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Re: Piston top thickness
[Re: MNobody]
#1417923
04/10/13 11:20 PM
04/10/13 11:20 PM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I'd call Ross & barring that I'd put a pointed tip pencil type metal pointer vertical in a vise then set your magnetic dial indicator next to it & rig it so the plunger comes straight down vertical touching the pointer then zero the dial & lift the plunger & insert the piston inbetween the two & let the plunger go to the bottom of the valve relief & direct read what deck thickness you have (& therefore how further you can go). Umless Ross tells you otherwise for their pistons .150" is the bare minimum
live every 24 hour block of time like it's your last day on earth
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Re: Piston top thickness
[Re: MNobody]
#1417925
04/10/13 11:30 PM
04/10/13 11:30 PM
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Joined: Jul 2008
Posts: 30,444
Florida STAYcation
dOoC
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,444
Florida STAYcation
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Quote:
If a guy had some 10:1 Ross flat top pistons with the valve reliefs in the top and wanted to cut them a little deeper to gain some piston to valve clearance is it possible? Thanks
DEPENDS on how much they were milled on the uNderside .....
Goldie .....wear are those TQ's you promised me ? .... 
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Re: Piston top thickness
[Re: MNobody]
#1417930
04/15/13 09:52 AM
04/15/13 09:52 AM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
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Quote:
Piston to valve clearance is already too tight on the intake valve, the only reason it still lives is the .528 solid cam. Right now the compression figures out to 8.25:1 just trying to help that out with a thinner gasket.
Are you sure you are measuring it right and how is ANY ross piston .092 in the hole ? are you using a stroker piston in a non stroker application ? I don't think a .528 cam has enough duration to have a piston to valve clearance , especially on a piston with valve reliefs that far away ...
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Re: Piston top thickness
[Re: JohnRR]
#1417931
04/18/13 12:03 AM
04/18/13 12:03 AM
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Joined: Feb 2005
Posts: 4,884
Michigan
MNobody
OP
master
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OP
master
Joined: Feb 2005
Posts: 4,884
Michigan
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No idea John i didn't build the motor. I was told they are 10:1 ross pistons but they are still in the block so i can't verify. Pistons .092 in the hole, .528 solid .026 lash I and E. 360 j heads have 2.02 intake and stock 1.74? Exhaust, chambers measured 72 cc. Head gasket is a fel pro .057 thick. All this gives me .017 clearance on the intake and .042 on the exhaust. And a compression of 8.25 if i figured it right.
Crap i screwed up and used the wrong stroke, it's actualy 7.5
Last edited by MNobody; 04/18/13 12:24 AM.
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Re: Piston top thickness
[Re: MNobody]
#1417933
12/07/13 01:31 PM
12/07/13 01:31 PM
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Joined: Feb 2005
Posts: 4,316
Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,316
Prospect, PA
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Quote:
No idea John i didn't build the motor. I was told they are 10:1 ross pistons but they are still in the block so i can't verify. Pistons .092 in the hole, .528 solid .026 lash I and E. 360 j heads have 2.02 intake and stock 1.74? Exhaust, chambers measured 72 cc. Head gasket is a fel pro .057 thick. All this gives me .017 clearance on the intake and .042 on the exhaust. And a compression of 8.25 if i figured it right.
Crap i screwed up and used the wrong stroke, it's actualy 7.5
Either I'm not following, or something is way wrong in the build or measurements. My first thought was backwards pistons too. But I still don't think that the valves would be this close even under that condition. Maybe 0.17" and 0.42"? 
What is up with that stroke statement? Motor must be a real stump puller. 
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Re: Piston top thickness
[Re: RapidRobert]
#1417940
12/07/13 11:24 PM
12/07/13 11:24 PM
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Joined: Dec 2013
Posts: 403
Romulus, MI
GTS340
mopar
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mopar
Joined: Dec 2013
Posts: 403
Romulus, MI
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Quote:
Quote:
Piston to valve clearance is already too tight on the intake valve, the only reason it still lives is the .528 solid cam. Right now the compression figures out to 8.25:1 just trying to help that out with a thinner gasket.
Advancing or retarding the cam one of the two I forget which one would reduce intake VP clearance. You could easily mill the valve pockets .030" deeper & with some easy math (A=Pi x radius squared) figure out how many addit'l CC's you'd be adding. I'd weigh the pistons before/after to see how much weight change there is & not saying you'd absolutely need to rebalance but HF has a gram scale on sale regularly for $9.95 & you'd have the info in hand for a baseline. I'd confirm your measurements. Holler how it turns out.
Valve relief volume calculation is a little more involved than solving for area of a circle (Area=Pi x R squared). See link below, not trying to be a know it all I'm just a stickler for accuracy when figuring static compression ratios.
http://www.lmnoeng.com/Volume/InclinedCyl.htm
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Re: Piston top thickness
[Re: GTS340]
#1417941
12/07/13 11:37 PM
12/07/13 11:37 PM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Hey I am a stickler for accuracy & I am wrong on occaision. I'll check that site out. EDIT I'm thinking (Area X Pi X radius squared) times .035" would be the addit'l volume removed then you'd convert from cubic inches to CC's then you'd add that number to the original valve relief CC amount. Sound good or bogus?
Last edited by RapidRobert; 12/07/13 11:45 PM.
live every 24 hour block of time like it's your last day on earth
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Re: Piston top thickness
[Re: RapidRobert]
#1417942
12/07/13 11:54 PM
12/07/13 11:54 PM
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Joined: Dec 2013
Posts: 403
Romulus, MI
GTS340
mopar
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mopar
Joined: Dec 2013
Posts: 403
Romulus, MI
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Quote:
Hey I am a stickler for accuracy & I am wrong on occaision. I'll check that site out. EDIT I'm thinking (Area X Pi X radius squared) times .035" would be the addit'l volume removed then you'd convert from cubic inches to CC's then you'd add that number to the original valve relief CC amount. Sound good or bogus?
If the floor of the valve relief were parallel with the piston top, or if the existing relief is deep enough that it is a full diameter that would work but on a small block the valve reliefs are 18 degrees from being parallel and generally not deep enough to be a full diameter. Or just break out the burette and piece of Lexan if they are flat tops.
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Re: Piston top thickness
[Re: Oyvind Mopar]
#1417945
12/08/13 04:16 PM
12/08/13 04:16 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
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Quote:
I would have pulled that engine and find out all about the internals before doing anything destructive...Something is wrong, and small corrections may not be enough. My 
I might have first wondered why no reply 8 months ago before deciding to drag this one up from the dead .  
But for the OP , I would have pulled a piston also , this sounds like a small block also ...
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How much V to P clearances are you looking to get? How much V to P clearance do you have now and what type, duration and lift cam are you using? Did you degree the cam or install it straight up or? 
