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32 Plymouth PB Connecting Rod Bearings

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Hello everyone, I am new to the forum and I need some advice about PB rod bearings.

 

Here are some pictures of my 31-32 PB as it sits in my garage on jack stands right now.

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The last time I drove the car,  It developed a rod knock, and I shut it down immediately.

 

When I remove the oil pan these bearing parts were in the pan.

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The #2 rod was a little loose and I took off the rod cap see that the side parts of the bearing in the connecting rod had come apart.

 

 

My question is is it possible to get these bearings inserts or do they have to be made from scratch from poured babbit?

 

The only info I can find on them is the bearing diameter is 2" and the thickness is 1 and 3/8". Also, the bearings appear to have the shape of a main bearing.

 

Thanks for any help anyone can give.

 

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your car has the headlight buckets and bar of a 1931 PA grille a PA and Door handles are a PA whats the engine serial number as I learned before it may be a 32 but a PA model the PB has dif grille and handles and single headlight stands,don't want to start anything Just asking, I also agree with 32plywood you need babbit job poured

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The block numbers are    314729-2    111831

                                                   H    

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Top left forward of block engine serial number will start with letters and number that will at least tell model of car if engine is original for example

Q=1928

U=1929

and 1930 U and 1930 model U

PA=1931

PB=1932

PC , PD = 1933 and so on

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PA-96207

Son of a gun, Ive been calling it  a PB for decades. I should change the title. Think it went down or up in value?

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It could still be a titled 32 just a late production but if engine is in it with PA I would say its a 1931 but so many opines out there. Both models are good value mine is a pb roadster  with low windshield and suicide doors but i had a pb sedan and it had all four doors suicide so they are different slight less horsepower you should be able to do 50-55 all day my 29 U is shaking at 45 lol 

i like the coupe though

cheers

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yes it is a PA car and a very nice coupe --- would look good setting next to my 2dr and convertible

 

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Is it true that a good machinist can convert to insert type bearings?

Do they not oil thru the crankshaft?

I am not familiar with the poured babbits.

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17 minutes ago, JACK M said:

Is it true that a good machinist can convert to insert type bearings?

Do they not oil thru the crankshaft?

Yes with enough time and money.

All connecting rod bearings, unless they have dippers, oil through the crankshaft.

 

All ordinary engine bearings are babbitt.  The difference is some babbitt is thin on a replaceable metal backing, some is thin on a cast backing usually bronze, and some is poured in the connecting rod or in the block for main bearings or camshaft bearings.

 

The only advantage to insert bearings is how easily they may be replaced.  Poured bearings in my Pontiac have always lasted in excess of 180,000 miles.

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Thanks for that.

I see discussions here about the maladies of the babbit bearings and would think that they may be finicky.

I have rebuilt many engines with inserts and would have thought that converting would have some advantages.

I suspect part of that is how they are driven. Attempting to keep up with modern traffic is one HUGE reason for old cars to fail.

This kind of work is over my head, back in the day when the rods started knocking we just threw the car away, or stuck something more modern in it.

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If you can find someone who did an insert conversion on the same type engine, and it held together, great. It is probably cheaper. Otherwise, I would stick with babbitt.

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When a Babbitt Bearing go bad, you can normally limp back home, and put in another rod.

 

When a insert goes bad, your dead in the water.

 

Also, inserts have a way of going obsolete, or in the size you want, or chewing up the crank, where it has to be ground.

 

Herm 

 

 

 

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I went back and looked at your burnt out rod, and the last time they were poured, somebody, used Lead Babbitt. 

 

In any case, the tinning was not very good, as there should be some showing in the rod part. 

 

The two half flanges show to cold of pour, as the flanges did not stick to the sides of the rod, and they are always the first part of the bearing to go. I will put some pictures  up of lead, and tin base babbitt, difference in color, Lead id the dark.

 

Also pictures of a bad flange not sticking, and the way they should be, and some others.

 

I couldn't find the 1931 Plymouth rods, and mains we did for the race from Peking, to Paris, so I put in a set of 1930 Buick Rods, and Mains.

 

About a month ago, we got done with another 1903 Curved dash Oldsmobile, i will see if I can show them.

 

Thanks,

 

Herm.

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Pictures of another 1903 Curved Dash Olds.

 

First two pictures are on a new made crank, that they messed up the radius on at a crank grinder in Texas, where the owner had sent it, you have to watch! Arnold Motor, in Spencer, Iowa, had to fix it.

 

This is all this post will let me post ?

 

Herm.

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1903 Olds Pictures.

 

I have many, it won't let me list any more.

 

That Sucks !

 

Herm.

 

 

  • Sad 1

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Get the crank micked and the rod re-babbited and you are good for another 80+ years.

My Pontiac averaged 166,000+ miles per babbitt job.  I don't think my Grandfather ever drove it over 48 mph for the 99,000 miles he drove it.  I added 400,000 miles over the last 60 years driving it as my daily driver.  Many of my miles were on the highway at highway speeds, 50-55 and sometimes over 60.  Nothing wrong with a proper babbit job.

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Thank you for the pictures Herm111. Your expertise is invaluable.The guy that rebuilt the engine in the early 60's was a local and is long gone, but there is only about 3000 miles on it since.

 

Is it feasible to just do the one rod for now like Tinindian says? Is this  something you could do Herm?

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Since you have the oil pan off and seeing the condition of this one rod, I would take all the rod caps off and check each bearing.  It is possible that only one is damaged but it is possible that some or all have been done incorrectly.

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Yeah, I could do that this weekend, but I'll just have to chance it with the main and thrust bearings. I can't do a whole rebuild right away,

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