Diamond Piston Questions

[ALLTRBO]

Roughly how much do the 3400 Diamond pistons weigh? I know exact weight depends on configuration, I just want a pretty close figure for now.

What is the dish volume for the various compression ratios?

These have full floating pins, correct?

Thanks for the help.

[SappySE107]

They are full floating unless you want to order press fit. I haven't had any orders for press fit yet so I don't know if I have to make a new spec sheet yet or not. Give me the bore and compression ratio and I can tell you the dish. There are quite a few options for the 3400, since I have 9.5 10.5 and 11.5 using the 3400 heads, and 9.5 and 11.5 using 3500 heads. The 10.5:1 stock bore pistons weigh 412 grams.

[mfuller]

My 11.5:1 (18.4cc dish) .040" overbore (93mm) 3400 pistons are 423 grams each.

[ALLTRBO]

Awesome, thanks guys.

The bore will be .100 over (Ben, you may recall that I asked you about this a good while back, you said it shouldn't be a problem for them), the compression will be 9.5:1 on 3400 heads.

Full floating i what I want so there's nothing to worry about, but much appreciated.

[SappySE107]

A good while back I was not getting all of the information that i am now. I can get them made but they will have a custom piston fee since .100 over is very much custom.

[2.8-350TBI]

Can you ask them what would be the minimum compression height piston for a long rod 3500 stroker? I dont want to make another thread and take up space...

I need to know so I can see how much I can actually offset grind the crank...

[ALLTRBO]

A good while back I was not getting all of the information that i am now. I can get them made but they will have a custom piston fee since .100 over is very much custom.

How much is the custom piston fee?

[SappySE107]

The .100 over set might be better off as a 3500 set instead, and use thinner head gaskets to make up for the quench. I have to write out the spec sheets for the 3500 pistons anyway so that wouldn't be a problem to go that route. I will post the answers once I have them (sent an email since it was a tech question and he might have to ask).

[ALLTRBO]

3500 pistons have a compression height of 1.25x", 3400's are 1.47x". I don't know the exact numbers because it depends on where you look, but it should be close.
I don't think a thinner head gasket would *quite* make up the difference.

This is for the "3200" I've been blabbing on about, a destroked 3500 using a 76mm crank and 5.85" rods. It'll be bored over about .021", hence the .100" over 3400 pistons. I have the 5.85" SBC Carrillo rods in hand so I'm committed to this combo.

I'll keep an eye out for your reply with the answers, thanks.

[SappySE107]

ah damn, forgot about the rod difference. Thats why I haven't setup the 3500 pistons yet but I forgot that was why.

[SappySE107]

The custom piston fee is based on the number of changes from a piston I already have setup. I have asked if its going to be 1 or 2 changes to take my .060 set and make them .100. The dish has to be changed as well to keep the compression ratio correct so that might be the 2nd change. Either way, its 7.50 a piston per change. 45 or 90 bucks, not sure yet.

Diamond likes to keep it around 1" min for the compression height

[ALLTRBO]

Okay, that isn't so bad. Let me know what they say about the definite cost difference. Either way, it could be worse.
Thanks Ben.

[2.8-350TBI]

Okay, one (?) about the forged pistons, are these forged strictly for racing, or are they low epansion for street use too?

Im wondering what piston to wall clearance diamond recommends for these pistons.

[SappySE107]

2618 alloy .004" clearance. The low expansion is not available in our bore sizes from Diamond.

[ALLTRBO]

Hey, good question. I was going to get to the wall clearance question sooner or later but I didn't even think of asking what alloy the alum was, heh. Now I know I'm not disappointed.