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Discussion Starter #1
'02 cases, I have SE 1550 cast Flat tops, D&D Fatcat pipe, Andrews 26N cams, '06 Big Boyz 'Street Heads' w/.030" Cometic HG's, Doherty PowerPacc AC, & ThunderMax AT.

I recently checked 'squish' w/solder & found that I have approx .040" in both cyls. Soooo...evidently the pistons are .010" 'down the hole', & the combustion chambers both measured a whopping 88cc when Bean had em. I don't have it calculated, but surely the compression ratio is considerably below the optimum for this build...possibly under 9.0:1 even? Anyhow, it's getting winter here now & I'm wondering; w/the squish I have, what might be gained from pulling the heads & having em shaved to get a bit more compression?

thanks,

VicW.
 

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I have a similar set up 06 heads, SE flattops, 26g cams. GMR did the heads for me and suggested I go with 9.5 to 1 and decked the heads to 83.2 to get there. Dan Baisley also suggested that andrews 26's be run at 9.5 to 1. I think you would see a nice Seat of the pants improvement bumping up your compression a little. I am curious why you did not have bean deck the heads when he had them or did he not suggest it?
 

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I am curious why you did not have bean deck the heads when he had them or did he not suggest it?
Yeah, Bean suggested it, but I'd heard of other ppl who had pinging probs w/this CR/26's & a guy at Andrews told me not to go over 9.25 or it'd ping. Trying to be conservative I suppose...not taking the relatively huge chambers into account (& not checking the deck ht) mostly just a rookie mistake. I'm hoping some of the gurus will chime in & give me an idea of what to expect...

VicW.
 

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Squeeze

Surfacing the head(s) will bring a couple more to the plate, run a touch smoother, and you will see an improvement in fuel economy.
 

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Hmmm...not a lot of extra UMPH to be had, huh? Ok, I think I'll pass & ride it as is until I get ready (read that save up the $$) for a 100/100 build. At least I don't have to worry about having to find high oct gas etc. Thanks a bunch guys, appreciate the honest input!

VicW.
 

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Discussion Starter #8
I know it does sound like an improvement, but the idle, MPG, & eng temp is ok now & 1-2 added HP/TQ pts doesn't sound worthwhile to me.

VicW.
 

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Discussion Starter #9
Hmmm, after talking w/Bean today I may have to rethink this. LOL!

VicW.
 

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The cams are the limiting factor. Increasing compression to 9.6 or so and tightening up squish will allow you to upgrade to other cams that like more compression and that is where you will see a real increase in performance. Bean did my heads and he cut them to 80ccs, about 9.8CR. I have run SE204s and TW44G cams and both made about 100+TQ/90+HP but with different curves.

My experience is limited but the static CR won't cause ping problems and you shouldn't be afraid of compression. Get the squish right and choose a cam that keeps CC less than 190pis and you should be OK.
 

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I'm afraid I offered some bogus data in my 1st post, please excuse my ignorance. The truth is that I don't have any idea what the chambers measure (I gotta start keeping records, the ole hair covered computer ain't what it used to be) & due to the pistons rocking the solder test was flawed as well. I may redo the solder test & use 2 pcs at a time, but that still won't achieve 100% accurate results, so prolly won't mess w/it.

Both cyls have 185 ccp @ 500ft elevation & w/this cam there's just no way that I could have 88cc chambers & a .010" deck. Bean thinks I'm right at 9.5:1 static CR as it sits & every CR calculator I've tried confirms this as well. I really appreciate all the input from you guys & please excuse the wild goose chase.

I have learned a BUNCH from all this; one thing in particular is to measure everything during a build & WRITE IT DOWN.

Thanks guys, you've been great.

VicW.
 

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Sleeps In Trees said:
I'm afraid I offered some bogus data in my 1st post, please excuse my ignorance. The truth is that I don't have any idea what the chambers measure (I gotta start keeping records, the ole hair covered computer ain't what it used to be) & due to the pistons rocking the solder test was flawed as well. I may redo the solder test & use 2 pcs at a time, but that still won't achieve 100% accurate results, so prolly won't mess w/it.

Both cyls have 185 ccp @ 500ft elevation & w/this cam there's just no way that I could have 88cc chambers & a .010" deck. Bean thinks I'm right at 9.5:1 static CR as it sits & every CR calculator I've tried confirms this as well. I really appreciate all the input from you guys & please excuse the wild goose chase.

I have learned a BUNCH from all this; one thing in particular is to measure everything during a build & WRITE IT DOWN.

Thanks guys, you've been great.

VicW.
185 ccp might actually be above that. That is where I would stay. Pushing 190 is time to be thinking about compression releases.
 

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according to my calcs, with 0.00" deck height (unlikely), SE flat tops, .030head gasket and 185psi CC, your chambers might be about 82cc and static CR about 9.6. Dump the 26s for 37s, Woods 6 or HQ0034.
 
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