Changing M10 Cams

[2002#3]

Is the physical and mechanical act of changing camshafts in an M10 a difficult proposition? 

 

Sometime in 2018 I might have an opportunity to change a 316 cam to a 292 or 304 cam to make a car less race-friendly and more street/spirit-friendly.    I assume there are numerous considerations in such a change (what has been done to the engine, use of new rockers and other cam-associated parts, etc.). However, at this time, I am thinking in general terms of being able to do it.  If it looks quite doable, I will be providing more info on the car and requesting specific advice.

 

Thanks, friends.

 

Larry

[AustrianVespaGuy]

Yes it's doable as long as you're comfortable pulling off the head and reinstalling it, as it can't be done with the head on the car. Drain the coolant, get a new head gasket, be careful with the valve timing, etc, and it's pretty straight forward if you can basically work on cars.  Only tough part that often crops up is rusty nuts holing the exhaust manifold to the head. My best advice is to buy/rent/borrow one of those spring compressor jigs that compresses all of the valves at once, allowing you to very easily pull out the new cam and then slide the other one in.  Unsolicited opinion, if it's not going on the track much, go for either a 284 or 292.  Anything from 300 up is pretty peaky for a street car in my personal opinion.

[kbmb02]

29 minutes ago, 2002#2 said:

Is the physical and mechanical act of changing camshafts in an M10 a difficult proposition? 

 

Sometime in 2018 I might have an opportunity to change a 316 cam to a 292 or 304 cam to make a car less race-friendly and more street/spirit-friendly.    I assume there are numerous considerations in such a change (what has been done to the engine, use of new rockers and other cam-associated parts, etc.). However, at this time, I am thinking in general terms of being able to do it.

 

Note: if your 316 is a ‘big journal’ Schrick camshaft, you won’t be able to downsize without changing cylinder heads. -KB

[Mike Self]

A couple--or three--tricks when pulling the cylinder head:  

 

1.  Before unbolting the timing chain sprocket from the cam, remove the upper timing chain cover from the head-and if you're gonna have the head skimmed to insure its flatness, be sure the machine shop skims the chain cover at the same time/the same amount.  Otherwise you'll have oil leaks where the two mating surfaces don't jibe.

 

2.  Carefully note the camshaft's position when unbolting the timing chain sprocket from the cam prior to pulling the head so when you install the new cam, you'll have it in the same position.  The bolts will align only one way so that's a help.

 

3.  After removing the chain sprocket but before removing the head, either use a zip tie to squeeze the timing chain around the sprocket, and use a bungee cord hooked between sprocket and the hood latch to tension the chain so it doesn't come off the crankshaft sprocket.  Prop the hood open so it doesn't accidentally close.  This'll make reinstalling the head with its new cam much easier.

 

cheers

mike 

[gracer]

As has been pointed out. You will not be able to "downsize" from a 316.  Once the cam journals have been bored out you have to stick with a big journal cam.  G

[2002#3]

Mike,

Wrote all of your suggestions to use when and if I ever have to pull a head.  Thank you.

 

kbmb02 and gracer,

This is great info to have for us pseudo hack mechanics.  Thank you.  If 316 cams require boring for accommodation, downsizing's not likely to happen in my garage.  Are all Schrick 316 cams large journal?

 

Larry

[TobyB]

1 hour ago, kbmb02 said:

Note: if your 316 is a ‘big journal’

I think you'll find this- "314" required a tiny relief cut to get it into the standard journals...

 

t

 

[oldguy]

schrick 316 and 336 cams are hollow and internally oiled.  Those heads have oil restrictors placed in them to do this.  The upper camshaft oiling system aka spreader bar is removed and is different.  On top of this 336/316/ and IIRC bmw 300 motorsport factory cams have larger journals bored into the head.  Schrick 304 cams require a notch to be cut into the second journal for lobe clearance.  All schrick 316/336 cams are large journals.

[jimk]

Sounds like it would be better cost wise to sell the head with cam to someone who has been drooling all down his shirt and build a replacement head. 

[jrhone]

Yup I was going to say. Find a good used head. Stick in a 292 cam. Bolt it on. Sell or keep the old one. 

[ShakeyC]

Yes you can get big journal small cam lobe cam's which fit head that once had a schrick 304+ cam. A 296 degree big journal cam with anything from 8-12.75mm lift this was my favourite all rounder to use in a oversized head. Im pretty sure you could get a custom cam one machined up once you know what measurements you have.

[AndySals]

I was under the assumption that you could swap a cam out with the head on. You take the radiator off, along with the dizzy anyway, and lift the engine. I'm sure I've seen pictures somewhere of it being done. The rockers were pressed down with a 'spider like' device. 

I had mine out while the head was off but I'm hoping to swap for a 292 with the head on in the future.

[Preyupy]

You can have the head off of a M10 in the chassis in less than 30 min.  Why in the world would you go through the effort to remove the radiator, lift the engine off the motor mounts and beat yourself up like that?  If you are changing the cam you should also be looking at the rocker arms (old rockers on new cams CAN be a problem)  what about a valve job while you are at it? 

[ShakeyC]

If just cam swap you can do it with the head on, i done this at dyno and trackside without special tools but with extra pair of hands can be done in 15mins.  Remove dizzy, undo gearbox and engine mounts, jack front of engine upwards and rotate it upright, whilst gearbox drop down and you can clock the cam outwards without removing radiator or anything else. Not the correct way to do it and you miss all vital inspection points but its possible 

[AndySals]

Yes I meant if it was just a cam swap without replacing anything else including head gasket or having to remove filters, carbs, manifold etc. I've not done it this way so I can't compare whether it's easier or not, I was just being hypothetical.