91cc chamber a460 head

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91cc chamber a460 head

Post  tconnection on May 14th 2012, 3:08 pm

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

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Re: 91cc chamber a460 head

Post  Lem Evans on May 14th 2012, 3:36 pm

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

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Re: 91cc chamber a460 head

Post  tconnection on May 14th 2012, 7:41 pm

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

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Re: 91cc chamber a460 head

Post  Lem Evans on May 14th 2012, 7:48 pm

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

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Re: 91cc chamber a460 head

Post  c.evans on May 14th 2012, 8:50 pm

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

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Re: 91cc chamber a460 head

Post  cool40 on May 14th 2012, 9:20 pm

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.
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Re: 91cc chamber a460 head

Post  Lem Evans on May 14th 2012, 10:58 pm

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

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

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

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Re: 91cc chamber a460 head

Post  c.evans on May 14th 2012, 11:14 pm

My mistake Lem. Thought it was the same town.

Charlie

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Re: 91cc chamber a460 head

Post  tconnection on May 16th 2012, 9:12 pm

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.

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Re: 91cc chamber a460 head

Post  Lem Evans on May 16th 2012, 9:16 pm

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 Smile )

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Re: 91cc chamber a460 head

Post  c.evans on May 16th 2012, 9:35 pm

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

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Re: 91cc chamber a460 head

Post  Lem Evans on May 16th 2012, 9:42 pm

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.

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Re: 91cc chamber a460 head

Post  tconnection on May 16th 2012, 10:29 pm

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

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Re: 91cc chamber a460 head

Post  cool40 on May 16th 2012, 10:37 pm

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! Very Happy
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Re: 91cc chamber a460 head

Post  dfree383 on May 16th 2012, 10:48 pm

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

Check your piston to valve clearance before you start cutting the decks
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Re: 91cc chamber a460 head

Post  Lem Evans on May 16th 2012, 10:49 pm

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.

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Re: 91cc chamber a460 head

Post  tconnection on May 16th 2012, 11:11 pm

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.

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