Also, looking at where the crack is, would the reinforced bars help?

its cracked in what i would call a strongish area..

So it's just a stub fitted to the water gallery opening through the block?

I'm certain that FEA on this DIY mod will show little to none improvement. Also as Marco has suggested it an extremely rare thing to happen I personally haven't seen a 20VT block crack like this. But then I think 2.5-3BAR boost is putting extreme cylinder pressure within this region.

i agree turboJ...
really high boost like 3bar would put stress on the bore!

but look at the phots.. its cracked it a weird place, it looks like its a good solid chunk of metal..
i expected it to crack in the middle of liner.

Simple physics - it's bending outside most at middle of the cooling hole, using the 'solid' points (sides of the hole) as 'pivots', so it's logical that's where they crack as there's a lot of tension there.

Looking back at the pictures though - http://i2.photobucket.com/albums/y39/TETEUS/Variados/blcrch.jpg - if you look at the 'sharp' part between the cylinders, the two holes at the right of the coolant hole we're talking about, there is quite some warping going on there - or are they all like that?

Marco the crack is at the expected place. My point is that I can't see the little stubs helping much if at all. The only thing I would suggest is a plate at the sump to stop twisting of the big ends but that's another issue. The solution I have seen is to reline the block with something less prone to fracture. I just can't find any pictures as an example on a closed deck block.

Oh sorry guys, i dont know that much about weak points on the engine blocks...

thanks!

TurboJ - have you actually read what I have typed? There's a huge gaping hole where say 20% of the cylinder lining sits next to and thus can bend. If you put extra supports there, it will distort less and thus will be less likely to crack. Of course it will add to the strength!

i think everyone here is missing the big picture look again at that block..admitttedly i am no expert but i have messed a lot with my race bikes look at the size of the squish.. look at the flat pistons and tell me how near deck hieght they are reaching you can see from the discolouration they have nearly and inch! like i say i know nothing compared to some of you guys but if that was my bike i know i would have trapped gasses sat waiting for next firing causing all sorts of issues and with high boost cylinder pressures would be bonkers..or am i completely wrong?..i know i couldn't run anything like that on a bike and thats all i know..and check those dyno graphs its flat lined un till 5k because of this set up then bang massive pressure to my admittedly limited knowledge and not knowing the technical terms i am probably not getting my point across well but if anyone else can grasp what i mean and explain it please do..

There is no proof of what pressure forces are going on within the cylinder at that time or how the forces are distributed against the cylinder wall. The crack is just a result of a failure but your not certain of the reason for the crack if it is bending, tension, compression or even cylinder pressure related.

I assume its just a piece of metal tube welded to the block. If that is the case what are the material properties of this piece added and the weld. I assume the piece wasn't cut out of an old fit block which means the material used can be anything. As you may be aware different materials behave in different ways so this piece added can have a complete different rate of thermal expansion and can cause an additional stress fracture to the current liner where it is positioned completely counteracting on what you are trying to prevent. Logically it seems like the right thing to do but you should consider everything I wouldn't like to say that because you have added a piece to a huge gap that it will be stronger.

You were questioning the 'why would it make it stronger'. I explained. Now as for your continued reasoning that is indeed a different story. But I would suspect someone who is doing this will have thought about that as well. In the pictures (admittedly a very bad point to start), the material used looks the same colour as the block. I would think these guys know what they're doing and if they have the basics right, they now indeed have a stronger block.

(Still, I'd be worried about cooling a bit, 20% of the holes are now filled.)

I found a post here:

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Main=34880&Number=429044#Post429044

Unfortnatly the pictures have now been removed. From my recall he re-done the liners in the proper manner.

The cooling is yet another issue that can be discussed you try to fix one problem then create another.

I'm surprised that none of the engine tuners/builders have spotted the obvious flaw in this engine setup.

I don't know much about the 20v lump, but FWIW it looks like a factory honing job on that cracked bore. ie an 100,000 miler.

O'right... this is where it gets interesting.

Hi Barbz, nice to hear that you are back again :-)))
Back to this engine failure:
I had some contact a few years ago with Mateus (MWT) - he has the strongest Marea in Brazil.
He told me that this failure was well known in Brazil at high power engines >>500HP.
Therefore in Brazil there is common to install this block guard or to install new stronger inliner. Then this problem is no problem any more.
I do not know why some people are discussing the sense of this modification. It helps definitely, we have the evidence in Brazil.
Last year I saw the first German car with this failure. Crack of first cylinder (I think) at the same position with GT30-turbo (I have pics on my other laptop).
My tuner Hartmut Lohman told me that this modification is common at a lot of Japanese cars, moreover I asked my professors for combustion engines in my university. They ALL stated to me this is an interesting modification, which ALSO will help to reduce blowby!
Therefore - install it, if engine is open.
Juergen

Hello Stichl, thanks. Good to see your positive contributions on the forum as usual.

I understand your concerns but there is a clear problem with their setup which is causing block failiures. They need to look carefully at there piston design and piston to deck clearances, without giving too much away. Having said that i can see the added benefit of a liner brace.
My coupe was running 1.8bar, 100hp of nitrous, producing over 500ft with no issues at all.

