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Old 11-21-2022, 02:04 PM   #1
Andy Somogyi
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Default B230 flat-top pistons

Anyone know where to find a set of flat-top B230 pistons?

Any ideas if other manufacturer's pistons interchange ?, like its a 96mm bore, 23mm wrist pin, so you'd think that be a common config.

I'm using a ported 531 head and shooting for about 11:1 compression.
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Old 11-21-2022, 02:55 PM   #2
Smorgesborg
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Hello,

4.8L ls pistons, with 158mm aftermarket connecting rods are a drop in replacement, theoretically. All the dimensions line up if you go with crank steering rods and bore out the wrist pin to 24mm. I'm working on doing that but I'm currently scared to crack my engine open.

Alternatively, accept a small 4cc dish and use b230e pistons which can be found on some websites brand new.

I'm also the guy on Facebook who kept telling you I've done the same thing you're trying to do.
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Old 11-21-2022, 03:30 PM   #3
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23mm wrist pin is not so common. And you can get to 11:1 without touching pistons.
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Old 11-21-2022, 04:28 PM   #4
Andy Somogyi
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Originally Posted by Smorgesborg View Post
Hello,

4.8L ls pistons, with 158mm aftermarket connecting rods are a drop in replacement, theoretically. All the dimensions line up if you go with crank steering rods and bore out the wrist pin to 24mm. I'm working on doing that but I'm currently scared to crack my engine open.

Alternatively, accept a small 4cc dish and use b230e pistons which can be found on some websites brand new.

I'm also the guy on Facebook who kept telling you I've done the same thing you're trying to do.
Thanks, I'll check it out. Wonder if you could also use LS rods? I'll have to look at sizing on those. It seems like custom length rods are pretty cheap, lot cheaper than pistons, not sure why.

Another option is looks like the older B23 used 24mm wrist pins, wonder if a set of B23 rods would work?

I'd prefer to go with flat-tops because of the better squish pattern. I've been researching combustion dynamics, and the squish effect is important for optimizing gas flow, swirl, and minimizing detonation.
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Old 11-21-2022, 04:52 PM   #5
Smorgesborg
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Thanks, I'll check it out. Wonder if you could also use LS rods? I'll have to look at sizing on those. It seems like custom length rods are pretty cheap, lot cheaper than pistons, not sure why.

Another option is looks like the older B23 used 24mm wrist pins, wonder if a set of B23 rods would work?

I'd prefer to go with flat-tops because of the better squish pattern. I've been researching combustion dynamics, and the squish effect is important for optimizing gas flow, swirl, and minimizing detonation.
Yep, just as I thought, you are literally doing the exact same thing that I tried to do, for the exact same reasons

That said, the reason why, for all your questions, is because the LS pistons have a compression height of 6 mm less than the stock. The 158 mm rods make up that difference. B23 rods wont-work because they're too short, and they are set up for the wrong size connecting rod journal. The B23 pistons have a significantly larger compression height, something along the lines of 44.7 mm. No other combination lines up as perfectly as 158 mm rods with LS pistons. The only exception would be using B23 pistons with custom rods that don't currently exist, since the b23 pistons are pretty heavy.
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Old 11-22-2022, 04:16 AM   #6
Andy Somogyi
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Yep, just as I thought, you are literally doing the exact same thing that I tried to do, for the exact same reasons

That said, the reason why, for all your questions, is because the LS pistons have a compression height of 6 mm less than the stock. The 158 mm rods make up that difference. B23 rods wont-work because they're too short, and they are set up for the wrong size connecting rod journal. The B23 pistons have a significantly larger compression height, something along the lines of 44.7 mm. No other combination lines up as perfectly as 158 mm rods with LS pistons. The only exception would be using B23 pistons with custom rods that don't currently exist, since the b23 pistons are pretty heavy.

Thanks for the info, I’ll look into it. Looks like Yoshifab has 158mm con rod, need to check wrist pin size.

I’ve got a B230 all ready to tear into, but I’ve got to get the B20 built, tuned and sold first

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Old 11-22-2022, 12:12 PM   #7
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Theres a nice set of new flat tops at JVAB, waiting to be used....contact John V
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Old 11-22-2022, 12:24 PM   #8
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Theres a nice set of new flat tops at JVAB, waiting to be used....contact John V
Actually Myles there are two (2) sets of forged CP pistons at 96,5mm bore and 39,7mm comp height for zero deck with 152mm rods and these pistons come with rebuilt 13mm rods at the big end and new bushes fort the .927" pins...

With a 49-50cc chamber this will get you 11,0 to 11,1 compression.

Din't you just PM me a price for a set of Wisecos for turbo motor at $785?

I'd sell these pistons AND the rods for that...

Could be in the mail today...Operators are standing by.
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