You knew it was coming, Pistons??

[joe_rocket45]

Re: You knew it was coming, Pistons??

Make sure you know before buying the pistons, the valve spacing on a cup engine is different that the std spacing on a 220.

I think with the boost you will want a full skirt, and a lower top ring than that set of pistons has.

I agree, that's partly why I brought up valve spacing and the piston skirts, IMO you want a beefy piston for your first go round, detonate those pistons and you could be looking at some real nasty carnage.

[TC]

Re: You knew it was coming, Pistons??

Make sure you know before buying the pistons, the valve spacing on a cup engine is different that the std spacing on a 220.

I think with the boost you will want a full skirt, and a lower top ring than that set of pistons has.

I agree, that's partly why I brought up valve spacing and the piston skirts, IMO you want a beefy piston for your first go round, detonate those pistons and you could be looking at some real nasty carnage.

Those pistons are just an example of what the connecting rod area of the piston might look like, I don't plan on buying those particular ones. Now what I do plan on doing is buying a set of custom pistons that are designed for my application. They are probably one of the few things I'll have to pay full boat for, but it will definitely be money well spent. ;)

[CDMBill]

Re: You knew it was coming, Pistons??

Right along with that piston design set of considerations will be the selection of the ring package. I've been happy with JE and I am running their Hell fire rings set a bit down compared to an N/A location to allow for up to 300 HP of spray. They have a Napier second and a support oil ring for the oil control set as the pin intersects the oil ring land due to the 6.8 rod length.

As you begin to narrow down your specifications for intended use and power level you'll want to spend time with your selected piston manufacturer and trusted machine shop/builder. They are many in Phoenix.

Odd size pistons require odd size rings and the cost will rise sometimes dramatically. My ring set cost close to $500 due to an in between bore size which I have to make the aftermarket block last as long as possible through several builds. See Jeff's comment elsewhere.

[JeffMcKC]

Re: You knew it was coming, Pistons??

TC, now that your on the Dark side,,,,, you will see what it like and no one quoting a something they have read 20 years ago will apply, take note call a couple of piston people compair to each ask them why they are moving things so you understand well enough to decide what to use.


If done right it will be a killer piece.

[SpiderGearsMan]

Re: You knew it was coming, Pistons??

it will be psycho

[TC]

Re: You knew it was coming, Pistons??

it will be psycho

Or as my one buddy says it, Captain Insano!!!!!!!


I sent the seller an email asking if he knew the piston weigh or bob weight the crank was balanced with. Also asked if it was internal or external balanced, which I'm sure it's internal, but it's best to make sure. ;)

[Tazracing]

Re: You knew it was coming, Pistons??

I'm sure you can find some use 358 pistons, as the fuel change made alot of stock, worthless to those teams

[TC]

Re: You knew it was coming, Pistons??

I'm sure you can find some use 358 pistons, as the fuel change made alot of stock, worthless to those teams

Problem is I'm going to boost the motor and those types of pistons your talking about don't have the crown thickness that a turbo piston has. I also plan on having both the top of the piston and the skirts coated, as well as the combustion chambers on the heads. This will reduce risk of detonation greatly and for $50 a piston it doesn't seem to out of line for the added protection.

Basically some of the stuff I'm going to buy used, and some of the stuff I'll buy new, pistons are just one thing I can't afford to skimp on, so I'll order a set custom made for my application, it's really the only way to go. And according to Ross's price guide it's only going to cost me around $1200 for the pistons and coating. And I haven't checked with anyone else yet so that price could be lower. ;)

[horsewidower]

Re: You knew it was coming, Pistons??

TC, I think you're making some great choices.

[JeffMcKC]

Re: You knew it was coming, Pistons??

The only problems and I really hope they are not is, with the rod lenght it may require a tall deck to get a turbo piston to work

and the bob weight. It will be internal and I wonder what the over balance is on it.

Nice when your done, stay on track

[TC]

Re: You knew it was coming, Pistons??

TC, I think you're making some great choices.

Hey I've been talking with a bunch of great minds on this site for years. So making these choices is actually pretty easy. ;) ;D

And it's really nice to be able to run this stuff by you guys and get your input/opinions, its definitely reassured me in making the right choices.

As a lot of people have said before this site ROCKS!!!!!!!!!!!!!

[TC]

Re: You knew it was coming, Pistons??

The only problems and I really hope they are not is, with the rod lenght it may require a tall deck to get a turbo piston to work

and the bob weight. It will be internal and I wonder what the over balance is on it.

Nice when your done, stay on track

I was thinking about that to, but then I thought about a SBC 400 using a 6 inch rod and realized that the difference is .355.

SBC 400 = 3.750 stroke + 6.000 rod = 9.750

My 350 = 3.270 stroke + 6.125 rod = 9.395

So if I'm figuring this right the pin location in the piston should be lower in my motor than in a SBC 400 running a 6" rod.

But your right the bob weight is going to be the factor, at least I have the rods and pins that came with the crank, that is a big plus, and hopefully the seller will have the piston weight or bob weight numbers. Or I guess my machinist will have to figure it out. ;)

[Brian Lohnes]

Re: You knew it was coming, Pistons??

What about a tall deck Dart Iron Eagle block? Not sure if that is a step back from the M or not, but it would give you more deck height if you needed it.

(watching with interest!)

Brian

[horsewidower]

Re: You knew it was coming, Pistons??

It would be good to keep the pin out of the oil ring.

At a minimum, your piston ought to have the first ring .250 down from the crown, crown thickness at the thinest point should be .200. I've blown out pistons at the valve relief, too thin, so be careful. Mike Lefever stated that his Bonneville engine had the top ring all the way down at .350.

Set up your ring package, then configure the piston. That'll tell you if you need a tall deck to keep the pin out of the oil ring.

[Tazracing]

Re: You knew it was coming, Pistons??

IF t.c. 's going for this to the moon rpm wonder.. sell those rods and get shorter ones. no need for the tall deck that
brings with it. a hole lot of issues

and maybe a reg deck, raised cam (not an issue with a belt drive) that give you shorter pushrods..
as long as we're spending others money