camshaft exchange without head unmount ?

[arnie]

Hi guys,

I'm just close to "throw in" a new cam shaft into my M30 engine and I'm curious if there's anybody, who did such an exchange without having the head off. Might be possible in general by using an aid frame, that is pushing down the valves to have them out of the way.

My biggest concern is the clearance space of the shaft by traveling through the front mask. Looks fu ... close to impossible. Any experience if positive or negative would be very helpful ...

Cheers

Ingo

 

[m5bb]

If engine is in the car, impossible as far as I know. On the block you have to be sure you don't push a valve into a piston when you remove the rockers.

 

[deQuincey]

it might be extremely difficult, yes, but i know a shop that did it in a friends coupe

 

[m5bb]

it might be extremely difficult, yes, but i know a shop that did it in a friends coupe

They must have put a hole in the fire wall because the rocker shaft has to come out the back of the head.

 

[arnie]

Thx guys,

I decided now to go the common way, after removing the radiator and having a better look to the position of the camshaft in relation to the front mask opening.
The engines angle denys a sufficient space, so that it only might ne possible by lowering the engine or the front axle.
Too much trouble for less benefit ....

 

[deQuincey]

They must have put a hole in the fire wall because the rocker shaft has to come out the back of the head.

the cam came out throught the front grille hole

 

[m5bb]

the cam came out throught the front grille hole

But the rocker shafts have to come out before you can remove the cam.

 

[deQuincey]

But the rocker shafts have to come out before you can remove the cam.

nope, there are ways to do this, first one is the specific bmw tool, but for that you need to have the cyl head out, in my case i did it but with the cyl head in a table, using screwdrivers and cables to keep the tension and force valves open

anyway i can nt speak for them, the truth is i didnt saw this with my own eyes i agree it seem very difficult to do

 

[Markos]

nope, there are ways to do this, first one is the specific bmw tool, but for that you need to have the cyl head out, in my case i did it but with the cyl head in a table, using screwdrivers and cables to keep the tension and force valves open

anyway i can nt speak for them, the truth is i didnt saw this with my own eyes i agree it seem very difficult to do

The real question is, can you do it without removing the head bolts.

 

[arnie]

The real question is, can you do it without removing the head bolts.

This is not the question, if you don't plan to pull the rocker shafts. Camshaft can be exchanged without disassambling the valve rockers. They can remain inside if you just push them down with a specific aid frame (see attached picture from the BMW repair hints).

This shows the situation when the head is off the block. So in general it is possible with a slightly different frame to do this swap while head is still on the block. Of course you have to take care, that there's no piston in top position, to avoid any contact between the valves and pistons.

K.O. criteria, that this might become pretty difficult, is really just the front mask opening. The engine just seems to sit to high inside the car, that this wouldn't succeed without additional strategies for lowering the engine (removal of the bearings or lowering the front axle). This was not that attractive, so that I decided to take the head off. And because I would have to build this frame on my own, I dropped this plan and went the "old school" way with the removal of the rocker shafts to get the camshaft out. It's already done and the head can go back to the car next days.

Cheers

Ingo

 

[Markos]

This is not the question, if you don't plan to pull the rocker shafts. Camshaft can be exchanged without disassambling the valve rockers. They can remain inside if you just push them down with a specific aid frame (see attached picture from the BMW repair hints).

I’m familiar with the frame. I guess I was under the impression that the tool uses the same bolt holes as the head bolts, which means at least some of them need to be removed.

 

[arnie]

I guess I was under the impression that the tool uses the same bolt holes as the head bolts, which means at least some of them need to be removed

You're right on this, but I would fix the frame with the bolts for the valve cover instead of using the bolts for the head. I wouldn't like to losen these bolts, even if it's just temporarily

 

[teahead]

Not that much work to just pull the engine out of the car.

But w/the engine out of the car, using that tool, one can remove the cam w/o removing the head, right?

 

[m5bb]

This shows the situation when the head is off the block. So in general it is possible with a slightly different frame to do this swap while head is still on the block. Of course you have to take care, that there's no piston in top position, to avoid any contact between the valves and pistons.

Oh but of course........

 

[restart]

There are a few of those frame styles. Most everyone has at least heard of the big six iron maiden. There are a couple of different frames and a few attachments available for them. Here is the 4cylinder iron maiden and the S38 tool. And some accessories

Always looking for a chance to show off tools

 

[StephenZ]

Man, those are some cool torture devices...;-).
I think, unless the head, valves, etc... were all recently refreshed, I'd just pull the head and do it all when I swapped to a cam. Especially if it was going to be a performance one...It's so easy to just yank it and it really makes the associated scope creep that much easier to do...

 

[Drew20]

I did have a go on my E24, with a home made iron maiden tool, made of wood and coach bolts. Needless to say this did not work and the head had to come off in the end. Even with the proper bmw tool you'd need to get the pistons out of the way to be safe I think (say 60 degs btdc) and also lift the engine a bit to get the cam to clear the rad, and remove the bonnet.... = far from straight forward.

To pull the head, I left the exhaust manifold attached (undone from the downpipe), and lifted with a crane, it can be done without a crane if you have a mate, or can get a foot inside the engine bay to lift from, or if you're properly ripped I guess!

 

[JFENG]

Having done head r&r’s on a number of old BMW’s, sometimes in dirt parking lots, I can second Drews suggestion with enthusiasm. On a carbureted car it’s quick to remove the intake/exhaust system. Zip tie the timing chain to the sprocket and get some tension on it so you don’t skip a tooth on the lower gear. Then just lift the head off. you don’t need to be ripped, but you do need to have a good back.