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Stroker pistons protrude more than expected...quench...
#1426558
04/28/13 07:33 AM
04/28/13 07:33 AM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
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Building a 512 based on the 400-block, using the 12.5 comp strokerkit, Stealth heads, steel billet main caps etc. from 440Source.
Probably due to the block decking and the line boring of the main caps the pistons now protrude up to .016 inch above deck (including piston rocking).
If I choose the .051 thick head gasket my min quench will be .035 inches.
I'm tempted to go with the .051 gasket, it gives me 12.5 static comp, while a .060 gasket would give a min quench of .044 and the comp drops to 12.2
It's an E85 engine and it likes compression. See measurements below.
What do you guys think about the worst case .035 quench on cylinder #4?
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Head gasket thickness inch 0,051
Cyl # Max out mm Max out inch Cylinder quench settings
1 0,35 0,014 0,037
2 0,25 0,010 0,041
3 0,35 0,014 0,037
4 0,40 0,016 0,035
5 0,35 0,014 0,037
6 0,25 0,010 0,041
7 0,35 0,014 0,037
8 0,35 0,014 0,037
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: Stroker pistons protrude more than expected...quench...
[Re: 440Jim]
#1426561
04/28/13 10:48 AM
04/28/13 10:48 AM
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Joined: Jan 2003
Posts: 9,997
Frostbitefalls MN (Rocky&Bullw...
gregsdart
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master
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Frostbitefalls MN (Rocky&Bullw...
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avoid any gasket with too big of a bore if you can. Too much crevice volume (far edge of the bores) can cost enough hp to make getting it to fit the bore worth while.
Last edited by gregsdart; 04/30/13 03:11 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Stroker pistons protrude more than expected...quench...
[Re: Swedcharger67]
#1426565
04/28/13 02:32 PM
04/28/13 02:32 PM
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Joined: Jan 2003
Posts: 75,005
U.S.S.A.
JohnRR
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Quote:
I'm tempted to go with the .051 gasket, it gives me 12.5 static comp, while a .060 gasket would give a min quench of .044 and the comp drops to 12.2
------------------------------
Head gasket thickness inch 0,051
Cyl # Max out mm Max out inch Cylinder quench settings
1 0,35 0,014 0,037
2 0,25 0,010 0,041
3 0,35 0,014 0,037
4 0,40 0,016 0,035
5 0,35 0,014 0,037
6 0,25 0,010 0,041
7 0,35 0,014 0,037
8 0,35 0,014 0,037
By going with a .009 thicker gasket you move the shorter pistons out to .050. If you are concerned with quench you need to look at all the numbers not just the minimum. It appears that the rods and/or pistons are not all the same length ?
I would do as 440jim suggests and cut all the tall pistons and get them all at .041.
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Re: Stroker pistons protrude more than expected...quench...
[Re: Swedcharger67]
#1426569
04/28/13 05:54 PM
04/28/13 05:54 PM
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Joined: Jan 2003
Posts: 75,005
U.S.S.A.
JohnRR
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Quote:
Quote:
By going with a .009 thicker gasket you move the shorter pistons out to .050. If you are concerned with quench you need to look at all the numbers not just the minimum. It appears that the rods and/or pistons are not all the same length ?
I would do as 440jim suggests and cut all the tall pistons and get them all at .041.
I'm more concerned about the minimum quench than the maximum.
Was assuming the heaviest rod could be the tallest, compared rod weights to the quench, but couldn't find any correlation.
Probably the biggest problem is can I trust my measurements? I need to do a new fresh round tomorrow to see what results I get.
Thanks for all comments! 
What are you using to make your measurements ?
I'm not sure how detrimental quench is with your compression and fuel choice, but the max number is as important as the minimum because once you get past a certain number you lose the quench effect. I try to build to .045 max, the engine the board built for the Enginemasters contest was run at .035, That motor was spun to 6700 rpm with no ill effects. If it was my motor I wouldn't be concerned with the .035, the spread you have to me is more of a concern. 
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Re: Stroker pistons protrude more than expected...quench...
[Re: JohnRR]
#1426570
04/28/13 06:03 PM
04/28/13 06:03 PM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
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Norrland, Sweden
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Quote:
What are you using to make your measurements ?
