Rear main thrust

4

4 pot truck

Junior Member
I see Snyders sells a bronze rear main thrust that goes in place of the rear main seal. If you fit this do you then have to file it to set the correct thrust?
I have just stripped my engine and have a lot of end play in the crank, the Babbitt looks ok but I assume the thrust surface must be worn.
I am new to this so any help and advice will be much appreciated.
Thanks Andy
 
Hello Andy.
I used it with success, although there is not much sense installing it if the main bearing clearances are excessive and cannot be adjusted, there is much info here on checking and adjusting bearings, PM me with your E-mail for pictures of when I installed my thrust.
Brian.
 
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4 pot truck said:
I see Snyders sells a bronze rear main thrust that goes in place of the rear main seal. If you fit this do you then have to file it to set the correct thrust?
I have just stripped my engine and have a lot of end play in the crank, the Babbitt looks ok but I assume the thrust surface must be worn.
I am new to this so any help and advice will be much appreciated.
Thanks Andy
Click to expand...

Hi Andy:
I've used this too. I my case, I opened the engine because of excessive end play in the crank. I wasn't thrilled with the condition of the babbet, but was able to get all the clearances into adjustment except for the end play issue. I was hoping to get another few thousand miles out of it if possible. There was a crack in the babbitt at the back of the rear main and it was worn severely, causing the end play.

To install the bronze thrust rear main I carved away the Babbitt on that end with a knife and put this one in place. Everything fit with 0.005-0.006 end play. I've attached two pictures, one of the original rear main showing the end play and the other of the new bronze piece installed. This repair was about 3000 mi ago without problems.

I hope this helps and best of luck to you.
Brian
 

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bdentremont said:
Hi Andy:
I've used this too. I my case, I opened the engine because of excessive end play in the crank. I wasn't thrilled with the condition of the babbet, but was able to get all the clearances into adjustment except for the end play issue. I was hoping to get another few thousand miles out of it if possible. There was a crack in the babbitt at the back of the rear main and it was worn severely, causing the end play.

To install the bronze thrust rear main I carved away the Babbitt on that end with a knife and put this one in place. Everything fit with 0.005-0.006 end play. I've attached two pictures, one of the original rear main showing the end play and the other of the new bronze piece installed. This repair was about 3000 mi ago without problems.

I hope this helps and best of luck to you.
Brian
Click to expand...


I am not familiar with this type of repair. Could you educate me a little more? I am assuming the bronze device is half a disk and fits into the cap in place of the poured babbitt. Would you then need to file or grind it to achieve the required thrust clearance.

We just went through a similar repair of a 30 Tudor that leaked oil excessively and had .015 thrust clearance. The babbitt was shot, though the crank journal looked good and the car ran very well. We sent the cap along with a core cap to Bill Barlow in Bend,OR and he re-poured it and added babbitt to reduce the thrust clearance.

We only had to remove one shim to fit the bearing. When the job was finished the car still ran very good, but it no longer had an oil leak.

Tom Endy
 
Hello Tom,
If you PM me your e-mail address I can send you the procedure I used with some pics, it was nice talking to you last Friday at the swap meet, maybe my turn to pay you back for the excellent help you have given us.
Thanks Brian.
 
Thanks for all the help on this guys.

Brian T, thanks for the pm with the info and photos. Yes my drain tube is missing as well so this will be contributing to my oil leak.

bdentremont thanks for your photos as well.

Cheers Andy.
 
4 pot truck said:
Thanks for all the help on this guys.

Brian T, thanks for the pm with the info and photos. Yes my drain tube is missing as well so this will be contributing to my oil leak.

bdentremont thanks for your photos as well.

Cheers Andy.
Click to expand...

I'd say the missing drain tube could be the main cause of your excessive oil leak.
 
I use these combination seal and thrust when installing insert main bearings. They have worked flawlessly in over 70 engines. When installing the part, set the seal in a non-hardening sealant. Permatex #2 or better yet a good automotive silicone. Make sure the seal is fully seated into the block and let it set up over night. Carefully file any amount of the part that protrudes above the surface of the block...file it flush. Any amount this part protrudes above the block will hold the cap from fully pulling down to the block. If you don't set this part in sealant, you will most likely have a leak.
I agree with Tom...the missing drain pipe on the rear main cap will cause a generous oil leak. Good Day!
 
Tom Wesenberg said:
I'd say the missing drain tube could be the main cause of your excessive oil leak.
Click to expand...
Even if you have the drain tube, make sure there is not an obstruction somewhere that might restrict the flow. Found a chunk of babbitt in mine last night. Of course that led to other problems as well, but I have no doubt that was the cause of the excessive oil pouring out the back end.
 
one thing I have found when I was checking the oil ways from the mains in the block was a piece of wood! It had been cut into a point. When I read on the internet about pouring babbits it said pieces of wood were put in the oil ways to stop the molten metal blocking them. This piece was down in the oil way from the rear main to the valve chamber!!
How does oil get to the valve chamber? I notice there are 2 slots in the oil pump shaft that oil comes out of but that is in the hole in the block when everything is bolted up.
Sorry for all the dumb questions!
 
4 pot truck said:
one thing I have found when I was checking the oil ways from the mains in the block was a piece of wood! It had been cut into a point. When I read on the internet about pouring babbits it said pieces of wood were put in the oil ways to stop the molten metal blocking them. This piece was down in the oil way from the rear main to the valve chamber!!
How does oil get to the valve chamber? I notice there are 2 slots in the oil pump shaft that oil comes out of but that is in the hole in the block when everything is bolted up.
Sorry for all the dumb questions!
Click to expand...

Sounds like some one was tiring to slow the oil to the rear main, thinking that would stop the rear main leak.
 
4 pot, the oil is pumped to the valve chamber and gravity feed to the mains. Most guys use a molding clay before pouring Babbitt.
Dan
 
We make that bronze thrust washer. We sell roughly 1000 of them a year, and when installed properly work very well.
 
I have not tried this, but have heard you could melt new babbit onto the thrust area with a soldering iron, then file to get proper clearance. I had considered trying this, (I have almost .015” play in mine) , but decided to go full rebuild.
 
I once used a piece of copper tubing, flattened out, as a temporary fix for a thrust that had disappeared. It worked fine for the race that weekend, and looked pretty good when I took it apart for new babbitt.
 
SteveB31 said:
We make that bronze thrust washer. We sell roughly 1000 of them a year, and when installed properly work very well.
Click to expand...

I had no idea who the source for these was. I personally think it is a great product and most certainly fills a need. Thank-you! :)
 
I make filler rod by poring Babbitt in a angle iron.
I fill small bubbles after a poor, and sometimes will add to the thrust surface if it only needs .005 or .010 added to it with a electric iron.
I use a thrust cutter after building up the Babbitt to get it smooth and even.
I do not think that you could get a smooth even surface with a file.
I would never try replacing the entire thrust or large missing pieces.
 

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David R. said:
I have not tried this, but have heard you could melt new babbit onto the thrust area with a soldering iron, then file to get proper clearance. I had considered trying this, (I have almost .015” play in mine) , but decided to go full rebuild.
Click to expand...

Before you do that, try filling about 5 minutes, which would be on the rear thrust, see how that works for you.

Herm.
 
Well my unit will need bored anyway so I have decided to go ahead with new babbit too.
Thanks Herm. I would have tried it had that been the only issue. Actually the babbit work is fairly inexpensive comparitively.
 
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