Camshaft position when replacing timing chain.

[1st 5er]

The Bentley, page 4-19, fig. 4-26.

Camshaft and crankshaft TDC position.
Camshaft sprocket mounting bolts should be straight up and down with the locating pin in the lower left-hand corner (A).
O/T mark on vibration damper should align with mark on front case (B).

I'm assuming this means perpendicular to the earth and not in a straight line with the O/T mark on damper and front case.

Accuracy? With a level or is eyeballing it good enough? (Eyeballing is of course before the beers.)

Just wanting to be 100% sure.

Thanks...

[pldlnr]

The Bentley, page 4-19, fig. 4-26.

Camshaft and crankshaft TDC position.
Camshaft sprocket mounting bolts should be straight up and down with the locating pin in the lower left-hand corner (A).
O/T mark on vibration damper should align with mark on front case (B).

I'm assuming this means perpendicular to the earth and not in a straight line with the O/T mark on damper and front case.

Accuracy? With a level or is eyeballing it good enough? (Eyeballing is of course before the beers.)

Just wanting to be 100% sure.

Thanks...

No, the earth doesn't come into play on this one. Use the cam sprocket bolts on the sides of the sprocket. A line between them will bisect the circle. That line should be parallel with the engine block. Here is a little pic:

[1st 5er]

If the motor were straight up and down as opposed to slanted,
then the up and down bolts would be perpendicular to the block surface.
Is that what you're saying?

If so, then a T-square set on the block will align with the up and down bolts, right?

[pldlnr]

If so, then a T-square set on the block will align with the up and down bolts, right?

That sounds about right. When I did the headgasket on my b35, I had a little anxiety about the whole thing. But, I had the ability to mark the chain and the sprocket together and then zip tie it. With the chain coming off, this makes it more difficult.

Can you find a place to scribe a mark with a tooth on the cam sprocket and the head? Maybe you can make your own mark at TDC before disassembly. Is the head coming off?

If the head stays on, just make sure it's at TDC on the crank and the number 1 cam lobes are pointing down at the cylinder. At the same time, the cam sprocket bolts should be oriented like we said. Then, just make sure you don't move it when you do the chain.

You could always take a picture before disassembly.

[1st 5er]

The head's not coming off this time, hopefully.

I had replaced the head gasket and ended up with a constant miss.
I replaced all ignition parts and secured all vacuum connections.
Ether uncovered no leaks so I think maybe I missed the timing by a tooth or two.
The engine is quiet, so no valve / piston interference.

Anyway, I've taken it back apart and wanted to be sure of the alignment as I wasn't sure when I did it the first time.

Thanks...

[cvillebimmer]

Couple more good pics...

[1st 5er]

This picture is worth the thousand words, thanks.

Couple more good pics...

[cvillebimmer]

Lucky for you! This is what I did, prior to asking...



Demet over on bimmerboard gets the credit for the pic.