Farmall m stroker

johninmn

Member
Is it possible to stroke a m crank and still
use the stock pistons? Reason im asking is
mine are pretty much brand new its only got
about 10-15 hours on a overhaul. So my
thought was to perhaps stroke the crank to 6
or 6.25 and use the stock pistons. They are
m and w type 4" high dome. If im not
mistaken m and w offered a stroker kit to do
just this as well?
 
When u stroke a crank the pin height on your piston changes because of the longer stroke. The pin has to be closer to the top of the piston by the same amount you have the crank stroked, otherwise your piston will extend past the deck of the block. I have a motor with a 5 3/4" stroked crank and M&W pistons. I was able to machine 1/4" off the top of the piston and modify the dome to make my crank work with the pistons. Taking off any more than 1/4" off the top of the pistons would get into the compression rings.

I've heard of other guys using different pistons with the correct pin height from other manufacturers to put into their Farmall motors. Or, you can have them custom made.
 
So it sounds like using my pistons is alot of work if possible at all. Let me ask this follow up question then is it possible to stroke to 6.5 and use the stock rods? Or 6.25? What is the limit on using stock parts? Im trying to build a stroker on a budget if its not clearly evident by now.
 
You start running into clearance issues around the rotation of the crank and the block at 6"-6.25" of stroke with stock rods. Also, u run out of pin height on the piston so you are forced to use custom pistons. By shortening the rods you gain more room for your piston pin height to compensate for the longer stroke. Also, they make the crank journals smaller to help clear the rods around the block.

It can get pretty addictive once you start to build. I had a 346 in. motor with an 8060 head, custom pistons, and stock rods that made 75 hp on the dyno at Lanesville. We had the cam reground to a different rpm range and I could tell a difference in it for sure. We never did dyno it after that, but I guarantee it made a solid 78-80 hp.

Once u get so much horsepower in farm stock classes it all comes down to getting the power to the track. Weight balance and controlling hitch height will kill any pull, no matter how strong the motor is.
 
I found a thread where some guys were talking about using 4020 diesel pistons in a 6" stroker m. Anyone ever heard or done this? Can you bore the block enough to use the 4020 sleeves? Im almost certain you'd hit water but could they be pressed or brazed in? Im not looking to go extreme but somewhere in that 325 to 350 or so cubic inch range
 
if you use 4.310 pistons and a murphy's 6.75 crank and rods their won't be any clearance issues . that's 394 cubic inches and about 240 lb. static compression for 9.1 to 1 compression ratio. should be about 90 to 95 hp. at 1450
 
Do you know off hand what a murphys kit cost? And these 4.310 pistons....do they also come from murphys or another application? You can email me if you dont want to put price numbers on here. I know murphys, baker and marlatt just to name a few build solid engines but i dont have 10 or even $5000 available to throw at a motor. Im trying to piece something together without breaking the bank. And i know i know if horsepower were cheap everyone would have it
 
stock narrowed rods to 1.5 inch .... use a 549 ih truck piston .... same wrist pin size as a M ... stroke crank to 6.5 inches....bore block and sleeve to 4.500 inch ... hard block up to the water plate on the side and braze weld sleeve to the top deck ... and siamese weld front two cylinders together ..and rear two through water plate ... cut cam down to 3/4 in. between lobes and clearance notch the webbing in block hump of rod to clear ... this combo will be 413 inches old skool design but with the right stuff makes plenty of power .......LOOK ME UP .....facebook/IHSMOKE
 
When you say siamese weld.....you mean weld right down between the sleeves effectively welding them together? And by weld do you mean actual weld like mig wirefeed?
Thanks for all the info ihsmoke
 
yes , weld them together need to find someone that is a craftsman when it comes to brazing in or welding sleeves as it is a very touchy job to do ... as for saving MONEY ...... pulling and hiring a track hoe to work is one in the same ..... the more you spend the bigger the hole is ....nothing cheap about a stroker moter
 

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