Turning babbitted rod bearings into insert bearings??

[chstickl]

Hi there again,

when I took my 37 Roadmaster engine apart, following questions came up that I could not yet find an answer to:

1. the rods have babbitted bearings and all overhaul kits I know only have insert bearings. Re-casting the rod bearings is somewhat cost prohibitive and I didn´t find a good source yet anyway. So, is it just that easy to just carve out the babbitted bearings and replace them with inserts??

What does it do to the stability of the rods?

Kanter seems to just offer that. Anyone experience with that?

2. I realized that the camshaft journals (main bearings) are getting thicker, the closer it gets to the flywheel. Seems to make sense to me as at the flywheel there may be the strongest forces on bearings.

.... or is it just lousy tolerances of the ancient manufacturing process? Should I mill down all journals to the same measure or would that kill the camshaft? I haven´t found a single table with standard measure for the main bearings. Does anyone have that information?

Thanks as always for your valuable hints,

Christian

[1939_Buick]

Same topic as this thread started by chstickl only a 2 days ago

http://forums.aaca.org/f165/37-roadmaster-casted-piston-rod-bushings-265375.html

Information in that and linked posts of sources for parts.

Edited July 21, 2009 by 1939_buick (see edit history)

[Mark Shaw]

Your machine shop should be able to establish the insert size (or babbitt thickness) from the stroke of the engine and the diameter of the most worn crankshaft journal. Ideally, all the crankshaft journals (including the main journals) should be machined to the same size and polished prior to re-babbiting or using inserts if you can find them....

[trp3141592]

Hi,

a) I think I can help with the crank journal data. I am attaching photos of the data taken from my 1942 MoToRs repair manual.

The MoToRs manual states that the rod bearings are not replaceable, meaning they are Babbitt as you have discovered. For my money, I'd get the cranks machined to standard undersize diameter and have the rods machined to take inserts. I suggest having the same shop machine both the cranks and the rods to assure that they are dimensionally compatible.

Here's what MoToRs said over 65 years ago.

--Tom

[chstickl]

Tom,

this is great information, thanks a lot for sending this. It clearly tells that the main journals are supposed to have all different sizes. Unfortunately the photos are not sharp enough to allow securely seeing the fractional measures. I have checked the internet already and it seems that this manual is out of supply. So could I ask you to take high res images from the tables only, as these are really fine print.

Thanks a lot

Christian:)

[eric_b_1937]

The 1930's - 1940's Motors manuals have a lot of info for your car. They are usually available at swap meets and ebay. Check your local libary or university they might have one on the book shelf.

[trp3141592]

Hi Chris,

I tried copying and blowing up the photos--you are right,they are too fuzzy. I'll shoot them again tonight when I get home from work, this time with the close-up setting, and repost them on the same thread.

Later:

I'm home. Below are photos in finer detail. The Clearances chart is in two halves. To read these more easily, right-click on the image, "Save picture as" to your disk, then open it with whatever picture viewer/editor you have on your computer. Then just enlarge up to where you can easily read the numbers.

I hope this is helpful.

--Tom

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Edited July 23, 2009 by trp3141592 (see edit history)

[1939_Buick]

The 1930's - 1940's Motors manuals have a lot of info for your car. They are usually available at swap meets and ebay. Check your local libary or university they might have one on the book shelf.

As Christian is in Germany likely to be very few local sources of information for him.

Have a look at Team Buick Reference. You can download a 1952 Shop manual which includes the 320 ci engine. May be of use. Unsure if the 320 ci changed much from 1937 to 1952

[chstickl]

Tom,

thanks a lot for taking the extra effort of taking high res pictures. I took them to my engine shop so they should be well prepared not.

Christian

Hi Chris,

I tried copying and blowing up the photos--you are right,they are too fuzzy. I'll shoot them again tonight when I get home from work, this time with the close-up setting, and repost them on the same thread.

Later:

I'm home. Below are photos in finer detail. The Clearances chart is in two halves. To read these more easily, right-click on the image, "Save picture as" to your disk, then open it with whatever picture viewer/editor you have on your computer. Then just enlarge up to where you can easily read the numbers.

I hope this is helpful.

--Tom

.

[trp3141592]

Hi Chris.

I am happy to have been of assistance. Let me know if other issues with which I can help happen to come up.

It'd be great of you'd post progress pictures for this great car!

.