building my new xe today and found this out....

[dumpycorsa]

Hi. I've been collecting peices over the past year or so to build myself a strong xe motor. I've been putting it together this weekend with my mate at his garage. I had most of the parts needed but asked my mate to order in the head bolts. I'm sure most of you who do your own engine work know that there are two types of head bolt, an early engine and a late engine head bolt and there's 5mm difference in length.The longer bolt is a "male" style hex bolt listed for the early engine and the later is a "female" style hex bolt. The block that I'm using was from a calibra 1992 (dizzy style xe). This originally had a GM head on it but my new head is a cos cast head from Autosprint. The Gm head was fitted using the longer bolts so we tried to use this style again. The bolts seemed to torque down and the head was tight. The only thing that made me suspicious was the fact that some of the head washers were loose even though the bolt was tight. We decided that this wasn't right so we took the head back off and made some checks. On the GM head the long bolts stuck out approx 27mm. The block was tapped down to a depth of 34mm but the long bolts in the cos cast head protrude by 34mm therefore will bottom out. If the shorter bolts are for the later style engine yet the cos cast head (which people say is on the early 20xe engines) needs the later type bolts whats going on. We thought to start with it might be a difference with the early and late bottom ends but it turns out that the platforms that the bolts clamp down on in the cos cast head are 5mm or so lower than the GM. Is it just an error with the motor factor shop and they have the two types of bolts mixed up (early is late and late is early)? My mate has his doubts about what cars the cos cast head is found on aswell. I've always assumed and been told that cosworth designed and help to produce the early engines casting the heads and forging the bottom ends then Gm started to cast them in a german foundry. My mate has always heard this and believed it but he has an xe removed from an opel calibra down the scrappy. It was a late dispack engine yet it has a cos cast head. He has an L reg calibra (dizzy type xe) with a coscast head and he has a 1988 Astra gte 16v with a GM head. Has anyone else noticed this? My xe in my nova ATM is a 20xe lump but with a GM head. Surely they couldn't of all had the heads swapped around? Sorry for the life story but this has really spun me out this weekend.:tard:

[ck]

its a bit of a mix n match tbh i think. there was a rare batch of late DIS coscast heads, and also some found on late LET's.

also was a bit of a mix and match as to whether its late or early head bolts lol. if you need the early ones without the washes either cut them off the late headbolts or buy some from vaux (about 80p each)

here is a clear guide to determin what u need.. hope it helps
http://www.sbdev.co.uk/Info_sheets/Head_Bolts/Difference_between_2.0L_head_bolts.htm

[Philsutton]

^^ my LET is one of them

[craig green]

Coscasts appear all over the shop, incl the late batch no doubt commissioned by GM to solve the porous warranty issues.

[The Simps]

I've got a late dispack head on my let.

interesting about the headbolts tho.

[burgo]

its vauxhall!! you really could have anything on there lol only way to know for sure is to check

[coombsey]

my car had the shorter ones on but when i changed head to coscast item didnt realise that there was two sizes so i brought the shorter ones and ripped the thread out the block had to buy the longer ones after i had the block helicoiled.

[The Simps]

ok, so I'm now putting a late coscast dispack head on an early XE bottom end - long or short bolts? best way to check?

[burgo]

best way to check is to fit the head and then measure the depth of the hole

or explain to your motor factor the problem and see if you can take both the long and short bolts and return the wrong ones

[Ste L]

late dispac coscast head on my xe :cool

http://www.corsasport.co.uk/carimages/5083/DSC00818.JPG

http://www.corsasport.co.uk/carimages/5083/DSC00821.JPG

[Novaboyleon]

mine all fitted perfectly with the longer bolts in my j reg calibra with coscast head that i sourced, took me long enough to get the right bolts though! also before you fit the bolts clean the hole out with a bit of rag as any oil could cause it to pressurise and split the thread

[dumpycorsa]

Gald I'm not the only one who has had problems. Like I've said the cos cast head uses the shorter bolts which are the ones with the washers on. The GM head uses the seperate washers. The short bolts are listed for the late engine even though it maybe early or late crazy. Worrying thing is though the head will tighten down with the longer head bolts but only just so it would be possible to torque the head bolts up and assume the head is down tight when it isn't. Wonder how many early style head gaskets have been done using the correctly listed early bolts only to find it blows again?

It's a mine field out there, I'm getting confused just writting up about it

[ck]

no your wrong, like i said it was a miss match regarding which heads have early/late bolts. i have seen both coscast and GM heads with both early and late bolts.

to determin what bolts are needed i specificaly put a link in my 1st post on page 1. its from sbd and clearly shows you how to distinguish what bolts are needed for your head.

[ck]

yes allways clean every last bit of sh!t out of the head bolt holes. if enough oil/water is in a headbolt hole there is a good possibility when bolting a head bolt in it will hydraulicaly lock and when tightened down will crack the block.

for you lazy ones: (thanks to sbd)
http://i70.photobucket.com/albums/i95/ckallis500/DifferencebetweenBLT-H1BLT-H2.gif

[dumpycorsa]

ok ck! I posted this thread up because it's something I haven't noticed before and I'm sure I'm not the only one! Not many people/garages may measure the width of the head or the bolt protrution or the thread depth in the block so now people who've read this will know to check first. I assumed that all cos cast heads are early and therefore use the early bolts. I didn't know both head types have two variants depending on year.

So the cos cast head that I've got must be a late head where as other people who've used longer bolts on a cos cast head must have an early ones yes?

Not all cos cast heads were cast at the same time then as they can differ in thickness.

[spanishfly]

To check late/early coscast, look at the valve guides. 13mm and 11mm.

[The Simps]

Well I've just checked mine and I've gotthe wrong bolts. Grrr

Mine is a coscast head with the dispack lugs on the side so I'm assuming late type.

The bolts I need are the short type.

[dumpycorsa]

Well I've just checked mine and I've gotthe wrong bolts. Grrr

Mine is a coscast head with the dispack lugs on the side so I'm assuming late type.

The bolts I need are the short type.

Same as mine then mate. Saves putting it all together then finding out they're wrong. Like is said could be easily done. I got mine as a bare head so had no idea that it was late. Here's my engine/head.

http://i41.photobucket.com/albums/e251/trish26gordon/DSCN3599.jpg


http://i41.photobucket.com/albums/e251/trish26gordon/DSCN3628.jpg

Hope this helps. Sorry but haven't got any above the head once it was bolted down showing the head bolts.:roll: