Head Removal Rb25det

[Japtastic-UK]

Any tips on removing the head, or tutorials any where, I am having to do this tomorrow and never removed a head before, cams and timing belt off already, is it just a case of nuts and bolts or is there anything out of the ordinary?

Cheers

Stewart

[Rancher]

Pretty straight forward. You might have to take the cams out to reach the bolts though. Do you have the alen key socket thing? I dont remember the size of it. I think like, 10 or 12MM. Remember to mark the cam caps so you know which order they go in!

[SECURITY]

the caps are marked with an I for inlet and an E for exhaust and are numbered so dont worry about them being in order.

besides the head studs holding the head in, there are 3x10mm auxiliary bolts holding it in. there are two on the rear of the head on either side, and there is one just ontop of the water pump (from memory).

the cams will need to come out.

there are a whole bunch of hoses and brackets that need to be removed from under the plenum too.

if you're removing your lifters as well, get some liquid paper and mark them the same way the caps are marked so you know which one goes where.

Edited August 11, 2007 by SECUR1TY

[blind_elk]

I've done this a couple of times - once on a RB20DET, once on a RB25DET. I'm almost certain that you DO NOT need to remove the camshafts. The head bolts (10mm Allen key) are easily accessible with the camshafts in place. The 6mm bolts (10mm head) are a bastard to get out. Leave the turbo and exhaust manifold attached. Remove the inlet manifold (you might have to split it).

There might be a heap of crap (like fuel filter) you need to remove to gain access to the real bolts. Watch out for all the hoses attached at various places.

[SECURITY]

I've done this a couple of times - once on a RB20DET, once on a RB25DET. I'm almost certain that you DO NOT need to remove the camshafts. The head bolts (10mm Allen key) are easily accessible with the camshafts in place. The 6mm bolts (10mm head) are a bastard to get out. Leave the turbo and exhaust manifold attached. Remove the inlet manifold (you might have to split it).

There might be a heap of crap (like fuel filter) you need to remove to gain access to the real bolts. Watch out for all the hoses attached at various places.

you can get away with leaving the cams in to get to the studs, but storing the head is another issue. with the cams in place you may bend a valve when putting it down or storing it. its a hell of a lot safer and a little bit of extra work for something that can cost you hundreds if something goes wrong.

the 3x10mm auxiliary bolts can be accessed with an extension with a swivel or a ball joint on the end. make sure you have a magnet though.

[aphid]

yeah cam's don't need to come out so i wouldn't worry about that, the head can be layed flat against the ground without worrying about valves touching, however i would suggest wrapping it up in an old beach towel or something to keep it out of the elements for peace i minds sake

[sweetr33]

yeah i pulled my head off and left cams in, take exhaust manifold off but leave intake manifold on, well thats wat i did anyway, much easier, just a couple of water hoses under on intake man side and your away.. not hard job once u got cam belt off.. i didn't hjave those 3 extra 10mm bolts security is talking bout but did see the place where they go, make sure engine was lined up to tdc before removing cambelt, u need cam timing to be correct to get socket and extention down to headbolts.... goodluck

[Japtastic-UK]

Thanks for the replys guys, cambelt and cams are off now any way, starting now, will try and take some pics along the way...

[shanef]

taking cams out or not depends if u can get an allen key socket with a snout long enough so it dont foul on the cams. the one i've got doesnt quite reach

if the motor's still in the car, have fun getting to all the bolts lol. i feel ur pain

[SECURITY]

taking cams out or not depends if u can get an allen key socket with a snout long enough so it dont foul on the cams. the one i've got doesnt quite reach

thats a good point. you'll probably get away with it when pulling the head off, but when putting it back on you'll need a shorter hex bit so you dont lose torque by the bit twisting. i had the cams in when i put the head back on, but our bit was too long and i could see it twist before we hit the proper torque. i ended up taking the cams out so i could use a shorter bit so i wouldnt lose any torque.

[Japtastic-UK]

Thanks for the replys guys, I am now at this stage (see pic)

Got a few questions.

1) I am going to leave the exhaust manifold on but by the looks of it the turbo needs to be moved/twisted to make that possible, it doesn't look like that is possible unless I remove the 3 oil feeds, is that correct?

