Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 belt screech

How do you cure the drive belt high pitched screech which occurs during any acceleration with the S3? Is it the belt being too tight, too loose or not centered? Help!

Screech is unlikely to be caused by tension, either too tight or loose. Much more likely to be an alignment issue. You should be able to see which side is rubbing once the trunk panel is removed. Primary rubbing areas are the front drive sprocket and the rear driven sprocket flange. Search this forum for guidance on how to align the belt. And don’t over tighten the belt when you are done with the alignment.

There's basically three adjustments for the belt;
The actual tension, the skew of the rear sprocket in relation to the front and step where the rear sprocket (indeed the whole swing arm and wheel assembly) is offset to the side of the front sprocket.
Skew causes the belt to run off to one side or the other of the rear sprocket when under load. The adjusters should be set so that when the car is on a secure lift with the engine running and in first gear the belt doesn't run hard over to one side or the other. If you've got the two sprockets in line, or at least the planes of the sprockets parallel but he belt is still hard against the side plate of the rear sprocket then you might have to adjust the left-right position of the swingarm using the adjusters on the pivot bearings. Once the skew and step are sorted out then you just need to move the wheel back on the tension adjusters till its tight enough. The Super 3 runs a very high belt tension, and probably the best way to set it is to download the Gates Carbon Drive app and set it to about 75 hertz.
If it still squeals after all that then WD40 on the belt will at least give you peace for a few miles!

I had a Plus 8 and it was a known quirk. When mine developed a squeal I took the belt off, cleaned all the pulleys and wiped the belt ( it was nearly new and good condition) clean. Replaced and tensioned. No squeals for 10 years! This was the simple first tion. A second option on Plus 8’s was fitting a slightly narrower belt ( see gomog).
Try the tension/cleaning options first before checking pulley alignments.
The KISS principle. I had a poster on my office wall....
Keep
It
Simple
Stupid
!

I think he's referring to the toothed drive belt to the rear wheel

What I've learned so far - to add to what Red 3 has said, to adjust the drive belt, loosen the axel bolt ( 24mm on one side and 36mm on nut side) loosen jam nuts on fore-aft axel adjusting bolts. you can then adjust the belt tightness. At this point you will need the Apple App called "Carbon Drive" by Gates who makes the belts. The magic numbers are 72-84 HZ -you take a spanner and repeatedly hit the middle of the belt suspended area and record the noise with your iPhone. this sounds bizarre but it works. Mine is at 79 HZ and there is now very little screech.
I f you eyeball or actually align your front wheels straight and then adjust the steering wheel straight, then go for a drive and your steering wheel is not straight, then you are "crabbing". This means the rear wheel is not adjusted straight. This requires Trial and Error with the axel adjusting bolts or some other ingenious method. Getting it straight should make the belt track in the middle of the sprocket(s). This raises the Question- Is the BB sprocket adjustable, ie is the bevel box adjustable. I am assuming my BB is straight and I am only adjusting the axel adjusters.
Finally my S3 was twitchy at speeds greater than 60 mph so I checked the toe in. This should be 0.5 degrees. At 28 inches apart ,the diameter of the front tires, the distance between the front and rear ends of the sticks that I attached to the tires should be 6mm. the front shorter than the rear- toe in. Mine was only 3 so I adjusted the tie rods until I had 5+mm. This seems to have fixed the problem. My S3 is now a quiet straight shooter!

Do you by chance have any pictures of this process?

My new S3 (330 miles now) definitely has the high pitched whine under acceleration and has a little screech when shifting gears under full load. It's hard to know what are "Normal" Morgan sounds and what I need to be concerned about...

AII I know is in the message above. What I would like to see is how the factory does the alignment, with pictures. I also think the factory should make available a service manual, as there are so many owners that do not have a close by dealer, especially here in the US.

Good luck with a S3 service manual, there has never been a hint of one for the M3W. Most of the servicing and maintenance information for the M3W has come via this forum, mainly learned the hard way by owners. I don't think the dealers got any detailed information either.

If you want to align the rear wheel straight with the body then there is a procedure that is detailed on the MTWC website 5 Speeder section. Assuming you don't have access to that it is essentially laying a laser level along the rear wheel sidewall rim and point it at a target positioned centrally between the front wheels and offset half the rear wheel rim width, plus the laser offset. On the M3W I use the number plate mounting screws to fix the target and mark the rear face, not an option on the S3. This will allow you to accurately align the rear wheel, you also have to juggle the drive belt tension and hope it doesn't all move as you clamp up the axle nut. Some trial and error involved to get it all perfect and the belt tracking well. Once you have a good tracking belt then you can mark the target point and reproduce the "good track" position easily after tyre changes etc.

A steel straight edge along the side of the bevel box drive sprocket and rear wheel sprocket helps a lot with alignment of the drive belt as well. You may need to adjust the rear swing arm pivot mount bolts to get this in alignment. The guide plates should be just that guides, not restraints. If the belt runs up hard against front or rear sprocket guide plates then eventually they will fracture.

Morgan actually support its products? Maybe only in an alternate universe and a rupture in the space time continuim, Think of it this way, you bought a vehicle, made by your cousin Vinny in his garage, that is sort of the Cadillac Johnny Cash assembled from stolen parts for decades....

Welcome to Morgan ownership

rc-kinda cranky-Matt