Im having my engine rebuilt and It should clean up at .040 but if not, why do the piston manufactures skip .050 and .070. I would think it would be important to have the option to save .010 of block if we could. Langs, Bobs, and all you other vendors. Can you convince the piston manufactures to make them. ????
Donnie, probably not enough demand. Gone are the days too when you could have a crank journal turned in the car to a couple thousandths and fit a new cap. You could also buy pistons in 3 or 4 thousandths oversize. No profit in those things. Most folks now just have the cylinders sleeved and start back at standard, what I do. You don't know how thin the metal is in a 90 plus year old block anyway. KGB
It depends on who you have your babbett and machine work done by. The guy that does my rods can bore them to the size you need. For T mains, it's easier for the machinist to do to standard undersize but I have had them done to fit a crank that was just cleaned up. We do it for Model A cranks all the time.
Hi: I understand that the machinest can bore to any size you need. Its just that there are no .050 or .070 pistons available. Those are two sizes that actually would help. My engine is going to probably clean up at .040 but if it does not then I have to go to .060. Seems like a waste of .010 of block thickness. I suppose EGGE Machine can make me a set of .050s if I needed them, I can not see where demand plays into it other than if they do not make them they do not need to stock them ... I agree with the sleeving as a way to fix the problem, but only after .080 is used. I will useally sleeve the engine if it needs .080 pistons but .080 will useally work OK. But it would be nice to have .070 as a option if it will clean up at .070 ...
It 's your money,spend it where you want.
There are still guys around who can cam grind pistons. (There is one near me). He has made me custom pistons from the aluminum castings I have provided him.
It is not economical however, but sometimes it makes sense.
Sleeves for a T block are not terribly expensive.
Now back to Donnie's original inquiry.
It is rare for a block to clean up at less than .020 from it's existing size. It is also rare that it will not clean up at .020 larger than it's existing size. The exceptions would be rust pits. Personally I wouldn't worry if every last rust pit did not clean up. Any pits will rapidly fill with carbon, and will not adversely affect ring wear.
Once again Les Schubert is correct. For a long time I don't even mike the inside of the cylinders any more. I always go to .030 and it cleans up well. I don't even do my own boring any more, I sold my fixture. Napa backs up to my door and I can load a block or blocks and tell them what I want and they have them back in about a week. They can keep their large fixtures in place, throw the block on them, hit a few buttons and its Done. I had to move my boring fixture every time I wanted to bore another block. I didn't think it was worth the extra work.
My main point is that we do not have the option, for example: Say my block is .030 and it will clean up with .010 In that case I have a choice of .040 for a piston. But say it will not clean up with .010 and I have to go .020 more to get it clean. In that case there is no option for pistons from the vendors. I have to go to .060 for the bore. In that case I had to remove .030 from my block to get there. At .060 there is not much chance of the next guy getting away with a re-bore. He will have to sleeve it. But if I could have stopped at .050 there is a good chance that .060 or at least .070 (if it was available) would get one more life out of the engine for the next guy. Sleeves can save a engine but they have problems too. They can crack a block,(remember that they are a press fit) or you can "blow thru" the water jackets. poor machining can cause them to work loose. I just want the option to make better machining decisions. For Texas T Parts Langs Bobs ect.... If you read this why don't you get a few made from your piston vendors and see if they sell. I bet they would sell as well as any of the other oversizes do .........
By the way some one was talking about sleeving a motor, Why? Unless its a very early block you can buy 3 or 4 blocks for what ONE sleeve will cost around here. I used to keep 50 blocks on hand to replace blocks that were bad. I seldom bid on a block at a farm auction any more as no one around here wants them. I counted the blocks that I have out back of the shop and the ones in the shop last year and I still had 50 blocks. Again why would you sleeve a block? I do sell 26/27 blocks from time to time. One guy took 5 and another took 3, but the rest of the blocks will not sell. I am rounding up a few of the blocks that are cracked and headed for the scrap yard with them.
Dave some folks want to keep the block that was original to the car, in that case sleeving is the only option regardless of cost. KGB
I agree with keith. Unless you change engine numbers you need to save your block. You say you have 50 blocks and no one wants them. Are they laying outside full of water. Are you asking too much. I have about 35 engines myself. I have all of them inside storage. It may be in the school bus, under the school bus, the better ones are all under the good shed. They are all in the dry. I also filled them with diesel when I got them. I do not believe in scrapping any of them. If the whole side of the water jacket is gone maybe. We only have so many blocks. I do not see any one recasting them soon. If they do we may not be able to afford them, or they will be crap.... Almost all cracked blocks can be repaired. Take care of what we have so our grandkids can carry on. And don't tell me the younger generation does not want them . Just last year I remember at least 4 or 5 "Newbie" questions. They were all from people 35 years old or younger. They had just acquired a car and were working on them. One of the "Newbies" was 16 yrs old. We are caretakers of these cars and parts.... Help to save them not scrap them ... I remember about 35 years ago when I started messing with Ts, parts were more plentiful. Some of the parts I am "using" today, and glad to have them, I would not have given a second look at back then....
You can get pistons any size you specify from a variety of companies. I've used the following companies multiple times for custom pistons and can vouch for all of them:
A custom piston with rings and pin are about $100 each from Ross or Wiseco. Arias or JE you are looking at perhaps $150 - $200. That's per piston.
Is it worth $400 - $800 to avoid boring the block to the next normally available off the shelf size? It's not to me - you decide if it is for you. It is the kind of expense I reserve for a really rare block, or an engine that you can't get off the shelf pistons for (non Model T).
Royce: I agree that its too expensive to go to a special piston. And if needed I will bore out to .060. but it just chaps my ... that the parts manufactures choose to not do the "right thing" and supply all the sizes from .020 to .080. in .010 increments.
Those part manufacturers are doing pretty good from where I am sitting. Pistons are dirt cheap for Model T's. I don't see a problem.
I can get another 1917 - 27 block for $300 or less if I need one. I can sleeve all four holes for $300 if I need to. What's the problem with having only a half dozen piston sizes to choose form? Its more choices than anything except a 350 Chevy!
IMO, the T new parts suppliers are offering swell family of parts to keep our T' running. After all, the T wasen't intended by Henry to keep running for a hundred years!
Back in 1924 the factory offered just 4 sizes of pistons:
stock 3 3/4", .0025", .005", .03125" and .033" oversize!
Besides, with .040" or .060" over, the bigger is better for performance.
Dan; We just put a set of NOS .0025 pistons in my brothers motor. We actually had to hone the cylinders out to get them to fit.