[Mk2] [Turbo] Cracked block anyone?

[royashmr2]

Question for all you big power guys.
Have you suffered from cracked blocks, between 2 and 3?

I've done 2 now. I ran with it at totb incase anyone wondered where my good times where. lol

What have you done about it?

Any help would be great.

Roy

[karammander]

i think the only way to get rid of that is sleeving and a good tune.

cheers karam

[royashmr2]

The first block I did was sleeved. See some of the posts in totb.

That went big time. Was it a bad sleeve? God knows.

[^Trickster^]

Peronally I think its 80% in the tune, and the other 20% is if your unlucky enough to have a extremely thin/weak cylinder.

Some people run a low temp stat and a 1.3bar rad cap as this reduces the boiling inbetween 2/3 which some people believe to be the cause of the cracking.

Truth is youll never really know whay yours has gone exactly.

Just very unlucky I think, id personally never run a sleeved block like, I just dont like the idea, id rather run an original casted one.

Graeme

[Century Motorsport]

It really is the luck of the draw.

You can sleeve it and should be ok but look what happened to my block which was sleeved - it cracked on the outside, caused by block fatigue.

Water wetter is a good idea, on big motors pull the thermostat out and make sure you give the motor a good space between dyno runs.

Its the constant heat cycles that seems to contribute most to cracking, but if you have a bad block its just a ticking time bomb and no build / tune will make any difference.

Nathan

[greeny]

what size pistons you running royash?

[2barGee]

I cracked mine directly over the water way I was runnig 87 mm pistons at around the 450 bhp mark.

I guess its luck of the draw where it goes in the end.

[larry93]

Have you tried this Roy ?

http://www.twosrus.com/catalog/product_ ... cts_id=297

not sure who has ?. might help ?

[royashmr2]

what size pistons you running royash?

There HKS ones 87 mm. I know its not ment to be good for them borin the block this much. but thats the size for the 2.2. Correct me if i'm wrong.

[royashmr2]

Have you tried this Roy ?

http://www.twosrus.com/catalog/product_ ... cts_id=297

not sure who has ?. might help ?

I've looked at this before but have never seen of heard of anyone runnin one. Would love to hear what people have to say

[Lee @ 3S Service Centre]

why dont you just build your engine from a rev 2 block? i cant remember a case of a rev 2 block failing.

[royashmr2]

why dont you just build your engine from a rev 2 block? i cant remember a case of a rev 2 block failing.

Yeah I've broken one of them. Thats just a myth about rev3 and rev2. Just most people mod the rev3 block. So they always seem to go wrong,

Just in talks with Darton for some sleeves. But still don't know if I want to run them.

Toysport do some nice blocks. But they want $35000 for 1 of them! lol

[greeny]

what size pistons you running royash?

There HKS ones 87 mm. I know its not ment to be good for them borin the block this much. but thats the size for the 2.2. Correct me if i'm wrong.

Same here!

Im running tysons block girdle, mine hasnt cracket yet (1.7bar on 99oct fuel), although i think your running a bit more power than me. we'l see what happens when the race fuel goes through it and 2bar.

If/when mine cracks, the only way id go is with the 2.2 5sfe block, Its standard with 87mm bore, so it would be finding one with great walls and a hone and new rings.

The only thing is theres no provision for oil squirters to keep the pistons cool, although i believe rogue machined some into the block on there 5s builds IIRC?? Patrick correct me if im wrong?

Apparently HKS did do the same pistons but 86mm bore, although this is what i got told, ive never seen any

[Andy F]

Im guessing Royasmr2 was running 2 bar +??
This is the point where the car really starts to come on song...but the weak points will be found pretty soon.
Bad luck fella

[greeny]

Im guessing Royasmr2 was running 2 bar +??
This is the point where the car really starts to come on song...but the weak points will be found pretty soon.
Bad luck fella

Your running 2bar+ arent you andy?

What block/size pistons you on?

[Andy F]

Hi Michael
Rev1 block and 86.5s
I have made a couple of changes to the car, so will be going for another map session soon, im aiming for 2.3/4 bar this time so who knows i could be in the split block club soon LOL
Group A block is the way forward, and i may have found one

[scotiamr2t]

Hi Michael
Rev1 block and 86.5s
I have made a couple of changes to the car, so will be going for another map session soon, im aiming for 2.3/4 bar this time so who knows i could be in the split block club soon LOL
Group A block is the way forward, and i may have found one

Jammy git if you have found one i've been on the hunt for one for god knows how long! Need to stick some pics up if you do get a hold of one.

[Andy F]

will do mate, but they look just the same...

[Gary ST165]

its been suggested on other 3sgte based forums, that the sudden surge of the thermostat opening can cause blocks to crack...

oil and water temps should be within 10 degrees celcius of each other.
hence a surge of cold water will cause the cylinder walls in contact with the engine coolant to contract at a faster rate than the material on the oil gallery side. this will can cause stress to the crystaline structure of the block...and may cause cracking.

race cars usually run a restrictor in place of the thermostat, and an additional electric water pump to recirculate the coolant after the ignition is switched off. the electric pump should in theory prevent localised hot spots where water temps can rise rapidly within the block and boil, especially after turning the engine off.


from what i have researched the ST185 TTE Group A blocks are cast of different material. there are a few visual differences from the standard rev1&2 blocks

[Andy F]