yet again iv cracked number 3 cylinder on my focus cosworth block I'm running the old 205 blocks at .50 over size bore iv now got 2 of these blocks that are cracked. I no it's £220 to get a liner put down each of them but will a new liner with stand 400bhp or will they re crack . Has any one relined a 205 .
I do have a 200 block but that's for a futcher big BHP motor I'm working on

 

surely it depends on the liner material used.

A proper motorsport liner should be up to the job really

 

I had the same issue on a 205 at .5, to be running 100 hp per pot on a 205 on overbore is really just asking to much if it imo

 

liner all 4 and job done - should be stronger too

 

No problems with liners if done correctly.

Take a look at westwood liners.

Wonder what the deck height of a 1800 185 pinto block is?
Anyone used one?

 

I'd be more curious as to why it happened in the first place !!

 

you right there mate . But I have chatted to a lot of lads in the past about these blocks and it turned out number 3 is the most likely cylinder to fale when pushed to 400BHP

 

blimey .I stopping at stg3 then..

must be gutting to have it happen again

 

Do you know what the reasoning behind that is? A technical reason as to why #3 fails Or is it just a case of in peoples experience thats the weakest pot.
I have no idea why so that's why I'm asking. be interesting to understand why

 

Im hoping my 205 block will be alright as im hoping to get a fair bit more than 400bhp.

Is it something to do with the #3 not getting the same amount of flow as other cylinders?

Would a different inlet not fix that issue?

 

Something to do with strain of being 4wd maybe twist on the block below no 3 ?

 

I would either get a 200 block, get your 205 linered or go all out and get the Ally Smith and Jones which seems mega bucks but the cost of a good 200 block and having that checked and worked on is not cheap either.

over 400bhp costs a lot to do if you want it to be safe and if you crack a block then you have some big costs coming your way anyway at a time when you might not want it.

 

I didn’t think there was enough meat in the 205 block too fit proper liners that strengthen the block. Obviously you can sleeve them but that’s not the same

 

Ive got a 200 block engine here also but im keeping that for a bigger build and for the 3dr.

450bhp should be reliable enough in a 205 block if done right, although i am now also thinking of reworking the head whilst i have the opportunity

 

i think in a road car 400BHP is ok with a 205 block but I use the car in anger on track so it gets a hard life . And looking back at it the motor started to show sines that some thing was going rong when I last did Bedford auto drome .

 

A 205 asmatic used to crack number 3 cylinder normally through heating issues it is just luck of the draw . I wouldn't be pissing about with a 205 if a 200 is available

 

The problem is a 30yr old block that has corroded from the water jacket.
The 200 blocks crack across the stud face, the old 205s crack the bores when old.
The fix is using a spun ductile liner. If fitted correctly will resolve your problem with a known material at a known thickness.

Been there, done that. Still would not buy a 200 block.

 

Im not gentle with mine either and they will also get to see a track and countless full bore launches so it needs to be reliable.

If you have a 200 block available i would go with that - if not do what Markk says and get the proper liners

 

Why not mark?

 

how much does it cost mark to do it right with the spun ductile liners ?

 

In all my 24 yrs of YB ownership ive seen more cracked 200 blocks than 205 blocks.

 

Around £800.

 

so would probably work out cheaper than a 200 block

 

Was that including long studded blocks or where they all standard/arp bolts?

 

but a 200 with a crack across the stud holes works fine when long studded so why don't you like them?

some years ago there was a long thread on here comparing 205 v 200 blocks and one of the contributors was Karl Norris. He described in detail the weak points of each and iirc was generally in favour of 205

 

All depends on a persons budget. I’m going 680 on a 200 block with ductile liners lots about like that perfectly strong enough. Of course the alloy block is better but expensive plus I certainly couldn’t see the point of putting a 20 year old crank in one so would also cost me 3 grand for a crank

 

and probably stronger too

 

If people tend to push the boundaries on 200 block cars then it is likely that more of them would have cracked. I wonder if there are more 200 blocked high power cars out there? Maybe something to do with more being 4WD????

I was always under the impression that the 200 was the better block to go for when going big power but it is only from what I have read on here.

 

Only ever use std bolts.

Never had a failure in a rally car.

 

Oh yes, a cast engine block with cracks in the casting is just fine. Why did they bother to cast it solid in the first place then ?
Sorry, structural integrity has been compromised as soon as they crack.
Scrap only at that point.

 

Stick a zetec turbo in lol

 

Or a Honda engine !

 

I think it's been well proven a longstudded 200 block can handle crazy hp.

 

Definitely plus the torque number will be pushed well beyond what it is now soon enough

 

But mark says it's all bullshit had a word with Julian today and mentioned this thread and he thinks he could off mark work as he obviously knows more than him pmsl

 

maybe a minor impact upon structural integrity but its nonsense to say they're scrap - plenty of 200 blocks around which were long studded to circumvent a crack from the stud hole

 

In trying to make sense out of what you wrote their, you feel that I am incorrect?

 

Sorry I disagree. Once cast is cracked it has lost structural integrity.

There are way to try to rectify or to try to re-gain this but every way to exactly that, bodging up the failure.

I could wrap the whole thing in C20 concrete, that will stop the sides coming out of it, does that make it correct?

The correct way is to replace the broken part.

 

A hairline crack from the thread to the water jacket isn't uncommon to find when the head is removed, if its a 200 block then it can be saved by long studding, I've lost count of the amount of times I've done this over the years and its completely successful with no problems even on high power engines.

 

You are still working round the fact that the part failed.
The fix is to modify the original part to stop it cracking in the first place.
I have done several of these and non have then presented any cracks post mods.

A crack is a crack. The part has still failed.