2) As regard to the intake, after I remove all the pipes/connections, can the head be removed with all that you can see in the pic attached? If so how do you get to the 10mm head bolt at the front above the water pump, there is no room to get any tool in there....

Thanks for your help, I'm taking pics along the way so hope to make a FAQ when all is done.

Cheers

Stewart

[SECURITY]

1) to make it easier for yourself, take the turbo off. or at least take every line going to the turbo except the water feed off.

2) yeah, you actually took too much off. mine came off with the entire plenum.

getting that front bolt off was a bitch. i had a sidchrome set with skinny heads around the spanners. they were the spanners with the recessed heads. you might be able to get a 10mm socket on it with a swivel.

p.s. i see you took my advice about the cams

[Japtastic-UK]

I actualy had them off anyway as I said in the first post Definantly worth it though as it made life a lot easier

Thanks for the advice, I'll pop down to Halfords today and see if I can get anything to go round that nut, I'm not very hopefull though, lost a lot of skin taking the top of the that plenum off

[sweetr33]

far out u took the top part of plenum off>??? i didnt do that when i pulle dmy head off... i pulled turbo and ex manifold off completely coz its easy as to do and saves a heck of alot of weight when lifting head... once you've taken head bolts out you probably will have to pry the head loose, there bit tight on the gasket sometimes, then slowly lift it n watch for any water hoses under the plenum u might have missed...gl

[Japtastic-UK]

Yeah the top part of the plenum was a bit of a bitch, saved a bit of weight though used one of those ratchet spanners which was a god send!

I grinded down the wall of one of my 10mm spanners and that got the front 10mm out.

The head is now moving and ready to come out but there are still some pipes under the plenum I have to get to, what a bastard of a job!

[sweetr33]

yeah but do it again n you'll be sweet hhaha like me

[Cubes]

Definitely head down to the local tool shop and grab a decent hex bit.

I bought a cheapy from the local autostore that was twisting so I went out and bought a sidchrome for $5 more from the tool shop. Perfect no twist.

IF the valves stick out or not will depend on the cams. The cams Im running (stock rb25de) have a reasonable amount of overlap and valves were open at TDC.

I grabbed some foam and sat the head on that then taped it up. So no issues with sitting the head down on valves.

I left the exh. manifold on but removed the inlet manifold. Gave me something reasonable to hold on to when lifting the bastard off.

While your there block the rear oil restrictor off. Grab a $2 piece of 6mm black rod from the local steel shop, chop it down chamfer grab a pin punch and smack the old down a little ~ the same height of the new and then smack the new blocked restrictor down on top.

Im absolutely stocked with how I now have ZERO oil out of the cam cover breathers. Catch cans absolutely 100% dry; not even a smear.

-------

Also remember upon removal to loosen in the reverse order as to what you would when torqueing them up.

If you want to save your gaskets should the head have to come off at a later date give them a spray with Hylomar.

[Japtastic-UK]

My worst fears confirmed...

Question is can the head and piston head be repaired? Or do I need to find second hand ones? I'll be replacing with standard as the car will be sold as soon as it's repaired.

There is no cyclinder damage as far as I can see.

[SECURITY]

that damage to the head looks like it can be machined/sanded out but im just a backyard mechanic.

send it off to get the valve seat repaired (if possible). you're (obviously) going to need 2 new valves.

if you dont want to send it off right away, sand the valve seats back with some fine sand paper (if you're keen/confident). put the new valves in fully assembles with the valve spring etc, turn the cyl head up side down, then fill it up with water and leave overnight to see if its leaking.

if it leaks then you're going to need to either get it machined, or get new valve seats.

new seats will cost a fair bit as the process is pretty hardcore.

they heat the head to expand, then freeze the valve seat to contract, sit it into position, then when they come to normal temperature they are very tightly in place.

thats where your money is going if you have to get new seats

id highly recommend replacing your valve stem seals too.

[Japtastic-UK]

managed to source a second hand head for £100 with valves so that saves me a lot of work and money

looking at the possibilty that the piston doesn't need replacing as the damage is so minimal?