Seems like I spent hours when I was a little kid with what the ol' man called a babbit knife cleaning up after a pour and then sanding and filing things to size/tolerance. He always told me it was because I had small hands and that small hands were best when working with babbit. the truth was I think that it kept me out of his hair and he didn't like the grunt work so much.
Just bought a 42 Chev, wonder if I should Plastigauge the bearings and adjust if necessary? Can this be done without disturbing the oilers? Can you get all the mains off with just removing the pan? Was thinking of taking the pan off and scraping out the sludge since it has no filter.
Mains cannot be plastigauged with the engine in the car because the crank weight is carried by the caps and the clearance you want to measure is now above the bearing journal. You must roll the car over on it's top to Plastiguage mains or remove the engine and put the bottom up while having a beer.
Interesting stuff. I was not too familiar with the poured bearings. I youtubed it and found some good stuff. It's pretty involved, I would call it an art. Cesar
Rods are not a problem as long as you are certain the rod and piston assemblies have been pushed down to contact the crankpins. Be aware, Plastigauging is an in-exact measurement much like a compression gauge. Plastigauge is to a set of inside and outside micrometers, as a compression gauge is to a cylinder leak down tester. They are both expedients. Analogy: The Doctor uses a sphygmanometer to measure your blood pressure. It has a manual bulb type air pump, a stethoscope, and a mercury manometer that reads pressure in inches of mercury. I was given a wrist style that runs on AC and gives an automatic read-out. I find it very useful to make sure I am still breathing.
Just Plastigage rods & mains one at a time, and don't turn anything while measuring. The mains can indeed be checked in the car - one at a time. The squirt & slurp oiling system won't be disturbed as it's all in the pan. My main concern would be acid etching or spalling of the bearing material.
Have you ever used boring tools on the babbitt and do you have the boring tools now? Wanna sell them? Pouring the babbitt is quick and easy, it is the sizing that takes effort
I asked the same question on another board and someone pointed out that the weight of the crankshaft hanging down, will prevent accurate measurement of the mains because the crank will not be tight to the upper bearing. Also taking the pan off disturbs the oiling arrangements which must be reset. Wish I knew what to do. Are you supposed to check and adjust babbitt bearings or just keep driving till the rod is sticking thru the block? I am sure I have read about tightening bearings as part of an overhaul, without taking the engine out of the frame. Wish I knew the details.
Rusty Just pull the engine and do it the way you know you should. You're a good wrench you could have it out in an hour maybe two and once you are done you'll sleep better knowing that you are good. Tightening the bearings as I recall with the engine in the cradle was a used car salesman trick and done it a piece of pig skin.
After some research including getting the factory manual, it appears adjusting the bearings was part of an overhaul and can be done in the frame. But, if you remove the oil pan you have to adjust the dippers, troughs and squirters of the oiling system. It is not very hard to do but you must use the correct templates and procedure. The templates do not look too hard to make if you have the dimensions. For the time being I will leave everything alone. If I assess the condition of the engine and it is time for an overhaul then I will have to consider whether to keep this one or look for a newer one with full pressure lubrication. Possibly a hopped up 261 for the nostalgia kick.
Here are some real time details/actual experiences from a bonafide Oldtimer garage owner that happened in the early '60's. Had an inserted bearing type crank reground and it came back marked .010"rods, .010" mains. Assembled and ran beautifully until it warmed up while doing a running adjustment on the valves and the oil pressure dropped from 40 psi to about 5. There was no noise as in a loose rod bearing. We used Plastigauge and checked all rods and mains and that showed proper .0015" clearance. After 2 days of oil pump, filter, pressure relief and whatever, we finally pulled the engine and miked the crank to discover the machine shop had ground the mains .020". Our mistake to not double check. Our shop truck was a '49 Chev 3800 pickup with the long box. We managed to knock a rod bearing out of that but the other five were good. Viable option of the day was to grind that rod journal with the engine in the frame and it was done "on location" at our shop. With the oil pan off and only the head removed to extract the offending piston and rod assembly, a grinding head that guided off the bad journal and reciprocated on guide rods attached to the bottom block surface, while a friction drive motor turned one rear wheel while the other was on the ground, thus rotating the crankshaft while grinding, through the drive shaft and (manual) transmission. This would grind the journal round albeit perhaps very slightly altering the stroke which was of no consequence. Reconditioned (babbitted) rods were readily available in undersizes to complete the job. It took an experienced guy to do this and by 196o it was about dead and gone for automotive use. I suspect there were older trucks and industrial equipment not warranting a full repair that it continued on and there may be fossils still doing it on occasion. That concludes today's history lesson. LOL
I can still lay my hands on the proper tools, I don't won any of them any more. If I had a babbit motor pass though my hands I would borrow what I needed to get the job done. Sounds backyard I know but that is what I would have to do. If I had the tools you would be welcome to them.
When I was a kid, my dad had a Bantam truck with rod problems. I've watched him pour and scrape the rod several times. He could pull the head, pan, and one of the pistons, re-pour, scrape to fit, and reassemble the whole thing in a couple of hours. I think the crankshaft may have been a little out causing the same problem over and over. Man that was an ugly pickup and had no power, but would run all week on a couple of gallons of gas. Got him back and forth to work though. The reason to add a shim to a babbit bearing is if it has no shims and the cap has been filed a little to tighten and is just a frog hair too tight. Happened to me on a straight eight Buick one time.
Straight 8 Buick...reminds me of my apprentice days with Red Mayfield. Red taught me the 'art' of shims, filing caps, and scraping bearings. Thank God for Porsches...I was finally liberated.
During the Great Race of 1908, the Italian entrants driving the 1906 Zust ran out of engine oil in Siberia. (engine design is total loss lubrication, common in the day, no oil seals). They scrounged up 30 small bottles of Singer sewing machine oil from a nearby village. The next day the engine began to rattle so they were compelled to stop. This was all documented in Scarfoglio's 1909 book "Round the World in a Motorcar". I will paraphrase what he wrote regarding the ability of their amazing mechanic. "July 1- A bearing has fused owing to want of lubrication, and as we have not a spare one, a new one must be made. Haaga patiently sets to work. "Will you have to cast one?" I inquire. "I will cast it" he replies. From a lump of mud he makes a mould round the bronze skeleton of the bearing. With a file he smooths the piece of wood which is to occupy its center. From the lid of a tin box of cough lozenges he cuts pieces which shall aid perfect fusion. And then, in an old iron spoon, over a fire of newspaper and pieces of a broken door, he melts half a dozen leaden bullets and cuttings from the bottom of a zinc pail. I watch him, wonder-struck. The metal liquifies and the strange mixture is poured into the mould. Then with sharp files he begins to trim and smooth the casting. At five oclock in the morning the motor breathes once more. It seems to me to be a miracle." When the car was being restored in the 1980s, analysis of the rod bearings confirmed that two contained about 70% lead (melted bullets) while the others were 0.3% lead(original). This was one of the many documented repairs done to the car during the race and without such records it would have been impossible to absolutely confirm that the car being restored was the actual car that went around the world in 1908. Incredibly resourcesful men in those days.
Beaner the car is running well right now. I thought it might be a good idea to check the bearings now rather than wait till the rod comes through the block. If it had full pressure lubrication the oil pressure would give an indication of bearing wear but on a low pressure system you don't get that. If there is a simple way of telling the condition of the bearings I wish I knew it.
The Jalopy Journal
