1952 Cub Valve Seat Question

[jakescubs]

This tractor has been the source of my woes for the past two years now, it seems every time I get something working another thing decides to break. I did a complete overhaul on the engine, as it was completely seized, the cylinders were pitted, and the previous owner snapped 8 head bolts off inside the block and completely destroyed the bolt holes. I got the cylinders bored .060 and threaded inserts put in by a very reputable engine shop in my area, and the engine ran beautifully when i got it back together. Of course, something had to go wrong, and one of the threaded inserts backed out of the deck and cracked the block. So fast forward to now, I bought an engine block on Ebay that’s in very good condition besides two of the valve seats, which are very pitted and worn(I did not notice the valve seat issue until I was able to do a thorough check of the block when it arrived). I could take the block up to the engine shop and get it counterbored and have new seats pressed in, but I’ve already invested so much money in this tractor that I’m reluctant to spend too much more on it. What should I do?

[Mht]

I salvaged a block last year that had badly pitted exhaust seats. The cost was only about a hundred bucks for seats and machining. I wouldn’t let a hundred bucks stop me from finishing a rebuild

[inairam]

Jake, You are not investing in the tractor, You are investing in your hobby. That is was I tell people anyway.

I assume you are going to swap out the new pistons and other things from the cracked block into the ebay block. The piston will not fit unless you know the eBay block was 0.060 over already. So a trip to the engine shop in your future.

If the ebay block is 0.060 over I used Neway cutters to cut the seats http://www.farmallcub.com/phpBB2/viewto ... 1&start=15 . I have heard of people running two exhaust values in one cylinder that had bad seats that took a lot of material to get to solid metal. ( not recommending not tried it my self just saying what I have a heard)

[jakescubs]

Thank you guys for your replies, I’m gonna make a trip to the engine shop tomorrow and get them to take a look at it. The cylinders are in good condition and haven't been bored oversize, so I hope I can get away with honing the cylinders and installing new standard pistons and rings. Since I’m a junior in high school, it’s been difficult to juggle school work and finding time to work on restoring my Cub, but I’m gonna be so glad when I can get it finished and plow some fields.

[tst]

I would be having a talk with the machine shop who put the seat in, if it was installed correctly it would never had come out, a good shop would stand behind an issue like that, I install a lot of valve seats in these engines, I use press in seats, do not like the thread types, never had a issue yet, just did this block a few days ago, it was seized from water in the block and ate away the metal around the seat, had to use a larger seat and machine the seat down to fit the block, you can still see a couple pitts in the block but that will not affect anything, the bluing on the seat is from fitting the seat, this block got 4 exhaust seats, you can see the one on the right is larger on the OD than the one on the right, ended up boring this .040 over because of the water damage

[jakescubs]

I would be having a talk with the machine shop who put the seat in, if it was installed correctly it would never had come out, a good shop would stand behind an issue like that, I install a lot of valve seats in these engines, I use press in seats, do not like the thread types, never had a issue yet, just did this block a few days ago, it was seized from water in the block and ate away the metal around the seat, had to use a larger seat and machine the seat down to fit the block, you can still see a couple pitts in the block but that will not affect anything, the bluing on the seat is from fitting the seat, this block got 4 exhaust seats, you can see the one on the right is larger on the OD than the one on the right, ended up boring this .040 over because of the water damage

I didn’t have new valve seats put in the original block because the original seats were still fine, the problem was one of the threaded inserts that was put in a stripped head bolt hole backed itself out and cracked the block. Eight of the twelve head bolt holes had to have threaded inserts put in.

[Rob in NH]

Tim, do you do your own machine work too?

[tst]

Hi Rob, yes I do, do not do crankshafts, I do valve seats, grinding and boring, some times I have another shop bore for me as I do not have a dedicated setup and takes to much time if I am busy to swap it around

[Rob in NH]

wish you were closer

[tst]

just put a couple stamps on the parts and throw them in the mail !

[Rob in NH]

would need lots of stamps haha

[jakescubs]

Update: I took the engine to my machinist, and he said that he could put in new seats for $90 a seat. He also said that the block needed new valve guides, so I’m gonna reuse the new guides I put in my old block. Any tips on how to press the guides out of the block?

[inairam]

Did you talk to him about the cracked block?

[jakescubs]

Did you talk to him about the cracked block?

Yes, he said the crack was most likely caused by the threaded head bolt hole insert backing out of the block.

[inairam]

Did you talk to him about the cracked block?

Yes, he said the crack was most likely caused by the threaded head bolt hole insert backing out of the block.

Did he offer any compensation or to help switch over the parts? If it was his work that caused the failure I think he should compensate you somehow.