Another 320/6 to 325i conversion

[DrGonzoPOW]

Looking at the breather hose coming from the cylinder head/rocker cover when i have the air filter housing off. It seems to kick out a fair bit of smoke when the car is running, its not a massive ammount but probably means something needs attention. Not long after i bought the car i fitted an E30 cylinder head as the previous one was burning the coolant. Ive run it on unleaded ever since and the performance has never been up to much ever since i had the head on.

My question, which im sure as ever has been covered before -
Is re-seating/grinding the valves and fitting new stem seals a job i could handle or is it better left to a proper garage? And if so how much are we talking for that job, or how much would it roughly cost for the whole head re-conditioning? Cheers

[e21-Mark]

It's all basic, mechanical engineering type stuff and a definite DIY do'able job imo.

[DrGonzoPOW]

Dumb question possibly but i assume the head needs to come off to re-seat/grind the valves ? Would it be a better option to buy a new cylinder head thats been re-conned and just bang that on ?

[--ALPINA--]

Head comes off! you will need a spring compressor and a complete head gasket kit, make sure if you gonna lap in the valves, DO NOT fit the valve stem seals untill you lap all valves and when you srip the valves mark them each so you know exactly what port it goes back in also the collets (dont lose any) as they can ping of the valve washer when compressing the springs, its easy taking apart and putting back, the olny thing you will hate is grinding the valves, you will need grinding paste and the tool once you ground it and its built up face the cylinder her with valves facing upwards and get petrol and pour onto the valves till it fills up on all of them and leave it for a while to see if any has leaked into the chamber, if so then re lap those valves again untill all valves have tight seals otherwise you loose compression with doing a comp test with a meter!!!

J

[DrGonzoPOW]

Ay, think i may just have a go. Would the smokey breather hose be a good sign of valve/stem seal wear then ?

[e21-Mark]

Check the bores once the head is off and make sure you can't feel a ridge around the top. You could also use a glaze buster to freshen the bores up too. I'm sure you can hire one cheap enough. Mind you, if the bores do turn out to be worn, another engine would probably be cheaper than a rebuild. In fact, you could just drop a 2.5 in and still run your carb'.

[DrGonzoPOW]

I still have the old 200 cast head from when it was replaced. Do you think that re-furbing that then just swapping the heads over would be a good idea? I mean its been in storage for a while so would that effect it in any way like warping etc?
Dont think having a 731 head is of any benefit really when just using a carb.

[e21-Mark]

If I were you I would total up the cost of gaskets, head work etc and if it totals more than £150, buy a 2.5 engine instead.

[E21meister]

Dumb question possibly but i assume the head needs to come off to re-seat/grind the valves ? Would it be a better option to buy a new cylinder head thats been re-conned and just bang that on ?

For the sake of keeping the car on the road, if you do find a re-con/decent old one then do it. As for building one, buy the parts then read how to do it. If you can get another old head to build up as so not to take the car off the road, all the better.

[DrGonzoPOW]

I was thinking that if i re-do the old 200 head myself then its giving me the chance to learn about it. I would like to be able to do a cylinder head change. One of the reasons i bought the car was to learn a bit about mechanics so i guess i should have a go.
I always wanted to go the motronic route and would love to bang a 325 engine in but ive bought that new carb now so its probably best if i use what i have for the time being. Think a new gasket set is about 50 quid so thats no bother. As far as i know the old head was in decent nick when it came off, fingers crossed it was just the gaskets that had failed.
What would you guys recommend for the re-build other than the gaskets ?

[E21meister]

Well Jimmi has covered the bases as to what you'll need to rebuild the head. Whether you rebuild it or not, you'll need new head bolts, a rocker cover gasket, wouldn't hurt to have a good quality degreaser to do the head and inside of the rocker cover.
Also, be prepared to buy gasket sets for the inlet and exhaust manifolds, as no doubt the old ones will be stuck on or will disintegrate when you try to get them off.

[DrGonzoPOW]

Ill just buy a whole kit to get them all. Am i right in thinking that the full ones will come with valve stem seals?
http://cgi.ebay.co.uk/BMW-320i-323i-520 ... 1c06994900
This is the one im looking at. The E30 320i ones are same part number as E21 parts on realoem.

Ps. would it be advisable to get the head skimmed and use a thicker gasket ?

[murran]

yeah get the full kit with stem seals, cam seal, inlet and exhaust gaskets. etc.
if you need a hand with it, i'll come to yours for a coffee!
not a bad idea to get it skimmed. no need for a thicker gasket really, a little better compression ratio can only be a good thing!

[DrGonzoPOW]

Well if im lucky i can use the warehouse where i work to do it. How much does skimming cost roughly ? Is there still plenty of clearance on the valves after a skimming with a standard head gasket. The Haynes says 'YOU MUST USE A THICKER GASKET OR THE WORLD WILL END!!!'

[e21-Mark]

I always wanted to go the motronic route and would love to bang a 325 engine in but ive bought that new carb now so its probably best if i use what i have for the time being.

You could still use the carb on a 2.5 to good effect.