Fly cutting pistons

[TT350]

Ok guys I thought some of you would like to see some
piston fly cutting in action.

I took a few pic’s this afternoon of me making an off the
shelf J.E. part # 170818 23deg piston work with my 18X
Brodix heads.

Here is a pic of the jig I made to hold the piston without
putting a mark on it. It works grate!

The two aluminum blocks I made in my CNC mill and they square the piston in the vise but the piston is not allowed to touch the back jaw of the vice, it clears it about .050.

The first thing I done was put some clay on the piston and let the valve mark the clay that next I put a transfer punch in the valve guide and marked the centerline of the valve,

Here you can see the market clay and where I circled the
punch mark with a Sharpie

Here is how I set the head on my mill to the correct angle (18 deg)

Next I line up the spindle on the mill with the punch mark. Notice the felt between the piston and the vice jaw, the felt is .125 thick so when it is squished down
so the jig blocks are held tite the piston is rock solid.

After all that is done I setup the fly cutter just a little past where the valve marked the clay, about a .075

This will give you an idea of how much the cutter will be removing.

Here is a close up of a finished piston.

 

[4C FED]

Re: Fly cutting pistons

And thennnn?

Where's the action shot?

 

[SY2932]

Re: Fly cutting pistons

I take it that you ARE taking fuzz cuts with 50% step over. That jig doesn't look very beefy to me... I would have cut a set of "V" jaws to bolt into the vise to hold the piston instead

. Made two sets of "V" vise jaws at work for holding round stock myself. Of course, a lathe would be even better

.

 

[badmatt]

Re: Fly cutting pistons

I want to see how this turns out

 

[TT350]

Re: Fly cutting pistons

I take it that you ARE taking fuzz cuts with 50% step over. That jig doesn't look very beefy to me... I would have cut a set of "V" jaws to bolt into the vise to hold the piston instead

. Made two sets of "V" vise jaws at work for holding round stock myself. Of course, a lathe would be even better

.

Here is a pison vice that summit sells
http://store.summitracing.com/partd...400405+4294925139+4294755310+115&autoview=sku
My settup is rock solid.
It it holding the piston front and back.
And to boot the pistons don't have a mark on them from holding them.

 

[TT350]

Re: Fly cutting pistons

Next on the list is piston squirters!

 

[badmatt]

Re: Fly cutting pistons

looks good but id check exhaust valve clearneces... and spark plug clearances.. aswell just to be safe if you already havent done that

didnt JE offer a set of pistons for your application or are you running 6.000" rods with a standard deck?

 

[TT350]

Re: Fly cutting pistons

The exhaust valve clears by a mile.
Most off the shelf 18deg pistons are for N/A motors.
To get a big dish for a 18deg head you have to have them made.

 

[SY2932]

Re: Fly cutting pistons

Here is a pison vice that summit sells
http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRO%2D66772&N=700+400405+4294925139+4294755310+115&autoview=sku
My settup is rock solid.
It it holding the piston front and back.
And to boot the pistons don't have a mark on them from holding them.

I'm surprised that you didn't jump on that aluminum vise that summit sells being that it is more than the cost of a good 6" machinist vise

. Nice set up (now that the rest of the pics are up), keep us informed how everything else works out !

 

[TT350]

Re: Fly cutting pistons

I studied that vice for a wile and thought about making one then the idea hit me and the rest is history!

This is the second set that I’ve needed to cut.
I couldn’t see putting the time into making a vice
or spending the money on one.