Cossie head conversion

[dunc]

Hi all

I know that a cossie head fits direct onto pinto bottom end but how do you:-

1) Raise compression ie planning block height, skim head if so would you need to machine pistons?

2) Obviously the timing belt would have to be changed to cossie belt is there any other complications

All help much appreciated

Regards

Dunc

[Blatman]

You won't get the best out of a Cossie head unless you have a 205 block and a cossie crank and rods.

Raising compression is best done with a set of atmo pistons from Cosworth, but they are >£600..............Using standard Pinto pistons will hold the engine at a disadvantage.

Even with a standard turbo cossie engine, making it into an atmo version will cost well over a grand, and saddling it with pinto pistons/cranks and rods will only have you buying proper cossie atmo bits anyway when you want to get some decent power.

I turned a standard cossie turbo into an atmo 8 years ago, and it cost me around 1500 quid. I bought the atmo pistons described above, and went for mild cams. It gave 173bhp at the wheels.

I've just finished a power upgrade (to 240ish bhp hopefully) and I haven't had to think about the crank, rods or pistons, despite the new rev limit being somewhere above 8000rpm. All I've done is port the head, and swap the inlet cam.

[dunc]

Thanks Blatman

i thought you would reply to this

am i right in saying that if you use the std 205 block and rods you are limited to @6900 rpm and i am being told that this should give @150-160bhp

is this right?

[Blatman]

The 205 block is a pinto block, selected by Cosworth to become the heart of the Cossie YB engine. Any block designated 205 will be fine, it's the Cossie rods and crank you need. They are steel "as standard", and are safe to over 8000rpm. I would suggest keeping the pinto crank and rods below 7000rpm would be a good idea.

My first atmo was standard Cossie everything, apart from the pistons, which were Cosworth Atmo pistons, and a pair of BD3 cams. This gave 9.5-10 to 1 compression, and 173bhp at the wheels.

[jamie]

I think that the transit used a 205 block don't no if the crank and rod was heavy duty being a big van?

worth a look and save pounds?

jamie

[stu999]

Jamie, I may stand corrected but the 205 block was originally designed to be used in the Transit so it would be more reliable/durable. This made it the natural selection to become the basis for the cossie lump, but the trannie motor doesn't have the steel internals (Transits rarely rev to 7500rpm or develop 200+bhp..... Of course, White van man drives them like they have.

Stu.

[jamie]

gone up in the world since the tranny got a vito 115mph S*** hot!!!

ja

[brian snelling]

I have built a couple of n/a cossies using 205 inj blocks and cranks with 2nd hand cosie rods.Used flat top 2.8 pistons but these need cut outs  and circlip grooves machined in them, or some other way of stopping the pin moving.The max compression ratio you can get is about 10.5 as machining the head just leaves the valves closer to the pistons.On the 2nd engine i machined the crowns to leave 1mm sticking up into the combustion chamber and only then did I get 10.5 c/r after machining .060" off the block.To get any reasonable power from the engine 200bhp 180 lb/ft +the head needs to be well hacked a lot of material has to be taken out of the exhaust and inlets.The exhaust guides need to be removed to get the them to any reasonable size and the inlets really need boring out on a milling machine,although on the 1st engine i did i used a adj reamer,not recommended.I had the cams reground

and used solid tappets and if you want more than about9.5mm

lift you will need crossflow isky springs outers and need the retainers slightly machined as the springs are narrower.As these heads have usually done a lot of miles before get them the cam carriers are usually fairly worn and using 60 lb  approx oil pressure alot of oil and pressure is developed in the head and the engine trys to spit it out everywhere ,dip stick etc so you need a catch tank with another breather from the head and a return to the block.If you are aiming for about 170bhp and 150/160lb/ft i would go for a pinto its a lot easier.

          brian snelling