I am currently rebuilding the engine of my 1914 model T. Engine has been rebored for new oversized piston, crankshaft have been grounded with new oversized rods. I didn’t do anything for the 3 first mains since they looked OK with a correct adjustment. The journals are in original size, I don’t know if the babbit is original.
Looking more deeply, I noticed that the babbit seems to be partially loose either in the block or in the caps. This can be seen when pressing the babbit against the housing, a little oil comes out. (first picture is without pressure, second one is with pressing the babitt and shows some oils coming out)
Is this important and should I have the three mains rebabbit or can it be used as is ?
How long has this Babbitt been used? If you still have shims in this bearing and if the slight looseness is only in the block I would probably save my money and use it as is
Most people would recommend rabbiting while it is apart. If the crankshaft is round and not worn egg shaped you might get by for a short while or a long while but it would always be a worry and asking for trouble. You will be happier after it is done in my opinion.
Your Babbitt looks good. The Babbitt does not "solder" to a tinned block, it is cast and then rapped against the block and line bored. You will probably need to add Babbitt to the thrust surface or get a rebabbitted rear main cap. In the engine the main caps are more heavily loaded than the block, the rods are are more heavily loaded than the rod caps.
If it were mine, I would use the block as is.
My engine is about the same. I did put new caps on the mains. Ask your self, how many miles a year will your drive her and how much can you spend to redo the mains. While I am not giving advice, if it was mine and the babbett looked that good I would use it. Tell everyone you have simi-shell main bearings!
You can't run loose Babbitt in anything that doesn't have crush.
You said the Block Babbitt, and the Cap Babbitt are loose, it won't last very long with out breaking up, it has no other choice.
The Babbitt wasn't Peened in the Block, and if the cap were tinned, it didn't stick.
Don't let the guy that done that babbitt job, do the next one!
It has been repoured.
Think of how much work it is to take the engine apart, as it now, and then decide if you want to do it again soon. To me there is no question...re-babbitt it now.
The block has been drilled with anchor holes where the babbitt is cast, so the babbitt will stay in place even if it's a little loose in one side. I think you can use it as is for many miles.
Picture by Luke Chenell in this thread: http://www.mtfca.com/discus/messages/179374/215485.html?1307938766
Use yellow timesaver lapping compound to make sure the crank shaft has a proper fit in the babbitt when adjusting the bearings. When a strip of paper from an ordinary news paper in the cap, tightened down, stope the crank from rotating, then you have the proper 0.0015 inch play.
The rear main bearing may have a good radial fit while the axial play is too much for a good magneto function - then you may have to buy a rebabbitted cap from the vendors or try solder some babbitt on the thrust surface - see the procedure here at the fun projects website: http://www.funprojects.com/pdf/Excessive%20Crankshaft%20Endplay%20Repair.pdf
In absence of a lathe the thrust can be faced with a file after being built up.
Another thing to check is if the center main has worn upwards into the block - the block portion of the babbitt isn't much stressed for the front & rear mains, but the center main tends to wear both in the block and the cap due to the inbalances in a four cylinder engine. If the center main has worn more than the front and rear & you pull shims to compensate, then you may put the crank shaft in a bend - giving it extra stress for every turn & a shorter life until it eventually cracks from metal fatigue.
Now all engines aren't worn much like that - both my 26/27 style engines with original babbitt were straight as an arrow when I checked the block babbitt with a steel ruler. Guess the bolts holding the hogshead to the engine block on the improved 26/27 Fords reduces some of the crank flex.
If your center main is worn more than the others in the block part you may scrape or grind the front & rear main down with timesaver to the same level (if there is enough material left) - or it may be time for new babbitt.
Thanks for your advice
I don't know the history of that engine, I bought it non running, with original pistons but with the fourth rod babbit melted. I already have a new third cap to adjust crankshaft end play.
I would like to have new babbit everywhere but it is not so easy here in France and moreover, directly in the block. European cars have babbit fitted on bronze bearings and "babbiters" are not familiar with peening as it should be done with cast iron housing.
What would be the risk if I use these babbits after checking that the three bearings are aligned ?
Not much risk if the bearings are in line & the crank round & straight + magnafluxed - you'll hear when adjustments or repairs eventually are needed. The sooner you check new knocks from the engine, the less repair it'll need
Do you still have any shims in the main bearings?
The "peening" requirement is greatly over stated!!!
Just one shim on first bearing, no more on second one, a lot on third because the cap is new
Speaking from experience it would be best to rebabbit while you have it apart. Nothing worse than getting it all put back together, have it run a little bit, start knocking and have to pull it out and start over again...
Schubert, of all the things that you can get by with out, Peening Babbitt in the Block isn't one of them.
By a statement like that shows me that you know nothing about bearing work, as that is BASIC!
Here are some pictures that gave up on the engines in less then a 100 miles, these are all I saved to show, no blocks, as they get melted out right away for cleaning, and I still have many more caps as there is no room for posting. All well known builders. The Model A ones, and one was done over twice before the owner gave up on with him, as he was going the get charged the third time.
One that was done twice is highly recommended by one of you that posts on here all the time!!!!!!!!!!
The last pictures are of our pouring, Peening, and finish line boring.
Listen to Kohnke Babbitting. Your babbitt isn't any good. Take the time now to take care of it or you may end up regretting it later. Is saving time and money now worth the potential damage to the engine and car later?
Earl's Machine Shop
You have two views on the issue. The most important thing you can do is get the crank magnafluxed. If its OK you can go with your babbitt and new cap. If the crank is cracked and must be replaced, then it will be time to rebabbitt.
I don't think Les Schubert would steer you wrong and I think Kohnke is being extra cautious.
What's wrong with extra cautious? Isn't it also extra cautious to magnaflux the crank? Use the very best parts, suppliers and materials you can find and you will ultimately enjoy your car far more.
If his car were together and running great and he told me his main babbit was a little loose I'd say to catch that repair the next time it's apart. Well, it's apart now. What better time to not only do things right, but to do them when it's easy and convenient?
I agree with Jerry now that we know he has no shims left ( which was a question I asked in my first posting to this subject) I stand by my position on peening. It doesn't hurt but is not needed. I have only done 50 engines. I have had NO main bearing failures. A correct preheat of the block and absolute removal of any oil etc. under the Babbitt is required. The pictures some one else posted have no co-relation to peening, they are related to poor practice (presence of oil appears likely). I am sure you can find a skilled "white metaller" on your side of the "pond"!!!
If the person is in doubt, they can pour the block Babbitt, then break it out for inspection(prior to machining). If it looks good underneath and is well attached to the locking holes they know what they are doing. If not they can learn. After pouring and prior to machining they have spent very little money and can recover all the material to try again. Doing good Babbitt work is no mystery. It is all about care and logic. Any conscientious person can learn it and it is a worthy skill to gain