Timing chains: duplex v single

[badfelafel]

Does a duplex timing chain sap power? any other possible disadvantages?

Any major advantage over just replacing with a normal single chain???

thx all

[RogerRust]

Its quieter and should never wear out. Thats why I've fitted one.

[bmcecosse]

Only necessary for driving a hotter cam - with stronger valve springs. If you want it quiet - go for the later Mini set-up still simplex chain but has a tensioner !

[Willie]

Fit the duplex type it is cheap and effective. If you try to fit the Mini type which has a tensioner you have to fit the larger timing cover and drill a precision hole in the block too. It also means that you have to fiddle with the dynamo adjusting bracket. Far simpler to fit the duplex kit.

[bmcecosse]

True enough! But duplex wears too and is not particularly quiet. To fit duplex you have to countersink the two holes in the front plate - so there is drilling with both.

[chrisd87]

I fitted a duplex to my new engine and it took me probably about 15 mins (with the engine completely stripped). They do look good too!

[dunketh]

Just out of interest, what does the 1275 midget engine have fitted?

I'm sure I read somewhere it was duplex as standard but the timing cover doesnt look particularly bulky.

Not that I'm fussed either way, so long as it turns the crank.

[bmcecosse]

Same cover for both. For interest - my 1340 Mini recently SPLIT the duplex crankshaft sprocket - losing all drive to the cam. I have NEVER heard of anything like this in all my days. Fortunately - the valves didn't hit the pistons (despite high lift cam!) and all is up and running again.

[glyna2006]

if you fit the covers with the breather on you need to split it sideways or it'll foul the fan blade.midget 1275 had duplex,if youve standard engine single chain is ok but the use of 2 rubber rings as tensioners were a bit crude but worked.There used to be a lot of ctattery mogs and a35's about but they seldom broke i can only recall 1....glyn

[picky]

i am rebuilding a 1275 midget engine and it had a simplex setup. I was told it came from a 1970 year. I will be replacing it with a duplex setup.

[glyna2006]

Picky you are right some had single chain I have 3 here with duplex glyn

[benw]

I replaced the seriously worn simplex on my 1098 with a duplex - not exactly silent now but much quieter than the old one (although maybe a new unworn simplex would be just as quiet?). Once I'd battled to get the old one off, the new duplex went on a treat. No idea if there will be any advantages, but its cheap and easy, so why not I thought?

[youngun]

How much is a duplex kit for the 948 engine?

[bmcecosse]

Check out Minisport/Minispares/DCN/MOSS websites and compare!

[rocco]

Extreme thread resurrection here but has there been any development in the past 15-years with regard to single v duplex timing chains?

ESM sell the duplex kit for less money than the single kit which seems a bit odd if duplex is an upgrade. Also, neither kit with the sprockets included contains the large rubber ring tensioners that come with the single replacement kit in the link below, but I don't understand why not.

https://www.morrisminorspares.com/engin ... ls-p830312

Any advice for me please? I understand that fitting the duplex kit involves using some kind of counter sunk screws and the original cover will still fit. It's confusing to know which one to choose.

[svenedin]

ESM actually have my car at the moment. The simplex chain was rattly and worn. They recommend a duplex and so that’s what they are doing. There was also an oil leak from the timing chain cover so it made sense to do it.

[kevin s]

I fitted a Duplex, it will stretch and rattle but it will take a lot longer than the simplex, the duplex doesen't have the rubber rings. Also when I stripped ours the sump was full of the remains of one of the rubber rings, with debris from it blocking the oil pick up.

To fit it you just need to replace a couple of the front plate screws with countersunk screws.(and countersink the front plate).

rps20210611_202221.jpg (57.77 KiB) Viewed 1095 times

[philthehill]

Add the tensioner from the 'A' Plus engine and the setup is near indestructible.
Add the steel cogs and the wear is near banished.
The cheaper cast iron cogs do wear.
A good quality duplex chain without split joining link is a must.

[NETTIE]

Hi just recently replaced my single with Duplex a massive improvement and a must especially if your engine is out makes the job a lot easier.

[rocco]

OK, based on this expert advice I'll buy duplex. Are the ESM kits made with steel cogs and a chain without a split link?
Who sells the best duplex kit if not ESM?