine brake from high rpm there is no smoke.

 

[jlr2196]

Sounds like the engine was built with some loose piston to wall clearance, once the engine starts to warm-up the rings begin to seal against the bore thus causing your smoke to disappear. Fairly common with diesel and older "built" V8's with forged pistons that needed the extra clearance but not so common among imports running forged pistons. Another possibility is valve seals.....

 

[herms99gst]

I was thinkng the same thing. If its only smoking at idle after a cold start it seems to me that u either have a valve seal or a few that or not installed correctly, or you have some valves that are not seating. Well, scratch the last one, you would have continuous smoke if it were the valve were seating incorrectly. So its obviously coming from the head. If it were the ptw clearances, you would smoke more during driving...not after a long period of siting. The oil would of had adequate time to return to the oil pan. when you say cold start, how long do you allow the motor to cool?

 

[Palmetto_TSi]

Sounds like the engine was built with some loose piston to wall clearance, once the engine starts to warm-up the rings begin to seal against the bore thus causing your smoke to disappear. Fairly common with diesel and older "built" V8's with forged pistons that needed the extra clearance but not so common among imports running forged pistons. Another possibility is valve seals.....

Pistons to wall clearance would cause piston slap on startup. Smoke is caused by rings or valve seals. Rings control compression in an engine, not the pistons.

 

[jlr2196]

Rings control compression as well as oil, hence the reason for the oil ring also know as the scraper. If the PTW clearances are loose than the rings don't have the ability to "push" against the bore as well as a tighter bore. Rings have a certain amount of outward springness to them. In case you don't know you can actually order "low tension" rings that don't have as much push against the bore in order to lower friction between the ring & bore, the trade-off is increased oil consumption & light smoking on cold startups until the engine reaches operating temp. Some of the engines with extremely loose clearances & low tension rings will even have a light, smoky haze during wot pulls.
PTW clearances are very much a contributor to oil control, compression as the rings.

 

[herms99gst]

I wasnt even taking into consideration the oil ring. I dont know what i was thinking.

 

[Bullet3]

Hey guys, been a while. I now have 4200km on the car and switched to synthetic 2000km's ago. I went on a road trip and after 1400km with synthetic, 95% highway driving I lost 2qts of oil.

I just did a compression test and the numbers were absolutely awesome.
All 4 cyl's read 110 first crank, 180 5th crank, and 190 max. I have yet to do aleak down test, but because its not constant smoke, I don't believe its valve seals, and the rings are crossed out with these results.

Tomorrow I'm going to pull the turbo and check it out, I'm thinking that's what it is going to be.