TRW forged pistons

[jpwalt1987]

Hey guys, I have a cracked piston in my friends engine and we need a new set. The pistons in the motor now are some very old TRW forged .030 overs that saw alot of abuse before we got the car. I dont want to have to rebalance the engine for a lightweight JE or Wiseco piston. Are the Speed Pro/sealed power forged pistons the same weight as the old TRW brand. This is what we are looking at.

http://www.jegs.com/i/Sealed-Power/844/L2481F30/10002/-1?parentProductId=755710

Thanks for any info. Jeremy.

 

[v6turbo87]

Back in the day the TRWs were sold as stock replacement pistons that weighed the same as factory stock pistons. I doubt that has changed but it could not hurt to call Speed pro for more info. You could also weigh the old and new pistons while you are doing the rebuild.

 

[A2000RICH]

Hey guys, I have a cracked piston in my friends engine and we need a new set. The pistons in the motor now are some very old TRW forged .030 overs that saw alot of abuse before we got the car. I dont want to have to rebalance the engine for a lightweight JE or Wiseco piston. Are the Speed Pro/sealed power forged pistons the same weight as the old TRW brand. This is what we are looking at. http://www.jegs.com/i/Sealed-Power/844/L2481F30/10002/-1?parentProductId=755710 Thanks for any info. Jeremy.

 

[earlbrown]

Are these so old the wrist pin is damned near solid or do they have normal looking pins?

 

[v6turbo87]

I used those pistons in my rebuild way back when. They have the near solid pins and that is the same part number. As you may know, TRW used the heavy pin to match the weight of the stock cast piston with the heavy "blast" plate in them. Lighter pins will require a rebalace-not that that is a bad thing but the OP wanted to avoid that.

 

[jpwalt1987]

Here is a picture of the wrist pin and some of the cracks.

 

[earlbrown]

Those aren't the old old ones with the heavy wristpins. The current units might be the same weight with the only difference being a coated skirt with the speedpro logo on it.

As far as I know the Maldin (sp?) MO plant still makes those pistons for FMO. I swore those heavy bastards off when I decided to build my own forged Buick pistons but I do know that 5-ish years ago they 3.830" forged weighs 790g with rings.

Personally I'd get a better/lighter set with a more modern ring pack and either live with it or have the crank rebalanced.

If you look closely the stock slugs 30gs heavier than the 'stock replacements'. If the builder didn't balance for the TRWs, odds are that engines been 'unbalanced' the whole time.

 

[jpwalt1987]

This is a new build with an eagle externally balanced crank along with the stock damper and flexplate, stock rods and the TRW pistons. The rotating assembly was balanced. I hate to have to go through the trouble of rebalancing the rotating assembly for a much lighter piston and then have to buy new rings also. Trying to get it back running on a fairly tight budget.

 

[jpwalt1987]

The other issue with changing to a piston such as JE, CP, or Wiseco is the use of a floating pin. We want to keep the stock press fit rods.

 

[earlbrown]

The rod decides if the pin floats or not. Running stock rods would just mean you don't have to use the locks.

 

[jpwalt1987]

Gotcha. Didnt think about just not using the locks.

 

[Eticket]

I know budget is tight, but I'd highly recommend a once over on the rods.... often they are bent and if the piston is cracked - especially a TRW, then the rods are suspect and the weak link the new build. Other guys don't like them, but I'd swear by the 2 set of TRW's I've used in a bang for the buck build.

 

[earlbrown]

I've always said it's hard to beat FMO pistons when it comes to 'bang for the buck'.....

.....except with these engines.


which Is why I designed my own line of lightweight forgings for Buick V6s.

 

[black owned]

I've always said it's hard to beat FMO pistons when it comes to 'bang for the buck'.....

.....except with these engines.


which Is why I designed my own line of lightweight forgings for Buick V6s.

Any of your forgings for a 4.1?i may need a set..

 

[earlbrown]

As long as your bore falls between 2.500" and 5.500"

 

[BMR]

What is the part number on those pistons? My basket case has a set of pistons on rods with ARP bolts in the trunk. They are 0.030" over pistons with what looks to be a Speed Pro or TRW number but a google search comes up with nothing. L3160F is stamped in the dish, along with the 30 over in the middle.

 

[v6turbo87]

TRW PN is L2481F for stock 3.8 bore replacements

 

[trixdout]

As long as your bore falls between 2.500" and 5.500"

What is the part number on the ones you designed or do we go through you to purchase the pistons?