This is a copy and paste from the GT4 forum that I put in a thread a while back regarding the thin thick walled issues

- from Adrian at Fennies point of view.

I'm not saying this is gospel or necessarily correct, but since they build loads of these engines its probably relevant.

BUT- notice that towards the final paragraphs, they rejected some ST185 blocks as well,

= rev 1/2 blocks.

However, only toyota will know if the blocks are the same for JDM stuff as for UK.

We know there are variations in heads for EGR etc.

"""Just to reiterate

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Toyota have changed the part numbers for the 205 block, they nor TTE or TRD or anyone else will admit to there being a problem on some blocks.

The problem is generally between 2&3 cylinder although we have recently found thin areas at the rear of no4.

A thick wall block will be between 150-160 thou thick, and a thin one will be approx 110 thou.

Now the problem comes when you ask

"how thick for how much BHP"

This is not an easy question to answer, my advice is don`t build any block less than 140thou unless its going to be left standard.

Measuring the block is not at all easy, best use an engineer who can ultrasound test the average thickness

- I say average as

- If you imagine the outer side of the cylinder is not uniform.

450whp is approx 570 flywheel which is big power in my book, I would not use any bigger than 86.25 bore on a thicker type block.

TTE group A blocks are fine, but hard to get hold of, and very expensive as you`ll need special pistons as well, the block is 3mm lower deck height.

I use a standard block as I don`t beleive tte one is the right approach for us, for one they will run out

- then what do we all do? For another the expense.

Only last week we rejected two ST185 blocks for rebuild, 1 was 120thou, and the other 110 thou, this was particularily annoying as I thought they were all ok

- just shows you trust no-one, and measure everything.

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Hopefully that`ll save some expensive mistakes!!!

Some people don`t believe what we say

- they think we make it up to sell blocks

- all I can tell you is what I have found

- the rest is up to you.

Regards

Adrian

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