MKII Square with swingarm

[rschurr]

Think i will open the engine and change the rods, it would be a much more stress-free ride then.

If you change the rods you have to make a total engin strip down (rod nuts changed to underneath and ARPA bolts) so you can easily clean also the sludge traps.


Rednose

[roger.fellows]

The later Mk11s had a duplex timing chain. I don't know the date but probably 55/56

[herblesjak]

Thanks for all the infos, very helpful!
I will open the engine and sludge trap, clean the oil ways and fit new rods.
This crankcases and engine parts are too worthwile and rare. I want to ride the bike without fear

Just because of interest: Does anyone has expierence with Carrillo Conrods?
On my 650 Triumph they were to heavy, rebalancing was required...

Regards
Herb

[Bob.Murphy]

The later Mk11s had a duplex timing chain. I don't know the date but probably 55/56

Something at the back of my mind says that the duplex timing chain came with different gearing in the distributor drive to make the dynamo turn faster . . . .

I.E. Its not a simple swap.

Is that true or did I dream it (I love cheese) ??

Bob.

[paul.jameson]

Bob is entirely correct in saying that the duplex chain has different gearing for the dynamo to distributor. What the duplex chain did was to increase the rotational speed of the dynamo in relation to the engine so as to improve charging. But if the dynamo shaft is turning faster than the engine, you need to slow down the rotation of the distributor to suit the engine rotation speed. Hence the different dynamo and distributor gears for the duplex chain. It seems to me that there is evidence of these later (duplex type) dynamo and distributor gears wearing more quickly than earlier simplex type gears. This comes from the range of these gears currently in my workshop. However, I intend to use the duplex chain on my Healey, partly because that was what was fitted when I bought the bike and partly to see how it goes. My previous MkII Squares, (including my first Healey) had the simplex chain. Whilst I did suffer from poor charging at 12 volts with the original dynamo, the fitting of an alternator to the Healey transformed it. I used a Lucas alternator for this first conversion but I am about to make a Bennet Longman pattern one using his drawings and account in Cheval for the current Healey project.

[MARK.WALSH]

Herb
all the advice offered is good. Strip it down for peace of mind.
I think you have bought a lovely looking bike. I really like the lines, and with the swinging arm and twin leading shoe it must handle and brake well. What you have is how the factory should have developed the square four, but unfortunately didn't..
welcome to the club
Regards
Mark

[herblesjak]

Hi Mark,

think the same, it's a good looking bike, frame and brake works well, for me the perfect Square Four.
They factory should have done a swingarm frame...
Thanks for the welcome

Herb

[simon.holyfield]

... I used a Lucas alternator for this first conversion but I am about to make a Bennet Longman pattern one using his drawings and account in Cheval for the current Healey project.

Which Cheval is that in Paul? I couldn't see it in the database.

[paul.jameson]

Simes,

Its April 2009 - almost 10 years ago. Bennett will provide you with the complete item for a suitable sum which you may well find worthwhile since the time taken to make one is significant. Bennett has his bits made by CNC these days which must speed things up no end.
The conversion to use a Lucas type alternator is much simpler and quicker to do but for a Mk II it involves removing parts of the cylinder fins on the rear nearside corner. Whether this would be necessary on a Mk I like yours I don't know as I am not aware that one of these conversions (about 6 were done in total) was ever fitted to a Mk I. In any case, the end cover for the Lucas unit used to be made from a cut down Woolworths milk pan and Woolworths have since gone out of business !
Let me know if you decide to make your own conversion to Bennett's plans. I now have extra information which will be of help to you.

Paul