1951 super c stills smokes

gary7764 · May 16, 2011

I finally got my conn bolt figured out now I need some advice. I got my commpression rings and oil rings in the engine and got it back together but it is still smoking and still have oil on my pistons. I put the correct rings in according to the book. Can some one please tell me if I have done something wrong or if it could be something else wrong. By the way whoever redid the rings before me had the wrong oil rings in. I did all the torques right and the gaps on the valves according to the specks in the shop manuel. Could someone help me please?

Oldiron29 · May 16, 2011

Gary, Did you remove the springs on the valves and check to see if the valve guides are good.
Could be getting oil through guides.
Have you taken compression readings and what are they? How long have you had the tractor? Never no what PO did. oldiron29

gary7764 · May 16, 2011

Yes sir I don't know about the valve guide but I took the head to a machine shop they grinded the valves and was supposed to check all that.

Oldiron29 · May 16, 2011

Gary, Thats good the head has been done rule that out. oldiron29

gary7764 · May 16, 2011

how else would the oil get ontop of the pistons? And how could I find out other than taking the vavle springs off. Just becouse they were supposed to check this dose'nt mean they did what they were supposed to.

Anonymous-0 · May 16, 2011

questions
new sleeves & pistons or just re ring job? if rering was a glaze breaker or hone run in cylinders to rough up surface so rings will seat?
ring gaps staggared or in line? time run and loads applied to break in engine (seat rings) it needs to be pulled to raise cyl temps. for rings to seat and seal up. any or all of the above may apply

gary7764 · May 16, 2011

I can see the oil on #1 and #4 spark plug holes. But not on #2 or #3.

Oldiron29 · May 16, 2011

Gary, Oil could get to the piston through the rings or the head gasket. To grind the valves they had to take them out. So they should have checked the valve stems and guides.
oldiron29

Oldiron29 · May 16, 2011

Gary, Did you try the new rings in the cylinder before install and see what the end gap was? I think, can't remember should be .017
oldiron29

gary7764 · May 16, 2011

I did re ring did not use hone to smooth survice becouse cylinder walls were smooth. Other questions did not understand what you are saying as far as pull to raise cyl temps.

teddy52food · May 16, 2011

What kind of oil rings did you put in? If they are the scraper type, they have to go in with the bevelup so they scrape the oil down. Maybe they are upside down on # 1& 4.

gary7764 · May 16, 2011

how do i check the end gap

Oldiron29 · May 16, 2011

Gary, You put the ring in the cylinder as if it would lay in the piston and see what the gap at the ends of the ring measure. oldiron29

Anonymous-0 · May 16, 2011

it needs a load applied such as disking harrowing ect so that the engine is working not just running this raises the cylinder temperatures and aids in the breakin process also raises cylinder pressures when on the power stroke which also helps the rings seat. you should have broken the glaze on the cylinder walls as the rings won't have enough friction on a very smooth surface to wear in properly (seat)

gary7764 · May 16, 2011

i put in 3/32 comp ring and 1/4 oil ring what the shop manual called for. but it had the smaller oil ring and the larger comp ring. But the shop manual says that the only the oil ring would change but that was for a kerosene. But for a gas engine was the same 1/4" oil ring and 3/32" comp ring. but the gap was smaller than what it is now but i did not gap it.

gary7764 · May 16, 2011

how dose the oil get on the pistons through the rings?

rustred · May 16, 2011

well thats your problem.have to hone cyls in order to seat the rings. you dont want smooth walls.once you got her running need to take it out and work it hard and to operating temp in order to seat the rings. just idling around will do nothing. since the cyl walls are not honed may get away with letting it sniff some bon-amy through the intake at carb. get it hooked to an impliment go in the field and make it work. get someone to walk beside and let it sniff up a couple table spoons of the powder. to check ring end gap need to install ring in cyl at top, not in worn section and measure gap with feeler guage. need 3-4 thousands for each 1" of bore. a 3" bore would require .012 max gap.
you may need to put on 100 hrs or so of hard pulling to get them rings seated.

