Any of the companies have 4.50 dia. pistons with a small dome,
flat top piston will not give me enough comp with 119 chamber.
JE pistons all have around a 40 or higher dome volume and end up at 13.0 comp.

 

Check the SRP line....they have 10cc domes that will work.

Just for reference....Wiseco is the parent Co....they make high $$ serious race pistons. Then there is JE...they make great race pistons...but more of an off the shelf deal usually for all the most popular motors,.....not as custom as Wiseco. Then there is SRP....they make pistons usually out of 4032 material which is great for street and lots of race stuff (I have them in mine). They are designed to be quiet and run with tighter clearances than the real race stuff. SRP was born from them getting the contract to make the pistons for the ZZ502 motors. GM helped get some funding for the CNC equipment to make huge volumes of pistons...and SRP was born. They now use that equipment to make lots of 540 type pistons too.

You can also check Mahle..they might have some.


JIM

 

Ok Jim thanks you are very imformative, is there such a thing as
keeping some of the weight out of the piston and pin if I'm
willing to pay a little more for pistons and pins. After looking at
the weight of internal small block parts for so long the weight
of big block parts is hard to take.

 

Little Mouse---I've read a lot of your brilliant posts here, and as such, you already know that there's sort of a general digression from open chambers plus domes, to small, efficient combustion chambers and flat-tops. I'm certain that the reasoning/physics have been discussed here.

I'm thinking seriously about an in-piston tub design. I was thinking about using the Merlin X 16 degree head (bbc--uses standard valvetrain components) that has an essentially non-existent combustion chamber (large enough to unshroud), and trying a -25cc or so inverted image bathtub design on the piston.

Does that sound sweet, or what?

My thoughts on this were instigated by (some) casual reading on the Heron combustion chamber design.

Think about the horrendous amount of turbulence and flamefront propogation violence that would occur with an essentially flat-top scenario and that combustion system design? And then think about the quench?

Any of you, .... please let me know if this is a reasonable idea, or if I should be locked up in a mental institution. Thanks.

 

I went with premium quality CP forged pistons for my 540, which are top of the line race/street pistons. They'll make custom ordered pistons to your specs. They made mine to the specs I gave them, sweet deal. CP was founded several years ago by guys who were the former top guys at JE. They weren't happy with some corporate upheaval, so they left at started their own company.

Here's a link:

http://www.cppistons.com/sitemap.html

 

Sure....just depends on what you want to pay.

For serious stuff most of us go with a pretty thick piston pin...kind of a double dge sword....you need good pin to handle the weight...and to do it you add more weight!

For example, a buddy's 632 used JE shelf pistons originally designed for a 565" motor..but with the right rods they work OK in a 632. The next time around we had a custom set made by Diamond Racing...really didn't cost much more. Even with a stout pin....we ended up getting 40 grams off of them! They also cleared crank a lot better.

Normal 540" stuff is going to be in the 600-610 gram range probably. Probe also makes some nice small dome pistons....but weight is similar. I forgot about them.

So you can check with Co's like Wiseco, Diamond etc for customs. You can go with longer rods...that helps..but you can only go so far with a short deck block...the pin is already in the oil ring groove.

How high you planning on winding this dude? They go 7000-7500 just fine with these kinds of parts.

You can also get lighter cranks....but you have to be careful....with all that stuff swinging around...you need strength. Make sure you get the crank with the center counterweights.

JIM

 

I like the concept...but that 16" Merlin head leaves a lot to be desired in flow. Need serious work and flowbench time from the ones I've seen. Dart makes a similar one.

JIM

 

Hey Jim, did you guys ever get the new flow #'s on Nicks' heads ?? I just sent mine back to Brodix for some touch up work.

 

Interesting, Jim. Funny that I've never checked flow. I guess I was 'blinded' by that ultra-cool valvetrain geometry, thinking it absolutely has to have superior flow #'s (hence the reason for the design).....I'm almost certain I've seen them somewhere, but now cannot find them. Do you know what the #'s are? Thanks.

Jack

 

I'll have to do some searching. My first info on them came from a Bill Mitchell employee who called them a *joke*. The potential was there, but they just didn't flow what you would expect. As I mentioned..Dart did some too. They are popular with some roundy pounder classes in the east I understand.

Most porters who use them start with an unfinished head and then put the ports where they want them. THAT works great...but it's not cheap!!


John...I'll shoot you an e-mail.


