Babbitt Bearings or machine my rods for inserts-1936 Buick

[NTArrington]

My 36 Model 80 has developed a knock. Teardown shows a galled piston on #8. We pulled the piston out and were able to clean the cylinder up with a hone. I am trying to get by with an "in frame overhaul" All bores are still standard with little out of round to them . I need 8 pistons-but my problem is what to do with the poured rod bearings. A machine shop can machine the rods to take modern inserts-which most certainly mean pulling the crank and grinding it. Or I can have the 8 rods poured and line bored-and hopefully leave the crankshaft in place with any minor tolerance variation due to the softer nature of the babbitt. My tolerances are good and within guidelines on the crank-it's just that the bearings have some hairline cracks and flecked edges. I know the babbitt is more forgiving material. What would you guys do?

[Guest Straight eight]

When I was overhauling my 1947 Super I found a late 49 engine that had the inserts, took em to a machine shop had the pistons hung, and the rods checked for straigntness, and straightened as needed. For highway driving, much more durable than the babbit. Also had the valves given a three angle grind, wow, what a difference. Have installed a Marvel Mystery Inverse Oiler so didn't need to use hardened valve seats. MMO burns leaving a lubricating ash that keeps the valves lubricated.. Over 20,000 miles and no valve recession.

[critterpainter]

I THINK that you can use the rods out of a late 320 (about 1946-52) in your engine, and the appropriate bearings. Or as an option have the rods machined to take the 320 inserts. I would look for a late set of rods if it was mine.

Bill

[RonNastri]

I have available a full set (8) babbit rods in very good condition. These are for the 320 cu. in. straight eight. Reasonable! $125 obo. Call Ron at 719-547-4682

[Fred Rawling]

My opinion is that if you expect to drive the car for a while, you should do the job right and pull the crank, have it trued up and not go for the quick fix.

You can use the later inserted rods in your engine.

[Guest unclefogey]

Just dropped my '41, mod. 46 off at the engine rebuilder today. Thought it was prudent to rebuild a 106K miler before attempting next year's trip to Seattle. Subject of babbit bearings was discussed and I was told I could have them for an approx. additional $1000 on the rebuild cost. Needless to say, the decision was obvious. Told rebuilder I had read something about three angle valve grinding. He looked at me with a puzzled expression and said that is the way they always grind valves.

[Mark Shaw]

Well, I had a similar problem and found a crank pin re-turning tool that I used to remove the taper and out of roundness of my #6 bearing journal with the engine still in the car.

You may see a two part shop article in the bugle in a couple of months. Meanwhile, send me your email address and I will send you part 1 about the re-turning tool. Part two will be about pouring babbitt and line boring the rod bearing.

[critterpainter]

Mark:

the tool worked!!!!! Glad to hear it!

bill

[Buicksplus]

Your engine rebuilder wanting $1000 extra for babbitting the rods makes it clear he doesn't want to do it -- but I don't see where those numbers are reasonable. I just had a complete rebabitting job done on 6 Chevrolet rods for $180. This was a local shop in Albuquerque, the last one that does babbitt regularly. I installed the rods on a fresh crank grind and they are doing just fine.

Reworking your rods to take inserts is not trivial, and takes quite a bit of machinist time -- and adds risk if not done right. If the 1948 rods will fit, that is a much safer route to go if you want inserts.

I have experienced rod bearing failure with babbitt (it's loud and ugly!), but our local machinist insists that a properly done babbitt rod will hold up as well as an insert. He speaks from much experience with Model A engines, with and without insert bearing conversions. Insert bearings can fail too. The real advantage to inserts is easy replacement with no need for precision reaming, not durability. That's what he says anyway.

PS I drove my 39 Buick for years and tens of thousands of highway miles with original poured rods. Never had any problem with them.

[The Old Guy]

When I rebuilt the engine in my 32 90 series back in 1975, I checked the crank, and it was within ,ooo4 for round and had no taper. The engine had 90,000 miles on it. I hand scraped the original babbetin the rods to allow a larger pattern, and pulled shims until I had 75-80% contact. I pulled a 1935 house trialer all over the country with the car and sold it in 1984.

