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Re: Anyone here ever have their pistons machined?
[Re: BSB67]
#1509444
09/29/13 01:39 PM
09/29/13 01:39 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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A thicker head gasket will lower compression, true. Don't know how much piston to head clearance you have. If you have a good PTH clearance like .050" or less. The easiest simple way is head gasket.
I never go the easy route as it usually does not give the most benefit. To cut a dish in your piston you need to have the material to do so and still have enough thickness. If you do have enough material that is the way to go but, be aware this will change your balance numbers.
If your head is open chamber design then the thicker gasket will be the way to go.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Anyone here ever have their pistons machined?
[Re: BSB67]
#1509445
09/29/13 02:22 PM
09/29/13 02:22 PM
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Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog
OP
Striving for excellence
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OP
Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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Quote:
Guess you did not like my previous suggestion to get quench and lower CR all in one. Don't even need to pull the motor. 
I don't want to appear ungrateful to anyones suggestions, it just worries me to go higher in compression to gain quench.
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Re: Anyone here ever have their pistons machined?
[Re: dvw]
#1509447
09/29/13 03:20 PM
09/29/13 03:20 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
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Quote:
I don't know your combo. That being said if you now have .035-.045" quench currently, adding head gasket thickness to reduce compression may make detonation worse. If you have no quench now I would definitely go with a thicker gasket.
Doug
The problem is he doesn't have good quench and wanted to make it worse with yet a thicker gasket to lower compression.
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Re: Anyone here ever have their pistons machined?
[Re: JohnRR]
#1509450
09/29/13 07:14 PM
09/29/13 07:14 PM
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Joined: Mar 2006
Posts: 9,848
MI, usa
dvw
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master
Joined: Mar 2006
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MI, usa
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Quote:
Quote:
I don't know your combo. That being said if you now have .035-.045" quench currently, adding head gasket thickness to reduce compression may make detonation worse. If you have no quench now I would definitely go with a thicker gasket.
Doug
The problem is he doesn't have good quench and wanted to make it worse with yet a thicker gasket to lower compression.
If the quench is poor already adding head gasket thickness won't hurt it. Am I correct in assuming this is an open chamber style head?
Doug
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Re: Anyone here ever have their pistons machined?
[Re: dvw]
#1509451
09/30/13 01:19 AM
09/30/13 01:19 AM
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Joined: Jan 2003
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U.S.S.A.
JohnRR
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I Win
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Quote:
Quote:
Quote:
I don't know your combo. That being said if you now have .035-.045" quench currently, adding head gasket thickness to reduce compression may make detonation worse. If you have no quench now I would definitely go with a thicker gasket.
Doug
The problem is he doesn't have good quench and wanted to make it worse with yet a thicker gasket to lower compression.
If the quench is poor already adding head gasket thickness won't hurt it. Am I correct in assuming this is an open chamber style head?
Doug
No it's closed chamber wit hthe piston not at zero . He already put in a thicker gasket , I think .051, so he has .070ish no quench , and changed the cam ... still pings ...
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Re: Anyone here ever have their pistons machined?
[Re: dvw]
#1509453
09/30/13 07:57 AM
09/30/13 07:57 AM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
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Quote:
So closed chamber with piston in the hole approximately .020". Using a .020" gasket ( how thick are the thinnest shim availible ?) would give .040" quench. Iron or aluminum head? I've had small blocks have less detonation with quench at 12-1 than w/o at 10.5-1. Would it work in this case? it would only cost the gasket set.
Doug
Doug he has numerous threads on this over the past year or so, I didn't keep a scorecard  . Pretty sure the original combo had the .020 piston depth and .021 shim gasket with .509 MP cam and it pinged , it has spiraled out of control since ...
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Re: Anyone here ever have their pistons machined?
[Re: JohnRR]
#1509454
09/30/13 08:56 AM
09/30/13 08:56 AM
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Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
B G Racing
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Quote:
So closed chamber with piston in the hole approximately .020". Using a .020" gasket ( how thick are the thinnest shim availible ?) would give .040" quench. Iron or aluminum head? I've had small blocks have less detonation with quench at 12-1 than w/o at 10.5-1. Would it work in this case? it would only cost the gasket set.
Doug
Doug he has numerous threads on this over the past year or so, I didn't keep a scorecard . Pretty sure the original combo had the .020 piston depth and .021 shim gasket with .509 MP cam and it pinged , it has spiraled out of control since ...
Maybe he should look for other issues:
Timing not accurate,bad marks,box, dist and etc.
Too hot of plug.
poor fuel or lean condition
Cylinder head temperture
Oil detonating in cylinder..
If some of the information mentioned is correct with his clearences correct timing should cure the issue provided he doesn't have other issues. 
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Re: Anyone here ever have their pistons machined?
[Re: dogdays]
#1509456
09/30/13 05:01 PM
09/30/13 05:01 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
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This subject has been beaten to death on the Q&A page.
R.
which is why it's moved to the race section ???
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Re: Anyone here ever have their pistons machined?
[Re: JohnRR]
#1509457
09/30/13 05:43 PM
09/30/13 05:43 PM
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Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
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CT
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Put a bigger cam in it To answer the original question I've never had a set of pistons machined but its been done many times before
Last edited by GTX MATT; 09/30/13 05:45 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Anyone here ever have their pistons machined?
[Re: dogdays]
#1509458
09/30/13 05:52 PM
09/30/13 05:52 PM
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Joined: Jul 2006
Posts: 4,179
California
mickm
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California
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Quote:
This subject has been beaten to death on the Q&A page.
R.
yes, but he's looking for answers and now has moved it from a more general thread to a more specific one.
he has done many, many things to try and take care of this problem, and it's still haunting him, so he's just trying to get as much info as possible before making the next decision.
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Re: Anyone here ever have their pistons machined?
[Re: mickm]
#1509459
09/30/13 10:40 PM
09/30/13 10:40 PM
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Joined: Nov 2003
Posts: 4,027
Dearborn Hts, MI
Sledge_57
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Dearborn Hts, MI
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Also it's now the "Unlawfl's Race & Engine Tech" section, so it belongs here.
Doug
1967 "Pedal Car" 500" low deck , TF 727, 4.30 Locker
Best to Date: 11.67 @ 114.9 1.64 60ft
"Kids in cars cause accidents. Accidents in cars cause kids..."
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Re: Anyone here ever have their pistons machined?
[Re: GTX MATT]
#1509460
09/30/13 10:41 PM
09/30/13 10:41 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
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I Win
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Quote:
Put a bigger cam in it
To answer the original question I've never had a set of pistons machined but its been done many times before
he did , it didn't make it any better
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