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Changing Head....(Updated)

Posted: Wed Aug 16, 2006 10:08 pm
by kam-325i
Ive decide'd to throw in the towel and take the head of my M20B25,
Water loss and mayo (both random) are driving me nuts.....

besides a replacement head (if mine is knackered) are these the right parts from ECP ?
Should be headgasket set, Head bolts & Cam belt

362110261
300110091
325110015

Should i do anything else while i have the head off ?

Can i use Dye penertrante to test for cracks in the head ?

Re: Changing Head....

Posted: Wed Aug 16, 2006 10:24 pm
by Ant
Get a new tensioner too Kam, and a new spring from BMW will ensure its 100% spot on.

not checked the part numbers, but H/G set, stretch bolts, headset and some fresh oil and A/freeze, all good mate

with regard to the dye, I use A/C dye, run for a bit then drain oil and look for it wiyth UV lamp, pulling the R/cover can reveal nasties too.

Get in there dude :D

Re: Changing Head....

Posted: Wed Aug 16, 2006 10:28 pm
by stonesie
I would send the head to a local engine company and get them to pressure test it then ring you with the results, if its ok get them to skim it.

While doing this job i would get a cambelt kit from either BMW, Gates or GoodYear so that you get a new tensioner too and idler pully if they have 1. I would also change the water pump while its a relativly easy job rather than a total mare later :wink:

Re: Changing Head....

Posted: Thu Aug 17, 2006 5:49 pm
by kam-325i
I forgot to look for the tenioner and water pump !!!

Is it easier to leave the intake manifold on until the head has been removed off the block ?

Re: Changing Head....

Posted: Thu Aug 17, 2006 6:37 pm
by Chris-W
No, take the intake manifold off first.

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:07 pm
by chu346
I disagree

Leave the manifold on :D

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:08 pm
by Ant
I always leave both manifolds in place, makes it a lot easier to man handle the head away from the block, man each side and no bad backs.

fit the ex manifold , but refit the inlet in situ once the new head/gasket is sorted.

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:23 pm
by chu346
Ant wrote:man each side and no bad backs.
:gay:





:lol:



Maybe that's where I got my bad back :roll:

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:25 pm
by kam-325i
Is it a PITA to re-fit the inlet manifold once the head is back on, or can it be re-fitted before you re-fit the head ?

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:29 pm
by chu346
You can do it either way, as i'm lazy I usually put the inlet manifold on first or leave it on if I don't need to change the gasket.

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:32 pm
by Ant
minor pita , but not as bad as trying to hold the head, and inlet etc in the air while you try and get the breather tube back in.

Chu, I'm getting old mate :lol:

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:35 pm
by kam-325i
I am going to take off both manifolds to replace the gaskets and check the studs, as by the looks of the bolts holding down the head, the head has been off before.

It might just turn out to be the one dodgy bolt thats holding down the corner of the head......as it is not a proper head bolt, just some normal 8.8 bolt......

Re: Changing Head....

Posted: Thu Aug 17, 2006 7:48 pm
by Ant
they should all be 8.8 grade Kam.

only the chromie cars had 12.9 Hex bolts, and most of those will have been binned by now in favour of the torque to yeild jobbies, supposedly to let the H/G blow, rather than crack the casting, was an advisory not full recall though iirc ??

Re: Changing Head....

Posted: Thu Aug 17, 2006 10:05 pm
by kam-325i
Thats a good point, i remember Nigel from Moseley M/S telling me about BMW changed from the 12.9 Hex head bolts to the Torx type.

Dose that mean i might have a early High compresion 2.5, as all the bolts (bar the 8.8 billy no mates) are the 12.9 Hex head type ???

Posted: Sun Aug 27, 2006 7:56 pm
by kam-325i
Do i get a prize for the most cracks in a head ????

Well, atleast i dont need to fork out for pressure testing....

Image

Image

Image
Exhaust Vavle in view

Anyone got a good head going !!!!

Do they normaly crack there ?

Re:

Posted: Sun Aug 27, 2006 8:26 pm
by Chris-W
Blimey.

I've got a head for sale - I'm only up the road (ish). Drop me a line if you like.

Cheers,
Chris

Re:

Posted: Sun Aug 27, 2006 8:57 pm
by tbmw
tht doesnt look good geezer
good luck sourcin a new head

Re:

Posted: Sun Aug 27, 2006 9:47 pm
by Demlotcrew
That head has been cooked! It should not be so white looking.

Andrew

Re:

Posted: Sun Aug 27, 2006 10:00 pm
by kam-325i
Demlotcrew wrote:That head has been cooked! It should not be so white looking.

Andrew
I thought that. but it's never boiled over since i had it, must of been from the previous owner....

The other valves are not that colour, they have a nice coating of carbon.
The top of the pistons look ok, no heavy deposits on them either

Re:

Posted: Sun Aug 27, 2006 10:11 pm
by stevetigger
WOW 8O

M50 I say! winkeye