gen3performance

iTrader: (9)

I need some input from guys who have built an LSX blocked engine. I have a standard deck LSX with a Callies 4 inch crank, manley rods, and mahle pistons. My machine shop called me and told me that my con rod bolts are hitting the block. I went there to verify and they definately are. Is this common. or is it just because of my con rod bolts. They are the arp 12 point headed ones. I know the 6 point heads are usually shorter. I thought this block could handle a 4.25 stroke no problem? Please help, any input will be appreciated.

ROCNDAV

iTrader: (100)

they'll have to clearance the block where the rods come in contact with the block. I had to do it myself with my 4.125 stroke crank, and I believe 383 (4" stroke) cranks have to as well.

gen3performance

iTrader: (9)

I still think that its bogus, I had the exact same parts in a 6.0 block and everything fit just fine. This block should have ample clearance shouldn't it?

Robin L

It's normal. Remember the LSX block is thicker at the bottom of the cylinders. Most aftermarket rods are beefy enough at the rod journal that they require some grinding at the base of the cylinder.

I am suprised that your engine builder isn't aware if this type of requirement.



Robin

gen3performance

iTrader: (9)

He has had to clearance many blocks in the past for gen 1 383's and so on, but we were all kinda concerned with this block because the claim that it would accept a 4 1/4 stroke. I guess we just assumed that it would drop right in ya know. We already started clearancing it, I just wanted to see if anyone else has had this prob.

-Joseph-

iTrader: (12)

Quite normal to clearance the bottom of the cylinders. I've had to do grind just about every one I've done, except 6.0L blocks seem to have a little extra clearance. Sometimes it depends on the connecting rod bolt and/or rod dimensions.

Edit: I had to grind cylinders on a 383ci and LSx blocked 402ci last week for some friends. Its a PITA, especially if you mock-build first to mark the areas, then dismantle, then reassemble...etc.

gen3performance

iTrader: (9)

10-4. I just wanted more input for my peace of mind. I thought it was funny when I talked to GM Performance Parts tech line and their answer was simply "it'll work. you might have to get creative, but it'll work".

ChevPower

iTrader: (8)

I had to grind mine with a 4" crank but i use L19 rod bolts Its no big deal took less than 5 min to do all eight cylinders

Jason99T/A

iTrader: (21)

I have had to clearance about every LS2 with a 4.00" crank I have built. The only one that cleared was one that used Manley Sportsmaster I-beams. I have only had to clearance a 6.0l block once, and that was with a 4.125" crank. 4.00" cranks clear just fine on them.

LS1 blocks w/ a 4.00" crank (382ci) require clearance as well.

Joseph is correct; it does take a bit of time if you mark each one, grind, re-check, etc.

I think the GEN III motors are alot easier to clearance than the older SBCs!

Jason

ROCNDAV

iTrader: (100)

I posted this a few years ago:





https://ls1tech.com/forums/generation-iii-internal-engine/231328-why-its-important-test-fit-parts.html

Grimes

iTrader: (3)

This has been a common requirement on modified engines forever (as mentioned before)....sometimes you luck out and don't have to do it though.

RAACCR

Common knowledge with any engine builder that clearancing may be required with aftermarket internals. They can't possibly anticipate all of the possible combinations you might try to stuff inside their cylinder case. On top of that, they've added metal everywhere to make it stronger, so you can pretty much guarantee it will require more clearancing than a stocker. I don't think you've got a legitimate gripe with GMPP.

Jeff@TotalPerformanceEng

iTrader: (6)

I say you just butter that spot up.. Then fire the motor and hold your foot to the floor for 20 seconds. That'll do it.....

A grinder works just as well..

Noyzee

iTrader: (37)

i also had to do mine, pretty normal