Engine Rebuild

Just askin

New User
I am in the process of rebuilding the engine of my 51 WD and want in "hopped" up to pull with. I have a 45 crank to put in and am wondering which pistons I should use (WD or 45 pistons, flat or dish,others)? I have read numerous posts and the opinions seem to vary greatly. I am building this engine from the ground up, so any advice would be appreciated. Thank you.
 
Im no expert, but i thing your WD as a 4 inch stroke and the 45 has a 4.5 inch stroke. If you get the wrong pistons, they will come too close to the top deck and make your compression about 12 to 1. You need to get pistons that have about the same piston top to pin center dimension as the 45 had originally.... mabe slightly more.
 
Thank you for the input so far. I have read that the pistons from a WD have the pins closer to the top, so this is the set I would want. Can someone verify this? Or is there a better option? Thanks.
 
Pistons from a 175 will get you the most you'll get without extra work. You can run a 175 gov spring and a larger carb to get basically 175 power out of a WD45 block. You might want to do some searching in the pulling forum, the topic has been discussed before. I think pistons for a 4" crank will interfere or give way to much compression on a 4.5" crank.
AaronSEIA
 
Nothing wrong with 12.1 compression its the biggest hop up one can do. new flat top pistons from a piston manufacturer . 50 year old pistons are 50 year old technology
 
picture of block with falt top you can see i run them up pretty high in bore .<a href="http://s738.photobucket.com/user/pankeyc/media/tractor%20parts/09240916201.jpg.html" target="_blank">
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a picture courtesy of a fellow engine building friend of his build with 4.400 piston bore
<a href="http://s738.photobucket.com/user/pankeyc/media/cfa36a5e-d9aa-4f86-8da7-b968d36e08e6_zps1c95362f.jpg.html" target="_blank">
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one of mine with a piston bore of 4.625 and a block bore of 4.950
<a href="http://s738.photobucket.com/user/pankeyc/media/bores/b33a06f1-cd78-4786-81af-2cc4294f398e_zps5b45c800.jpg.html" target="_blank">
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notice sleeve to head bolt placements . Now for the big boy and bolts moved to accept 5.020 sleeve od and 4.800 piston bore
<a href="http://s738.photobucket.com/user/pankeyc/media/bores/a1ac0ae7-e436-47bf-8450-5a11999d4e0a_zps5946f0c4.jpg.html" target="_blank">
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last two blocks courtesy of mlpankey
 
Thank you again for the advice. I will probably head down the 175 path. Any other tricks or headaches I should be looking out for? Do I need to be look at a cam also?

Aaron SEIA, where abouts are you located in SE Iowa? I am located there also.
 
175 piston is like 8.2.1 compression and only comes in 4 inch bore if your truly going to pull it your giving up cubic inches and compression .most pulling are at least 1/8 inch over bore for 240 inches and have at least 10.1 compression. Cam change is beneficial but not if compression doesnt go up . overlap will kill power in a 8.1 comp. Motor where it will make power with a compression ratio of double digits.
 
I am still learning on the fuel needed for diff. compressions, but if I go to 12:1, won't I need better fuel? Thanks again.
 
I'm just outside of Mt Pleasant. You also need to look at what you want to do with the thing when you are done. Parades with some for fun pulls? Bit of plowing and farm work with some pulls for fun? Hit the circuit and see who you can take down pulling? A WD45 made 43 PTO horse at Nebraska and a 175 made 61. Thats a pretty good jump with some simple part swapping. I did find a high compression 4 1/8 overbore kit for a 175 on eBay, but it didn't say what the compression was. As soon as someone says "pulling", it's assumed the builder wants some huge cube huge power, huge bill WD engine. Figure out what you want to do, then decide on what to put in the block. The topic has been discussed extensively in the pulling forum here and the other AC site.
AaronSEIA
 
Thanks Aaron, I am just south of Fairfield, do you pull with Laplanders or Bald Bluff? I have been looking at the pulling forum and there is a lot of good info there. I have pretty well decided where to go for long term but, the use of the tractor is def. a factor. Thanks again
 
I don't pull at all, just a fan. I watch the Laplanders pull at the Henry County fair. Knowing the end use of the tractor makes deciding what to do to the engine a lot easier.
AaronSEIA
 
If you decide on 4" 175 pistons. I have a barely used set with sleeves. Took them out of a rebuilt wd engine. They are meant for the 4.5 stroke
 
Running WD pistons with a 45 crank will work. Not quite what the 175 will get you, but a very easy swap. Still have low enough compression that a decent fuel will work. I've had a number of folks use WD pistons and been very happy.
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