What's the going rate for custom 4.1 forged pistons?

[earlbrown]

I was just working with a high end piston maker for some custom slugs that go in my BBC jetboat. While I was talking to the sales manager about his capabilities he mentioned he can make me a Buick piston in any bore size from 3.500" to 5.500" with no trouble at all. Turns out I can get them in ANY O.D. I want and ANY compression height I want with no increase in price. (which would have been good info before I had to deck the shit out of my block 'cause of those FM hypers)

Before I go through all the trouble to design something cool what's the current prices and lead time for a forged slug with pins locks and rings?

 

[TexasT]

Not sure on the current pricing but you have my attention when you said any bore, and any compression height.
I need some 4.00 bore with a stock height so I can run stock crank/rods and use SBC rings. Low budget please.

 

[earlbrown]

Stock height actually kinda sucks. The pistons are pretty far in the hole as it is. PLUS, if you're talking about running a 4.1 the deck height is .025 taller than a 109 so that puts you in hole even further than normal. That's the main reason I've been working on this. I want to be able to get my compression I want and the quench I want without having to deck the crap out of my blocks.

They wont necessarily be "low budget" like a shelf priced hyper from Slummit.... I'm trying to build a badass modern piston with a thinner ring pack for shelf price forged slugs.


Right now we're working on the optimal dish diameter and depth. It's a balancing act between taking the compression out of range (high or low), I want them to work with a 3.800" all the way to 4.55" bore. And I'm trying to design them to require less timing to make more HPs.

Right now it's looking like somewhere in the $500 range for a set of 6 pistons, wrist pins and locks. Mahle Moly rings around $100 a set. And somewhere around 10 to 14 days lead time to get them if they're custom. If they're a normal size and CH around 5 days lead time.

 

[dr_frankenstein]

500 is great! last set of true racing 4.1 slugs i dropped right around 950 for the set.

sign me up!

 

[earlbrown]

Was that $950 for pistons, pins, locks and rings?

 

[dr_frankenstein]

Was that $950 for pistons, pins, locks and rings?

pistons, pins, buttons, and rings. by Arias for blower V6

 

[earlbrown]

I'm surprised you could get Arias that cheap. They think a lot of their pistons!!

What was the lead time to get them?

 

[dr_frankenstein]

I'm surprised you could get Arias that cheap. They think a lot of their pistons!!

What was the lead time to get them?

2 months.

and they were only that cheap because they had messed up on my order in the ring pack, a std pack instead of the metric i wanted. in return for the mess up they cut me a break and i decided to let it be. I dont like the buttons much, but thats what it came with for oil ring support since it ended up std, the mess up put my pin in the ring pack.

I also have a set of Venolias that i got from Mike years ago that I have been copying for my current design and they were not cheap to begin with either. think i paid around a G for them back then.

and they dont offer squat for quench, basic dish design that is extra heavy in the crown for the blower mocking typical v8 race blower stuff... not ideal for street nor turbo...

so if you can manage 500-800 dollar sets of well designed Max effort street style pistons.... the cost alone would negate my previous design... weather it be blower design or not.... 5 to 800 is freaking awesome for some 4.1 slugs! id stuff every block i got and keep my fancy pants junk for my stage motors.

 

[charlief1]

I'd suggest that if you can get this done make sure to allow for a .600 lift which would give just about anyone the valve clearance they need. I'd love to have a set for the crank I bought that uses the BBC rods. I'm looking at using the 6.135 rods or maybe the 6.3 rods but either way I'd have to have the pistons made for this.

 

[TexasT]

Sounds good. If the deck is that much taller adjusting the compression height sounds good to me. I just want to be able to use stock crank/rods. As long as they are forged I am happy. I wanted the 4.00 so I can use off the shelf sbc rings. Should be something that could work, but the $100 stuff you mention would be fine too.

Keep us posted on your progress. I'd like to put together my 4.1

 

[earlbrown]

600 lift is pretty up there but there's a lot of factors that make that lift number possible/not possible. Cam timing, duration, ramp speeds, piston to head clearance, etc...

If you're running a stock length BBC rod and a stock stroke on a 9.535" 4.1 block, a 'o deck' would be a compression height of 1.700" A 6.300" rod would be a 1.535 CH. Either one should be doable with a thin ring pack.
With the slugs I have in mind you'd end up with right at 9.25:1 with a .050 gasket and a 49cc combustion chamber. If you want a stroker crank the piston would need to be a little further down in the hole to avoid ultra high static compression.

I'm not sure if there's an extra charge to put BBC pins in it though. I know it's free to move the CH but I haven't asked about changing the pin size.

 

[earlbrown]

. Should be something that could work, but the $100 stuff you mention would be fine too.

The rings I'm looking at are pretty nice rings. 1.5mm plasma moly faced Mahle ringsets. Slummit sells them for $137.

 

[turbobitt]

I was just working with a high end piston maker for some custom slugs that go in my BBC jetboat. While I was talking to the sales manager about his capabilities he mentioned he can make me a Buick piston in any bore size from 3.500" to 5.500" with no trouble at all. Turns out I can get them in ANY O.D. I want and ANY compression height I want with no increase in price. (which would have been good info before I had to deck the shit out of my block 'cause of those FM hypers)

Before I go through all the trouble to design something cool what's the current prices and lead time for a forged slug with pins locks and rings?

Heck with the pistons, lets see pictures and details on the jet boat.
Allan G.

 

[earlbrown]

this is what she looked like when I first got her..

H2O Nympho

I'm still going back and forth between my polished tunnel ram or a Procharger with a water cooled intercooler on the new build..

 

[novaderrik]

i'm gonna suggest that you get them designed with a reverse dome instead of a traditional dish... this allows you to have a nice tight quench around the outside of the piston and keep all the combustion action within the chamber, thus allowing a higher static compression ratio and less problems controlling detonation. once you have the reverse dome part figures out, then you can then use that same shape on all bore sizes because the head will be in the same place relative to whatever size the bore is.

 

[earlbrown]

Actually we are talking about a reverse dome instead of a dish. Once the dimensions are figured out, they'll be the same on all bore sizes. The cavity won't be chasing the OD of the crown as it gets bigger.

The thought process we're working on isn't so much as the piston having a cavity cut out of a flat top but more like a flat top with a 'fence' around it to keep the early combustion corralled so that it pushes down on the piston instead of flatting out across the bore first then pushing down on the piston.

The tech I was talking to earlier was telling me about some engines he was working with using that method that make more torque earlier in the rev range and did it with 2* less timing. Everything else being the same as far as compression, cam etc.. Nothing but a change in crown shape.

 

[turbonut85]

I priced JE 4.1 pistons last year...$970 for pistons/pins.....

 

[turbobitt]

I priced JE 4.1 pistons last year...$970 for pistons/pins.....

That sounds way to pricy compared to what I spent. Will have to check to be sure. I know they used a 4" SBC blank to make them.
AG

 

[forzfed]

Never mind the boat, where are the naked women? I paid about $900 for my diamonds with pins and rings.

 

[earlbrown]

The Nympho is a panty dropper. If I'd known how effortless that boat makes it, I would have got one YEARS AGO!