transam69230

iTrader: (49)

I had a 416 put together buy a so called experience engine builder. He built many SBCs and BBCs but I guess LS motors are just too much for this guy. lessened definitely learned.

I spent a whole summer chasing a RPM missing with no luck and no choice to but tear it down. I tried new valve springs, 3 sets of coils , multiple sets of plugs, crank sensor , and other stupid stuff.

Well it turned out that the piston was making contact with the reluctor wheel as you can see in this picture. Has anyone ever heard of this?

Albertan

Yes #8 should have clearance for the reluctor. While you have it apart have a look to see if one of the other pistons has the clearance. Guy probably didn't realize there should be one different.
Actually, I think I read it here. I know I checked the engine I just bought and it is okay.

Whistler

iTrader: (46)

That used to be more of a problem back in the day, you'ld have to grind a little clearance on the # 8 on 4" stroke engines. I still check every time, but most pistons these days have the clearance built into all 8 so you can use any bank 2 piston for the 8.

Whistler

iTrader: (46)

Another thought.. How special was this builder that he didn't rotate the engine before delivery? LS powertrain is going on 15 years old but I still hear goobers refer to " them neew mauwters"

427

iTrader: (3)

Sometimes the piston will clear if the wheel runs true, but if the wheel starts wobbling or the welds break and it separates you will see that. Most newer pistons use that style forging with a 2.250 long wrist pin, that combo should miss with any of the 8 pistons in that hole.

Kurt

RezinTexas

sorry you had to find out that way, post the name of the shop.

ramairws6

iTrader: (33)

Hahahaha, join the club. Hmmmmmm, i seem to recall someone telling you what your problem was and what to check for on it....

https://ls1tech.com/forums/generatio...-pin-boss.html

ramairws6

iTrader: (33)

Just to keep you up to speed Kurt. This was the issue when it went together to begin with. So maybe we need to rethink the competance of the builder!??

https://ls1tech.com/forums/generatio...ight-spot.html

thompson

iTrader: (4)

It is really a common issue even with the best piston manufacturers to pack 8 pistons with no cuts in them for the reluctor. We have had correct the issue many times on assembly. I agree with above being the largest concern. How was the motor put together and never turned through? That is amazing that it was assembled and never even turned 1 revolution by the machinist before it was sent to you.

transam69230

iTrader: (49)

It was not built by a sponsor so there isn't really anything I can do. I learned my lesson that is for sure and it sucks that it happened and the only thing I can do is move on.

I guess that is what I get for having someone with little experience assembly my LS3.

427

iTrader: (3)

A little problem!

I was mostly addressing the piston issues these days with reluctor clearance. Most companies have narrowed the pin boss and shortened the pin so the wheel will clear in the basic 4 inch stroke engine. Some pistons still come with a design that has one piston cut for number 8 cylinder, but it is not as common as it was 5 or 10 years ago. I have cut a few number 8 pistons in my day!

Kurt

Grr

iTrader: (2)

I told you it was an issue with the reluctor how many times?