Shimmed valve adjustments?

[bayerische]

I think this is my first thread in this section, so please be gentle:(

Anyways, I'm reading the buyer's guide about M3s in the June '05 issue of Bimmer. On the "M3 Maladies" page, the writer says, "All BMW Motorsport engines except the E36's U.S.-spec S52 require shimmed valve adjustments at regular intervals, using special and expensive shims." What the hell does that mean? So I'm assuming E46 M3 guys know this and do it??

[JB///M3]

It means that the S52 motor does not need a valve adjustment to keep the intake/exhaust valves in the right parameters of clearance...i believe they are hydrolic and kept in adjustment by fluid being pumped in/out...

all the other motors are not however, and at certain service intervals require the removal of the valve cover to check the valve clearances, shims are different sized thin plate type pieces of metal that go below the valve spring (i believe?) to keep it mechanically adjusted... u check the clearances with a special reader tool u insert where the shims are placed to see what size (if any) is needed...

theres way more to it than i have said, but hopefully it sorta makes more sense

[Def]

Yea - most Honda engines have mechanically adjusted valves as well.

[bayerische]

It means that the S52 motor does not need a valve adjustment to keep the intake/exhaust valves in the right parameters of clearance...i believe they are hydrolic and kept in adjustment by fluid being pumped in/out...

all the other motors are not however, and at certain service intervals require the removal of the valve cover to check the valve clearances, shims are different sized thin plate type pieces of metal that go below the valve spring (i believe?) to keep it mechanically adjusted... u check the clearances with a special reader tool u insert where the shims are placed to see what size (if any) is needed...

theres way more to it than i have said, but hopefully it sorta makes more sense
Yeah I think I get it, thanks.

[Hammdy]

It means that the S52 motor does not need a valve adjustment to keep the intake/exhaust valves in the right parameters of clearance...i believe they are hydrolic and kept in adjustment by fluid being pumped in/out...

all the other motors are not however, and at certain service intervals require the removal of the valve cover to check the valve clearances, shims are different sized thin plate type pieces of metal that go below the valve spring (i believe?) to keep it mechanically adjusted... u check the clearances with a special reader tool u insert where the shims are placed to see what size (if any) is needed...

theres way more to it than i have said, but hopefully it sorta makes more sense
Actually the shims are between the cam and the tappet. On a lot of motorcycle engines they are between the tappet and the valve stem.

[greatcasa]

My buddy who has a 95 M3 with a supercharged S52 motor and knows quite a bit about cars in general and especially the M3 said that this info is incorrect. He said that it is the only the E30 M3's that need to have regular shim adjustments. I read that article and I found so other errors. In the M3 Patheon it listed the M3 Coupe from April 1996-April 1999 as an S52 with a 3.0 liter engine, and we all know it was a 3.2 liter engine.

[bayerische]

My buddy who has a 95 M3 with a supercharged S52 motor and knows quite a bit about cars in general and especially the M3 said that this info is incorrect. He said that it is the only the E30 M3's that need to have regular shim adjustments. I read that article and I found so other errors. In the M3 Patheon it listed the M3 Coupe from April 1996-April 1999 as an S52 with a 3.0 liter engine, and we all know it was a 3.2 liter engine.
Yeah I saw that too, kind of confused me.