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

[androo007]

Fair enough.

Found this, thought an interesting read

http://www.alltrac.net/phpBB2/viewtopic.php?t=44563

Obviously the Americans bloat out their numbers but still seems to be a theme.

That said all I can find is 1 camry for sale in London. ....complete car. Gah.

[craig]

When my block cracked I just accepted it. I didn't think twice about just swapping my block out for another rev3 turbo block.

I've owned mk2 turbos since 2004 and this is the first cracked block I've had. Just one of them things.

[jimGTS]

find a rev4+ block

[androo007]

Thanks for the advice gents. I decided to go for a rev 2 bottom end after all, just to eliminate any small chances that there *may* be.

Ps Craig, when you're up at Peters, do me a favour and see what exhaust I have will you? It's a JASMA stamped one looks v similar or same as japspeed/greedy. Had a v quick listen to the japspeed on yours and now I'm tempted to get one!!

[craig]

No prob mate.

[androo007]

Thanks dude.....if you really like mine and are still after a jap one I might be able to be convinced to swap

[Dale_V]

Thanks for the advice gents. I decided to go for a rev 2 bottom end after all, just to eliminate any small chances that there *may* be.

youve eliminated nothing by getting a rev 2 block

the only way to minimise suffering of a cracked block is to go rev5, as they have extra meat around the water pump... but you still have the issue of it cracking in the bores

rev2 blocks... cracking in both places are still on the cards.

[androo007]

Yes, but it's well documented a number of rev 3 blocks are weaker than the others.

All it does is reduce those odds in my favour. Yes there are the usual small risks but reduced.

I'd be interested to see who has cracked sub 500bhp rev 1-2 blocks vs 3 in addition to the ones mentioned here

[craig]

Thanks dude.....if you really like mine and are still after a jap one I might be able to be convinced to swap

Get one bought mate, they're cheap enough.

[androo007]

Thinking more about this, the cast iron that's used on these blocks are considered really strong. This leads to....

1) over boiling - creating bubbles and cooling inefficiencies.... hey presto, crack

2) long warm up time - giving it the beans and stock thermostat opening causing a gush of cold water to enter the hot block - crack. Anyone monitor water temp from the rad rather than block?

Note there is a water channel between 2/3 iirc.

Therefore my preventative methods will include:

Radiator temp sensor
Water wetter
Higher performance rad

[Odin_S]

I still don't buy rev 4+ are better it's more the fact there are more rev 3 blocks out there and the blocks are newer.

How many high powered rev 4-5 turbos are there out there as oppose to rev 3?

Like a previous post said the only way to conclusively say is to get say 20 blocks of rev 3 and 20 of rev 4 etc then do some NDT e.g. ultrasonic testing. Less than this is just anecdotal and speculation. Toyota never documented adding anything to the block for rev 4+ could be wrong.

[raptor95GTS]

or just get a 5S block and be done with it

[androo007]

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.

[raptor95GTS]

yep but if you're going for power and the block breaks, how much is that to get another one done? I know it's a lot of money but sometimes it's not any cheaper doing it twice. I've read a few folks having built engines and the damned thing has split double quick time.

[androo007]

Yeah, I guess it's pot luck. If it does then new block machining and a days labour to swap, along with gaskets and rings. Not that bad tbh so not too concerned.

In the meantime I'm trying to find a 5sfe anyway, just incase but only if luck happens..... I really am not that concerned

[Odin_S]

I still think 5S-FE is the new silver bullet to mask bad tuning. I remember when sleeving the block was the silver bullet now noone does this any more.

I've seen on MR2OC in the US a 5S block fail so it is possible

[androo007]

Yeah, I've done an awful lot of reading up on it recently. Ultimately I think it is partially pot luck....a number of blocks were badly cast, and contained flaws.... we know that. We also know this was mainly the Rev 3 era.

Water pump cracks are 500hp + cars - if you're going for that power yes a 5s makes sense regardless. 2/3 cracks aren't that common but does happen. Unlucky if it does but can happen anywhere. rev 3 more subjective to it.

Essentially:

If under 50pbhp go 3s
Keep a good conservative tune
Use WI

[blogsy]

Read this on another Forum. The guy is not allowed to talk on this one.

"Not many people know these exist but are fully aware about the Caldina and 5s-fe block upgrade to the 3sgte block found in the ST205. 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), But also a total redesign around the #1 head stud above the water pump as this is also a common crack centre.

People who have tried to use these with great success, in both the GT4 and MR2 world, I have not yet heard of a Caldina or 5s block cracking because of these improvements. The only down side is they take modifications to get them to work with the st205. Mainly the oil cooler area where the block either needed to be drilled out and other holes tapped. 5s for example didn't have the piston cooling oil squirter's either so these would need to be machined into the 5s to bring it up to the normal st205 3sgte specification level.

Well I have a very short number of these blocks from a special supplier of mine Its direct from Japan and they are ST205 blocks but with the material and
re-enforcement upgrades of the Caldina. So all the benefits but a direct replacement for the st205, no modifications needed for oil cooler or the squirter's.

Not many people know about there existence but its a bit of a fluke. When the st205 was discontinued so too was the engine block. The Calinda block had a totally new redesign around the 3s frame. The blocks are basically the same but they are drilled differently for the Calinda application. Because of the 10 year law Toyota has to produce all parts for there cars for 10 years after they have stopped production. So by law Toyota had to be able to supply the st205 engine block. But to save money instead of running 2 castings (st205 and newer Calinda) they just cast one type the new Caldina, but were drilled to be a direct replacement for the st205. There wasn't a part number change it was just a way of streamlining the production run. The older style 3s although still had the same part number were shipped out to overseas dealerships and warehouses, Belgium being the main Toyota warehouse, but Japan started stocking these new re-enforced items. I have enquired in Japan about sourcing new blocks but the 10 year rule has passed and they have stopped producing these blocks now. And any blocks purchased outside of Japan get the older weaker style versions because of the huge old stockpile. Buying a new ST205 block from Japan you will again get the older weaker style version because the new stronger type is now sold out and instead of just redrilling a new batch of Caldina 3sgte's which are still in production they are bringing back ST205 3sgte blocks back from overseas dealerships to meet demand on the home islands.

So to obtain these you have to be in a unique circumstance where you the ST205 engine had failed in Japan after 1999-2000 and was replaced with a new factory engine, This has to be done prior to import as only Japan got these engine blocks. And before 2009 because they stopped production because of the 10 year law. Replacements after that will be hit and miss depending what was left over in the warehouse.

I have been buying these up from my contact in Japan when they have come up. They do sometimes happen in cars found over here but its the same as described above that the engine was replaced in Japan and then the car imported to the UK. I have seen 2 so far inside the UK, so very rare. and can only be found in JDM imported cars

[androo007]

Ah yes read that. Cods wallop imho.

I'm sure it's a case of the minority shouting when it goes wrong but majority goes well.... and a bit of luck. Speaking to 2 specialist mr2 builders both say it's v rare and that's coming from people that build them day in day out.

[C35Rob]

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?