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Guru Reveals Shocking Secret!

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Dave Richards

Dave Richards

Jedi Knight
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/ubbthreads/images/graemlins/yesnod.gif It’s true, the mystery oil that even Dave Russell admitted he didn’t know the composition of! /ubbthreads/images/graemlins/devilgrin.gif

This reporter, while lurking on the MG side today, discovered the following post, purportedly written by Peter himself. /ubbthreads/images/graemlins/jester.gif

Use hydraulic oil, not jack oil. Available at farm type stores. Used in the rams and pumps, etc. Has anti-foaming agents, seal swelling agents (even though that is meaningless in a shock)and comes in various viscocities. We use 20w in our shocks.... and have done for 15 years. Peter

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www.nosimport.com
 
Yep Dar 100,"use Hydraulic oil"-Available from just about every Harley Davidson shop around.They just call it "Fork Oil" to confuse Peter.---Keoke- /ubbthreads/images/graemlins/grin.gif
 
I once asked Peter what oil to use to top up the shocks that he rebuilt for me. His answer was - You don't need to top them up. If one ever leaks, send it back for a free replacement. I didn't press the issue & so never knew what he used.
D
 
Castrol does fork oil (synthetic) in two weights: 5 and 10; I think some other manufacturer's may be heavier.
 
[ QUOTE ]
What is ATF.......5?

[/ QUOTE ]

ATF= Automatic Transmission Fluid

5 = single weight oil, usually multi-grade oil is used, i.e., 10w40.

edited to add:
I think I've mis-understood your query.

I don't think ATF is rated, but it seems pretty thin....
 
[ QUOTE ]
Is it lighter than ATF?

[/ QUOTE ]
It's a little hard to know. SAE 20 engine oil varies from about 200 to 400 SUS at 100 degrees F. A rather broad range spec.

I would expect the various 20 fork oils to be similar to the 20 engine oil at the same temperatures.

The average ATF is around 190 SUS at 100 degrees F.

It appears that SAE20 is a little thicker at 100 degrees than ATF. I don't know what the viscosity of various hydraulic fluids is.

I think that it's probably a good idea to stick with ONE selected fluid, & change the damping rate by the shock valve calibration if needed. The LBC lever shocks can be recalibrated by adjusting their valves.

Maybe Peter will comment.

When I had leaking shocks, I topped them up with Harley Davidson fork oil.
D
 
/ubbthreads/images/graemlins/iagree.gif

Thats right Dave, they are adjustable the only problem I see for the DIY is getting them ballanced.---Keoke
 
[ QUOTE ]
Is it lighter than ATF?

[/ QUOTE ]

-- WTN,You can get it in several weights: SAE 10, 15, 20. I use the Bel Ray Product in the SAE 20 Weight.---Fwiw--Keoke

P.S.: if you have conventional rebuilt or new shocks the additive that swells the seals will prolong their life.
 
Thanks Keoke......

I was just kinda wondering if there was any 5 weight or less stuff out there for my dashpots.

As always.....I wanna go faster. /ubbthreads/images/graemlins/grin.gif
 
If you want really fast piston action, just leave the oil out or run the level very low. Actually, some old SU carbs didn't have dampers, early MG & a couple of others I believe.

Edit: In fact they didn't even have springs, just the weight of the pistons to close them.
D
 
WTN; I never looked to see if they had anything below SAE10.They might but you could cut the springs in half.---Keoke- /ubbthreads/images/graemlins/lol.gif
 
[ QUOTE ]

I believe that the Armstrong shock valving IS adjustable, provided that a person knows what they are doing. Buying new valves just gets you out of having to adjust them. Here is a good reference:
https://www.singercars.com/4ax/armstrong.html
D

[/ QUOTE ]
Hi Dave,
Thanks for that article. Though after reading it, I’m pretty sure I couldn’t adjust them myself. I kept looking for page 2. I couldn’t find nut U and screw Q in the diagram. Don’t know what O, W, or V do. I may have an old set of rear shocks in the garage. I’m sure having one in my hand that I could dismantle with impunity would help. /ubbthreads/images/graemlins/hammer.gif
 
Guru? Me? LOL. Just "experienced". But thanks.

A few points of (maybe) interest. Within the family of large valved (7/8") shocks there are 2 different valve bodies, 2, or 4 holes. with variation of O-rings or not. 3 different large springs .072, .081, .092. 3 different small springs .055, .060, .066. There are several shims for under the large spring, and the small spring has a nut to adjust. We also make a .098 big spring. The "heavy duty" valves that are marketed are a combination of the above, each component of which is found stock within a different shock or shocks.
Our experience with units we've gotten as cores is that ATF is a poor choice. It doesn't seem to lubricate well. A shock with ATF in it invariably feels kind of "gritty", and there is a greater than expected amount of metal flake in the oil. I advise against it, but I truthfully don't know the lubrication properties of it.
Other factors affecting performance differences will be piston construction. There are 3 poppet valve designs, and 4 different piston seal designs. 1 with cup like a wheel cylinder, 2 versions of a piston ring, and 1 with no seal at all.
The above assumes a good bore. Not all are... especially the ATF cores.
If any of you are going to the MG2006 (can I say MG here?) I will be conducting a tech session Sat AM. I'll have lots of internal bits laying around.
Oh, and WTN...if you race wide open all the time, no oil. If you want to accelerate, you need some oil. A little heavier than 10w aids in richening the acceleration mixture.

I apologize for the long post. Peter
 
Gesh, I read it all as always and learned something as usual.

Thanks Peter
 
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