Cracked Piston solutions?

[JDPlowboy]

Has anyone ever replaced stock Pistons with mahle Pistons without balancing the rotating assembly? I know for years people were cutting and costing Pistons and not having any trouble. Why couldn't you just swap all 8 Pistons and roll on with a stock application?

 

[quinton]

I've heard of guys doing it.

 

[ikeG]

I have done it with no problems.

 

[Chevy1925]

Has anyone ever replaced stock Pistons with mahle Pistons without balancing the rotating assembly? I know for years people were cutting and costing Pistons and not having any trouble. Why couldn't you just swap all 8 Pistons and roll on with a stock application?

its been done, problem is you are increasing the chances of a breaking a crank and hurting the stock bearings more (assuming stock bottom end). if you dont care, roll on!!

 

[SickLL7Crenshaw]

its been done, problem is you are increasing the chances of a breaking a crank and hurting the stock bearings more (assuming stock bottom end). if you dont care, roll on!!

Yep lol several guys down here do this. 15k miles later there bearings look like they have 150k on them. And most of those engines done like that have a nice vibration at idle and at 1800-2000rpm from what I can tell riding in them. No thanks.

 

[ikeG]

If you have a few to pick from, you could weigh each piston and replace it with the closest one in weight. These engines are so far from perfect balance from stock that you wouldn't believe it.

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[JDPlowboy]

If you have a few to pick from, you could weigh each piston and replace it with the closest one in weight. These engines are so far from perfect balance from stock that you wouldn't believe it.

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That's what I have noticed when replacing stock Pistons with stock Pistons. The stock weight has so much variance!

 

[JDPlowboy]

If I balanced the rods to Pistons I could see that being done. But I'm just trying to stay away from
Taking the crank out

 

[ikeG]

I have done it with no problems.

Ok, a pm made me reread the original post. I misread it. I thought jd asked if anyone swapped stock-for-stock Pistons. I have never swapped a stock for a Motorsport piston. However, if for some reason the Motorsport Pistons would weigh the same or a few grams variance, then I would definitely do it. But I doubt they weigh near the same. I've never weighed the two compared at the same time.

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[Chevy1925]

If I balanced the rods to Pistons I could see that being done. But I'm just trying to stay away from
Taking the crank out

why? your damn near to that point as it is.


stock balance is all over the damn place but you are adding MORE weight with the mahle pistons (assuming you are going cast, not forged).

 

[JDPlowboy]

why? your damn near to that point as it is.





stock balance is all over the damn place but you are adding MORE weight with the mahle pistons (assuming you are going cast, not forged).

Time, money and stock truck. Just trying to get options figured out.

 

[JDPlowboy]

I've swapped stock for stock several times and haven't had any problems several years of running under their belts. Just looking for a better option not sure why these lml Pistons junked out.

 

[Chevy1925]

how about some info on the engine you are playing with? 100% stock? what model? if not stock, list mods done to the engine

 

[JDPlowboy]

Lml with 50hp tune. Only modification was straight pipe

 

[JDPlowboy]

It's getting a new set of gm Pistons and rings

 

[Chevy1925]

It's getting a new set of gm Pistons and rings

:thumb:

 

[kidturbo]

I did a Mahle upgrade to a LLY some years ago and didn't balance it. As mentioned above they are a few grams heavier than stock. Spun it 3-4k for extended periods, it's still running fine today...

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[JDPlowboy]

I did a Mahle upgrade to a LLY some years ago and didn't balance it. As mentioned above they are a few grams heavier than stock. Spun it 3-4k for extended periods, it's still running fine today...

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This is what I was looking for. The factory rotating assembly is just roughly balanced from the factory anyways.

 

[Chevy1925]

This is what I was looking for. The factory rotating assembly is just roughly balanced from the factory anyways.

ah yes cause one engine that has "lasted" is all we need for good info now a days :roflmao:

 

[kidturbo]

I ask two well respected engine builders about the balance deal before deciding. The weight difference for Rpm range was not enough to be concerned with. If spinning 8k they said certainly do it, but no need for less than 4k engines.

I posted the actual weight difference on here back in 2010 under my Cracked Piston thread.

That said, my new billet crank engines are balanced to within a gram overall with even the oil weight accounted for..

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