JIM

 

I have not made up my mind for sure on a 509 or 540 but I'm
going to use a tall deck block and use longer rods, there is no
doubt a 540 would make more torque and the same hp at lower
revs then a 509. I know people use pistons with oil ring supports
all the time but I do not like the idea if I don't have to. I will
want the engine to make power in the 4000 to 7500 rpm range.
A 540 or a 509 I figure is going to have to much torque for any
street tire to use it, would be ok out on the freeway.

 

If I was going to a tall deck..I would for sure build a 598!! They are killer!! No use having all that block with no more cubes. The long rod etc won't add any power close to another 50+ cubes!! They will rev inthe 7000-7500 rpm range too.

My pistons...and 99% of all 540's have support rails on rings...they work fine. Mine doesn't use any oil.....have taken numerous cross country trips in it. Vettemaniac had his 540 in literally his daily driver. Got 18.9 mpg on highway with 3.08's and a TKO. Last time we went to KY from TX his also never burned a drop.

If you want a real screamer..and don't mind buying titanium valves etc...a 4.500x3.76 combo is wild!! Twist it to the moon. Larry Robb has one in his C-2 making 860 HP on pump gas at 8100 rpm!! Shifts at 8600 rpm!!

You're right on the TQ thing....I have purposely skewed mine higher in the RPM range to make it more driveable under full power with the 10" slicks I use. Having all that TQ come on hard and then fall off quickly makes for an awful short powerband...I like mine now where it hangs on a lot longer.


JIM

 

well I have always been a big bore short stroke person I blame it
on my 302 If I build this torque monster 598 how in the hell
Im I going to hook any of it to the ground with street tires.
Probably going to use a 4.00 stroke 6.535 rod and tall deck block.
Besides I can go around singing, shes real fine my 509 instead of
409.

 

You just use REAL big heads and intake and build incredible power up high!!

Pef427 just put a 598 in his C-3...we test fired it and he did the initial round the block cruise with it a few months ago. He's driving it to the Forum Cruise In in May!!

JIM

 

Here's some more info on CP's premium forged pistons. They are made of 2618T-61 forged aluminum, which is the highest grade, best material for high performance/race pistons. They don't come any better, and they can stand up to just about anything you can throw at them. And like I said before, you can custom order them any way you want them from CP.

My 10.75:1 static compression ratio pistons, have .170 domes, and weigh 619 gms. The CP 9310 steel wrist pins that I got with the pistons, have .150 wall thickness and weigh 145 gms.

As a comparison, the less expensive lower grade 4032 aluminum pistons have more silicon in them, so they do expand less, allowing for tighter piston to cylinder clearance. So, its like Jim said, it depends on how you plan to use them, or may end up using them, and how much you want to spend.

 

If you are giong to build a tall deck motor make it at least a 598.

 

To hook on the street, your best bet is probably to go with the Mickey Thompson ET Street Radials.

 

I don't know how good it is on airflow but dart has a 383 runner
oval port head with 18 degree intake valve 235/184 and a 102
size chamber.

 

Rick is right..the 2618 material is used in most race stuff. One big advantage of it is that it tends to go *plastic* and deforms a little under incredible abuse. That sounds bad, but it will save really bad things from happening in the event of things like dropped valves etc. or heavy nitrous use. They can take a lot of abuse. We were recently involved with a 632 that dropped a valve. The 2618's took the hits well and surely saved catastohic cylinder damage.

The 4032 stuff is slightly harder...the best advantage is they wear real well and allow tighter clearances. SRP says you can run .002 or so wall clearance on a 4.500 bore..but I went with .0045 on mine. Still quiet......and when I've had it apart pistons/walls look fine. Mine has routinely lived in the 7000+ rpm range under power and lots of street miles. Can't complain about them.

The best advantage today is that there are so many 540's etc around that you can get really good parts for good prices. I put mine together almost 7 years ago and there just wasn't as much available without going to really high$$ custom stuff. We searched for months to get a block......crank and rods weren't too bad....but piston choices under 13.0 compression were real limited.

Make SURE you double check pin clearances. Many come awful tight and will show signs of seizing if left that way. The 632 I was talking about was initially assembled by a professional shop...I use the term loosely. Swallowed a valve due to lifter issues they missed, but when we tore it down we also found the pins were showing signs of galling...and it only had a few dyno pulls!

Needless to say, we did it all ourselves this time around. Trust no one!!

JIM