stevooo1181

How strong are gen 3 factory flat top pistons?
I'm building a TVS 1900 L33 5.3L
My goal is 400-450rwhp (8-10psi) and use as my daily driver.

Can the stock 5.3 flat tops take that power reliability?

96capricemgr

iTrader: (1)

You will have no problems so long as the tuning is good, bad tuning and you will crack one.

redtan

iTrader: (5)

Lower compression helps, and at that power level you shouldn't have any problem if you keep fueling good and timing down to prevent knock.

stevooo1181

unfortunately the L33 has 9.9:1 compression
i know Positive blowers are more harsh compared to a turbo
will that be an issue with boost?

redtan

iTrader: (5)

You mean fortunately right? Because that is more forgiving than the 10.5 or 10.9 of the later engines.

LS2s and LS3s with their higher compression are just fine at those boost levels, so yours will do even better. And the thicker liners will help also.

A.R. Shale Targa

iTrader: (2)

Primary ring end gap needs to be .020"-.022" and the secondary ring end gap at .030"

stevooo1181

Thx for the replys.
I guess I'll just have the stock pistons coated and use em.

96capricemgr

iTrader: (1)

Coated? Believe some of the skirts are from the factory. Are you talking thermal on top?

N20zuki

You'll be fine...

anheuserbusch08

iTrader: (11)

Lol leave the stock pistons alone just run good fuel and get a good tune. Yall play it too safe I have a year on my 5.3 and 12-13 lbs of boost running 10s on a stock bottom end stock pistons stock rings never touched the bottom end lol

stevooo1181

I know a guy who will do the thermal coating and anti friction for $50.
Cheap insurance that the pistons won't go boom

redtan

iTrader: (5)

Here's my take on this: if there's an issue with fueling or spark or cylinder pressure, no amount of thermal coating is going to prevent the pistons from going "boom".

A good tune and proper fueling will go further in keeping your pistons alive. Not saying those thermal coatings aren't good, but they are not there to prevent piston damage. They have their benefits of course, mainly in efficiency and power making, but they are not to make the pistons stronger.

stevooo1181

My take on the thermal coating is the added resistance against heat.
Like from running too lean.

Strength is definitely affected by heat.
I probably don't need it, but for $50 why would I say no?

joecar

Severe/prolonged detonation will burn right thru the thermal coating...

the importance of a tune that errs on the rich side can't be stressed enough

(also consider that it has been found that the rear cylinders tend to run leaner/hotter)

MYSTIC-1SC

iTrader: (14)

Like others have said with a proper tune, and adequate fuel setup you will be absolutely fine.

redtan

iTrader: (5)

Yes there's increased resistance from heat. But when you run lean or too much timing, pressure and heat spike immensely and not even the best coatings will prevent damage.

Again not saying those aren't worth it, but they are not done for protection against otherwise catastrophic damage. As long as that's the mindset you're going with then it's ok. But if you think that a coated stock piston will be stronger and handle severe conditions better then you're going to learn otherwise quickly.

RonSSNova

iTrader: (3)

I just pulled my L33 apart after two years and 80 passes. Most at 15 psi and the last ten or so at 18psi. I am upgrading to forged.

Everything looked the same as when I assembled it. No additional scuffing (they were fairly scuffed as received) rings all free.
They are amazingly stout.

I run E85 at 11.5:1 and 16 degrees timing. No detonation in the logs and the plugs always look excellent.

Guesstimating 800 rwhp based on performance.

Ron

stevooo1181

That makes me feel better.
Ur setup is far more aggressive and didn't go boom.

RonSSNova

iTrader: (3)

I should note that I disassembled, cleaned and inspected the engine when I received it. It was essentially filthy inside.
Especially the piston ring grooves.
Re-gapped the top rings only to .024".

lazermule

I thought all 5.3's had dished pistons and the 4.8's had the flat tops?

I believe one could use 4.8 pistons in a 5.3 to bump the compression a bit though, correct?

LM