Zfan

I picked up a L76 G8 motor (LS@ short block with L92 heads) for my Datsun 240Z and wanted to do a cam only build. I picked up a cam 230/242-600/605 on a 112 plus 1, double valve springs and push rods (7.425) plus DOD kit.

Well, I pulled the motor apart and clayed the pistons, made solid roller lifters out of my old lifters, re-used head gaskets and checked the PTV clearance...I am screwed, the exhaust valves are ok (.100 but the intake side are a joke, maybe .020 at best.

Looks like fly cutting pistons in the block which suck or pull the whole thing apart. Sure would have been nice to know this ahead of time, since I stated I didn't want to go this route.

Does anyone know the cost for fly cutting pistons these days, I had some JE's cut outside of the motor but that has been 10 yrs. Sorry for the rant, just venting frustration!

Grr

iTrader: (2)

that shouldnt be that tight, are you tightening the rocker to 0 lash and not opening the valve?

bww3588

iTrader: (49)

I don't find it hard to believe. That cam is well above what is generally accepted to not cause ptv issues with the ls3 heads.

I've never fly cut in the block, I've either pulled it apart and done it in an end mill or just bought pistons with valve reliefs.

You can rent the tools from Lindy to do it, although, I'm not sure if they have one for the 2.165 intake valve.

bww3588

iTrader: (49)

Another option you have is an adjustable timing set. You can retard the cam a few degrees and that can free up some real estate.

Zfan

Bingo, major brain fart!!! I set them at engine assembly torque specs forgetting I was assembling a solid lifter thus needing lash set. I doubt it will make a huge difference, maybe .020-.040, not enough overall to get the required .080 clearance needed.

You would think as many motors, sbf or first gen sbc that I have built or assembled that this would not happen, God getting old sucks!

Thanks
Mike

Tainted

iTrader: (9)

FYI the 6.0 motors with the larger cams are notorious for ptv clearance issues. that intake valve is a little to large for that bore. I know its a little late now but id recommend some nice cathedrals instead for what you've got.

KCS

iTrader: (20)

Did you get .020" with checker springs or real springs? That will make a difference as well.

TurboMonte100

iTrader: (1)

**Edited**

See newer post.

low2001gmc

iTrader: (148)

i got a 232 238, 598 600, 113+4 with no issues....lq9 with milled .015 ls3s and .040 cometics

Cwarta

iTrader: (12)

I have a bigger cam than the Op by quite a bit and didnt have to fly cut with .035 milled heads even on my 6.0, BUT i do have aftermarket heads and a 5 angle valve job...

Tainted

iTrader: (9)

Its the overlap that gets u

Grr

iTrader: (2)

Well if you pick up some, I would run it. I would imagine you will get around .060 on the intake side which is more than adequate. I have no problems running the intake side down to .040, my last motor ran .035 on the intake and revved to 7200 with no issues

DirtyDirk

I just spent $110 to have mine fly cut out of the block.

Zfan

Real, I have checkers but did not use them.

TurboMonte100

iTrader: (1)

As posted above be sure to use light springs, and set the lash right at zero. Don't run them down as you would for operation. I did the same thing the first time, after years of working with solid rollers in small and big blocks I did'nt stop and think about the lifter adjusting. I just ran the rocker bolt down as if it were to run, and then had little to no clearence.

I would guess that in operation you will have nearly .100

Atomic

iTrader: (37)

Do you remember at what crank angle (ATDC) or had the least clearance? It is generally between 5 and 15 degrees ATDC depending on the cam lobe.

Zfan

Ended up with approx. .085 on the intake so we should be safe. Thanks everyone.

Grr

iTrader: (2)

your welcome