guys, I no a 4wd head is better than a 2wd head but how do u tell the difference if they were both bare i.e no manifolds, cams.
cheeRS

 

2wd has a mounting bracket on the exhaust side

Steve

 

Easy spot is the 2wd head has the lugs for the turbo hanger and 2 bolt thermostat housing.

 

so u cant put a 2wd thermostat housing on a 4wd head?

 

I'm pretty sure you can, IIRC the bolt pattern is the same just the 4wd stat housing has an extra mounting lug.

 

Looking at the face of the head the waterways are different...



A 2WD head.





A 4WD head.


TT

 

Not all 2wd have 2 bolt for the stat housing, only the early 3 drs have 2 bolts.

4x4 has less water jackets and the turbo feed.

Edit: i believe the combustion chamber differs too.

 

cheers matey, the 4wd has better waterways don't it?

 

Yes, supposedly....

Although you get many big HP YB's using a 2WD head!!. I myself have a 4WD head

TT

 

u using a 4wd head on a 2wd?

 

No.

Building up a YB turbo as a project. Dont know what I'm going to put it in yet

Have a 200 Block, 4WD head and other bits and bobs.


TT

 

im sort of in the same boat as u, my dilemma is I have a fully re built 2wd head but its just had its last skim machine shop said, so in 2 minds to buy another head, wanted to go 4wd as "there better"

 

my brother had a 2wd coscast head on and then took it off and put on a 4x4 (cant remember what it said on it but was not coscast) , however he took it
back off as he felt the car did not goes as well .

so is there a difference to coscast head to a non coscast head ?

 

I think the cambers are a better shape on the 4x4 head .

 

no idea what coscast means

 

Also there's a difference in the 2wd heads..... On early 2wd heads the head bolt washers are smaller than the later 1's...


Steve

 

^^^^ like mine, my 2wd head seems to be working fine after 28 years granted it's had a lot of machining

 

I am guessing its to do with the cast of the head (as the name would suggest ) it says it on the front of the head , I have heads as I said with and without so would be interesting to know the difference

also did some heads come with over size cam followers from ford ? and sure they are stamped on the back of the head , cant remember if its a number or letter sure its number , anyone any info on that ?

 

And here's my late spec 2wd head.

 

4x4 head has smaller combustion chambers than a 2wd head.

Hence why if you use 4x4 pistons on a 2wd head you lower compression slightly to around 7.8:1

 

To be honest if you can find an unskimmed head 2 or 4wd then either will work fine or one that's had a first skim,although I've had engines that have had 1.5 mm took off and still make the power,so as long as it's not cracked etc then take your pic

 

ah that's interesting never knew that

 

if you were using a head with a lot off it you could always bore it , fit larger pistons and that would lower the compression ? although don't think I would bother

 

that would raise the compression matt

 

would it not just up the cc ,
my example a push bike inner tube 65psi of pressure in it (small area)
a car tyre 35psi (large area )
so would a bigger area (bigger pistons) not have less pressure ? as its trying to compress a larger area ?
I could be really wrong but that's the madness behind my thought lol

 

your wrong and clearly mad lol

 

lol o well thanks anyway

 

Increasing the bore would increase the swept volume what you need is to increase the clearance volume to lower compression which typically involves increasing the volume of the combustion chamber

 

yea I am understanding that now lol

 

Coscast was a patented casting process Cosworth developed and they started marking their heads as such, just after the 3dr cosworth engines were built.

Pretty sure it happened around the same time on the red top vauxhall heads they also produced