Technical TRW Piston L3170F Identification/Help

I would first like to introduce myself real quick and say hello.

My name is Rob and I'm from the east coast of the U.S. and have been a cl***ic car owner and enthusiasts from my youth.

I just recently inherited some automobile related items that also include a 1970 Chevelle that was setup for the street and drag strip. Also in the mix of items were a couple of BBC and SBC engines and various types of transmissions.

In particular was quite a few boxes of parts. In one of those boxes was a complete set of pistons with wrist pins, but no retainers. The pistons appear to be for a SBC 355 with the stamping of L3170F and 30 which surely denotes 30 thousandths overbore.

Part of the box had a partial TRW label. The pistons are of a 4 valve relief style which are clearly non high performance in nature, but I would like to actually identify and verify there manufacturing specifications for the correct engine family, but I'm not finding any actual information online and was hoping someone here could help me out.

Any help in sending me in the right direction would be greatly appreciated.

Kind regards,
Robert

 

welcome to the hamb!

We love pictures....might give us clues to the age of the pistons, which might point us to the era catalog that might list them

 

Doesn't come up in any of my books.

 

Are you sure on number ?
Do not see L3170F

in the Super seating numbers with a
L3169F = 396
L3171F= 400-402 bb
& looks that L31's interchange numbers
To or from L23's

 

Thanks for the fast replies everyone.

Here's what I have below.

 

Just for reference

 

Any date on Box ,
Wonder if SealPower ?
But I thought seal Power and TRW we're all stamped?

 

A L3170 search picks up a couple of Facebook and eBay hits, but no technical information.

your best bet is to somehow find a late seventies or very early eighties TRW or Sealed Power catalog. TRW made these for Sealed Power. It looks like they were discontinued by 1994. I think Sealed Power was acquired by Dana, in the late eighties or early nineties. Mahle bought Sealed Power in the Dana bankruptcy

The good news is that F means power forged.

 

they're cast pistons, not forged...the valve reliefs look wrong for Chevys...

how about 340?

https://www.jegs.com/i/United-Engine-Machine/648/1267.020/10002/-1

https://www.forabodiesonly.com/mopar/threads/new-speed-pro-340-cast-pistons-428p-040.576929/

https://www.forabodiesonly.com/mopar/threads/factory-72-340-pistons.212203/

https://www.summitracing.com/parts/uem-1267-030/make/dodge

https://www.ebay.com/itm/383753868218?

https://www.ebay.com/itm/116670374661

you can measure skirt diameter, compression height, and pin diameter to see if they are right for a 72-73 Dodge 340 piston.

 

Hi Eddy,

Am I seeing this piston part number being listed for a BB engine?

 

I just measured the piston skirt, piston height wrist pin height and diameter and this is what I came up with just using a straight edge ruler so this isn't going to be extremely precise.

Piston Skirt = 4" 1/16
Piston Height + 3' 1/2
Wrist Pin Height = 3"
Wrist Pin Diameter = 15/16

 

Unfortunately no date on the box.

Only a bar code sticker that reads -
Baltimore MD
Part# L3170F 30

 

you probably need to make more accurate measurements, for them to be useful. A dial caliper is really handy...

Chevy 355 pistons would be 4.028" at the skirt, close to 4-1/32".

Mopar 340 +.030 would be 4.068", close to 4-1/16

Pin diameter for Chevy is really close to 15/16", Mopar is closer to 1".

Can you get a picture of the label on the box? And any stamps on the flaps that might have a date or company logo?

 

Unfortunately the box only has the TRW sticker which is in the photograph I posted a few replies up and the barcode sticker I previously mentioned.

I will get my dial caliper out and post more precise measurements in a little while.

 

Those are not TRW forged pistons. As mentioned in previous posts those are cast pistons. Probably Sealed Power.

 

the funny thing is they look identical to the Silvolite pistons, aside from the part number

 

Hello gentlemen, good morning and Happy Thanksgiving.