Moondoggie · May 16, 2011

I had the same problem with my 340 last year. New rings, redid the head and honed the cylinders. Smoked till I was about to tear it apart. Then did 15 acres with a bush hog last fall. Hasn't smoked since. Just work it and the rings will apparently seat themselves.

rustred · May 16, 2011

it is pumped out along side the cyl. wall and ring. thats why need to get the engine under load so every time that spark plug fires it forces the rings into the cyl wall and wear in to match, thats how you seat rings. you hear everybody talk about engine break in but they dont have any idea what that means.

rustred · May 16, 2011

only at the very top or bottom, in other words not in the wear section of cyl.
for example if you fitted a ring to the worn section at the top of cyl. and had a sleeve with a lot of wear then the ring can cause scoring or break when at operating temp due to expansion as it travels down in the less worn area. sleeves wear in a taper, wider at top than bottom.
but in these cases sleeve should be replaced or bored. but thats the reason.

rustred · May 16, 2011

i cant follow this explanation. basically rings need to fit snuggly in ring groove with very minimal side clearance, and proper end gap in cyl. if the ring is able to move up and down in groove then the piston groove is worn out and the piston is junk. put together this way the rings will break , score the cyl, and total the piston. the top ring groove always wears the most. i hope yours are as explaned cause if you have ring groove spaces then may as well tear her down again.

Allan in NE · May 17, 2011

You just learned lesson #2 in engine rebuilding and you learned it the hard way. Of course it's gonna burn oil; only now it is gonna be worse than it ever was before.

"Re-ringing" an engine is an absolute total waste of time.

Take it back down and do it right with new sleeves or rebore and new pistons/rings.

There is no way you can get the taper/wave out of those old cylinder walls, I don't care if you hone it until the middle of next month.

Also, those piston lands wear and there isn't any way of recouping the metal that is now gone.

Allan

dhermesc · May 17, 2011

He didn't hone the cylinders.

Actually we've had pretty good luck honing cylinders, but its a judgement call based on the condition of the cylinders - not based on trying to get it done as cheaply as possible.

mkirsch · May 17, 2011

New rings don't seal tight against the cylinder walls. Even though they both look round to the naked eye, at the microscopic level they are very different shapes.

Oil pushes up past the rings through these tiny gaps between the ring and cylinder wall.

The rings and cylinder walls need to "grind" against each other so they match each other's shape perfectly. That's the purpose of honing the cylinder.

Honing puts tiny grooves in the cylinder wall that act like micro-sandpaper on the rings. By the time the grooves are worn away (break-in period) the ring and cylinder fit together perfectly and make a tight seal.

Re-ring jobs are only a partial and temporary fix, if the pistons and sleeves aren't completely shot. It has to be done RIGHT, though. You need to hone the cylinders so the rings will break in. You need to gap the rings to make sure the cylinders aren't too worn for a re-ring job.

El Toro · May 17, 2011

I think you need to install a new sleeve/piston kit. If you didn't have your crankshaft measured for wear you need to have that done at your local auto machine shop. There's no short cuts if you want the engine rebuild to last. Hal

Allan in NE · May 17, 2011

"By the way whoever redid the rings before me had the wrong oil rings in."

Yeah, guess he could take it all apart and hone it. That then would make a total of three times is has been done wrong.

Kee-Rist, he's gonna wear the bolt threads out on that thing. :>)

Allan

dhermesc · May 17, 2011

I guess if your in the habit of delaying maintenance until you have nothing left new sleeves probably are a must everytime the engine is cracked open.

rustyfarmall · May 17, 2011

(quoted from post at 18:41:11 05/16/11) i put in 3/32 comp ring and 1/4 oil ring what the shop manual called for. but it had the smaller oil ring and the larger comp ring. But the shop manual says that the only the oil ring would change but that was for a kerosene. But for a gas engine was the same 1/4" oil ring and 3/32" comp ring. but the gap was smaller than what it is now but i did not gap it.

That shop manual was printed 60 years ago, and the recommendations are based on factory original pistons. It is highly un-likely the original pistons are still in the engine. Much more likely the pistons you have are aftermarket, and they may or may not use the same thickness rings as the originals.

1951 super c stills smokes

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