91cc chamber a460 head

I have a diamond dome piston. I dont know the volume right off. The chambers have been polished. Im wanting 14.5 to 15:1cr. About how much do i need to have shaved off? The regular 91cc and the dome suppose to give i think 13:5.
Thanks

If the heads are the newer generation TFS stuff....they should CC ~ 87cc as dlivered.

Lem i bought these from you about a year ago. How long have you had the new ones? These are the ones that have the engraving if that matters. They dont have the m87, just a -2.
Thanks alot

The M87 are machined chambers. The reason the machined "10 bolt" chambers are 87cc is because the original were always ~ 87cc.

tconnection wrote: I have a diamond dome piston. I dont know the volume right off. The chambers have been polished. Im wanting 14.5 to 15:1cr. About how much do i need to have shaved off? The regular 91cc and the dome suppose to give i think 13:5.
Thanks

Mr. Waters I presume?

The next step is to find your job card on the pistons and call Diamond if need be. You are going to have to find out the volume of the domes, in order to calculate the compression ratio. IF there is no paperwork on the pistons,,, then the old school way is to mock up your engine with grease around the pistons rings and take the piston 1.000" down deep in the hole. Using your beret, fill the cylinder with fluid. Subtract that amount, from the calculated volume of a cylinder with your bore size, and a stroke of 1.000" (V=pi x r2 x h). The difference is the net volume of the dome. Then use the compression ratio calculator on Diamond's website homepage.

For every .005" you mill off of a TFS A-460 head, you reduce the chamber volume by 1 cc.

Hope this helps,
Charlie

c.evans wrote:

tconnection wrote: I have a diamond dome piston. I dont know the volume right off. The chambers have been polished. Im wanting 14.5 to 15:1cr. About how much do i need to have shaved off? The regular 91cc and the dome suppose to give i think 13:5.
Thanks

Mr. Waters I presume?

The next step is to find your job card on the pistons and call Diamond if need be. You are going to have to find out the volume of the domes, in order to calculate the compression ratio. IF there is no paperwork on the pistons,,, then the old school way is to mock up your engine with grease around the pistons rings and take the piston 1.000" down deep in the hole. Using your beret, fill the cylinder with fluid. Subtract that amount, from the calculated volume of a cylinder with your bore size, and a stroke of 1.000" (V=pi x r2 x h). The difference is the net volume of the dome. Then use the compression ratio calculator on Diamond's website homepage.

For every .005" you mill off of a TFS A-460 head, you reduce the chamber volume by 1 cc.

Hope this helps,
Charlie

this ^^^is the only way to realy know what you have for c/r. i have also put the head on,turned the motor on the stand and filled it through the plug hole.i cut my old A460's .100 to get to 70cc.

"Mr. Waters I presume?"
///////////////////////////////////////////////

Charlie, were not addressing Chuck or Chad waters.
///////////////////////////////////////////////////////////////////

tconnection.......call me if you need to.

My mistake Lem. Thought it was the same town.

Charlie

Mr. C, lol! It's the same town. I'm Smith. Ive talked to Lem a number of times and worry Shaun as much as i can.
I have a spec card but not at hand at the second. I called trick flow and the fellow said this part # is 91cc.

tconnection wrote:Mr. C, lol! It's the same town. I'm Smith. Ive talked to Lem a number of times and worry Shaun as much as i can.
I have a spec card but not at hand at the second. I called trick flow and the fellow said this part # is 91cc.

Which means he aint never CC'ed one )

tconnection wrote:Mr. C, lol! It's the same town. I'm Smith. Ive talked to Lem a number of times and worry Shaun as much as i can.
I have a spec card but not at hand at the second. I called trick flow and the fellow said this part # is 91cc.

X 2, you need to call Lem, not TFS.

Charlie

c.evans wrote:

tconnection wrote:Mr. C, lol! It's the same town. I'm Smith. Ive talked to Lem a number of times and worry Shaun as much as i can.
I have a spec card but not at hand at the second. I called trick flow and the fellow said this part # is 91cc.

X 2, you need to call Lem, not TFS.

Charlie

Every chamber needs to be CC'd and nothing assumed.....i.m.o. As Charlie suggested....things aint what is published.

The dome vol is 12.5cc, 1.235 comp height, 4.530 dia.
78cc=15.5cr
83cc=14.7cr
Im having .030 shaved off. I'll cc them when i get them back home so i'll know what they are. But is.030 safe whether their 91 or 87?
Thanks

tconnection wrote:The dome vol is 12.5cc, 1.235 comp height, 4.530 dia.
78cc=15.5cr
83cc=14.7cr
Im having .030 shaved off. I'll cc them when i get them back home so i'll know what they are. But is.030 safe whether their 91 or 87?
Thanks

you should be ok,just make sure you check piston to valve!

tconnection wrote:The dome vol is 12.5cc, 1.235 comp height, 4.530 dia.
78cc=15.5cr
83cc=14.7cr
Im having .030 shaved off. I'll cc them when i get them back home so i'll know what they are. But is.030 safe whether their 91 or 87?
Thanks

I suspect that the v/p clearance will be okay.....with a .030" cut make sure the intake to head fit is still good.

Crap, i didnt think about that. I aint going through that. i guess i need to find out how much is allowed before an issue is accured.