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Engine rebuild, what block?
http://www.gt4dc.co.uk/forum/viewtopic.php?f=13&t=6113		 Page 1 of 1
Author:  donna [ Tue Dec 04, 2012 10:25 pm ]
Post subject:  Engine rebuild, what block?
Hi all,

I've been tossing up if to go forged or not for a long time now. At first I thought it was way to expensive but i have now found some one who can offer me a build at a more reasonable price.

Now my question is can the st205 block handle power around the 400ish mark? I've been looking around and found may stories of these cracking under high torque.

Is there a stronger block that can be used easily?
I've heard that the 185 block is stronger is this true. If so I've been offered one for £80. I'm not sure what condition it's in yet. Im sure if it's in good nick and I don't use it one of you guys might want it :D
Author:  dale [ Tue Dec 04, 2012 11:09 pm ]
Post subject: 
my brothers runs more than that for over 10k miles, i think around 15k and has run flawelessy with some serious abuse on track at 2bar boost so i would say if its built right and tested prior to the build there should be no problems. :)
Author:  TrackToyFour [ Tue Dec 04, 2012 11:45 pm ]
Post subject: 
If you already have a block then check out the the link below on the http://www.gtfours.co.uk menu. If you don't have a block then its almost pot luck what you might get unless you buy it subject to bore wall thickness measurement.

On the GTFours web site use the menu on the left hand side to select: What is -> Thick 205 cylinder block

Unfortunately its not possible to link directly to the page.

Here's a taster below:

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Author:  donna [ Thu Dec 06, 2012 7:53 pm ]
Post subject: 
Thanks for the info guys.

I hear it depends on the build and the cooling of the car to reduce the risk of the cracking.

What cooling mods are best to keep the temps down.
I'm guessing FMIC and swirl pot. Anything else that should be added to the list?
Author:  andycaca [ Thu Dec 06, 2012 8:17 pm ]
Post subject: 
a davies craig electric water pump controlled either by the ecu or standalone controller will also help.

having sealed ducting to the engine radiator and FMIC will force cooling air through the radiators instead of escaping around the side.

i ragged my car for approx 20 minutes on track a few weeks ago (its built as a sprint car, 2 mins max usually) and although the turbo was glowing red when i came in, engine temps were still under 100c.

the EWP will help with circulating the coolant when the engine is turned off (keep the rad fans going tho), a critical period i think. i dont like to hear coolant boiling in the block!

edit: i tend not to overrev my car unless its crucial, such as hanging onto a gear longer whilst exiting a corner. apparently the water pump cavitates (forms bubbles) when its speed gets too high. if i were to routinely rev my car over 7000 i would definitely ditch the standard water pump and rely on the EWP.
Author:  Nibbles [ Thu Dec 06, 2012 8:53 pm ]
Post subject: 
IMO going for a pressurised header tank system is more important than having a swirl pot. This maintains pressure as the engine cools down to prevent localised boiling. From experience of a swirl pot on a friends st205, it was an absolute pain to get water to flow though it as it just airlocked. Once bled (by undoing pipes) it worked ok. It would worry me what would happen in the event of a small leak as it's not self bleeding.

Alternative is to use evans coolant with a much higher boiling point. I have heard this is not so good at conducting heat as water / antifreeze mix.

There has been much debate about both cracking and water systems on here, worth some searching.

e.g.
http://www.gt4dc.co.uk/forum/viewtopic. ... eader+tank

http://www.gt4dc.co.uk/forum/viewtopic. ... eader+tank

http://www.gt4dc.co.uk/forum/viewtopic. ... block+wall

http://www.gt4dc.co.uk/forum/viewtopic. ... block+wall

http://www.gt4dc.co.uk/forum/viewtopic. ... block+wall
Author:  donna [ Sat Dec 08, 2012 9:31 am ]
Post subject: 
That certainly gives me a lot to think about.

Thanks Chris, I have seen some of these links from searching around but not all of them. I thinks this is going to be a hard decision to make.
Author:  Nibbles [ Sat Dec 08, 2012 12:08 pm ]
Post subject: 
If you can do the work yourself, just changing block if it fails isn't such a huge expense. About £150 for the rebore / hone plus cost of secondhand block. The rest is just a matter of swapping the bits over and double checking clearances as you go.
Going to an engine builder to do it is another matter though as they will probably want to do a full rebuild.
Author:  TBDevelopments [ Mon Dec 10, 2012 8:44 pm ]
Post subject: 
i've ultrasounded all my engine blocks and all st205 original engines are the same thickness within a few 0.1mm

There isn't really a thick/thin wall version out there.

Tim
TB Developments
Author:  TrackToyFour [ Tue Dec 11, 2012 1:01 am ]
Post subject: 
TBDevelopments wrote:
i've ultrasounded all my engine blocks and all st205 original engines are the same thickness within a few 0.1mm

There isn't really a thick/thin wall version out there.

Tim
TB Developments
That's because Adrian has grabbed them all Tim :wink: :lol:
Author:  TBDevelopments [ Tue Dec 11, 2012 1:06 am ]
Post subject: 
I doubt that lol i've built and measured hundreds of 3sgte's now and there is negligible difference.

Only version change you can get is engines replaced in Japan after 2000 typically come with the new re-enforced castings like the Calinda but drilled for st205 usage. Again these have the same thickness in the walls but have much more meat around the water pump head stud area. Also they have a different nickel content. So with the blocks being effectively caldina engines I've yet to see one of those crack.

i've managed to collect a little supply of these for my customers if there needed, have 7 so far

Tim
TB Developments
Author:  TrackToyFour [ Tue Dec 11, 2012 7:51 pm ]
Post subject: 
Very interesting! I presume the block you describe is the Gen 4 3S-GTE ST215 Caldina?

While we are on the subject there are a lot of stories going around that the Gen2 3S-GTE block as fitted to the ST185 is 'better'. Have you measured any of these blocks and found a difference?
Author:  TBDevelopments [ Wed Dec 12, 2012 2:56 am ]
Post subject: 
yes i have st185 again is no stronger than the st205 version as far as wall strength goes.

The calinda is the new gen4 3sgte casting with the re-enforcements but as you know there is also some differences that make it more difficult than a straight drop in, oil cooler etc being the main difference. The blocks i have are exactly the same as the caldina are factory drilled for the st205. They also have the same higher nickel content in them like the caldina to make them more pliable to flexing.
Author:  TBDevelopments [ Wed Dec 12, 2012 2:58 am ]
Post subject: 
This was a build i did a while back for a customer. Here you can see the st205 oil cooler threads etc but the extra meat on the water pump head stud.

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