1275 timing chain

[win]

I am rebuilding a 1275 midget engine, some parts were missing, it had a duplex timing chain, but no cover.
I have obtained a cover, it looks like a standard one, except for the breather can and outlet pipe.
I need information on which tensioner to use as the duplex sprocket does not use the rubber ones, I have seen discussions about tensioner pads, any advise welcome.
Also what thickness rear plate when using a standard ribbed Morris gearbox.

Regards Win.

[bmcecosse]

My advice - don't use a tensioner. I tried it once with a duplex chain - 100 miles it lasted before the rubber pad disintegrated. It's fine without a tensioner, provided the chain and sprockets are in good condition. Make sure the duplex cam sprocket doesn't rub against the timing case....... And -thick rear plate - inspect it carefully for cracks, and if it's not from the 1275 engine then it will need some 'opening up' around the rear main bearing, and at the top dowel location. You also need to be careful with choice of oilpump - the 'steel backed' pump is considered to be the best - and should fit under the cover without any problems.

[IslipMinor]

Win,

The 1275 MIdget engine never used a timing chain tensioner at all. The later 1275 engines fitted in the Marina/Ital did have a tensioner on the A-Plus block, but so long as the chain and sprockets are in good condition, it is very reliable without a tensioner.

Timing cover - the 1275 Midget had the oil separator on the timing cover and it is part of the crankcase breathing system. If you don't have the breather on the timing cover, then you must have one on the rocker cover (which the 1275 Midget did not). The rocker cover breather does not have an oil separator, so you could well suck in oil along with the fumes. Better to get the proper Midget cover, as the in-line engine really does need an effective breathing system, or you will get horrible oil leaks!

The rear plate needs to be the thick one from a Midget, or something with the same thickness, then the ribcase Minor gearbox will fit straight on - just be aware that it is not as strong as the Midget box, neither does it have the same close ratios either. Driven sensibly it should be perfectly OK, but if you are planning to modify the engine, then even the 'proper' Midget 'box is a bit weak.

[win]

Thanks gents

[Kevin]

The rear plate needs to be the thick one from a Midget, or something with the same thickness, then the ribcase Minor gearbox will fit straight on

Just a small point richard how would you suggest the standard clutch return spring is mounted as the midget back plate doesn't have the little extra flange shape with the hole for the spring in it.

[bmcecosse]

Drill a little hole ? If need be - attach a bracket??