Clutch judder

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LaughingBoy
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Re: Clutch judder

Post by LaughingBoy »

Well I have installed a new lightened flywheel and heavy duty diaphragm clutch cover plus roller release bearing. The judder is now much worse! Kevin's point about engine movement affecting clutch actuation is making more sense as the heavier duty clutch is likely to move the engine more than the old spring clutch thus exacerbating the problem. Also the original Minor linkage has the chassis to gearbox cross-shaft which would surely limit engine movement. In my setup the cross-shaft has been discarded so the problem is much worse. Kevin - does that make sense or am I misunderstanding ...?

Also I do not have a gearbox steady cable to restrict forward movement. My plan is to get rid of my poorly designed mechanical linkage and install a hydraulic clutch and perhaps a g'box steady cable.
jaekl
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Re: Clutch judder

Post by jaekl »

Actuation of the clutch does NOT move the engine forward. It will push the crankshaft forward but if anything the clutch linkage will move the engine/gearbox rearward. The throw out bearing - clutch interaction is an internal force and has no net external force effect, but the linkage does.
kevin s
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Re: Clutch judder

Post by kevin s »

jaekl wrote: Fri May 13, 2022 12:27 pm Actuation of the clutch does NOT move the engine forward. It will push the crankshaft forward but if anything the clutch linkage will move the engine/gearbox rearward. The throw out bearing - clutch interaction is an internal force and has no net external force effect, but the linkage does.
I believe it will in this case because the relay shaft is missing and the clutch cable is pulling from the body to the gearbox.

A hydraulic clutch will help and it's something that really needs doing anyway but it's difficult to be sure , Judder is complicated, I suspect there are multiple root causes though, for instance ours has started juddering lately when heavily laden or on steep hills, looking at it the barely used Left hand mount is beginning to fall apart already (rubber pulling off backing plate) I think the mounts which if I understand correctly were originally designed for the 803 are barely up to the job on a 1098 and really begin to suffer when we push output beyond that, I have cunning plan to fit some Mazda mx5 mounts I happen to have lying around, particularly as we are contemplating fitting a warmed over 1275 A+ engine with mazda gearbox at sometime
philthehill
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Re: Clutch judder

Post by philthehill »

Morris Minor engine mounts in good condition are well able to cope with an increase in bhp - in my case standard mounts are coping with 135bhp plus.
The engine steady bar from the body to the rear head stud must be serviceable and well secured to the body - in my case the body bracket is welded to the box section cross member.
The engine steady wire is not an absolute must but does help to locate the engine in the fore and aft position especially when braking - in my case the Ford based gearbox rear mount is securely mounted within the Minor gearbox cross member so does not allow the engine/gearbox to move for and aft.
The way to go with the clutch actuation is to fit a hydraulic conversion.
It may be worth checking the rear axle to spring mount pads for serviceability. Replacing the mount rubbers with poly mount pads will help locate the axle more positively.

kevin s
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Re: Clutch judder

Post by kevin s »

To be fair the problem with the mounts is not the design but the quality of what is available now. I'd also like to do away with steady bar to help with nvh and because the bracket on the bulkhead on ours has been very poorly repaired in the past.
philthehill
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Re: Clutch judder

Post by philthehill »

The last engine mount rubbers I obtained a couple of years back were from MMOC club spares and they were BMC NOS items and were perfect.
You can now get Poly engine mount rubbers but they are expensive.
https://www.ebay.co.uk/itm/MORRIS-MINOR ... SwLi1ccuYb

I can recommend the ESM Grumpy's engine steady kit. It does exactly what it says on the tin.
https://www.morrisminorspares.com/engin ... it-p830094

kevin s
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Re: Clutch judder

Post by kevin s »

While you are right that the poly ones would be the sensible thing to do, I happen to have these. and I like a challenge.
rps20220514_205946.jpg
rps20220514_205946.jpg (77.4 KiB) Viewed 271 times
Want to keep the body and engine standard but it shoild be fairly easy to make an adaptor to fit them to the front plate (machine a block of alloy or use steel U channel) then chop the top of the body side towers off and weld a new plate on lower down

It will be interesting to see what if any effect they hsve, if it's a disaster only 12 bolts to to back to standard anyway.
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