Burning oil on right side.

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jsouthard

jsouthard

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Jul 26, 2008
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Hey Guys,

Recently restored that '69 Fastback. Everything is running great, pulling great, idling great and she looks fantastic.

One problem is she is aggressively burning oil out of the right side. The left side plug is burning perfectly but the right side plug is fouled. I thought the issue was the original 12v coils, so i replaced them with the CNW single coil conversion. Still doing it.

I thought I may not have broke in the seals yet but after 500 miles i would think she should be broke in. Also, it has happened since the original start up and continues (over 500 miles later).

Boyer
Mikuni
Single coil conversion
new plug wires (have been switched)
timing on
New battery

Any suggestion on where to look will be much appreciated.

Thanks,
 
J
1. It could be the intake valve seal popped off which in tales removing head again or you can do a search to see how it is done with a rope or what Ludwig did.
2. Piston ring put on upside down??? Guessing there.
But these are the things that I would suspect.
Hope you get it right.
CNN
 
I would think easiest place to start looking would be a compression test, see if the rings may be the problem
 
You want to determine if the problem originates from the head or the piston of that side. By disabling the rocker feed line so that the head is starved of oil is a good test method and will not hurt/damage the head as it can go a long time before wear starts. The head is way over-oiled to begin with. If the problem persists you can rule out the head. If it clears up you can check for a popped off seal or loose guide or whatever.
 
maylar said:
When does it smoke... at idle, on decel, or under power?
Click to expand...

It doesn't smoke at initial start-up. And the first couple miles it's all good. Once she warms up it appears to be happening at all stages. Idle, 1/4 throttle, 1/2 throttle etc.

xbacksideslider said:
I gather that this is a new top end?
Maybe the rings on that side haven't seated?
Click to expand...

This is what i am hoping. I'm going to give her hell this weekend and see if she settles in. I think i may have been a little soft on her to begin with.

I am in the process of moving to Baltimore, MD from Nashville so i really don't have the time to dig in right now. Thanks for all the suggestions guys. I will keep the thread updated when i get back to Nashville.
 
Re: Burning oil on right side / Power Loss.

After a compression test i found that i was getting a fairly close rating on each side. 160 Left, 150 Right.

I pulled the head yesterday. Definitely a carbon build up on the right side (where she was smoking) compared to the left. At this point I'm really at a loss. I was getting a leak past the copper head gasket anyways. Any suggestions on ways check if it's the head that's causing the issues before i reinstall it?

Reminder... The two issues i have been having are... 1.) Heavy burning of oil on the right side and 2.) Power loss / at 4k RPM's or above.
 
A shop can do a test on the head to verify the integrity of the valve sealing--or you can pour a little gas on the upturned hemispheres--very little if any should leak through overnight. I'd put a new valve seal on that side even if it looks all right.

If the rings are right-side-up, is there any chance that the end gaps are too tight? If the ring ends are butting against each other the rings will never seat properly--best of luck


Tim Kraakevik
kraakevik@voyager.net
'72 Combat, '74 RH10 850
 
kraakevik said:
A shop can do a test on the head to verify the integrity of the valve sealing--or you can pour a little gas on the upturned hemispheres--very little if any should leak through overnight. I'd put a new valve seal on that side even if it looks all right.
Click to expand...

I did the gas test last night and almost all the gas slowly leaked (and or evaporated). Looks like it came out through the intake valves more than it leaked through the exhaust vales, which i would have guessed. With that said, it leaked very, very slowly. no mess or gas spills on the workbench. Just a little pooling out of the intake ports.

I'm going to take off the barrels this week and check to make sure the rings are on properly.
 
Dunstall's tuning brochure recommends filling the exhaust and intake tracts with petrol in turn from the opposite direction, with the head tipped fore and aft respectively--the greater volume of gas and separate tests might help confirm the leakage path


Tim Kraakevik
kraakevik@voyager.net
 
I pulled the barrel to take a peak today. Everything looks OK to me. I've added some pictures to see if anything stands out to you guys. It looked like two of the ring gaps may have been overlapping (or close) on the right side, which was the smokey side.



Overall everything looks pretty good. There was a little wear on the push rods but besides that i don't see any other problems with the pistons or rings. Hopefully one of you can see something that i don't before i put her back together.
 

Attachments

Did you try the suggestion above about disconnecting the oil supply line to the head for a while ?
If doing this stops the smoking, you know the oil is coming from the head. If it continues, then its rings. Otherwise, too many things it could be right now ...
 
Something does not seem right. Did you say you have 500+ mile on these pistons. Holy crap. I know it's only 500, but man, those are cleeeeean.
.
jsouthard said:
I pulled the barrel to take a peak today. Everything looks OK to me. I've added some pictures to see if anything stands out to you guys. It looked like two of the ring gaps may have been overlapping (or close) on the right side, which was the smokey side.



Overall everything looks pretty good. There was a little wear on the push rods but besides that i don't see any other problems with the pistons or rings. Hopefully one of you can see something that i don't before i put her back together.
Click to expand...
 
pvisseriii said:
Something does not seem right. Did you say you have 500+ mile on these pistons. Holy crap. I know it's only 500, but man, those are cleeeeean.
Click to expand...
That's what I thought.

Dave
69S
 
It's been a while but i thought i would update the findings on from this issue.

We pulled the top end down and found that the clearance in the barrels on the right side was just a little too great. Once the engine warmed up and expanded, it was enough for oil to get past the rings and burn out the exhaust.

Feedback from the machinist;

"The piston clearance is .0055" now before honing, and will probably be .0065" after honing. 7 thou is about the limit for clearance. Normal clearance is .003-.004". I recommend going to 40 over pistons and bering it out. I am normally not wild about doing this, but you are right on the edge, and whoever assembled the engine before installed an addition oil control ring in the same groove with the middle compression ring, so I am not wild about the possible ring land clearance.

Re-bored the barrels 40 over with the correct clearances and there's no burning oil.

Problem solved!
 
Alrighty JS, now just keep an eye on the carb air boots and bores may last for the next generation to deal with. I'm still working on catching up on riding time to equal the down times of dealing with what you just did.
 
jsouthard said:
It's been a while but i thought i would update the findings on from this issue.

We pulled the top end down and found that the clearance in the barrels on the right side was just a little too great. Once the engine warmed up and expanded, it was enough for oil to get past the rings and burn out the exhaust.

Feedback from the machinist;

"The piston clearance is .0055" now before honing, and will probably be .0065" after honing. 7 thou is about the limit for clearance. Normal clearance is .003-.004". I recommend going to 40 over pistons and bering it out. I am normally not wild about doing this, but you are right on the edge, and whoever assembled the engine before installed an addition oil control ring in the same groove with the middle compression ring, so I am not wild about the possible ring land clearance.

Re-bored the barrels 40 over with the correct clearances and there's no burning oil.

Problem solved!
Click to expand...

Doesn't quite sound right Joe, yes 0.0055'' is getting up there but still fully usable and a spacer rail in the second ring groove? sounds more like it got butchered not assembled
 
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