"tinning" mains with brass

I

Ian in Mississauga

Senior Member
I've seen this topic on fordbarn but my searches have all failed. The idea is to braze the mains then bore before pouring babbitt. Any help appreciated.
 
I've heard of it being used on hot-rod engines back in the day. The idea was that after you braze the main saddle and bored it over crank size , the brazed spots can be tinned with babbitt. No peening needed because the brass will accept babbitt ,and become one with the block . I might give it a go sometime to try out
JIMI
 
Braze will tin to cast iron, and Babbitt will tin to brass.

This method was used by Floyd "Pop" Dryer for the main bearings in his 5 main cylinder block.

The Dryer cylinder block was a replacement for the 3 main Model B cylinder block.

I have a copy of the Dreyer 5 main cylinder block drawing, and it specifies that the iron casting be bored to 2 3/8 inches, brazed and bored to 2 5/16 inches, and then Babbitted and bored to 2.250 +.001/-.000 inches.
 
Ian in Mississauga said:
I've seen this topic on fordbarn but my searches have all failed. The idea is to braze the mains then bore before pouring babbitt. Any help appreciated.
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Do not know about Babbitt 'sticking' to brass. However, regarding whether brass will 'stick' to the cast iron A/B block...I've seen where brass was used seemingly successfully (seemingly, because only time will tell) to braze up cracks on the tops of blocks. Do not know metallurgy , so cannot say whether a good practice, until see if it holds/works !

Matter of fact, I'm going to be putting this exact idea to the test in near future...we'll see.
 
I once talked to an old time racer who said they would braze the mains and finish with babbitt. He laughed and said you could rebuild the bearings with a soldering iron.
 
The cast iron alternator mounting bracket broke on the large front end loader where I used to work. I successfully brazed it back together, and it never broke again while I worked there.
 
hardtimes said:
Do not know about Babbitt 'sticking' to brass. However, regarding whether brass will 'stick' to the cast iron A/B block...I've seen where brass was used seemingly successfully (seemingly, because only time will tell) to braze up cracks on the tops of blocks. Do not know metallurgy , so cannot say whether a good practice, until see if it holds/works !

Matter of fact, I'm going to be putting this exact idea to the test in near future...we'll see.
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I have no experience with brass and babbit. Brass will bond well with clean cast iron. If the cast is clean, it is best to use no flux. The problem with tring to braze water jacket cracks is if the inside of the water jacket isn't completely clean the grease and crud inside will migrate through the crack and ruin the brazing job. Small craters will appear like fish eyes in paint and the brass won't flow and fill the imperfection. After this happens I don't know of anything that will correct the problem . Flux is for brazing dirty metal (not water jacket ) and will make an ugly mess that will return even if you grind the braze smooth and if on the outside of the block, epoxy or paint won't stick for any length of time. I've sucessfully brazed chunks broken out of haeds caused from prising but only if both sides are completely clean. For me, brass would be a last resort for water jacket repair. Good luck.
 
thick babbitt is not ideal for racing
so they would build up the mains with the brass to get a thinner Babbitt and less chance of pounding out the mains
tk
 
1930 coupe said:
Does the brass have to be tinned in the usual manner with solder before pouring the Babbitt?
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Would the brazing alloy make a difference??



:rolleyes: I would venture a thought that if this brazing does work, then theoretically it eliminates the controversial argument that once a block has been converted to (-machined for) inserts, then a block can never be returned to Babbitt. :p Sure seems like 'one could braze up a block that has been machined for inserts. Then machine it back to standard size and drill a few holes and you are set.

The one other thing that I do ponder about why this bronze was added is that the higher forces of a racing engine are forced downward where it is the babbitt in the caps that is taking the added abuse. Therefore what does it really matter about the block as that babbitt rarely ever wears unless you have a poorly machine crankshaft. Thoughts??
 
"The one other thing that I do ponder about why this bronze was added is that the higher forces of a racing engine are forced downward where it is the babbitt in the caps that is taking the added abuse."

Keep in mind the maximum wear on a crank is on the under side, not the top.

As Kelley noted, thinner babbitt will take more load and last longer.

Many years ago one of my customers was a bearing (babbitt) company in Seattle and I saw 2 blocks there that had the main saddles brazed up waiting for babbitt. These were sprint car engines.
 
1930 coupe said:
While this looks good on paper, and I supposed it could be done.
Lets get away from paper theories and go out in the real world.
It is very difficult to heat a engine block hot enough to make the brass stick without cracking it. If you could find someone willing to try it, you have a 50/50 chance of getting a ruined block back. If he is successful it might cost more than you could get another good block for. Unless you are building a $20,000 engine to try to set a speed record at Bonneville I see no advantage for doing it. A standard Babbitt job done properly is more than adequate for our engines.
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I've never tried brazing block saddles but have done a lot of brazing cast iron over the past forty five years. Cast iron only needs to be cherry red and my thought is that only the saddles would need heat, not the whole block. I've never had anything that I brazed unstick or turn loose. Babbit only bonds to cast iron or steel, There is no penetration of metals.
 
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Terry Burtz said:
Braze will tin to cast iron, and Babbitt will tin to brass.

This method was used by Floyd "Pop" Dryer for the main bearings in his 5 main cylinder block.

The Dryer cylinder block was a replacement for the 3 main Model B cylinder block.

I have a copy of the Dreyer 5 main cylinder block drawing, and it specifies that the iron casting be bored to 2 3/8 inches, brazed and bored to 2 5/16 inches, and then Babbitted and bored to 2.250 +.001/-.000 inches.
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Hey Terry,
Thanks for sharing this interesting information :) !
Recently, I spent some time in an engine shop and discussed an A block that the shop was asked to 'fix'. The owner or agent had 'hogged' out the valve ports and put in huge valves. Also had ported this block to the point that it was so thin that the eventual cracks thru to the water jackets appeared when it was run. I said...no way that this block was salvageable ...from what I saw. This shop welded and brazed until the block was strong again, then ported and put new seats with large valves. I saw the finished product and it 'looked' awesome. Whether it gave good service..will never know.
Now there was a time, not too long ago, where I showed pictures here of a B block and it's crack problems. I was told by pretty much all that commented...it's not worth messing with. I've had this same shop perform their skills on my B. I feel that brazing is an art to do correctly for a proper lasting job. Anyone who says that it can't be done and / or shouldn't be done...well, maybe haven't seen it done.

BTW...Mr. Burtz, I just put one of your rear seals on a C crank and am saying a prayer that I got it right;)!
 
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