Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Muted Bevel Box- Name Your Price?

Just pretend its a Sopworth Pup--

As many knows I had written many posts about this extremely annoying problem.
On both our cars the bevel box was screaming like a pig in a slaughterhouse.

I installed on both cars new bevel boxes and 75% of the noise was gone.
No, it’s still not noiseless but the sound is bearable.
The painful screaming noise is gone, which was the main goal.

Did now about 2000 miles with the new boxes and they are both OK.

Did this this week a 500 mile tip to the Vosges in extremely hot weather (+30C)
We had the idea that they made just a bit more noise as with normal temperatures, but not much.

Both boxes are running on straight Millers SAE 140 mineral oil.

Putting the bevel boxes in and out is a not to much complicated job.
Can be done with average mechanic skills and tools.

To my opinion “lapping” could even improve this “better” bevel boxes.
But don’t forget that you never get the M3W noiseless !!!

For us this improvement made a big difference in experiencing the joy one can have from a M3W
For that reason I can’t understand why MMC don’t offer a solution to all customers who are suffering from this problem.

Why they don’t offer a possibility to buy a “better refurbished bevel box” with a trade-in of your “screaming pig” ?
Looks to me that it isn’t too difficult to refurbish the old trade-in boxes with better pairing gears.
Who cares if the housing is used before by others as long it don’t scream.

Perhaps MMC is afraid of selling “better bevel boxes” and still getting complains about noise from this “better” boxes.
Because “noise” is for everyone is a personal thing.
Let them test bevel boxes with a dB meter and offer them as noiseless till a certain amount of dB.
This way it wouldn’t cost too much and for 100% sure this could bring back the joy for many with a “screaming” M3W.

I have an early 2012 model which had a screaming bevel box. We endured for almost three years and then got a second box . Unfortunately this also was a screamer.

During the last year I have removed the bevel box ( an easy job ) for numerous reasons.
I decided to have a go to improve the situation and gave to a diff specialist. He put in new ( better?) bearings, changed crush collar to a shim arrangement adjusted backlash etc. Result was basically no change except for when the screaming was at a peak.

Not to be daunted I tried again with a gear manufacturer. They had quick look and could see the wear was indeed at an extreme (can't recall if heel or toe).
This was adjusted to be a more central pattern.
Net effect was similar to above. Another change of when it was noisy, but little reduction overall. Possibly less screaming but more general gear nose.

Hence I was very interested to read your comments on lapping effectivity. I had tried to find somebody to do this before but unsuccessfully.

I would be keen to find out if sending my box to 3 Star Classics was a possibility. Hell would take it over in plane myself given the low cost of fares from NZ to Brisbane !!!
Given they have done a couple already, they could be considered experts ! With a better chance of success.

This has rekindled my interest in perusing the lapping. The weather is utter crap here at present so a couple of weeks off the road is a small price for the chance of a quieter future

Some people say to get quieter once you get past the two thousand mile mark. So the answer may be to drive it more even though it is painful to drive it once it warms up because of the awful howling

Very interesting thread and fingers crossed something positive emerges.
I know a number of people who have done way over 2k miles, I have done over 10k and little or no difference after the first 1k by which time the brand new box turns into the fabled screaming pig.

Please keep us up with developments.

My findings are that the BB scream issue is entirely temperature related and virtually non-existent in winter. That's not to say it should be expected though.

Perceived improvements by using different oils etc. never remove the scream but may alter the temperature at which it starts.

We all like to think a particular modification has been worthwhile but my own experience and that of others it seems, is wishful thinking at best.

Shimming a bevel box is an easy exercise given patience, a wide range of shims and engineers blue. Reading posts above though it seems that there is an issue with crown wheel and pinion matching requiring lapping in.

I'm not aware of any parts supplier offering replacement crown wheel and pinions in any other than factory matched sets.

First drive with ZX1 seems quieter up to 60mph(used to start howling at 50mph)still howling like a banshee at 70mph! slight improvement . more miles at high speed needed , it continues!!!!!!!!!!!

Here is what you are saying in this thread….

-Changing gear oil makes little difference

-New bevel box is no guarantee of improvement…maybe 50/50 chance at best

-3 Point Classic in Brisbane has performed 2 lap jobs on 2 bevel boxes successfully.
The cost was $1300 including r&r as per Trevor V

My desire is to find someone who can fix the noise issue. Then one by one we can send them our units to put right. I am not looking for a magic bullet but a reliable and noticeable improvement!

Can Trevor V or anyone else weigh in on a recommendation or references of 3 Point Classic? Do they need to replace the ring and pinion as part of the service. How much does mileage matter. I am at 1300 miles (my second one) and the noise is steadily increasing.

I need more info before taking the next step. Let's keep this going and together we can find a solution.

Can someone send Mark Cerrone at the factory details of what the guys from Brisbane have done/ achieved ?

I had 8,000 miles on the first bevel Box and I'm at 15,000 (23,000 total) miles on the 2nd Box. They are both noisy. I have tried every brand of snake oil diff lube known to man that was supposed to quiet them down.
The only thing that helps is ear plugs, open pipes and partial deafness!!