Saw these on ebay. Are they any good. Saw someone else using TRW's but they were a little different, different part #. Wondering if anyone has used these.
http://cgi.ebay.com/ebaymotors/ws/eBayIS...m=#ht_935wt_854

I have used those pistons, they are low compression if that is what you are looking for.

You can use them for turbo or blower application.

They are not designed to really be for a blower or turbo, but they are forged.

They have a big chamfer @ the top sides & it exposses the top ring more.

What type of engine combo are you looking to build?

MBHD

250, lump port, .050 milled from head, about 67cc, 1.94 intake, 1.60 exhaust, solid lifters, .577 lift cam, roller rockers, zero deck block, ARP bolts throughout, powerglide with manual valve body, 3000 stall, 3.73 rear ford 8.8 narrowed. Still have stock pistons and the budget is running low for forged pistons. Thinking about topping it all off with a little nitrous. What do you think?

I am not to savy on these particular pistions but do not like the chamfer if you are wanting to use nitrous a lot. Nitrous is like a "blower in a bottle" and having a "weak" upper ring land is not what you want. For nitro and nitrous I went extra thickness on the top, once to 3/8" and another time 5/16" above the top ring. I even use .220" on high compression gasoline. I personally have never seen this much chamfer; hopefully some one here will respond with an explanation..Good Luck

Depending on camshaft duration specs @ .050 I think these pistons would not give you enough compression.

I am guessing the duration on your camshaft @ .050 is more than 240 degrees duration?? Just a guess though.

I believe you need a true flat top piston to bring your compression ratio up to match your camshaft & stall speed.

As far as nitrous goes, these would not be a good choice because as I stated earlier , the top ring would be exposed to such things as detonation & will destroy your top ring & ring land of the piston.

I cannot think of any reason why TRW would put such a huge chamfer on the top sides of those pistons other than just to lower overall compression.

MBHD

MBHD

You need to tailor your engine build around the use of nitrous. I agree with others that have stated the top ring is too high and is going to be exposed to the shock and higher temps related to nitrous useage. Also, nitrous doesn't like moly coated rings either, it will flake off in a hurry and trash your cylinders. Stainless is a much better choice, but more pricey. Cam choice is also critical when using nitrous, when using the higher HP shots, its not good to use the same cam as you would for a N/A setup, a wider LSA should also be used.

How about the silvolites? Or just the stock pistons? Will either of those last? Nitrous not happening any time soon, maybe for christmas. I would like to get it together before summer is over. Camshaft is 290 advertised. Not sure what actual is, rough measure on v-blocks with degree wheel(makeshift) puts is somewhere around 250*. I got all the head parts from Tom Lowe, ready to take it to the machine shop, just trying to make a decision on pistons. My block was already .060 over, so i went to pick 'n pull and got an untouched 250 block so I can start fresh with the block. Looking for suggestions.

Again, you need to plan for your final objective....and thats the use of nitrous. For very low HP levels of nitrous, a cast piston can last for a while, provided you get the engine tuned real good before you start to mess with the nitrous. Carb jetting and timing are going to be the two things that will get you in trouble fast when you start to go forced induction, so think through all things carefully and moved forward step by step slowly when you actually begin using nitrous. How much of a HP nitrous setup are you planning to use.

If starting with a fresh block, my pistons will fit the ticket.
http://www.12bolt.com/250292_inline_products/pistons

Only offered in .040 . Nice top ring land, performance rings and the deck of the block will not need to be cut nearly as much to get zero deck. Hopefully the price is low enough. Tom

Tom,
Do your pistons work with the stock rods, and are the pins not press in? I am going to have to put off machining for a bit I guess, and I will probably get a set. Just wondering what else I need to do to use them. I know the crank will be fine but how much wil the stock rods handle?

His pistons are made to be either press fit or floated, depending on the type of rod used, so you can use them with the stock rods with no problems. Just add some ARP rod bolts and polish the beams on the rods and balance, shotpeen and recondition them and they are good for 400 HP+ pretty easily.

Photwenny,
I dont think U want those L2396F pistons with all the $$$/time invested in your motor already. Agree that they would weaken the rings, but also they offer almost no quench area.

I would suggest either the L2314F pistons or the ones on Tom's website noted here. Either of those plus a near zero deck will give nice quench.

I ran your engine thru the Gonkulator and it computed to
With the L2396F's
CR 9.1
Torq 276 at 4500
Powr 296 at 6200

With the L2314F's (Toms similar)
CR 10.0
Torq 296 at 4500
Same octane requirement as above due to better quench.
Powr 311 at 6100

I would guess the L2396F (mid-late 70s) was cut that way for smog, so it has less ring crevice and less quench too. Not good for performance or octane behavior.

So I saved a few bucks and just ordered Tom's pistons. Want to do it right the first time.

Those pistons will do a lot better if you do plan on Nitrous.

I would suggest a progressive Nitrous controller,much easier on the engine,head gaskets & much easier to get the car to hook up,easily adjustable.
They are pricey,but I was never a big fan of squeezing a lot of nitrous all @ once , well for my inline 6 anyways.
With V-8's I had better luck w/nitrous.

MBHD

will go with a progressive controller for sure. now looking at rods. any suggestions for h-beam rods. saw these eagle rods on ebay. seems like a good deal. the stock rods are the weak link now.
http://cgi.ebay.com/ebaymotors/ws/eBayIS...I#ht_2841wt_939

You should look at Crower I beam rods.

Looked at crowers site, lots of choices, any specific rod suggestions?

U PUT A 250 PISTON IN A 230-*WILL STICK UP .104 IN OUT OF BLOCK

FOR SALE
NEW OLD STOCK
TRW FORGED PISTONS
PART NUMBER
L2289F
.040 OVER
250 CHEVY
1966 THRU 1968
1.655 COMPRESSION DISTANCE
6 PISTONS AND 6 PINS

8 New TRW L-2314-F .030 Over Power Forged Pistons For GM 307 Non Coated Skirts For Sale
ON RODS+ARP+RINGS +balanced

250 CHEVY FORGED PISTONS 1966 THRU 1968 L2289F TRW .060 OVER

RODS+ARP++balanced

NOS CLIFFORD LONG TUBE HEADERS 194-230-250-292 CHEVY INLINE 6CYL -

CAMS 470HD 518HYDCLIFFORD 565SOLID-ENGLE

CLIFFORD VALVE COVER

CLIFFORD 4BBL INTAKE

MAKE OFFERS[b][/b]--------------
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These items need to be put in the "Swap Meet" section so people can know they are for sale. They probably aren't going to be looking in the discussion forums for that.