Carbureted LSX forum - Need help, my 6.0 build just took a turn for the worse.

Basically here's the boat I'm in. I started building a LQ9 with LS3 heads. Heads have been cut .030" and I had Pat G spec me a cam. Needless to say I've ran into a few problems with my build mainly due to not having a machine shop close by that knows these engines.

My latest set back is I had to have the stock flat top pistons fly cut. Well, the machine shop cut the pistons wrong, now I'm screwed. I would like to just buy a set of forged pistons and rods, however that's just not in my budget right now.

My only other option is that I have a LQ4 that I could put in the car. I definitely do not want to get into having to fly cut the dish pistons and with the cam I already have that would have to be done too. SO, I'm gonna have to have another cam for sure. I can swing buying another cam, but not pistons and rods.

I have the LS3 heads and have the stock 317 heads that are on the LQ4, I have carburated intakes for both style heads. What do you guys think my best option is, I really need to get this car going to run points. It's a track only foxbody mustang with a TH350, 8" PTC converter, 4.10 gears, and 950cfm carb.

Thanks for any help.

that stinks.

If you go with the LQ4 you can't use your cam?

I'd hang on to those LQ9 rods, they are supposedly really stout.

I'd still run into PTV issues with the dish pistons and lose compression. This sucks.

I'm ready to just buy a car done lol.

Run the lq4 with the 317s and buy an off the shelf cam for now. Like a tsunami cam or trex. Think you can even shave the heads .030 and have no ptv issues. Save the custom cam and ls3 heads for the built motor when you have the funds to get it together. jmo

I had talked to TSP and they recommended the Tsunami on a 109 lsa for the LQ4. I may try that.

How did they mess up flycutting? If I may ask? When I had mine done, I took the valve out and marked the piston at TDC, with an 8mm centering punch. Hope all goes well. Eric L

How did they mess up flycutting? If I may ask? When I had mine done, I took the valve out and marked the piston at TDC, with an 8mm centering punch. Hope all goes well. Eric L

I marked the same way as you did. I measured with a dial indicator. I had .010" intake clearance and .060" exhaust clearance.

Shop said they'd cut .075" on the intake side and .050" on the exhaust to get me a hair more than the .080" intake and .100" exhaust minimum I've read I needed for my build.

BUT, they apparently cut the depths backwards. As now I have .060" intake and they must have cut .100" on the exhaust cause I have .160" on the exhaust.

I may can get them to cut an additional .020" out of the intake side, cut I'm worried the exhaust side may be too much.

I dont think you would have a problem running the pistons as is with .060 clearance. Most people have found that you can run the LS motors a little tighter piston to valve. I would run it. Whats everyone elses thoughts on this? Eric L

I am running the Trex with my heads(317s) milled .030, plenty of PTV room.

I'd just get the intake sides re-done.

As long as the piston top thickness isn't compromised... A little extra clearance isn't going to hurt a thing.

I'd just get the intake sides re-done.

As long as the piston top thickness isn't compromised... A little extra clearance isn't going to hurt a thing.

I totally agree. Just make sure that there's no sharp edges and you should be fine.

I'd just get the intake sides re-done.

As long as the piston top thickness isn't compromised... A little extra clearance isn't going to hurt a thing.

I totally agree. Just make sure that there's no sharp edges and you should be fine.

+3. Especially if you're running NA. If you're spraying it.....I would be a little more concerned about the deep cuts.

Another option, if you're interested, are the new Pro-Tru pistons from Wiseco. They are designed to work with stock rods (bushed rods; not the older press fit rods, but I'm 95% sure LQ9s had bushed rods ). They have a +4cc dome and valve pockets that will work with both LS3 or cathedral port heads. Best thing is.....they come with wrist pins and rings and are pretty cheap for forged pistons. Here's a link: http://www.texas-speed.com/p-771-wiseco-pro-tru-4cc-dome-piston-set-for-3622-stroke.aspx

These are what I plan to eventually slip into my LY6.

mahle makes pistons for stock rods. using them in my build b/c of the valve reliefs.

I don't know if I'd do just those pistons, since you'd have to balance anyways I'll wait and buy rods too I guess.

Thanks everyone

mahle makes pistons for stock rods. using them in my build b/c of the valve reliefs.

Do you have a part number?

EDIT: Nevermind....I found them. Thanks and sorry for the hi-jack.

I'd just run those oem pistons, .060" PtoV is good (bare minimum) on the intake as long as you have your valvetrain under control.
save and buy your rods/pistons in the future.

Those are nice slugs.

Do you have a part number?

EDIT: Nevermind....I found them. Thanks and sorry for the hi-jack.

i know some ppl are sayin i wouldnt do them, ie forged pistons. but like GC said its nice insurance plus i wanted to spray mine a lil and i didnt want to weakin the slugs by having to take to much out, i was looking at a good bit coming out of my reliefs.

I sprayed 150 on the 6.0 all day, but it was not fly cut, either way, those slugs for 600 are not bad, mix that with ARP bolts for the rods and you are in great shape. But you may still be 200$ or less from some scat I beams.

Eh.
I know the stock lq9 replacement pistons with rings are less than 400$ shipped new.
If there is gonna be no spray involved,they should be fine.
And they will replace the stock slug. As is. No balancing necessary.
If everything is ok. Prolly just gotta file to your needed ring gap.
I ordered some hbeam rods with arp 2000 series rod bolts, forged pistons,rings,wrist pins,locks. For 1100$ shipped. Need to rebalance anyway. So just went for forged stuff.
4.085 bore 6.125 rod set. 3.622 stroke
Boring gen 4 ly6 6.0 .080over:headbang:
380ci(379.73actual)

I sprayed 150 on the 6.0 all day, but it was not fly cut, either way, those slugs for 600 are not bad, mix that with ARP bolts for the rods and you are in great shape. But you may still be 200$ or less from some scat I beams.

i wold spray 200 all day on stock pistons, but not on fly cut ones. hence going for a better piston with reliefs in them. and have arp rod bolts. anyways back to the op, just remember, nothing is ever budget friendly. ever.

Hell, I would hit this ol girl with 250, lol, kit just doesn't go that high.

zones
I knows yous gots some drill bits and a cordless drill in ur monster garage.
Drill em beetches out. :mullet: