[Mk2] [Turbo] Cracked blocks – should I be worried?

[Odin_S]

The upgrades address a cracking issue by using a different material mixture during the casting process to make the block less brittle (flex more than crack)

right,

this is touted around so much on the internet, I'm not disputing/arguing/whatever that blocks do crack, because it's clear to see that people have cracked them, across all revisions, at all power levels, or that the casting was changed around the water pump area because that's plain to see

but

where, other than re-quoting anecdotal evidence from various forum posts, is there hard conclusive evidence that toyota actually changed the composition of the iron used in the blocks to increase the ductility of the material? because it's not your usual press release kind of stuff is it?

My point exactly, the internet can be an unhelpful friend as people with problems usual get heard the most.

Not to say there isn't a problem, but i think most cracking is down to detonation.

Even running a standard CT20b and ecu can cause detonation if boost is raised. Hense why we come back to how the car is tuned.

Any blocks cracked running standard boost?

[gnzyza]

Did Toyota cast blocks in house?

One thing is for sure blocks do crack, I'm not a metallurgical expert but would think it would be due to det or sudden thermal changes so its worth factoring into your tune /build.

[Ryan S]

Total rubbish. Rev3 block is as good as any. Does anyone remember Chris' car? 635bhp rev3 block with standard rods and cams (IIRC). Chris also reckoned the cracking was down to bad tuning. Also, I know of a stock GT4 (not a single mod) that cracked a block. It was a st185 i think so it really can happen at any power level

[Martin F]

Total rubbish. Rev3 block is as good as any. Does anyone remember Chris' car? 635bhp rev3 block with standard rods and cams (IIRC). Chris also reckoned the cracking was down to bad tuning. Also, I know of a stock GT4 (not a single mod) that cracked a block. It was a st185 i think so it really can happen at any power level

Agree, If it's going to happen then it's going to happen, You may think higher power is going to increase the chances but one or two blocks out there fail at low power levels as well, it may well be tune related but imo it's the luck of the draw....

Taking everything into consideration Toyota did a pretty good job with the quality of parts for the sw20.

I have seen and heard of many more major issues with other performance cars and even newer cars....

[greeny]

That's true.

Raptor easy to say....if you have another 1200 to add to the build cost plus the ability of getting hold of a late 5s to begin with.

Anyway I'm happy and sure with my decisions so full steam ahead.

Why does a 5s block build add 1200 + the block?

Everything 3s will drop into a 5s block apart from squirters/oil cooler and rear crank seal.

96+ 5s blocks are the strongest and you start with a 87mm bore.

If you want to run a 3s block, get a 96+ 3s block and sleeve it.

Caldinas are just the same as the late 3s blocks, reinforced corner but still 86mm bores and weaker walls than 5s.

Beams blocks have the same revisions to the blocks as Above.