Duplex timing chain kit

[SUE482]

beware, I have just purchase the duplex timing chain kit (10M820) and I have found that the camshaft sprocket wont fit the camshaft locating plate 10M140, see here its approx 0.1" larger diameter than the original I took off. I didn't find out until I had assembled the timing gear and tightened up the nut, tight as ducks bill. Not pleased I can tell you Something else not fit for purpose.
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[bmcecosse]

Tzzzhhhh -criticism of a supplier! It will be The Stocks for you!! Far better with the single chain with Mini tensioner anyway. The duplex is for silly high rated valve springs, and super high lift cams.........

[philthehill]

Sue
Have just checked the dia of my new Kent Cams duplex chain camshaft gear which I have had running and so I know it fits and works.
The dia of the gear against the cam thrust plate is 31.7mm and that reduced dia is of 2.8mm depth. If the measurements of the ESM duplex cam gear is not the same as above the problem lies with the gear. If they are the problem must lie with the internal dia of the cam thrust plate. The cam thrust plate can be relieved with light filing to fit. No need to buy another plate. Please note there is a right and wrong side for the cam thrust plate in that the soft side must go against the cam thrust face.
Regards
philthehill

[SUE482]

Roy both the sprockets were very worn else I would have used a single chain but I couldn't find a replacement single camshaft sprocket only the crankshaft.
Phill I have measured the diameter of my original camshaft sprocket and it is 1.25"(32mm) and the diameter of the duplex 1.32 (33.5mm) a bit of filing then.

[bmcecosse]

The simplex kits with tensioner are readily available from most Mini suppliers.

[SUE482]

Another small problem surfaced when I tightened up the camshaft sprocket nut, the camshaft end face and the sprocket face bind on the camshaft locating plate. It needs 40thou of shims to give sufficient working clearance yet there's no mention of shimming in the workshop manual. Is this another blow to this kit?
Panic over, camshaft sprocket binding on the locating plate, not enough clearance to take in all the tolerance required, a file quickly rectified the problem

[bmcecosse]

Make sure the two sprockets are very well aligned - the actual teeth - not just the rim of each sprocket. I assume you know about the c/sunk screws..

[philthehill]

Sue
I have never ever in over 40 years of assembling BMC A series engines had to shim the cam gear. Yes you may need to shim the crankshaft gear to give the correct alignment.
I have just placed a genuine BMC camshaft thrust plate over my Kent Cams cam duplex gear and there is a 12 thou working clearance between them. The dia of the hole in the cam thrust washer is 33.3 mm, the dia of the thrust face of the cam duplex gear is 31.7mm with 2.8mm depth so there is plenty of working clearance. I also got my spare block with camshaft and checked the clearances and with the dimensions stated all was clear and turning easily. There should be 3 to 4 thou end float for the cam shaft when all assembled.
Have you fitted the countersunk screws under the crankshaft gear?