46 A with later model A pistons

Rottenground · Dec 24, 2017

I have found some 584000 and up m&w style pistons I have tore mine down and Installed them they are alot taller piston than the original it covers up some of the spark plug hole. Anyone tried this before? Some guys I talk to says it will work. Some don't. Sure should help on power thanks.

MSD · Dec 24, 2017

Taper the side of the piston so it uncovers the spark plug. Compression may be a factor to consider though.

Rottenground · Dec 24, 2017

(reply to post at 10:52:41 12/24/17)

I have been told to grind it down a bit to help uncover it how much does it need to be open It won't allow it be totally open unless I get into the top ring groove . What about the compression will it be to much I am wanting some power for pulling also it still has babit rods will it be too much for them thanks

MSD · Dec 24, 2017

Stay 1/8" from the groove and you'll be ok. Rods will be fine with the compression you'll be making. There is a formula the builders use to calculate the compression. You'd need to find how many
cc's of liquid the cylinder will hold with the piston at TDC and how many your head holds to do it. How close does the piston come to the top of the cylinder?

Rottenground · Dec 24, 2017

It comes within a 1/4 of an inch or so I didn't measure. on the rods I found some worth the money and was wondering about them

Rottenground · Dec 24, 2017

Also head has been milled .130 them m&w style piston in a later A are suppose to be 6.50 to 1 mine still has the all fuel head but on an hoping for at least 6.00 or 6.25 to 1

Mike N Mo · Dec 24, 2017

I have put late A pistons in an early styled before. Grind onto the top ring groove to clear the spark plug hole, move the top compression ring down to the 2ng groove, eliminate the 2nd compression ring. You'll still have 4 rings instead of 5, it'll work just fine. Many of the big A/G pullers use only 1 or 2 compression rings. I've had early and late A M&W style pistons side by side before. The compression height is the same, the early piston has a deeper slot/groove for the spark plug hole, and the ring pack is moved down on the piston.
Mike

ndbjda · Dec 25, 2017

Once the tractor starts ignition advance comes into play so it fires before the piston gets to the spark plug. If the piston isn't covering the plug electrode it will start just fine.

MSD · Dec 25, 2017

Actually I wouldn't worry about it covering the spark plug. By the time the piston gets there it has already fired so would not matter. If your still concerned grind as much as you can off to uncover
it but I would still leave the ring.The more you remove the less compression you will have.

Rottenground · Jan 22, 2018

(reply to post at 16:13:13 12/24/17)

Mike how much did the later pistons add to your tractor did You have any problems with it. Any idea what the compession will be. I may use mine a little around the farm other than pulling. Thanks

46 A with later model A pistons

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Mike N Mo

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ndbjda

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MSD

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