M30 head to TDC

[Dash01]

I have the M30 head off the engine and on the bench. (Forgot to set it to top dead center while still on the engine with timing chain attached.)

So, now the head is detached, how to correctly set it to TDC before placing back on the block?

[Adnan]

I have the M30 head off the engine and on the bench. (Forgot to set it to top dead center while still on the engine with timing chain attached.)

So, now the head is detached, how to correctly set it to TDC before placing back on the block?

Hi,

TDC would be piston #1 at top of stroke on the compression cycle. Set the head such that both valves are closed on #1. Confirm by going half a revolution on the cam and see that #1 is on the exhaust stroke.

Can someone else please confirm this? It's been a long time since I did this.

Regards,
Adnan

[Dash01]

Thanks, Adnan, that's essentially what I'd planned to do.

But, is there any way to make sure the cam gear is precisely in correct position with dowel pin at 7 o'clock position, so that the chain won't be even one tooth off?

[Adnan]

Thanks, Adnan, that's essentially what I'd planned to do.

But, is there any way to make sure the cam gear is precisely in correct position with dowel pin at 7 o'clock position, so that the chain won't be even one tooth off?

Hi,

Sorry, I don't. If you're afraid of piston/valve contact, then a quick visual check of where the open valves are with respect to the piston position should be sufficient. What if you install the chain in the crank pulley and look for the corresponding location of the cam matchmark and eyeball it that way?

You'll be close enough by setting #1 to compression that you won't hit anything. Of course, avoid moving the cam much once in place. I don't have my Bentley anymore but is there a photograph of the cam that can serve as reference?

Regards,
Adnan