Slo_crx1

I'm going to check out a motor this afternoon and see how it is, otherwise i think i'll take ya up on that block...and this time i can probably come and pick it up lol.It was running a vafc2 that was wbo2 tuned by my buddy, walbro 255lph pump, 450cc dsm's, and one of those crappy b&m fpr's turned up to 65psi. I think it had issues to begin with, timing was manually retarded completely and the vafc's richest setting dropped down to around -28 that still gave me a 10.5:1 afr. It was a mystery motor though...i know the kid who owned it before me beat the living ---- out of it, and for all i know it probably had 200,000 miles on it There was no other reason it shoulda popped like it did...hell even my z6 i ran at 12 psi on the afc for longer than that and i never even had one issue with it.

turboDA6

why did it pop? cuz the vafc.... tuned or not

mycrx

head studs r a must, head bolts pull the block toward the head, example rips the ------- threads right out of the block, plus the bolts loose tensil strenght, head studs pull the head onto the block, less bullshit and no worries.

Slo_crx1

I'm not denying that the vafc had something to do with it, but even if it did run lean it should never have cracked the sleeve, if anything torched out a piston and broke a rod. The rotating assembly is still fine, just the sleeve was shot.What would studs have to do with the sleeve? Head studs are def. on the list for my new project though along with a few other goodies

turboDA6

detonation from hella advanced timing? look at steavemodes old motor, 4 broken pistons lol and they were forged

Guy-Fast

yup afr's mean nothin with all that timin in the motor

Slo_crx1

Even with the dizzy fully retarded i don't think it would've advanced that far Manually retarding it all the way is alot of timing being taken out. I do know that a couple days before i started loosing boost for no apparent reason...everything was tight and clamped down good, but slowly started dropping a few pounds. I tried advancing it back a hair to see what would happen and it detonated pretty bad, so i dropped the dizzy back to where it was before. Still never got the psi back, but not that it really mattered after that anyway. I picked up a b16 block i think i'm gonna do up for boost, so this time around i want it chipped in TE and depending on what head i decide on, i might keep the vafc hooked up just to use a vtec head and try running it with a chipped pr4. Besides, LS heads flow like buttmud Isn't there another head that's non-vtec that flows almost the same as a b16 or b18 vtec head? I remember a thread on it going back a while...

Guy-Fast

Its the b20 head but it has 84mm chambers no go on 81mm pistons


Valve Job on a ls head does wonders

Jcushing

yes the P8R head has vtec valves in it but it has LS ports so it flows real close to a b16 head but with porting flows real well. it has 47cc chambers with an 84mm chamber bore. i have one so if anyone has any other questions hit me up

Slo_crx1

Well, i'm set up to do p&p jobs, maybe i'll spend a little time with the LS head and see what i can get it to flow on the flowbench. Even with a new set of valves and cams and a decent p&p job, my biggest concern is revving the motor up high...from what i've heard the LS heads are notorious for popping off rocker arms.