Morris Minor Owners Club

The damping effort required and the oil specified was thought out by Morris engineers and the units were designed around those parameters

Erm i think things are getting a little blown out of proportion. The handbook states that a 20w oil is ok! After all it is only slightly thicker and im not filling them with tar!

Just taken it for a run and a marked improvement!

BMC has been saying it repeatedly for a long, long time now. I'm happy you "aprreciate and trust" his advice. Many of us simply don't, and every so often somebody reaches the point where they feel that that fact has to be pointed out, before it becomes gospel by virtue of repetition.

Cam wrote:
The damping effort required and the oil specified was thought out by Morris engineers and the units were designed around those parameters. If you start drastically changing things, you can take the units outside of their design safety specification and it's a gamble.

I agree that the mounts are engineered to a certain damping level, but what's the difference between thicker oil, and uprated dampers from a mounting point of view?

Personally, as the damper is also the top mount I'd be wary of imcreasing the resistance using either method, but my point is an increase of 50% on the mountings is an increase of 50% on the mountings, whether it be from thicker oil or uprated dampers. Given the design, telescopic dampers are probably the safest way to increase the damping, but of course they're not a cheap easy solution.

If the dampers/ crossmember were used on the larger 1500 cars (as I think I read here) then maybe that implies room for extra damping on the original units though? Heavier car, heavier engine and so on?

well i will stick with what the service book says i should use.thats my personal veiw.

anyway why take the advice of bmc when he also suggests just putting one bolt on the starter motor.

i think i know what i would do, but thats me

Stick with the handbook? The handbbok says an SAE 20 or 20w oil is suitable.

Mr Cam, Mr Cam!
You're confusing everbody! 20w-50 oil doesn't get thicker as it get hotter, as you well know! IT JUST GETS LESS THIN THAN A STRAIGHT 20 GRADE. ( If you doubt it look at your engine oil pressure gauge - any multigade just like a straight oil gives higher pressure when cold.)
So in a damper, if you use a 20w-50 oil instead of a straight 20 grade, the forces on the attachments will remain no more than than caused by a 20 grade but with the multigrade they will decrease less as the temperature climbs. NOT INCREASE!
But whether its worth it is a different point.
Phew! Regards to all, MikeN.

Heh-heh !! Well done hickup - glad it is working for you - better top them up after a week's running. In fairness - probably if you had just changed the old oil for new (standard) oil you would also have noticed some improvement. 20W50 does not get 'thicker' when hot, it just gets 'less thin' (actually viscosity not thick/thin) than mono-grade oil would do at the same temperature ! I have always urged anyone working on the front dampers to pull the mounting bolts up snug and tight - they sometimes are not all that tight to start with. I have never broken a bolt here - and I used to rally the Minor (below) and that had EP90 oil in the dampers. We have already been over the hydraulic oil story - yes CAR BRAKE hydraulic oil is different and should not go in the dampers, but industrial hydraulic oil as used in the dampers is essentially the same as engine oil - it's just the engine oil has a few more additives, which won't do the dampers any harm. Quite a few of the add-on front tele damper kits mount on the original bolts (via some form of bracket) - and that's probably why they say take the valves out of the lever arm dampers to prevent over-loading of these bolts. My own front tele dampers do not use the bolts - they mount up on the front inner wings near the bump stop mountings - plenty of strength there and no problems so far. So I have both 20w50 oil in dampers AND tele dampers - the ride is fantastic - soaks up dips and crests beautifully at high speed - and the handling is much improved too, yet the ride is not 'hard', just well damped. Colin Chapman always advocated soft springing and good damping - and guess what, it works !
The single bolt in starter is a personal preference - hanging over from my Rally days with both Minor and Mini - makes getting the starter off so much easier/quicker (especially on the Mini) - and I have never had one come loose so far - but hey - only been doing it for 40 years, it could happen yet !
Some folks are so sceptical - I try to give honest tried and tested advice to help folks save hard earned cash/save time and trouble/ improve their Minors. Take it or leave it - it's no skin off my nose!

thanks for the explanation bmc
we all try and help in one way or another

Ok i've done the rear dampers as well. I had topped up the front dampers buit the nearside just leaked most of it although there was an improvement. So i decided to change the oil in it flushing several times. The improvement was great so did the offside as well. To stop the leaking i used hylomar blue on the thread of the bottom bolt.

