Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Something to check

A few weeks ago I went for a short run , but soon was aware something was very wrong with the engine.
One cylinder was misfiring, loosing power and making a bell like clank in time with the engine.
"Oh No" I thought, this sounds expensive as I nursed it gently home, luckily only a couple of miles.
Very close to home tickover went and turning into my street the engine finally gave out completely, but in a graceful way not locking up.

Long story short, the key which secures one of the timing pulleys to the end of the cam had eaten into the pulley itself, gradually making the keyway bigger until it met itself and was barely driving the cam round, if at all, picture below. The end of the cam with the keyway was also damaged.

Thinking it could have done untold internal damage to the valve train, I quickly decided it was a job for my dealer.
I think it says a lot for the robustness of these engines that after a deep investigation only a new pulley, cam and drive belt were needed. Additionally a new valve and collar were reccomended and fitted, as they must have taken some punishment as the pulley expired.
I have just received the car back a month later, most of the time with the dealer being spent aquiring parts.
Plaudits to Oakmere Morgan for a quick diagnosis and fix once the parts were available.

So my message is , keep an eye on the timing pulleys, looking for any wear around the keyway - there should be none.
I have no idea how long this took to fail, or even why in the first place it did, which is worrying !

In the picture below the one on the right is OK , the left one is the clearly the damaged one.
It looks like the wear has started at the front ( making it more visible than if it started at the back) as there is the remains of the keyway existing at the back - but this is conjecture.

The big deal to find out is what caused that to happen.

It is likely that the retaining bolt was not properly torqued with Loctite, and allowed the cam pulley to fret away the keyway eventually failing.

This is very interesting. Remember that a while ago S&S changed the type of pulley nut and at the same time introduced the requirement for applying lashings of Loctite.

They must have had a reason for making this change - maybe you've discovered it?

Probably true, having had all that apart to replace the cams i knows what it takes and what could happen if shortcuts were taken.

Loctite is not a solution for bad engineering or design!

Not only is loctite not an answer to poor design / inspection but it has to be realised that tightening the nut is not what keeps keyed pulleys / hubs on to shafts. The shaft and pulley have to be a light interference fit and there must be no clearance on the flanks of the key in either of them. If the key can be top and Botton fitted as well, so much the better. The only reason for the nut being there is to stop the pulley sliding off the end of the shaft. If a keyway is loose and can move even slightly it will undo the nut in the first few seconds of running.

Long gone are the days when all keys were hand fitted and therefore inspected by the fitter. These days the work is deskilled and keys and keyways are made to assemble as produced and the danger is that when manufacturing tolerances fall outside the design tolerances the the only thing to save the day is the inspection dept. picking up the error. Inspection relies more and more on statistics to provide adequate sampling and a small number of failures is regarded as a fair price to pay for the money saved. There are, in fact, statistics to provide acceptable failure rates - higher rates in lower cost vehicles and ( as I was taught at college) zero at Rolls Royce!

Sorry to hear of your expensive breakdown Graham but you are, after all, just one more statistic.

Early on in production there was an engine which had the pulley come off and smash through the front cover.

Does anybody remember seeing this? It may have been on a factory visit, it may have been a photo on TM. That's all I remember, but it made a mess.

I remember seeing that on here a few years back now, it wasn't a pretty sight and fairly low miles I seem to recall.

There were a handful with this around 2015/16 where the crankshaft pulley bolt unwound and broke through the cam cover.

S&S came out with a modified mounting bolt which cured the problem.