Crack in block
- Thread starter ckain16
- Start date
JM 35 Sedan
Well-known member
Some cracks are okay, and sorta expected/acceptable, but unfortunately, that's not one of them. I'm certainly no expert on this subject, but it could probably be pinned at the ends of the crack, and welded. Just adds more $$'s to the build. Can you post a picture?
hulleywoodworking
Member
Not too long ago, you would have been advised to scrap that block and find another, as there were plenty of good blocks out there. Today, this is not quite the case; I've read stories of guys looking at a dozen or more blocks to find one that is not cracked. It appears that the supply of perfect blocks is dwindling.
In my own case, my 8BA block in my 51 F1 had the same crack, from cylinder wall to valve opening. The machine shop that rebuilt the engine was able to pin it, then sleeve the cylinder. This block did not have hardened valve seats, so instead of just installing a valve seat at the valve with the crack, I had them install at all valves. Modern gas burns hotter, and I read that valve seat erosion is likely without the hardened valve seats.
The shop baked and blasted the block and Magnafluxed it before attempting to repair the crack. This was the only crack, so they fixed it; after sleeving the cylinder and installing the valve seat, they pressure tested the block before going any further. The block passed, so I had them complete the rebuild.
The pinning and sleeving added $572.84 in labor and materials to the cost of the rebuild. The Magnfluxing, pressure testing, and valve seats would have been done with or without the crack, so they were not an additional cost.
Yes, it would have been nice to have or been able to find a perfect block, but I am happy with the result that I got using this block.
Of course, if you are planning to make this a faster, higher HP engine, then I would recommend that you do find a perfect block. Mine is all stock, so the repaired crack will not be an issue for me.
In my own case, my 8BA block in my 51 F1 had the same crack, from cylinder wall to valve opening. The machine shop that rebuilt the engine was able to pin it, then sleeve the cylinder. This block did not have hardened valve seats, so instead of just installing a valve seat at the valve with the crack, I had them install at all valves. Modern gas burns hotter, and I read that valve seat erosion is likely without the hardened valve seats.
The shop baked and blasted the block and Magnafluxed it before attempting to repair the crack. This was the only crack, so they fixed it; after sleeving the cylinder and installing the valve seat, they pressure tested the block before going any further. The block passed, so I had them complete the rebuild.
The pinning and sleeving added $572.84 in labor and materials to the cost of the rebuild. The Magnfluxing, pressure testing, and valve seats would have been done with or without the crack, so they were not an additional cost.
Yes, it would have been nice to have or been able to find a perfect block, but I am happy with the result that I got using this block.
Of course, if you are planning to make this a faster, higher HP engine, then I would recommend that you do find a perfect block. Mine is all stock, so the repaired crack will not be an issue for me.
Frank Miller
Well-known member
Baking and blasting, I think it is more akin to a tumbler in steel shot, is the best way to clean a block. You will need to put a preservative on it as the heat burns every last molecule of oil out of the cast iron. So I'm told.
Ronnie
Well-known member
$572.84 in labor and materials just for that. You have been duped . All that for the sleeve and installation with a crack pinning. Did you get a kiss as well? Materials a sleeve and a few pins. Holy cow!!! There is less than $100.00 of materials. Did he wear ta mask?
R
R
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hulleywoodworking
Member
And when was the last time you had it done and what did you pay?
aonemarine
Senior Member
When I took my first flathead to the machine shop to be tested, they found a crack. I asked about repairing it and was given the best advice on what to do.
To quote the machinist.....
" look at how much you are investing into rebuilding this engine, Starting off with a cracked block is not a wise decision. Find a good block to start with. You will be happier knowing you did."
It was not about if the crack could be repaired or not, and I'm sure the comment will raise great debate. But in the end I am sure we would all like to start out with a good un cracked block.
I have since purchased tools and equipment for pinning cracked blocks and experiment on two of them. The one block the crack ran well down into the bowl area of the exhaust. The casting was so thin that I was barely grabbing 3 threads on the plug. I quickly decided that block was best set aside. The other block had a small crack that stopped at the seat. it was pretty easily repaired and I would not hesitate to use it.
I also dare not start the welding VS pinning debate...LOL
To quote the machinist.....
" look at how much you are investing into rebuilding this engine, Starting off with a cracked block is not a wise decision. Find a good block to start with. You will be happier knowing you did."
It was not about if the crack could be repaired or not, and I'm sure the comment will raise great debate. But in the end I am sure we would all like to start out with a good un cracked block.
I have since purchased tools and equipment for pinning cracked blocks and experiment on two of them. The one block the crack ran well down into the bowl area of the exhaust. The casting was so thin that I was barely grabbing 3 threads on the plug. I quickly decided that block was best set aside. The other block had a small crack that stopped at the seat. it was pretty easily repaired and I would not hesitate to use it.
I also dare not start the welding VS pinning debate...LOL
Ronnie
Well-known member
Now that the correct shop.That is a good quote. Granted some may be higher But not 400% that is steep to say the least.
R
Frank Miller
Well-known member
Did you get it done in MA?
hulleywoodworking
Member
Is that all they are doing-sleeving it? If so, I paid $31.29 for the sleeve and $142.80 for installation.
aonemarine
Senior Member
Yes I have had it done, to install the sl3eve it was 100.00 plus the sleeve. Pinning price will vary as it is based on the labor/ difficulty of the job.
aonemarine
Senior Member
I think you have me confuse with another poster...Never said you got dumped.
hulleywoodworking
Member
Sorry. Deleted my post. Got posters mixed up.
aonemarine
Senior Member
I was wondering why you put me in the pan like a piece of bacon.
oldford2
Well-known member
Ol Ron,
I had Frank pin a block for me about 8 years ago. Excellent craftsman. You sort of hint he is not doing it any more?? Thanks
John