A friend of mine had commented that my rear dampers were useless (he works for tune up so i trust his judgement) so I thought id do those as well. I have a feeling they are a bit knackered although theyve improved now ive changed the oil. As i flushed the old oil out i noticed a few metal shavings come out on one of the dampers! However it is behaving itself, ill just keep an eye on it.

Indeed we do - thanks, pickup !

No worries, i apreciate the advice!

MikeNash wrote:Mr Cam, Mr Cam!
You're confusing everbody! 20w-50 oil doesn't get thicker as it get hotter, as you well know! IT JUST GETS LESS THIN THAN A STRAIGHT 20 GRADE. ( If you doubt it look at your engine oil pressure gauge - any multigade just like a straight oil gives higher pressure when cold.)
So in a damper, if you use a 20w-50 oil instead of a straight 20 grade, the forces on the attachments will remain no more than than caused by a 20 grade but with the multigrade they will decrease less as the temperature climbs. NOT INCREASE!
But whether its worth it is a different point.
Phew! Regards to all, MikeN.

Mr Mike, sorry for the confusion, I was oversimplifying as usual and took it a bit too far I guess. I just wanted folks to be aware that there are two sides to this and it's up to the individual to make the choice. But most importantly just to be aware of the effects.

For more info on oils, have a look at: http://www.carbibles.com/engineoil_bible.html

I agree that the mounts are engineered to a certain damping level, but what's the difference between thicker oil, and uprated dampers from a mounting point of view?

everything
The good uprated damper kits reduce the load on the original damper bolts, as they use telscopic dampers mounted to the inner wing.
Thicker oil increases the load on the original damper bolts. Bear in mind that the original damper is multi function, and if the bolts fail, you loose some control of the steering as the suspension will be not very connected to the car.
Renewing the damper bolts may be worth considering if you are putting them under increased load. The old ones will have had a lot of punishment over the years.

A monograde 20W oil is not the same viscosity as 20w/50 (except at about minus 10 degrees). At normal UK temperature 20/50 is a fair bit thicker than a 20W oil.

As for hydraulic jack oil - I'd be equally worried about it being too thin unless it carries a viscosity spec.

ok so after all this what do we use then

ok so after all this what do we use then

well - most people's preference is to stick to the design intent and use a 20W oil.

Hopefully our specialist suppliers will have already made sure that the 'jack oil' they sell is rated correctly... but at least if enough people ask them if it correctly rated or not, then if a supplier considers to sell 'any old oil' for the dampers, they would think twice.
;-)

rayofleamington wrote:

I agree that the mounts are engineered to a certain damping level, but what's the difference between thicker oil, and uprated dampers from a mounting point of view?

everything
The good uprated damper kits reduce the load on the original damper bolts, as they use telscopic dampers mounted to the inner wing.
Thicker oil increases the load on the original damper bolts. Bear in mind that the original damper is multi function, and if the bolts fail, you loose some control of the steering as the suspension will be not very connected to the car.

Yebbut - I'm sure I've heard tale of uprated standard lever arm dampers. Which are a marketed item, rather than a home done "bodge" of simply using thicker oil.

So, when using those (changing the suspension reaction rather than design) what's the difference between that and thicker oil?

And what about the 1500 cars? Any ideas about their dampers, mountings, and workload?

And is the Minor suspension loading that critical, or did the designers add a fair bit of safety margin?

These are the sorts of things I like to think/ read about - Highly unlikely to ever put them into practice due to funds and being far too flipping lazy!

Yes there are 'uprated' standard lever arm dampers around - and I have my own suspicions that they may just have more viscous oil ! For the MGB (similar type of damper) - uprated valves are available. But if you study the valves on the Minor damper, the pre-loading can be adjusted. I have done this in the past but no obvious difference - the more viscous oil being much better. The Wolseley/Riley 1500 used the same crossmember - did they use different dampers? And what are the unused holes on the crossmember for - are these for different (ie W/R) dampers ? I would imagine that it's highly unlikely all 4 securing bolts will snap all at the same time - but I do urge a good tightening up. I also think there will be much less stress to the component parts if they are heavily damped - than if the suspension is crashing between the bump and rebound stops due to poor damping ! When I got my car the dampers were useless - and both front bump stop mountings were cracked and distorted. Now the car very rarely hits the bump stops - even though it is running slightly lower than standard. And I agree completely with rayofL - additional tele dampers make the world of difference - but keep the originals working too, and share the load.

My suspension is rather low and i was going to get the ride height increased so i didnt punch another hole through the top of the wing. I don't think ill bother now as i dont think its touching the bump stop at all.