Re: 5.2 Mag pistons on non mag rods.
[Re: scratchnfotraction]
#575934
01/07/10 05:00 PM
01/07/10 05:00 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
yes,you need to narrow the 318 rod also,IIRC
not necessarily. the magnum I junked had plenty of side clearance between the rods and the pistons....
that said, 318 mag pistons are essentially the same CH wise as '85-up 318's, but they have the thinner (and more expensive) metric ring pack. if you're overboring a 318, I'd just go straight to the KB167's. they're not that much more expensive, and they use the much cheaper LA ring pack--piston/ring combo will probably price out the same between OEM mag pistons and KB167's....
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 5.2 Mag pistons on non mag rods.
[Re: mod5v]
#575936
01/08/10 09:50 AM
01/08/10 09:50 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Aw crap well there goes that .5 comp advantage. I'm looking for 8.5-9.0 comp with "302" heads. the KB 367 i think are to high want to use 87 octain gas. the sp pistons only give about 7.8-1. 
http://kb-silvolite.com/test/kb_car/performance.php?action=details&P_id=134
KB 167's with a 1.81 CH end up .012 in the hole with a factory deck of 9.6". use a thin Mr. gasket head gasket (4.14" bore, .028" thick) you end up with .040 quench and
10:1 with a 60cc head, 9.5 with a 64cc head. use a 4.08"
bore, .039" thick fel pro, and those drop to 9.7 and 9.3
sil-vo-lite 3234H are magnum replacements, 3247's are later LA replacements. only difference between the two are metric vs. standard 5/64 rings. they both have a 1.741 CH and no valve reliefs, which making the same assumptions (9.6" DH, thin head gaskets, 60 & 64cc heads) would be 9:1 or 8.66:1
http://kb-silvolite.com/test/silv-o-lite/spistons.php?action=details&S_id=628
http://kb-silvolite.com/test/silv-o-lite/spistons.php?action=details&S_id=53
these federal mogul pistons are the 85-89 replacements, with .004" CH higher than the silvolites:
http://www.summitracing.com/parts/STL-526P30/
gives another .05:1 over the silvolites:
interestingly, according to summit, the speed pro magnum replacements use the LA ring pack, and are .01" taller still (1.755 CH), which would yield 9.3 & 8.9 depending on 60 or 64 cc heads and all my other assumptions:
http://www.summitracing.com/parts/STL-H814CP30/
they work out to 1/2 the price of the KB's...you'll need to be a little careful on lift and/or duration since there's no valve reliefs.
FWIW, my stock '86 long block has the pistons .055" in the hole. when I had my stock pistons out and compared them to some stock mag pistons I have, the CH was essentially the same (lining up pin bores). of course, if there's only .01" difference, that's tough to see and measure with the method I used.
my combo: stock 86 long block reringed, pistons .055" in the hole, thin mr gasket gaskets, OEM magnum '671 castings, comp works out to 9:1 with 64cc heads (didn't have the opportunity to measure). cam is a reground roller, bullet cams HR259/316 lobe for both intake and exhaust (259 adv, 208@.050, 127@.2, .316 lobe lift, .506 calculated at the valve). installed at 108, 112 LSA. I had well over .1" V/P clearance, and it runs great on 87 octane, never a hint of detonation. if I had decked the block .030 (would have ended up with .043" quench, I woulda had 9.7:1, and I think it would have still run fine on 89, might have even run on 87.
Last edited by patrick; 01/08/10 09:55 AM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 5.2 Mag pistons on non mag rods.
[Re: patrick]
#575937
01/08/10 11:52 AM
01/08/10 11:52 AM
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Joined: Sep 2004
Posts: 2,093
oberlin, Ohio
Rapid340
top fuel
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top fuel
Joined: Sep 2004
Posts: 2,093
oberlin, Ohio
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Quote:
my combo: stock 86 long block reringed, pistons .055" in the hole, thin mr gasket gaskets, OEM magnum '671 castings, comp works out to 9:1 with 64cc heads (didn't have the opportunity to measure). cam is a reground roller, bullet cams HR259/316 lobe for both intake and exhaust (259 adv, 208@.050, 127@.2, .316 lobe lift, .506 calculated at the valve). installed at 108, 112 LSA. I had well over .1" V/P clearance, and it runs great on 87 octane, never a hint of detonation. if I had decked the block .030 (would have ended up with .043" quench, I woulda had 9.7:1, and I think it would have still run fine on 89, might have even run on 87.
What does it run and what does it weigh?
1971 Factory Appearing Duster 340 11.000 @ 122 mph
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Re: 5.2 Mag pistons on non mag rods.
[Re: Rapid340]
#575938
01/08/10 03:32 PM
01/08/10 03:32 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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it's in a 4200lb (with me) 5th avenue with an A500 and 3.55's.
got it going this past summer, so no times. feels about as strong as the 360 it replaced (stock long block, comp XE262)
both engines had/have headers, RPM air gap, and eddie 600.
if I had to SWAG it, I'd put it in the low 14's. the converter might be holding it back. I put the stock one back in since I found a crack in the hub of my MP166K one.
consistantly getting 17mpg....
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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