Changing Head....(Updated)

[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 ?

[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

[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

[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 ?

[Chris-W]

No, take the intake manifold off first.

[chu346]

I disagree

Leave the manifold on

[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.

[chu346]

man each side and no bad backs.

Maybe that's where I got my bad back

[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 ?

[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.

[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

[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......

[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 ??

[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 ???

[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....






Exhaust Vavle in view

Anyone got a good head going !!!!

Do they normaly crack there ?

[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

[tbmw]

tht doesnt look good geezer
good luck sourcin a new head

[Demlotcrew]

That head has been cooked! It should not be so white looking.

Andrew

[kam-325i]

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

[stevetigger]

WOW

M50 I say!