MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Uprated Lever Arm Damer Valve

Gentlemen
After I changed my 1275 3 layer rear leaf springs to the four layer 1500 springs with heavily improved handling as a result, I feel that I can stiffen up the damping as well to suit the new springs. The hight of rear of the car was only increased with a few mm's.
I saw this:
https://rimmerbros.com/Item--i-AHH7218
.....but the product discription link doesn't work.
Do any of know of the product and which oil grade do you recommend in combination with it? People recommend full synthetic motorcycle damper oil, grade 20......
Jan
Jan Kruber

Not damer, but damper, sorry, but it's not possible to edit the headline......
Jan
Jan Kruber

I refilled my original LA dampers with Silkolene SAE30 motorcyle fork oil. I felt it improved matters somewhat.
Oggers

Jan,
be aware that the SAE numbers have a range and there are different qualities to the same grade of different oils.

See here for 'heavy' - https://www.millersoils-shop.co.uk/classic-shock-oil-46

and here -
https://cdn.opieoils.co.uk/pdfs/millersoils/Classic-Shock-Oil-46.pdf

And here for 'light' -
https://www.millersoils-shop.co.uk/classic-shock-oil-32

and here -
https://cdn.opieoils.co.uk/pdfs/millersoils/Classic-Shock-Oil-32.pdf

Some people use a 20 weight oil, some 30, but remember the range and that different oils have different qualities.

See below for oil ranges.



Nigel Atkins

Those uprated valves are such a rip off. £30 for a few shim washers and/or a spring.

I have quite a few spare valves and springs, depending on what you have, what I have and what you want, I might be able to do a swap with you for something stiffer.

20w oil is standard. Heavier can work, but it can also damage the internals.


Malc.
Malcolm Le Chevalier

BTW - for those that don't click on the links I put in my last post 32 and 46 aren't the SAE weights, they're 10 and 15 SAE.

And I don't know what's best for car and not bike or other way round.

I'd suggest contacting the oil manufacturer and tell them what you're doing and want to achieve and see what they say.
Nigel Atkins

Bear in mind that using a heavier oil to harden the damping has a potential drawback.

The shaft that the shock arm fits onto is splined. If the resistance from heavier oil is too high the splines will strip and the shock is then useless and no longer repairable
Dominic Clancy

Here is my source of info

https://mgaguru.com/mgtech/suspensn/fs110.htm

SAE 30 hydraulic (fork oil) seems fine, although at the top end of the recommendation.
Oggers

More to bear in mind, what suits a race track doesn't always suite real world road use. I've had to soften my adjustable dampers as I found with the state of many of our roads items have been rattling loose which suggests more wear tear on the suspension system and car.

I'd forgotten hydraulic jack oil is equivalent to SAE 10W.

Not all oils are the same or equal, don't just go by the published numbers, there's lies, damned lies and published specifications. :)
Nigel Atkins

One and a half year ago I bought the Moss reconditioned dampers. Apart from being a little to soft in the compression stroke, they work fine mechanically and they are still oil tight.
1) Do you know with which weight oil the dampers were delivered with from Moss?
2) If it is thinner than w30, maybe I could poore in some thicker oil.....
Since there is only one valve in the damper it has to be a compromise, right, same amount of oil in the same time frame, on the compression and the rebound stroke respectively.
3) Does the board agree on that or am I far out here?
I consider the Rimmer Bros valves and some suitable oil for a quick and easy fix here and now, before ordering an upgrade at Peter Caldwell, when the present dampers start to leak, which I have read is a "when" and not an "if"....
Last a comment about motorcycle fork oils, be cautious when using fork oil: I once read, that when talking automobile motor oil weight, they are the same grade, regardless of the brand.
This is not nescessarily the same when talking motorcycle fork oils. It seems there are no international standard present for those oils.
https://transmoto.com.au/comparative-oil-weights-table/
Malcolm, I read somewhere, that it was possible to DIY an upgrade by swapping to valves from eg Healey 3000, is it some sort of swap you are talking about?








Jan Kruber

Jan,
you are getting the idea now about comparisons of numbers and specifications not being straightforward.

I don't know the answer but are all Centistoke (Cst) testing scales standardized the world over?

According to Morris lubricants "All grades can be freely mixed if required to provide an even greater state of suspension tune." - no doubt what they refer is to mixing of their oils as the additives are the same throughout the range.

Also note for the same weights as Millers the Morris cSt figures are different. - https://www.morrislubricants.co.uk/fileuploader/download/download/?d=0&file=custom%2Fupload%2FFile-1460028526.pdf

Fuzz Townsend's Classic Oils has Morris 15wt as -
"Recommended for a wide range of motorcycle and automotive applications, including lever arm dampers on classic cars."

and for 20wt
"Recommended for many suspension damping systems, especially where a high damping effect is required. Suitable for lever arm dampers when used in competition."

https://www.classic-oils.net/Oils-by-Application-and-Type/Damper-Oils/
Nigel Atkins

This may be useful but at that price they seem very proud of their product https://www.ebay.co.uk/itm/MG-midget-SHOCK-ABSORBER-REBUILD-AND-UPRATE-KIT-FOR-ARMSTRONG-LEVER-ARM-SHOCKS/263401651445
David Billington

Many years ago, the quick fix was to silver solder two of the four holes in the valve to stiffen the shock.
J Bubela

Nigel, I have been messing with motorcycles for many years, I'm allways cautious when buying fork oil because of the confusing weight / grade informations on the can's, not as straight forward as with engine oils.
David, then I would rather add another $75 and have both dampers upgraded at Peter Caldwell....
J, but this affect not only the compression, but the rebound as well, wouldn't it?
Anybody know of the oil grade in the reconditioned dampers delivered from Moss, in "real" weight or in cSt?
Jan Kruber

Jan, I do kits like that moto-build one for less than half the cost! :-o

I am not convinced Moss even change the oil judging by the filthy, stinking oil that comes out of fairly recently refurbished shocks I have had. 20w oil is widely regarded as the correct weight.

Malc.
Malcolm Le Chevalier

Yes, there are different valves and different stiffness springs for bump and rebound, so they are actually very tunable devices.

Just a few bits in the tuning kit :-)

Ignore the carb jets obviously.


Malcolm Le Chevalier

Malcolm, can I have your email, please? Mine is jkrub007 at outlook.dk
Jan
Jan Kruber

This thread was discussed between 13/08/2018 and 14/08/2018

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.