I'm not sure how detrimental quench is with your compression and fuel choice, but the max number is as important as the minimum because once you get past a certain number you lose the quench effect. I try to build to .045 max, the engine the board built for the Enginemasters contest was run at .035, That motor was spun to 6700 rpm with no ill effects. If it was my motor I wouldn't be concerned with the .035, the spread you have to me is more of a concern.
I use a dial indicator to find TDC, feel with a finger which side of the piston is lower, press that edge down with "some" force and measure at the opposite side of the piston, to simulate worst case piston rocking. There I use a feeler gauge next to the piston and just feel the edge with my finger. I've also used a steel ruler across the piston and a feeler gauge. Both methods give about the same result...using my finger is faster and easier... 
Last edited by Swedcharger67; 04/28/13 06:06 PM.
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: Stroker pistons protrude more than expected...quench...
[Re: dvw]
#1426572
04/28/13 06:10 PM
04/28/13 06:10 PM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
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Quote:
You saying that when you rock the piston in the bore it protrudes to the dimensions listed. If so what's the average between High and low? My bet is between .005"-.010". You have .035" when rocked I would run it. Doug
Yes, that's right, the numbers given are when one side of the piston is pressed down using some force with my thumbs, i.e. worst case (?).
Yeah, I have to spend some "quality time" doing more measurements tomorrow...
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: Stroker pistons protrude more than expected...quench...
[Re: Swedcharger67]
#1426574
04/28/13 08:05 PM
04/28/13 08:05 PM
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Joined: Jan 2003
Posts: 75,005
U.S.S.A.
JohnRR
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Quote:
Quote:
What are you using to make your measurements ?
I'm not sure how detrimental quench is with your compression and fuel choice, but the max number is as important as the minimum because once you get past a certain number you lose the quench effect. I try to build to .045 max, the engine the board built for the Enginemasters contest was run at .035, That motor was spun to 6700 rpm with no ill effects. If it was my motor I wouldn't be concerned with the .035, the spread you have to me is more of a concern.
I use a dial indicator to find TDC, feel with a finger which side of the piston is lower, press that edge down with "some" force and measure at the opposite side of the piston, to simulate worst case piston rocking. There I use a feeler gauge next to the piston and just feel the edge with my finger. I've also used a steel ruler across the piston and a feeler gauge. Both methods give about the same result...using my finger is faster and easier...
Feeler gauge and your finger ???? You need a tool like this if you want any reading that are remotely accurate ...
http://www.summitracing.com/parts/pro-66797
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Re: Stroker pistons protrude more than expected...quench...
[Re: JohnRR]
#1426576
04/29/13 02:34 AM
04/29/13 02:34 AM
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
Swedcharger67
OP
enthusiast
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OP
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Joined: Dec 2010
Posts: 208
Norrland, Sweden
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Quote:
Feeler gauge and your finger ???? You need a tool like this if you want any reading that are remotely accurate ...
http://www.summitracing.com/parts/pro-66797
Yeah, regarding a tool I came to think of the TDC finding toool I have fabricated, this one can easily be used for measuring the pistons as well. Will try that, but in this case of course there will be no more piston rocking than "normal" rocking...normal? Normal? What is normal rocking?
Quote:
Other than a custom-made gasket I don't know where you would get a .060" gasket.
I have EXACTLY the same problem due to decking and line honing ... pistons .016 above the deck. I use the .051 Felpro gaskets and I'm not worried about it. HOWEVER, every one of my pistons is dead on .016 above the deck - no variances. Mine is a 528" stroker kit with very short piston skirts.
You are right, the 060 would most likely be a custom gasket.
- Interesting, how du you measure the distance above the deck?
Martin, 67 Charger, 512 cui, E85, MegaSquirt MS3X sequential ignition & injection
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Re: Stroker pistons protrude more than expected...quench...
[Re: Swedcharger67]
#1426577
04/29/13 03:02 AM
04/29/13 03:02 AM
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Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
jyrki
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master
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Finalnd, Perkele
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You do not take the rocking in to account. Measure the height from the center of the piston directly above the pin.
Plynouth VIP '67 TT IC EFI
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