Squirrel, those piston look amazingly close to what I have, but as I stated these were in a TRW box and there's a manufacturing stamp in a circle on the inside of the skirt that reads 1267 and below that number it reads 92.

Not sure of the significance. Odd thing is that my relative never owned anything that was Mopar related. He was a GM guy.

Here's what I have measured with my digital caliper.

Piston cir***ference = 4.040" or 102.63 mm
Piston length = 3.506" or 1.380 mm
Compression ring gap = 0.81" or 2.06 mm
Oil ring gap = 0.190" or 4.82 mm
Wrist pin cir***ference = 0.985" or 25.03 mm
Wrist pin length = 2.998" or 76.16 mm

 

@squirrel nailed it with the above link^, 340 Mopar.


The blue arrow shows how close the valve reliefs are, as compared to a SBC piston. Red mark shows a straight sided relief cut and the green area is angled maybe to aid in flow. No SBC piston ever had that configuration.

 

when you say "cir***ference", you really meant "diameter?

And where did you measure the piston diameter? If you measure at the top, it will be way off. You need to measure near the center of the skirt, like this



The pin diameter matches Mopar, it does not match Chevy.

 

I come up with the same as Squirrel from here

https://www.thewrenchmonkey.ca/products/auto-parts/sealed-power/428p

 

Just saying 99% gm here ,but I have
Ford , Mopar , Toyota performance parts around after 55 yrs being involved.
I am sure all TRW piston I have seen
where stamped TRW & #
All where forged thoe .
This is why I asked if box had date
To kind to narrow down what catalog to look into / time frame .

 

I'm a Chevy guy, I've built a couple 340s over the years.

 

Yes, I meant diameter and I measured at the top of the piston.

Here is what the measurement is from the bottom edge about a half in down and going towards the top of the piston crown measures.

4.067" and 103.31 mm

I can not understand as to why he had these types of Mopar pistons in his possession since he never owned or built any Mopar engines.

He has had plenty of engines to include 350's, 383 strokers, 427, and 454 BB engines in which I have 3 in my possession.

 

Eddy, the box is not revealing anything as far as a date. The piston does have a stamp code in a circle like a clock with the numbers 1267 and below that is the numbers 92

That and what is stamped on the top of the piston and the TRW label is all I have to go by.

 

Thanks for the information you provided in the link.

At least it seems to show that TRW did manufacture the L3170F pistons.

 

The interchange list that Oneball posted shows the part number as from TRW.

Keep in mind that TRW was bought and sold a few times over the years. They made a lot of forged pistons in the 60s-70s. Then another company (sealed power? speed pro?) seems to have bought their performance piston manufacturing line, and the TRW name ended up being used to sell lower quality parts, made by other companies. My guess is that the TRW label is probably from the 1980s-90s, and the pistons were made by Silvolite (or another 3rd party), and sold to TRW with their part number, and label on the box.

If you look up the corporate history of the company, which is kind of hard to do, you might find the real trail of what happened? But I'm just guessing a little bit here.

the 92 in a circle might be the year it was cast, or it might not be. 1267 is the Silvolite part number for that piston.

 

TRW "L3000" series pistons were cast pistons.
The "L2000" series pistons were Forged pistons.

 

I bought a bunch of engine parts once, coincidentally for a Dodge 340, but when I went to use the parts in one of the boxes, that box actually contained SBF bearings. Shoot, a re-purposed box. Yes, the parts were new.

 

Thanks Squirrel.

I'm now convinced that these are indeed TRW branded 5.6L (340) MOPAR pistons as attested by the 1267 stamping inside the piston skirt.

This Summit link confirms the piston specifications that I had measured with my digital caliper.

https://www.summitracing.com/parts/uem-1267-std#overview.

 

glad I could help.

you're gonna have to make up your own story about how the pistons ended up where they were. I can imagine lots of things that might have happened.