I talked to the new owner at the BCA national in Batavia last year, and complimented him on the beautiful job he had done in detailing the Buick. I asked him what he had done to the engine, and He said "all I did is clean it up , as it still runs great ,and carries good oil pressure" The original bearings had some edges missing, but it must not have hurt anything, as it still sounds GREAT!

[Guest Ken G]

Old Guy,

Please would you elaborate slightly. I don't understand "pulled shims". My engine has Babbitt bearings (they all did in 1925) which were renewed only two or three miles ago by my cousin, but I suspect a problem. Are you saying that it might be possible to thin the Babbit layers and add shims rather than pour new Babbitt? If so, where do the shims go; are they of soft bearing material (surely not) or are they outside the Babbitt, so the effect is to simulate thicker Babbitt layers that can be turned to produce the required small clearance?

Ken G, 1925 Rover 16/50 (San Francisco)

[Mark Shaw]

Ken,

This is one of the advantages of Babbitt bearings. When new bearings are made at the factory or during a rebuild, shims are added at the ends of the bearing caps to allow removal later; thus allowing for wear.

The shims are held in place by the bearing cap bolts. Upon removal of these bolts, you should find very thin sheets of metal between the bearing cap and the rod. Usually only one or two need to be removed to make the Babbitt bearing fit tightly around the crankshaft bearing journal.

[Guest unclefogey]

I am not afraid to admit that much of the information contained in the posts since mine which referenced the rebuilders quote for babbitted bearings, is way over my head. The only experience I have had with engine rebuilding was helping my father in 1958, I was 14, rebuild the engine in a 49 Plymouth. It had a rod knock before and after the rebuild, probably due to the fact the crank was not taken out.

Because of the comments by the Old Guy about his experience of opening her up, doing minor adjustments, and then putting everything back together with great results, is there a possibility that at 106K miles (the engine purrs in its present condition, but leaks and burns a lot of oil) the lower end could be checked out and receive a diagnosis of, "This thing isn't in bad shape, why go though the trouble and expense either babbitting or modification to inserts?" Or would it be penny wise and pound foolish to not do some type of replacement of the bearings given all the other work on the top end?

I will probably need the name and address of the New Mexico shop that did the Chev rods if I am going to open a conversation with the rebuilder and not look like a complete dunce. It appears that finding/buying set of 1948 rods for a 248 might be a better route to inserts than machining my rods, correct? I should have known this was not going to be easy. <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" />

[The Old Guy]

As Mark stated, the shims are between the rod ansd cap. removing shims will tighten up the clearance , but the hole will actually be oval. The tight spot will be in line with the rod. By removing babbet with a scraper after finding the tight spot with blue dye, you remove a little at a time until you have the hole almost round. It requires patience, but will give you a better bearing than you can have poured today.

I was a tool maker for 40 years, so perhaps I am simplifying things too much.

[Guest unclefogey]

Thanks to those, especially the "Old Guy", who showed the usual helpful attitude by providing understandable answers on this thread, I had a conversation with my rebuilder today. With the information, I was able to ask the questions and am now confident that his initial answer about the cost of babbitting was not driven by an adversion to even try this process. He knew of the shims and "rounding" for a proper fit, but explained the shims might not be there. He agreed that machining the present rods for inserts was a very intricate and time consumming job, so they usually buy new rods set up to accept inserts. So, for now, I can go back to sleeping well. <img src="http://forums.aaca.org/images/graemlins/laugh.gif" alt="" /> But, I am still thinking about the temperature sensor.

[Guest BJM]

I have read a recent article in Hemmings Classic cars regarding a babbit shop. I am a "modern" ASE mechanic but I still can not picture what "babbit" looks like or how the heck it works. I know a bearing surface is necessary. I know where and how an insert bearing works. But these are machined parts you can hold in your hand and just looking at them you can understand that, along with a slim layer of engine oil work to reduce friction and absorb the wear of the crankshaft or rods.

Now, based on my understanding (which is minimal mind you) - babbit is "poured" onto the block, crank, rod ends or where-ever a bearing surface is required. This occurs to me that the bearing metal must be molten when poured, and that seems crazy. And insert bearing, well made ones at least, are perfectly round and even width all the way around. Babbit it seems, would have high spots and low spots. I just don't get it. Does anybody have a close up picture of what "babbitt" looks like? especially as it sits where the bearing surface should?

