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best compression, high or low

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Old Mar 22, 2011 | 09:00 PM
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From: Merthyr Tydfil
Default best compression, high or low

whats best, a small gasket to increase compression from offset or larger gasket so lowering compression to run a higher boost. pig to idle and drive when off boost but more fun on boost. bit like cosworths wotj low compression pistons.
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Old Mar 22, 2011 | 09:09 PM
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From: Rl'yeh
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Don't muck about with compression on a Scoob engine unless you know what you are doing. Best way to get det, (knock), and destroy the engine.
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Old Mar 22, 2011 | 09:34 PM
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From: Merthyr Tydfil
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whats the calculation on compression then to keep it safe. skimming heads after gaskets gone due to pipe splitting. so wondering whether to use 1.6mm again or 1.3
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Old Mar 22, 2011 | 09:59 PM
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From: Rl'yeh
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Dunno about calculation, best to ask one of the engine builders on here, API, Allan Jeffery etc.

If your heads have been skimmed, then use a thicker gasket to keep the cr the same. Roughly speaking, extra gasket thickness= what was skimmed off the heads.

You DO know that LOADS of cars bottom ends let go soon after doing the heads, don't you?

Might be worthwhile doing the bearings while the engine is out?
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Old Mar 22, 2011 | 10:03 PM
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From: C+K MOTORS
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Give Merlin24 a PM,he worked myn out for me when i built mine
He a fountain of knowledge on subaru engines!!
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Old Mar 22, 2011 | 10:05 PM
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From: Merthyr Tydfil
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fully forged less than 1.5 = 2k ago. some arseholes sliced a split in my water hose and it pressurised. had the motul 15/50 motorsport double ester oil in for higher temps. so hoping all is good down there. be very unlucky if there is damage, got hot, water killed spark and cut out. touch wood. not splitting block again. hoping for best.

the damaged pipe was a perfect cut through pipe fibers. wont part car there overnight again.
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Old Mar 22, 2011 | 10:06 PM
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From: Merthyr Tydfil
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Originally Posted by prodriverules
Give Merlin24 a PM,he worked myn out for me when i built mine
He a fountain of knowledge on subaru engines!!
your everywhere lol hows tricks. finally bought some scooby stuff lol. be running soon
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Old Mar 22, 2011 | 10:08 PM
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From: C+K MOTORS
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Originally Posted by mje_wrx
your everywhere lol hows tricks. finally bought some scooby stuff lol. be running soon
Not to bad mate,been very busy at work of late but given the current market im quite chuffed to be so busy!
Good to hear the ball is rolling on the car,bet you can't wait to get her back out and running again.
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Old Mar 22, 2011 | 10:12 PM
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From: Merthyr Tydfil
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Originally Posted by prodriverules
Not to bad mate,been very busy at work of late but given the current market im quite chuffed to be so busy!
Good to hear the ball is rolling on the car,bet you can't wait to get her back out and running again.
itching, just hope alcazar isnt right about bottom end. oils flashpoint in 239 degrees. so shud still be protecting bearings. soon find out tho.
il cry if it knocks
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Old Mar 22, 2011 | 10:14 PM
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From: C+K MOTORS
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Originally Posted by mje_wrx
itching, just hope alcazar isnt right about bottom end. oils flashpoint in 239 degrees. so shud still be protecting bearings. soon find out tho.
il cry if it knocks
Tbho i would have thought it will be fine as yours is forged with ACL bearings on the crank
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Old Mar 22, 2011 | 10:23 PM
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From: Merthyr Tydfil
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Originally Posted by prodriverules
Tbho i would have thought it will be fine as yours is forged with ACL bearings on the crank
makes me stop worrying now
il keep u posted mate. gonna so some tart up on wheels etc, she lookin battered in garage.
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Old Mar 22, 2011 | 10:27 PM
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From: C+K MOTORS
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Originally Posted by mje_wrx
makes me stop worrying now
il keep u posted mate. gonna so some tart up on wheels etc, she lookin battered in garage.
No worries,like i said before as well if you need anything just give me a pm and ill help you out
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