Head replacement project under way

[Mr. BILL]

The rebuilt cylinder head I bought on Ebay came yesterday, along with a black powder coated valve cover. I picked up the necessary stuff to complete the job today and started the demolition, I mean dis-assembly. So far things are going OK. I'm about 70% ready to pull it out.

I'm planning on taking the head, along with the intake and exhaust manifolds out as a unit. I'm not sure how I'll handle the install. I'd be appreciative of any suggestions, hints, tips ect.

One thing I'm not sure of, is how you loosen the belts on an M20. It has a gear type adjustment and Bentley just glosses over how to tighten/loosen. I could use some clarification how that works.

Also, it seems like a good time to replace all those hard to get to coolant hoses that run thriugh the intake. Should I, or are those 14 year old hoses going to last a good while longer? I'd also appreciate any suggestions as to what else I should replace while I'm in there.

Thanks in advance.

Bill

[winfred]

i like to leave the exhaust manifolds atached to the head pipes and just pull them back out of the way, you can jam a hunk of wood between the tranny and the exhaust to hold it.
for the belts i just walk em off so i don't need to screw with the adjustment, to remove loosen the 13mm on the top back side and the 13mm nut/bolt on the bottom then you can back it down with the 19mm adjuster.
the hoses you are going to need to deal with as you see fit, they usually hang in there but with the intake off it's the easy time to do em, i like to bypass the shitty little leak master on the side of the throttle body, by running a piece of heater hose from the nipple on the bottom of the thermostat housing (which can and does rot off) to the fitting thats screwed into the block by the starter.
one thing that helps when installing the intake onto the head do not remove and clean the spring loaded vent tube that comes up out of the block, instead squash it down and if you're lucky theres enough grunge on there to make it stick and it will stay out of the way till you pull it back up into the bottom of the intake, leaving it in also plugs up a bolt/screw/nut sucking hole.
it's a easy head job, torque's are #1 22lb #2 90 degrees #3 90 degrees (90 degrees = 1/4 turn) do not reuse the head bolts dealer list on a new set is $24 (the m30 is the one that they say you can reuse them on, i don't reuse them on that motor ether it's cheep insurance) you will feel the bolts give on the 2nd 90* pull, it's strange but when you've done as many as i have you get use to it.
extra tip, the m20 e34 is a notorious bitch to bleed the cooling system, drill a small (1/8" or less) hole in the thermostat and place it in the 12:00 position when in the housing this will burp the block



The rebuilt cylinder head I bought on Ebay came yesterday, along with a black powder coated valve cover. I picked up the necessary stuff to complete the job today and started the demolition, I mean dis-assembly. So far things are going OK. I'm about 70% ready to pull it out.

I'm planning on taking the head, along with the intake and exhaust manifolds out as a unit. I'm not sure how I'll handle the install. I'd be appreciative of any suggestions, hints, tips ect.

One thing I'm not sure of, is how you loosen the belts on an M20. It has a gear type adjustment and Bentley just glosses over how to tighten/loosen. I could use some clarification how that works.

Also, it seems like a good time to replace all those hard to get to coolant hoses that run thriugh the intake. Should I, or are those 14 year old hoses going to last a good while longer? I'd also appreciate any suggestions as to what else I should replace while I'm in there.

Thanks in advance.

Bill

[Mr. BILL]

Thanks winfred, a couple questions if I may. I decided to take the intake off before removing the head. I have everything loose, except the tube you mentioned. I can't seem to get it to pull down out of the intake. I have been trying to do it by hand. I know there is a special tool, but is there another trick to getting it loose?

I like your idea about leaving the exhaust mainifolds on the pipes. Those are always a bitch to line up. I noticed the t-stat housing has the lower nipple that looks like it's been filed off on an angle at the bottom. I may replace it.

I really appreciate your help!!!

Bill

[winfred]

i usually use a pry bar and a hammer to drive it down, be careful it's sheet metal and you can poke a hole in it if you hook a edge, the special tool holds it down, if you do pull it out and can't get it to stick you can wrap a large zip tie around the tube and sorta keep the spring compressed and tube outta the way. the part that rots off of the thermostat housing is a pressed in potmetal insert that corrodes badly, some of the replacments had better inserts that didn't crap out, the pot metal nipple and that thing on the throttle body are the kinda stuff that leaves you on the side of the road, i had to rescue mom right after i got her 90 325isa because the throttle body thing started pissing and it overheated (i was planning to eliminate it but it crapped before i got the chance)


Thanks winfred, a couple questions if I may. I decided to take the intake off before removing the head. I have everything loose, except the tube you mentioned. I can't seem to get it to pull down out of the intake. I have been trying to do it by hand. I know there is a special tool, but is there another trick to getting it loose?

I like your idea about leaving the exhaust mainifolds on the pipes. Those are always a bitch to line up. I noticed the t-stat housing has the lower nipple that looks like it's been filed off on an angle at the bottom. I may replace it.

I really appreciate your help!!!

Bill

[Mr. BILL]

Do you place the pry bar on top of the spring and try and drive it down br tapping on it?

[winfred]

theres a crimped into the tube ring that the spring is against, hit that

[Mr. BILL]

Head R&R update... I was able to get the gead off today. I took extra time to clean the tops of the pistons with a Scotch brite pad and some Carb cleaner. The pistons looked pretty good, only a tiny ding on #4 where a valve hit it. I was careful, but got some tiny bits of carbon into the holes in the lock. I hope that's not going to be a problem.

So far, no real problems. Tomorrow, I'm going to clean everything up and start putting it back together. I think I've git about 14 hours invested so far, but I'm taking my time.

[winfred]

clean those head bolt holes out, liquid in there can crack the block when the bolt is screwed down on it


Head R&R update... I was able to get the gead off today. I took extra time to clean the tops of the pistons with a Scotch brite pad and some Carb cleaner. The pistons looked pretty good, only a tiny ding on #4 where a valve hit it. I was careful, but got some tiny bits of carbon into the holes in the lock. I hope that's not going to be a problem.

So far, no real problems. Tomorrow, I'm going to clean everything up and start putting it back together. I think I've git about 14 hours invested so far, but I'm taking my time.

[Mr. BILL]

Will do, thanks winfred. You suggestions ahve helped a lot!

[carolina525]

clean those head bolt holes out, liquid in there can crack the block when the bolt is screwed down on it


I used a shop-vac with a McDonalds straw rigged to the end of the hose and was able to suck most of it out... I see a slight glistening in the holes but not the puddle that was there before... Is that enough or is there a trick to getting them bone dry?

[winfred]

they don't need to be completely dry but you can flush then with brake cleaner and then suck or blow them dry, if you dry them out a drop of oil on the new head bolts wouldn't be a bad idea

[Jimmy535i]

I removed my cylinder head leaving both intake and exhaust manifolds in the car and was able to re-assemble with no problem. You will need to take a block of wood and
push the exhaust manifold far enough away so that the studs clear upon re-intallation
of the exhaust manifold. Good Luck

[Jeff N.]

....then it goes back together reaaaaal nice! :)

Jeff



they don't need to be completely dry but you can flush then with brake cleaner and then suck or blow them dry, if you dry them out a drop of oil on the new head bolts wouldn't be a bad idea

[winfred]

a chaser would be better, you don't want to remove any metal like a tap can, i have a full set from snap on in metric corse sae and fine sae and i use the **** out of them


....then it goes back together reaaaaal nice! :)

Jeff

[Jeff N.]

a chaser would be better, you don't want to remove any metal like a tap can, i have a full set from snap on in metric corse sae and fine sae and i use the **** out of them