One of my customers has a LS3 swapped land rover with some nasty piston slap that does not go away at all at operating temp(and yes I know for sure that's what it is). Oil is clean.

Is this to be expected from a 415 stroker? I assume pistons have to be shorter and probably poke out the bottom of the cylinder making them more unstable, but should it still go away or is it just how it is?

Build specs:
415 ci LS3

LS3 block/ heads
Scat forged 4.0 stroke crank
Scat 6.125 forged rods
Mahle forged pistons 4.065 bore 10.8:1 compression
King rod/ main bearings
HV Melling oil pump
1.7:1 rocker arms
Ls3 intake manifold
87mm throttle body
42lb hr LS3/7 injectors
GM LS9 camshaft

 

I cant comment on the noise, but that is an interesting combination. I ran an LS9 cam in my LS6 and it has zero bottom end. All the power is up top. That seems the opposite of what you want for a big cube, heavy rover.

 

I agree. Unless this build is boosted, the LS9 camshaft is a terrible choice for a heavy street vehicle.

 

How much time is on the build? What were piston to wall specs set at? Quality machine work, or just another cheap shop over in town? Cylinder finish matters. Stroker builds can be noisy if the wrong piston taper was used. I like Mahle stuff, but I’m not sure how keen they are on build a “stroker specific” piston, or was this just a shelf piston? Sorry for all the questions but all this matters, to get it started in the right direction. Obviously reliability isn’t high on the list with that much stroke in the short LS3 cylinder, but most stroker builds aren’t designed around 100k miles…only torque. Reliability and oil useage isn’t typically considered.

 

These are good questions that I have some answers too. It was built by TurnKey Engines. I do not know much about them or there quality of work but they seem to be decently sized. As far as the specific internals, I do not know what they are or any of the details on clearances and whatnot. I did find this link that looks similar to the engine, but specs seem a little different. https://www.turnkeyenginesupply.com/...ct/ls3-415-600 I imagine I could stick a borescope down the hole and see if there's a p/n on the piston if I have to.

And yeah the ls9 cam is a terrible pick for this application especially considering THEY MADE IT CHOP AT IDLE WITH THE TUNE!
Just trying to figure out whether to tell him to let it ride or take it back. It has 1300 miles on it.

If you bought a ls3 stroker and it sounded like perry the platypus at operating temp would you send it back or run it?

Also Dawsonville GA? We're neighbors basically.

 

I had my tuner add chop with the tune to my BTR stage 2 cam. Sounds wicked when it's cold. I've gotten a few compliments from people.

My LS1 has pretty bad piston slap. It's also got 115,000 miles on it but it runs great. I don't know that piston slap is the end of the world.

 

Isn't "adding chop" sorta like stuffing a rolled-up sock in your pants? With roughly the same result??

 

I would definitely return it if he is able to. That's a hack shop at best. Best thing he could do is try to find a leftover GM LS3 crate motor maybe. If he has to build from scratch, I would do an iron 6.2 build.

 

We have Mahle pistons in a 415, 418 and 429 and all are whisper quiet. Mahle are low expansion aluminum they should not have piston slap. At operating temp, no engine should have piston slap.

 

Aluminum blocks too?

 

Yes. Yes it is.

 

Yessir LS3 block and ls7 block.

Mahle Powerpak pistons

 

Mahle makes excellent pistons. Some shops like Diamond, and even though my LS7 has Diamond pistons, I personally think Mahle is somewhat superior. Thomson Automotive chose the brand of piston. I learned after the fact that if you have certain preferences, you better specify them to the builder BEFORE the build. I've had no problems with the Diamonds, but they weren't my first choice. Oh well. I've also heard good things about JE pistons, FWIW...

 

Yessir. If it’s noisy at temp at 1300 miles, I’d question the shop/builder and look at options. Yes, Dawsonville Ga. Where are you?

 

Isn't modifying a pristine car destroying it's value? If people are getting offended at exhaust noise, isn't that a bit silly? I want a car that sounds a bit rowdy but drives well on the street.

 

That isn't my point. If your engine chops via tuning tricks, some might think it has the horses that the chop would indicate, but don't really exist. False advertising, like the rolled sock in the pants
I'd rather a smoother idle via a cam like the Ghost cam that delivers good power with a smoother idle. A sleeper.

 

It all started when I put baseball cards in the spokes of the wheel on my bike as a kid. That one deviant act was my downfall. The first car I tried to get my dad to buy for me was a 66 Mustang with a big cam and after driving it he said no. Guess that kind of noise possesses some people.