The Stovebolt Site Forums The Shop Area General Truck Talk To Babbit or Not to Babbit?

Just me looking for more advise.... You all have been helpful so far, so how about this...
I have an original 216 in my 40 with Babbitt (or babbett, babbet, babbit not sure of the spelling) bearings. I would like to know if the babbitts should be machined out and replaced with insert bearings or should I keep it the way it is? The journals look very clean and I wouldn’t mind saving some money if at all possible. I’m about to drop the engine off for machining and was told that it is about $500 just to bore out the engine for bearings. I just don’t know what will be the great benefit if I invest the money. Is this a no brainier… should I be boring it out? Is that the right thing to do?
I don’t expect to be driving this truck that much and I’m not looking for a lot of horse power, just want the truck stock as possible, at lease from an outward appearance.
Any comments or suggestions?

Thanks for the help in advance!
Kevin

I guess that your mains are not inserts? If that is the case, someone will have to make the call on how good the existing bearing surfaces are. The rods can be machined to take inserts. That way, if the crank is ground, you can go with undersize inserts.

The mains are inserts. Would that have been stock?

Kevin

Kevin,

I faced that same decision when I restored my '39. My engine was shot and needed to be rebuilt anyway. I really wanted a stock truck and I was able to find a local engine rebuilder who was experienced with babbitted engines. Like you, I didn't need a power house and I wasn't going to drive it much, so the decision to stay original down to the poured babbitt was pretty easy. I didn't regret it! The engine ran great (still does, last I heard from its new owner) and it was cool seeing 15 lbs of pressure and knowing that was correct!

Sure, you could pay the money and get the engine modified to accept insert bearings (and even make a full pressure motor out of it) without changing the exterior appearance, but for me, there is a certain satisfaction in running a splash oiler/dipper/whatever you want to call it. I think they sound better, too!

I'm running the original splasher in my '49 1-Ton now and love it, too. Sounds like a sewing machine when it idles. It won't stand up to redlight drag races but you shouldn't be doing that with your truck anyway.

For whatever its worth!
Regards,
John

insert mains should be stock. My '39 had insert mains and that engine had never been apart.

Regards,
John

Fantastic! Thanks John.

Regards, Kevin

Yes, the mains are inserts, the rods are poured. Used to be you could buy new rods that accepted the inserts. It would at least be worth a call to a mom & pop parts store to check.

The biggest enemy of poured babbit is high rpm. If you go the babbit route, do not drive down the highway with the engine revving over 2600 rpm. Occaisional bursts over 2600 won't hurt the engine much, just don't make a habit of it.

Am I right in assuming they are going to recondition the rods? If so, they will need to re-pour the bearings.

Maybe this is a stupid question, but do your rods even need rebabbitting? If they have shims and can be reused as is, why not do that and save the $500-$600 it will cost to either rebabbitt them or machine for and buy insert bearings. You had mentioned that the crank journals look good and you wouldn't mind saving a few bucks...

Guys, I'm new to this Babbitt world. So excuse my ignorance. When I pulled the engine apart I noticed the shims. Would those have been from a stock engine or is that the way you build in clearance. What should the clearance be with a Babbitt? If the Babbitt is good would you remove the shim to take up the wear? Or must the shims be in place? If the babbitts are good is there something that still needs to be done to them; honing or polishing something to freshen them up?

P.S. Barry, I wished you were in So Cal so I could drop my parts off for you to work over.
Thanks for the help!
Regards,
Kevin

Hey Kevin- Babbitt is made from lead and tin and maybe a little copper I think. It comes in solids "bricks" or ingots and must be heated up to be molten enough to pour. It can then be poured into somewhat rough forms placed around the rod or main bearing journal areas. After it cools, it looks similar to lead. It is soft enough to scratch easily. It can then be machined to size and shape. Rod clearances I would guess to be in the .0015-.002 range. Shims were typically added on the parting lines of the rod and cap or block and cap surfaces, so that after the babbitt wore in some and got a little loose, it could be easily adjusted to be tighter again. Most of the wear occured up and down and not side to side on the bearing surface. Modern insert bearings are a copper shell surfaced with a thin coat of babbitt type material. They are easier to make, easier to change and seem to last fairly long. Poured babbitt makes a good bearing surface, but takes someone experienced in it to pour and machine and adjust. I think this added up to extra expense and labor for the car companies and they replaced babbitt bearings with snap-in style bearing inserts as soon as they could. Babbitt is still used in some large industrial bearing applications.

So Barry, if the babbitts are not worn to badly and I remove the shims I may get by?
I'm looking for info so I won't look to stupid when talk with the machinist. Better to look stupid on the internet then in person!

Thanks for all the help!
Regards, Kevin

Now, let me say I am not replying to your question to Barry. I am only a hobbyist but I really like these discussions.

I reacted to the cost of having your mains bored? Unless there is an obvious alignment problem with the mains, new inserts would be the only thing needed.

There are things to look for on the bearing surfaces. Dropouts or little divets mean they have to be fixed. Ditto a mottled surface with tiny holes. In the absence of these, a good even dull surface shows that they still have life to them.

Shims: In the AD motors, they came with .004" of shimms, a combination of .001 and .002" shims. The official "wear limit" in the specs was .004".
The practise was to remove shims, one at a time on each side until with the rod torqued up to specs, there was interference. Then, you inserted one shim more and that was the adjustment. With the motor apart, this is easier to do because you can swing the rods back and forth.

A good machine shop should be able to do all this for you. There is no need to machine every possible piece of the motor.

Kevin- Truckernix covered it perfectly. If your engine machinist looks over your rods (that doesn't sound good), and thinks they can be reused, then that would be the cheapest way to go. If he says they are junk, then you will have to either: 1) Replace them 2) Rebabbitt them 3) Have them machined for insert bearings.

Here is one way to go if you find your bearings are beyond service. I am not affilliated with the seller even though we are from the same state (but not the same state of mind)

Thanks for all the help Guys! I think I'm educated enough to visit my local machinist now.
Regards, Kevin