Next Oversize pistons for 3 5/16

[my4dv8]

I have done a search but just checking to ask if there is a 3 5/16 x 4 inch stroke oversize available ,like 25thou over ?? It would sure save an old overbore block.

[J Franklin]

How about sleeves if you can not find the size you need?

[my4dv8]

Yes I did suggest that to the owner , as it is really only one bore hole that needs help, but he wants to replace all. The current pistons are Ross 3 5/16.

[Brian]

Ross will manufacture to any size, but 3 5/16 plus .030" at least should be in stock. Email them....

[GOSFAST]

Originally Posted by my4dv8

I have done a search but just checking to ask if there is a 3 5/16 x 4 inch stroke oversize available ,like 25thou over ?? It would sure save an old overbore block.

The first numbers to establish would be if the rings are available for a certain bore size.

Assuming you have a 3.312" bore with some "minor" wear there is a ring set out there for a 3.317" finished bore. It is a "metric" set (1.5, 1.5, 4.0) but we use these all the time. Once you've established this size is available you go back and order the pistons to "match", so to speak.

Ross, for instance, would build the pistons to that ring configuration and you'd be good to go. The "finished" pistons would be in the area of 3.313" (nominal). The "stocking" pistons for a finished 3.312" bore would be around 3.308".

We always try to "save" these hard to find blocks with "minimum" boring & honing whenever possible.

(Add) Make certain to use a block plate on the final honing! Especially on these Flatheads. They are strong but they are also "thin" by todays standards.

Thanks, Gary in N.Y.

P.S. We just built 2 Flathead pistons sets, Ross, for inventory, using a 3.228" finished bore size. The "moly" rings, metrics, are available from Speed-Pro as a stock ring size for a certain 4 cyl application. We use 2 sets for each package! These sets would be +.040" over for the OEM 3.188" bore.

[Ross6860]

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Originally Posted by GOSFAST

The first numbers to establish would be if the rings are available for a certain bore size.

Assuming you have a 3.312" bore with some "minor" wear there is a ring set out there for a 3.317" finished bore. It is a "metric" set (1.5, 1.5, 4.0) but we use these all the time. Once you've established this size is available you go back and order the pistons to "match", so to speak.

Ross, for instance, would build the pistons to that ring configuration and you'd be good to go. The "finished" pistons would be in the area of 3.313" (nominal). The "stocking" pistons for a finished 3.312" bore would be around 3.308".

We always try to "save" these hard to find blocks with "minimum" boring & honing whenever possible.

(Add) Make certain to use a block plate on the final honing! Especially on these Flatheads. They are strong but they are also "thin" by todays standards.

Thanks, Gary in N.Y.

P.S. We just built 2 Flathead pistons sets, Ross, for inventory, using a 3.228" finished bore size. The "moly" rings, metrics, are available from Speed-Pro as a stock ring size for a certain 4 cyl application. We use 2 sets for each package! These sets would be +.040" over for the OEM 3.188" bore.

Great info...

[Ol' Ron]

I just bought a set of 3 5/16 +.020" from Egge thay come with metric rings from a Volvo. They also make a 3 5/16 + .5-" over. Great piston very light.

[my4dv8]

Thanks , knew we rely on the barners to come through .

[Kahuna]

My engine has +.015 oversize from Egge. 3.330"

[38 coupe]

I have heard that some of the Egge pistons hit the head unless you cut down the crown. Does anyone know about this?

[flatjack9]

I have not had that problem.

[Ol' Ron]

I've been using Egge pistons for over 20 years and never had that problem. I usually have to mill the heads to get the 40-50 thow piston to head Clarence.That may not make any sens to you but that improves turbulence an economy.

[Lawrie]

Egge will make a custom size piston,the did for my LB block,.065.
Lawrie

[my4dv8]

Yes that makes a bunch of sense, more turbulence means better burn = more power and economy.
often EGGE piston can be a little tall anyhow.

Originally Posted by Ol' Ron

I've been using Egge pistons for over 20 years and never had that problem. I usually have to mill the heads to get the 40-50 thow piston to head Clarence.That may not make any sens to you but that improves turbulence an economy.