Gearbox strengthening is being taken care of, in fact a more robust solution is being developed.

Has anyone had a look at their dyno runs and graph?

The jap cars you are probably thinking of are hondas, but they are a completly different block design and layout to fiats.

Care to expand on that a little ?

MAHOOSIVE

Hi my friends, :-)

last year I had a 2.0 20vt engine,and was using a precision turbo mor or less gt35r and was making a maximum pressure of 1.4 at 7900rpm and it happened in 3rd speed...
Please see the photos on my block:

1ºcylinder:
[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/30062010474.jpg[/IMG]

4º cylinder
[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/30062010476.jpg[/IMG]

5º cylinder:
[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/30062010475.jpg[/IMG]

3 cylinders literally cracked :-(,pistons were good...

now in my engine fiat stilo 2.4 20vt I did this work:
I think it has more security,and also want to use aquamist...

Please see the photos on my new block:

[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/12082010248.jpg[/IMG]

[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/12082010246.jpg[/IMG]

[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/12082010244.jpg[/IMG]

I want to make more than 600hp in the new block....please people give me your opinion..

cheers

Carlos Vieira

Encosed you will find the pics regarding block guards...

http://www.gmx.de/mc/dXyq718Ioa7V5mUHjAktGKaDkOKnmq

Press button "gmx media center starten"

Ps: standard minimum deck clearance is 0,8mm - thus I had to shorten my pistons to get this clearance.
Take the piston and measure protruding to the block.
original gasket has 1,6mm.
maximum clearance needed is 0,8mm -> 1,6mm - 0,8mm = 0,8mm.
Maximum allowed protruding of the pistons is 0,8mm.
If not available, you have to skim the pistons...

I hope that the brazil guys did consider this...

Ciao
Juergen

Hi Carlos,

interesting to see - it seems to be a similar failure to the failures, I know.
It is the maximum cylinder pressure, which kills the block. This maximum pressure occurs at the maximum torque and can rise (at high-performance Turbo-Otto-engines) to the pressure, modern diesel engines gain (up to 200bar!!!) - it seems that a torque of about 600NM seems to be the maximum load for the standard Fiat block.

http://www.mintelonline.de/Dokumente/Technikerschule/Ringvorlesung/Ringvorlesung_ZKG.pdf

Unfortunately this pdf is in German language – please have a look to page 6 – this shows in a pic a typical elastic deformation, which can lead to a fatigue break etc…

hi Juergen...

so what you're saying is that the block was gone, because he was already fatigued...that his reasoning was good because can also be an important detail,and I had not seen this problem this way,although he only had 80,000 km but 11 years have passed...well seen Juergen :-)
tell me your opinion about my work in new block 2.5 20vt

thanks..

Carlos, welcome to FCCUK pal.

Very interesting info, many thanks.

to those with not a so good understanding, the block guard just shifts the load path of the liner to the external block which is square & reduces the stress on the liner / block interface.

I assume the liners are shrunk into the cast block at manufacture, the bored, honed.

As per Barbs previous comments, the piston deck / clearance was odd, however this is a known "weakness", considering you are approaching 600NM / 600hp.

prepare for the unexpected

Hello Carlos,
I find your solution very well done...
maybe better than my solution...
What oversize did you use for the pins to mount it solid into block?! Did you re-measure roundness afterwards?!
I had to realize that my block changed dimenstion / roundness up to 2/10mm measured from wall (with press-fitted pin beyond) to other wall (with pressfitted pin beyond).
I did not use much force to mount it - therefore I was quite amazed about this 2/10mm.
Therfore I had to realize that reboring afterwards is very important...
Juergen

I do not think that the original liners are shrunk. From my opinion they are cast with complete block and bored afterwards...
Juergen

"cast with complete block" > that would surprise me.

hi juergen,

yes I divide the spaces between all the water holes,to be always with equally spaced,and to make the hole, I made a screw type system to be under pressure, and never loosen...well if you see the pictures, has holes with two screws,and other holes with 3 screws,because the area without reinforcement, was considerably larger...
[IMG]http://i1193.photobucket.com/albums/aa353/uel-24/12082010246.jpg[/IMG]
...you realize what I'm saying?
after all is done, measure the shirts of the block to know that as pistons had to buy!because the cylinder walls, got a little or nothing oval,that only the machine is that you can see,then I bought with the pistons measure 83.60mm,and then extend the cylinder walls for measures of new pistons,And now it's 100% right cylinder walls...was the 1st time that someone did this an engine fiat in Portugal...and now made another block for a friend of mine who asked me a 2.0 20vt engine :-]...
I think the job was well done,can I have problems in cooling water mor or less 15%, but also think I will have more security in the pressure turbo and also ignition...
to the power of this engine, I do not want to take risks...

carlos

Hi Taz,
thanks for the reception,

with the help of each other, we always know where we can improve...I've seen this thread and also the friend ktm, from the beginning,I thought I should discuss with you all, what happened my old block, and the new block!My intention is to avoid it happening again to someone, what happened to me,because this is very sad...

yes it is already a deficiency of origin this block,and my intention is to improve a little security,and also know it is not 100% sure, but it's safer that is :-)

Carlos