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Fri Apr 01, 2016 4:31 pm

Just rebuilt the top end on my girls 1600. New rings & valve job. No doghouse. Timing checked. Points checked. Fires up fine. Idles fine. Getting white smoke out the exhaust. No backfiring. Thought maybe excess oil, but it's between the dipstick marks.

Fri Apr 01, 2016 4:34 pm

Is this after it's broken in?, or the first few minutes post reassembly?

Fri Apr 01, 2016 4:38 pm

First few start ups. Been letting it warm up so I could set the carb. No white smoke at idle. Just after I let up on the throttle.

Fri Apr 01, 2016 5:17 pm

Get out on a quiet road and do a few long solid pulls followed by a long foot off the gas decel, speed up, slow down, speed up, slow down without touching the clutch or brakes. Then report back how the smoke is.

Fri Apr 01, 2016 5:30 pm

Roger that

Sat Jul 02, 2016 10:15 am

Lots of white smoke when I decelerate

Sat Jul 02, 2016 10:24 am

definitely smoke and not moisture.?? Might have a ring in upside down- or just pre-break in jitters.- run it hard and back off for about 20 miles-

these chrome rings on a recent hone?

Sat Jul 02, 2016 1:21 pm

I was pretty careful installing the rings. I honed cylinders. The rings are the standard rings. Only thing I can think of is maybe I didn't separate the ring gaps

Sat Jul 02, 2016 2:41 pm

It's not the ring gaps- they walk anyway when the engine is running. Who did the heads- were the guides sloppy and they left them alone? Smoking on decel is usually through the valve guides. It's probably light gray smoke, which is oil.

Sat Jul 02, 2016 3:27 pm

Bruce Amacker wrote: It's not the ring gaps- they walk anyway when the engine is running. Who did the heads- were the guides sloppy and they left them alone? Smoking on decel is usually through the valve guides. It's probably light gray smoke, which is oil.

that is what i am thinking too

Sat Jul 02, 2016 3:53 pm

I think you could be right. I swapped out the heads because of broken exhaust studs. There was no smoke with the previous heads.

Mon Oct 24, 2016 6:55 am

UPDATE:

I removed the heads and could see there was oil in the combust chamber, and pooling in the cylinders. The ports for the manifold intake had oil as well.

Convinced it was the valve guides, I swapped out the heads with known good heads. I'm STILL getting white smoke. Lots of white smoke when I throttle. No smoke at idle. It has to be the rings right? Its baffling that I just installed NEW rings. Could I have defective new rings?

Mon Oct 24, 2016 7:43 am

You may want to check the cylinders for out-of-round specs as well as wear tolerances.

Mon Oct 24, 2016 9:17 am

What does the smoke smell like?

Mon Oct 24, 2016 10:21 am

BarryL wrote: What does the smoke smell like?

can't say I was smelling the smoke. what kind of smell should I look for?

Mon Oct 24, 2016 10:55 am

Oil or water. If it's condensation, no worries. If you can hold a piece of newspaper behind the exhaust and get oily spots on it, worry.

Mon Oct 24, 2016 11:48 am

thanks for the tip! Ill do that next. I'm 97% convinced its the rings.

Mon Oct 24, 2016 6:42 pm

brese73 wrote: BarryL wrote: What does the smoke smell like?

can't say I was smelling the smoke. what kind of smell should I look for?
Go back and goose it by hand with the carb throttle while getting a blast of it. You can smell the richness of gas vs oil vs ?. Oil is usually bluish. Reason I ask is it has happened that someone accidently put diesel in the tank. All it takes is a little and it will burn white like a skywriter. Oil in the intake port is usually bad guides and will burn lighter colored than ring oil but you said you switched to (known good guide?) heads. Have you tried emptying the gas tank and reload with different gas?

Mon Oct 24, 2016 10:48 pm

Did you replaced the Oil pump for a larger one?

If the heads are overflowed with oil even with tight valve guides some will pass and get into the cylinders.

Tue Oct 25, 2016 11:32 am

little bit of history:

-motor was in a 69 bus that sat on a farm for years. without cleaning it up too much, was able to start it up. no smoke.

-I pulled the motor out of the bus to clean it up a bit. mice built a nest in the tin. the studs on the exhaust ports had eroded away and broke off when I pulled the muffler. I installed new rings. I replaced the heads with what I was told were good heads. in addition, I did valve job but did not replace the guides. got smoke.

convinced the smoke was due to bad valve guides, I replaced those heads with KNOWN good heads that were previously installed on my other bus. still got smoke

I never changed the oil pump. I will empty the gas tank and fill with new gas to eliminate that as a source. I will also hold newspaper up to the exhaust to confirm if its oil or condensate. I will also pull the manifold to see if Im getting oil in the intake.

what baffles me is that the motor did not smoke before I did rings, valves, heads, etc.