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Distributor drive fitting

Posted: Tue Mar 01, 2022 8:08 am
by stag-gered
Hi,

There are a few posts regarding refitting of the distributor drive, including one that refers to the apparent discrepancy between the workshop manual (AA.28) and the Haynes manual as to whether piston Nr 1 or Nr 4 needs to be on its compression stroke.

My engine is a 1098. The head is off so I can see the pistons; the sump is off, so I can see the crank; the timing case is off, so I can see the dimples on the sprockets. It would appear sensible to fit the drive while the sump is off - no need for the bolt and no risk of dropping it into the sump. However, how do I determine which piston (1 or 4) is on the compression stroke? Both manuals start with the drive slot vertical and the smaller portion to the front, so is it for 1 or 4 on their compression stroke?

Hopefully someone can point me (or the drive) in the right direction!

Thanks

Re: Distributor drive fitting

Posted: Tue Mar 01, 2022 10:01 am
by philthehill
Forget about any other manual - The BMC wksp manual (Fig AA.20) states that No: 4 should be at TDC and about to go down the bore on the firing stroke.
I would advise that you use the bolt as the drive goes down into the block. Much easier than fiddling around from the bottom of the block.
To determine if No: 4 cylinder is at TDC on the compression stroke - put your finger on No: 7 cam follower, turn the engine until there is no lift with cam follower on the back of the lobe and No: 4 piston about to go up the bore. When No: 4 piston is at TDC you can then fit the distributer drive shaft.

Re: Distributor drive fitting

Posted: Tue Mar 01, 2022 10:30 am
by stag-gered
Thank you, thank you, thank you. Very clear. I forgot to say the cam followers are also out, but easily rectified. Thanks for the advice on using the bolt rather than fiddling around from below. Off to the garage now to install.

Re: Distributor drive fitting

Posted: Tue Mar 01, 2022 11:34 am
by stag-gered
All in place! :tu1:

thanks again.