Duplex Timing Chain Kit

[zippy500]

hi,
I see these kits advertised. Are there any advantages to fitting a dual chain over the single.If so

Are they easy to fit.

Thanks

[rayofleamington]

Most people would say less noise and better life / stronger

[RogerRust]

To fit the duplex chain you need to countersink and fit a new screw at the bottom of the chain. Its best to remove the front plate to do this, so it gets to be quite a big job.



I changed the waterpump at the same time and the whole job took a couple of days. Half a day was spent removing the four bolts that hold the engine mount tower to get the front plate off.

It was worth it though the engine sounds like a sewing machine now.

[RobThomas]

Using the A+timing cover off the 998 Metro and the tensioner strip is easier and does make it quiet. I used this with duplex chains on all of the engines I built. New had a breakage and never heard a single rattle. Can't remeber if it can be used on the simplex chain of the minor or whether you need to get the pulleys off the Metro too. Even so, it ought to be a lot easier than pulling off the front plate.
If you do want to do the countersinking job then you could plug the hole with bluetak to catch the swarf and then drill it down.

I sold a load of these Metro covers to someone in Texas. Wonder what he did with them?

[Willie]

I thought changing to a duplex set up was quite straightforward and I didn't
remove the front engine plate. Rob, yes, I originally fitted the Metro chain
tensioner assembly to a single Minor chain. It was more of a job than fitting
the duplex kit and,of course, needed a Metro timing chain cover and the timing marks had to be repositioned. Theadjuster for the fan belt tensioner
also had to be modified.

[RobThomas]

Thanks for reminding me. I guess mine were all done from the point of view of building up an engine from scratch rather than a mid-life rebuild.
If you use a 1275 midget front plate then you don't need to countersink but you'll need to shorten the dynamo adjuster reinforcement plate if the engine is the thin flange block that came in about 1969 when they went from EN40 cranks to cheapo cranks. By the way, those early Midget cranks go for up to £500 and they come with cooper S rods, too.

Phew! Testing the memory, here.

[bmcecosse]

Duplex is really only necessary if you are going for a high lift/long period camshaft with heavy valve springs. If you just want quiet - fit the single with tensioner.

[wanderinstar]

Rob,
That bloke in Texas probably sold them to Minisport. They are selling them for about £120 each.
Bet you wish you had hung on to them now.
Ian.

[RobThomas]

I bought them for £1 each (if I took them off, myself) and then added postage. Can't remember how much I sold them for but it was a good deal!!
I also sent 10 type 9 siearra boxes by airfreight.