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#1 Gear lever vibration

Posted: Sun Oct 27, 2024 7:45 am
by MartinA
Hi. I had the engine (4.2) and gearbox (4 speed synchro) of my FHC rebuilt when the car was restored and it has a few irritating faults:

1. The gear lever vibrates which causes the chrome bezel on the gator to rattle against the gear lever shaft. The gearbox works smoothly and I have removed the noise by attaching a rubber washer to the inside of the chrome bezel, but would like to sort it properly if possible.

2. The gear lever moves slightly under torque forwards and back by approx 0.5 to 1”.

3. The clutch is heavy - it was fitted new when the box was refurbished along with slave and master cylinders, but is nowhere near as light as my previous S2.

I have checked the engine mounts, engine stabiliser and belt tension in case these were leading to engine vibration referred through the gearbox, but this didn’t make any difference. In addition the gearbox spring has been replaced in case this was too spongy, but again no difference. Any ideas on what may be causing the vibration and lever movement most welcome. Thanks in advance.

Martin

#2 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 8:42 am
by politeperson
Do you have the rubber bush missing between the gearbox mount and the gearbox cross member?

Image

#3 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 9:21 am
by mgcjag
The locking pin hasn't been left in the rear gearbox mount has it?....Steve

#4 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 9:45 am
by MartinA
Thanks - I don’t think the bush is missing or the locking pin left in, but will check. Thanks.

#5 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 9:53 am
by mgcjag
Rear engine stabiliser to bulkhead adjusted correctly

#6 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 10:44 am
by MartinA
I think so - it looks pretty tight and the engine block is not quite level. Should it be completely level?

#7 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 11:47 am
by malcolm
In terms of gearbox movement, I think they all do that a bit under load?

#8 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 3:57 pm
by Allrand
Make sure that the engine stabiliser mount doesn't carry any weight. It should just be tightened from below and above to lock the engine in it's natural restng position. The mount just resists or damps any up and down movement of the engine.

#9 Re: Gear lever vibration

Posted: Sun Oct 27, 2024 6:00 pm
by nefematic
I had the same symptoms after an engine swap. Mainly, I made responspible the fact that I didn‘t balance the crankshaft/flywheel/clutch. Turns out though I had slightly misaligned the engine/gearbox at the main engine mounts: the engine was not straight and level. Loosening up both engine mounts and the stabiliser, I double checked the engine was level and straight, and refastened. (There is more leeway than I thought possible). Made a good difference. No more gearshift lever moving aound at torque changes.

MartinS

#10 Re: Gear lever vibration

Posted: Mon Oct 28, 2024 8:51 am
by MartinA
Thanks for all the suggestions - I'll investigate further.

Regards,

Martin

#11 Re: Gear lever vibration

Posted: Mon Oct 28, 2024 8:13 pm
by nefematic
Martin,

Regarding the nervous chrome bezel: My friend David fixed that for me (as he did multiple other things as well). The unnerving rattle he fixed by putting a rubber O-ring between the brass bottom and the chrome top. When tightening the chrome the rubber O-ring expands inward - pressing on to the gear lever shaft as a sort of gasket. No more rattle and a fixed height. Good fix.

MartinS

#12 Re: Gear lever vibration

Posted: Wed Oct 30, 2024 1:05 pm
by Jack the lad
The prop shaft u/j's especially the front one would be my first port of call.