New Motor Burning Oil

[BCbrad]

Hi Folks, last summer I rebuilt my motor. Full rebuild, new pistons, rings, cams, rebuilt head. It still burns oil, I am quite sure I did things correctly... wasn't rushed or anything. Any tips on starting out where to start troubleshooting, its disappointing after all that time and money.

[DanD]

How did you hone the cylinders for the rings, and how did you break it in ? Did you have the valve guides and seals replaced ?

How does it smoke ? Is it like puffs on acceleration and deceleration, or is it like a mosquito fogger ?

I used Deves rings on a rebuild a few years back, and I really had to work the engine during break in. The cylinder head was done by one of the big parts suppliers, so there was no problem there.

[BCbrad]

How did you hone the cylinders for the rings, and how did you break it in ? Did you have the valve guides and seals replaced ?

How does it smoke ? Is it like puffs on acceleration and deceleration, or is it like a mosquito fogger ?

I used Deves rings on a rebuild a few years back, and I really had to work the engine during break in. The cylinder head was done by one of the big parts suppliers, so there was no problem there.

The cylinders were bored to match the new pistons by a machine shop. I ran is for about 20 minutes around 3k rpm. Yes the valve seals and guides where replaces. The smoke is fairly constant at idle, high revs give and initial bigger puff and then the exhaust goes clean. Also, once the engine is warmed up it does not seem to be as bad. Also, it is definitely not coolant.

[GeorgeT]

It used to be that a rebuilt motor would use oil until the rings would "seat" and then stop. How many miles are on the rebuild?

[narfire]

Perhaps pull a plug or two and have a look at the top of the piston. See if there is any oil there. Perhaps a slight chance a ring broke while pushing the piston down at re build ? I did it on my first Spider when I was a kid trying to rebuild my engine almost 40 years ago.

[BCbrad]

I didn't log the miles on it when I put it on the road. But I would say 300 miles tops. I did compression tests today.

cyl 4 = 129 dry & 147 wet
cyl 3 = 148 dry
cyl 2 = 124 dry & 149 wet
cyl 1 = 149 dry

So these are very disappointing too me. Is there any chance they will seat or did I screw something up? I really don't want to pull the motor again, it wasn't a job I enjoyed. Is there any danger in continuing to drive it this way?

[majicwrench]

NOt sure why compression is disappointing you, squirting oil in cylinder will ALWAYS increase reading......but the oil consumption should disappoint you. As was mentioned is possible (ask me how I know) to damage an oil ring on install. What do the plugs looks like?? Engines need to be driven hard to properly break in rings, but really, you should not be seeing smoke, so something is amiss.
What do plugs look like??

[vandor]

> The cylinders were bored to match the new pistons by a machine shop.

Did you wash the grit off the cylinder walls with soapy water after they bored it? If not, then all the tiny particles from boring stay on the cylinder wall and destroy the rings in short order.

[BCbrad]

NOt sure why compression is disappointing you, squirting oil in cylinder will ALWAYS increase reading......but the oil consumption should disappoint you. As was mentioned is possible (ask me how I know) to damage an oil ring on install. What do the plugs looks like?? Engines need to be driven hard to properly break in rings, but really, you should not be seeing smoke, so something is amiss.
What do plugs look like??

My understanding is that if the compression is raised with some oil in the chamber that means that the rings are not sealing.

The plugs were very consistent; black dry soot. No other coloration, build up, or scale.
http://i61.tinypic.com/dcuh6t.jpg

[BCbrad]

> The cylinders were bored to match the new pistons by a machine shop.

Did you wash the grit off the cylinder walls with soapy water after they bored it? If not, then all the tiny particles from boring stay on the cylinder wall and destroy the rings in short order.

Yes, I did do that. I remember that, but the reason was different... something about the cutting oil used. Probably because it would be contaminated just as you say. But I was thinking more of the fluid than the contaminants.

[majicwrench]

Wet compression test, unless you do them constantly to know what they mean, basicly useless. Any time you put oil in a cylinder it will bring up numbers, ring good or bad. Wet compression test is really not a good test of anything, been decades since I have seen anyone in a shop do a wet test.

If you really wanted to do a wet test, would measure amount of oil inserted and do all four cylinders.

[azruss]

what do your plugs look like. If you have a cracked ring, you should have one plug that looks different from the rest. Are you sure it is oil smoke you are seeing and not fuel.

[DanD]

If you had a bad ring, It would smoke all the time. Initial ring break in usually centers around working the engine up and down through the gears, and letting compression push the rings out to properly seat them and break them in.

I think there is hope that you just need to drive your car a little more aggressively and break in those rings. Go out on a windy road and work the car up and down through the gears. Don't just cruise in one gear at a constant RPM, run up and down the rev range. You are not going to break the car.

Compression getting behind the rings is what pushes them out and seats them, NOT spring tension. If you drive it like a garage queen, the rings will never seat properly.

[DanD]

http://www.ntnoa.org/enginebreakin.htm

[djape1977]

roughly honed cylinders.
no help but to re-do the block.
seen this more than once...