after my block cracked i decided to invest in a ultrasonic thickness gauge to allow me to measure the thickness of these so called thin, thick wall blocks to see if there was a difference in my block.

i measured two blocks 1 1994 wrc block and a 2004 Toyota bought block and the results were almost identical, there is no noticeable difference, if anything the 1994 block is ever so slightly thicker !!!!!

I still think there many of been a batch of early blocks with issues but i don’t think for a second this is epidemic to all early blocks i think this affect very few blocks, ive certainly only seen two blocks in all of the 3s-gte engines ive rebuilt that i would term to have had manufacturing inadequacies that caused them to fail

hence the reason i am 99% convinced my failure was due to distortion.

the results from the small test i did are below.

i have currently sent off a block to a specialist company who test bed blocks for manufacturers, i am getting them to do cylinder wall distortion mapping, and basically destroy the block to see if they can figure out were the weak points lie.

£4000 later i just hope they don’t come back to me and say sorry, the block is inherently floored and there’s no way of reliably running big power through this engine.

i will keep anyone interested in there findings informed, and hopefully we will find a definitive answer and solution.

Ian, What power figures were you running prior to your failure? I dont recall reading any of block failure postings over the past three years with engines running normal/stage1&2 loads and owners not totally abusing the engine. The pro team have had several but that was with massive power expectancy Very interesting reading tho.

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Le Latern Rouge...300ish bhp 13.8 1/4
more to come... gonna love track days.

Blimey Ian, How much did that little toy cost? I had a brief look at these items and had to get someone to pick me back up off the floor. Excellent info m8, nice to see it being shared for all to see. Awaiting some info on the 3sgte weakness areas.

So does thsi mean you are offering an ultrasonic testing facility now too?

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

624bhp and 474 ft/lbs on road fuel @ 1.8 bar, do those figures give me the right to be classed as a pro(stitue) Ive personally seen 2 completely stock engines that have cracked out of the hundreds ive rebuilt.

Dont ask m8, lets just say i am not happy to lie down and accept that 2 or 3 rebuilds a year are acceptable, once a year off season is fine, my engine will not be touched untill i find the cause and a cure to the problems, and yes i can ultrasonically test blocks if anyone wants me to m8

Ian - some great info there.

From what I recall the problem with the thin/think block is most apparent between No2 & No3, approx 25mm down from the top of the block. This I believe is where the 2 cyliners seperate to allow water to flow around the cylinders.

Incidentally I hear that very occasionally approx 25mm down on No4 is also prone to a little "thinning"

I too feel that it's the luck of the draw regarding the blocks and a new block/part number is no gaurantee on the thickness of the block.

I ultrasounded mine with 2 seperate bits of kit to help ensure that the readings were accurate and comparable, (they were).

I have the figures somewhere and from memory at the thinnest point, (25m down between No2 and No3), the wall of each cylinder measured approx 4mm

Note that the affected area seems to be of a very small nature and is very easy to miss

Have you thought about a ladder type brace on the mains to e.g. the block wall and each other? Have seen this typre of setup on other high powered engines.

Also as Mr Datajon KEEPS mentioning, it seems common practice to bolt the head to the block with VERY long bolts that pass all the way down to the mains area to help clamp the engine block to the head, and not just the top 25mm of the block to the head

Look forward to hearing the results of all this testing

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

yeah as with the diagram above this also indicates the thinnest area of the block is approx 20 to 30mm down in between the two cylinders, but i honestly don’t believe this alone is a weak point.

i just need to call on jon to see if there’s anything he can do to aid in the long hardware to tie the head and block, and a crank girdle is already in the pipelines

but what i really want is a definitive (or close as possible) answer to what the true cause is, what combination of circumstances cause the failures, and what’s possible to prevent the cracking from occurring.

my main concern is i have never seen a block crack in the area mine has or to the magnitude of this crack, i need to be 100% sure that i am aiming for right causes before i look for solutions, hence the silly amount of money being thrown at professional block distortion mapping, and the chopping up of a good block.

Unfortunately i haven’t got the time or finances to throw in 2 or 3 rebuilds a year just to keep it running at 600+ bhp as others do, doing this means its defeated us and we are just resound to the fact that the 3s-gte block cant run 600 + bhp with a reasonable amount of longevity.

Ian, huge thanks for sharing this info with us Makes a nice change from the 'secret squirrel' approach that many have
I don't suppose you've had a chance to take the engine out yet have you? Some pics of the crack or region where your failure occurred would be very interesting.

You may be interested in the following info from 'The History of the Turbocharged Racing Car' in the context of the Toyota Group C Le Mans Sports Prototypes. The Toyota 87C ran a '3S-GTM' engine which developed up to 900bhp on the bench (Race Spec: 680bhp@8,500rpm and 470lb/ft@5,500rpm) however a spate of cylinder bore cracking arose early in '87 and prior to Le Mans a new block casting was introduced with a 2mm greater wall thickness to cure the problem. They also had early headaches with the valve seats but this was cured by using a 'special, undisclosed material developed by Toyota'. This engine ran in '87 and '88 and was probably the ultimate development by Toyota of the turbocharged four cylinder.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Ian,

I don't really have any comments at the moment - but thanks very much for taking the time to share this with us.

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GT4DC Events Co-ordinator
1996 ST205 UK

Ian;

Don't know if this would be of interest to you but a guy on MR2OC has developed a 4130 chrome moly girdle that bolts between the block and the sump, and to all the main caps to aid with exactly this issue

He's just announced a price of $550 for the girdle, main cap spacers and spacers - for the oil pickup for example, and ARP studs.

http://www.mr2oc.com/showthread.php?t=2 ... ge=4&pp=30

Should definately help with the stress from horizontal forces...

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"The gene pool could use a little chlorine..."

Need to be a member to get on there SB kido

Cheers for this info Ian, I would love to hear the outcome, although I never plan to run the figures you are I would love to run a stable & very reliable circa 400

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ST205 WRC #0002249

It's free to join and is an excellent technical resource IMHO

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"The gene pool could use a little chlorine..."

See http://www.supras.nl/phpBB2/viewtopic.php?t=4341 for a Dutch monster 3S-GTE project incl girdle pics.. If you want a translation in understandable English (since Babelfish often messes the grammar up) just let me know what part..

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René - Carlos Sainz 2433•5000
Turbocelica.nl | ST185 CS restoration and full rebuild

If it ain't broken.. it soon will be

thanks meurz, a translation would be good, has he ran the girdle for a while with any sucess ? or is it something hes just about to try ?


tia

The two girdles are different.

The US girdle;


The Dutch girdle;


The US girdle is bolted to the main bearing caps and block, the Dutch one is only bolted to the main bearing caps.
Which is better?
Who makes the Dutch one?

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1991 Jap ST185A
ST205 Head Gasket.
Some random RV & no-name BOV
Blitz Nur-spec SS backbox
Apexi Air Filter

ST205 Front Calipers - Yes, really!