[Shaggy]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I have read a recent article in Hemmings Classic cars regarding a babbit shop. I am a "modern" ASE mechanic but I still can not picture what "babbit" looks like or how the heck it works. I know a bearing surface is necessary. I know where and how an insert bearing works. But these are machined parts you can hold in your hand and just looking at them you can understand that, along with a slim layer of engine oil work to reduce friction and absorb the wear of the crankshaft or rods.

Now, based on my understanding (which is minimal mind you) - babbit is "poured" onto the block, crank, rod ends or where-ever a bearing surface is required. This occurs to me that the bearing metal must be molten when poured, and that seems crazy. And insert bearing, well made ones at least, are perfectly round and even width all the way around. Babbit it seems, would have high spots and low spots. I just don't get it. Does anybody have a close up picture of what "babbitt" looks like? especially as it sits where the bearing surface should? </div></div>

Google is your friend.

http://www.gasenginemagazine.com/complete-archive/1352/

Among many others.

(BTW, that's "babbitt" with two "t"s)

[Buicksplus]

3 Jakes:

Here is a picture of six freshly babbitted and reamed 1940 Chevrolet rods. The babbitt is similar to solder, a fairly low melting point allow that is melted and poured into the rod bearing area. If done right, it sticks to the cast iron, just like body solder. Once cooled, it must be carefully reamed to the proper diameter, usually the crank journal diameter plus .0015, depending on the machinist. A typical babbitt bearing, once reamed, is probably .040 - .100 mils thick, depending on the crank journal diameter.

A modern insert bearing also uses a soft alloy like babbitt on the bearing surface of the steel shells. But with an insert, the babbitt is a very thin deposit, just a few mils I believe. Because the shells are made with great precision, there is no need to ream an insert to size, they are sold with specific diameters, probably to a tolerance of .0001 or so.

It used to be practically any gas station could pour and ream a babbitt bearing. But in the early 30's, the insert started to catch on -- I think the Ford V-8 was one of the first production engines to use them. GM mostly went to full inserts by 1935 -- but for some odd reason Buick continued to use poured babbitt on the connecting rods and Chevrolet used it for both rods and main bearings. But by 1948 (1954 for Chevrolet), even they went to inserts.

Hope this is helpful and maybe even accurate!

Bill S

Albuquerque.

[Guest mowog]

For what it's worth, and I'm not sure who wants to know (bullrunbattle?, 3Jakes?), but I recently swapped-out my '38 babbitt rods for inserts from Terrill Machine at $35 each. Best buy. I bought pistons from them, too. The motor's back in the car now, but wouldn't you know the starter quit on me when I was trying to crank it up last weekend. Anyway, Terrill's a great outfit. If you haven't yet, give 'em a call. Good guys.

[Guest mowog]

BTW, sorry, their phone: 817-893-2610

[Guest BJM]

Thanks Bill. That makes more sense. The poured babbitt is not yet uniform so a 2nd operation is performed to make it 'round' and within tolerances. Now the shimming makes sense as well. Basically pouring the babbitt to maximum thickness, then if adjustments are to be made, pull out the shims.

Thanks

[Bill Stoneberg]

3Jakes,

If you would like an example that you can examine up close, send me a PM with your address. I will send you a worn example of a rod from an 47 Buick.

When I rebuilt my 47 I too switched to inserts.

[Guest BJM]

OK Bill I'll do that. On the subject of the 248 smaller engine - I am looking close at a pair of 1949 Supers up in Minnesota on ebay. My intent is to purchase them to part them out and (hopefully) make a little money on the side, and get some parts I may need for my Roadmaster. Since these are 49's, shouldn't they have insert bearing and the applicable rods? And in that case - perhaps someone on the forum would be interested in them.

Thanks

Jake no. 2

[Bill Stoneberg]

It depends on when they were made. 49 early still had the babitt bearings while 49 late had the insert.

If you run into a set of Side sweepspears for a 49 convertible, I am interested.