Cracked B230 cylinder, best way to prevent in future

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linuxman51
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Cracked B230 cylinder, best way to prevent in future

Inlägg av linuxman51 »

First, the engine setup:
E-85
2.5L 16v FS324 cams HX-52, nitrous(why not), ~9:1 compression ratio (or possibly lower). 96.5mm bore size.
block is 1995 b230f

Running about 35psi when it broke, Ethanol percentage has been steady at 75% for the past tank and a half of fuel, about 17 degrees of ignition timing up top(crept up to that via tuning at the track). ~.78 lambda. Max rpm's 8100. Stock valve size, but ported head. (not that that matters for this)
Car traps 133mph off the spray, and 142mph on the spray
Block was pinned.

When it likely cracked: 34psi, 17degrees, and ~.95 lambda. I think injector, because only #3 showed any signs of trouble. 1,2,4 all looked good, plugs looked good when the head came off.

I had an issue (suspect faulty injector) sunday at the race that resulted in problems with the #3 cylinder, with it finally cracking up to the deck (don't know how far down the crack goes, haven't gotten the block out of the car). In reading other threads here on Savar, I've noticed two things:

96.5mm bore size may be "too big" for the power level I'm at and the power levels I'm hoping to get to, and

Pistons did not have a 'full skirt'

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So, my question is this: Is it better to sleeve a block, perhaps to a slightly smaller bore size (say, 94 or 95mm) and retain the cooling system and perhaps run a little tighter piston to wall clearance, OR

fill the block with hard-blok and run whatever pistons fit with minimal machine work to the bores? I've seen talk of 2-3cm from the top, with tubes for coolant, but I'm having a hard time picturing this. Are there any photos of this process?

Is there anything else I need to consider/do with the block? It may eventually get to 900-1000hp, but I'm in no rush to see those numbers yet.

The engine went out on a high note, I outran an F1x procharged 2015 viper at a roll race event 8)
https://youtu.be/1tuFK_EGNGc

only have a few pictures right now, perhaps something else jumps out.
Bild

Bild

(and yes, no roll cage. that's also on the summer project list along with switching to a wagon chassis)
1990 740 gl
2003 Evo 8
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Re: Cracked B230 cylinder, best way to prevent in future

Inlägg av Performance_seeker »

Sorry, can't help you with your engine questions but your Volvo does sound good!! :thumbright:
Martin, Mopar 512 cui, E85, MegaSquirt MS3X fully sequential ign. & inj.
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Kadett4wd
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Re: Cracked B230 cylinder, best way to prevent in future

Inlägg av Kadett4wd »

Many guys in Sweden have cracked their blocks using non fullskirt pistons.
I´m not a very very good volvotuner, but there´s a lot to read about that on this board.
///AMG
Att jag blir tyst i långvariga oeniga diskussioner beror OFTAST på att det inte är lönt diskutera längre, inte att ni hade rätt :D
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linuxman51
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Re: Cracked B230 cylinder, best way to prevent in future

Inlägg av linuxman51 »

Yeah I've been reading about that. The pistons I get for the next block will be full skirt
1990 740 gl
2003 Evo 8
HenrikGM
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Re: Cracked B230 cylinder, best way to prevent in future

Inlägg av HenrikGM »

We have cracked 2 blocks with oem volvo pistons also. Stock bore.

It stopped completely once we started using concrete fill in the block.
As tall as 35mm below deck has been tried, without runniing into cooling problems.
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