The Stovebolt Site Forums The Shop Area Engine Shop Quick main bearing question

So, I was putting my rear main bearing back on, and two of the lock washers broke. I know I know, I suppose I should have had new ones here when I started, but I never really thought about it. Can I just use some grade eight split lock washers?

I don't know what split washers are but those lock washers are nothing special. In addition, I don't know why they were used. Those lock washers only come in to play after a nut has backed off and there is little tension. At that point the bearing would not be functional.

I just phoned around to the local hardware stores, and they don't even have graded washers, so I'm just going to put on regular ones anyway. I just checked the rear clearance, and it's 3 thousands, which I understand is just within the tolerances. I really don't feel like adjusting the rest of the bearings, so I think I'll just leave them alone. I know that's probably not the best, but the rings occasionally let out blue smoke while going downhill. And I did fins about five drops of coolant in the clutch area, Which I presume is from that rear frost plug, as per your pictures and experiences. I have a spare 216 that I was going to rebuild next winter, after I build a garage this summer. I'm on the fence about adjusting the mains though. I mean it is the right thing do now that the pan is off. Right now there appears to be a two thousands shim on both sides of each of the mains. I suppose I should recheck it with one removed. I guess I'll think about it while I go and get the washers....

What lock washers?? There shouldn't be any lock washers on the main bearing bolts as they rely on torque alone to stay tight.

-Ed

Are you talking about the pal nuts on the connecting rod caps ?
I have never seen lock washers on the main caps .

The 216 has lock washers on the main bearing bolts. I think it is kind of crazy but that is what they have.

Christopher,
it is difficult to tell drag when adjusting the mains. A good technique is to use a piece of .001" shim about 1.4" wide and about 3/4" long. Place it across the bearing and button it up. If it locks the crank, the clearance is .001 or under. You can use .002 to tell where you are.

Fred

Nope, there were lock washers under each and every main bolt. I'd show you a picture, but it's back together now. Who knows if they're original. My truck was rebuild about twenty years ago, and has hockey pucks for engine mounts. Which is next on the list of things to do. The long list!

I think I'm at about two thousanths. They were all at three thousanths before I started. I still have one shim left on the cam side of things, so that's positive. And, it was much cleaner in there than I thought it'd be. I would imagine that's from the quart of Kerosene I have been putting in before changing the oil. Now that the pan is clean, I think I'll calm down on the solvents.
Say Fred, did you use aluminum pistons when you rebuilt yours? I should have taken a picture of mine from the bottom, but they sure looked like aluminum to me. I suppose that means I'm ready for the drag strip.

Yes, I picked up some aluminum pistons on Ebay. My old ones were in fine shape but they were cast iron. They were still very large and long but somewhat lighter than the originals. I probably have a throbbing 92.5 HP now!

Did your cast iron pistons look like cast iron? Or were they shiny like aluminum. I can't believe now that I did not take a picture. I was in such a panic to get the oil pan back on, and the starter before it got dark. I'm pretty sure mine must be aluminum, because they have a little slot on the skirts. We shall see today how it runs.

It is pretty hard to tell by looking inside , I would think. I would guess that they are the colour of oil. When I was working with them, they were a dull grey colour. An interesting detail is that the top ring was further down from the crown than the originals. I would guess this is to give some strength because they are aluminum.

Boy, I really should have taken a picture!! Mine are all aluminum-y grey like, except for the underside of the tops, they were a little brown. I would imagine that the cast iron pistons would be a much darker grey, or blackish even. I'm sure I need a ring job. It's not bad, lots of compression, 120# to 125# in all six, but I think I've got a broken oil control ring, or rings. When I coast down a long hill, I get some blue smoke when I get back on the throttle. But only sometimes. After seeing how clean it was in there, I don't really know when I'll ever get to fixing that. Probably on the 12th of never.

Boy Fred, if we ever meet up it looks like were both ready for the drag racing seen with the light aluminum pistons. HaHaHa.

Christopher, I thought one old-timers would bring this up, but your blue oil smoke description is symptomatic of bad valve guides. When you get off the throttle the vacuum is at it's highest and oil is sucked past the valve guides. There's very little combustion occurring in the cylinder at this throttle setting so the oil is not all being burned. When you get back on the throttle and the cylinder gets a full load of air/fuel it burns off the oil that is left in the cylinder. Best to look into a valve job before you conceder rebuilding the short block.

Look in your mirror at night when pulling away from an intersection. If you are pushing smoke on acceleration this is a sign of worn rings. You may not see anything in the daylight but it will show up at night in the street or headlight. Your compression pressures look quite normal for an engine that has a few miles on it and really shouldn't be any concern.
Denny Graham
Sandwich, IL

You know, I was thinking the same thing Denny. The previous owner had his mechanic rebuild the head, just last april, because it failed a compression test. But then again, the head bolts were at 35 foot pounds when I re torqued them. The timing was set so far retarded that the truck would only run at idle, and the same mechanic rebuilt the carb at the same time, and left out the accel pump check valve ball. Plus, when I removed the rocker arms to re-torque the head, I found that the mechanic had not cleaned out the sludge from the rocker arm tube. In fact, it was about an eighth of an inch thick in there. I'm sure you remember my aggravation early on in my stovebolt career. Unfortunately the combination of my big wooden box, and tiny stock mirrors, I can't see my exhaust at night. One of my friends has those super-duper bright annoying headlights on their car, so maybe I'll get her to follow me and I'll concentrate on it. I only get the smoke sometimes when I decelerate. I wonder if the oil control ring could be broken and turning or something.

I haven't looked in my shop manual yet, But I suspect that the head must be removed to do the valve guides. If that's the case, there isn't much stopping me from pulling the pistons out the top and putting new rings on. Boy, is that ever a long way down the list!

I am excited to say though, my rear main isn't leaking yet...
And the rebuilt starter- The truck fairly flips over when I hit the stomp now!

Hey Denny, off topic sort of, but is there some place like stovebolt where I can find information about my 49 pontiac? Can I ask about it here or chevy chatter? Its a flathead six, and not stovebolt, so does that leave me out in the cold?

Christopher,
have you had a look at the "Old Car Manual Project" site? There may be some information on there for your Pontiac. I will look through my material to see if I have anything.

I am concerned about what you said about your oil filter delaying the buildup of pressure. I haven't put mine on yet and I may decide not too.

Once more, I don't think you got a ring problem, it's worn valve guides. You don't know what this mechanic did to the head. If he didn't bother to clean things up and assure that there was oil flow then he might not have even looked at the guides. He might have just tried to lap in the valves to get a little more life out of it before spending $400 or $500 to do it right.

On installing new rings in a worn cylinder. If your rings are worn then you can be sure that the cylinders are worn also. Chances are there will be a ridge at the top and probably some taper. So even if you use a ridge reamer and hone the cylinders, your still going to have the taper and your still going to have to come up with some sort of a compromise when you fit all the rings to each cylinder.
Just get a good valve job done for now with new valves (they’re cheap) and guides and see how she runs after that. An hour or so to get it off and an hour or so to reinstall it and a good auto machine shop should have the head back to you in a couple of days.
Can’t help ya on the Pontiac, Fred’s probably got the right idea, try Keith’s TOCMP.
Denny Graham
Sandwich, IL