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MG MGB Technical - Dampers
|I have no doubt there will be many views on this topic.|
My Roadster V8 nconversion has been in constant development since I built it over 10 years ago. I got rid of the original multi leaf"cart" springs several years ago and replaced them with single leaf RV8 ones. Even without anti-tramp the resistance to tramp is good and the ride quality was a vast improvement. BUT I have never found decent dampers. Originally I had MGB spec Spax units.................hard as hell!! Replaced them with Gaz units................too hard too!! Replaced them with RV8 Spax units, these were better in terms of compliance BUT they are incredibly noisy. The valves clatter like a machine gun.
Has anyone used dampers, on a B which don't loosen your fillings or sound like a battle field?
It's a brilliant, beautiful car but oh that clatter!
|Allan, Peter Caldwell, at worldwideparts.com, rebuilds original Armstrong shocks to better than new specifications. He even builds ones with adjustable valving. His prices are very competitive and he is known for his quality work. Take a look, it's worth a shot. RAY|
|Thanks Ray, I have been in contact with Peter and admire what he is doing, but I'm told lever arms are not good with parabolic springs. Not exactly sure what the reason is though, might have something to do with the drop arms and their lack of any sort of lateral support and location. Telescopics, I think, do offer this support especially if they are angle slightly.|
|Alan, I have had a similar problem. Mine is s/c not a V8 but I managed to wind up parabolic springs. I had changed from cart springs to try to get a more compliant ride. It was suggested than Konis were the damper of choice but I found it was way too hard. In discussions with GAz I was told that the 0 setting was no damping at all. I disconnected the lower link and had a (gentle) drive. It "wafted" along-beautifully smooth but totally impractical for proper driving. But it did start the solution. So yes I have Gaz (set on 4 "from zero" for general use and 6 for holidays with luggage).|
My parabolics were modified (extra half leaf from centre to the front pivot) which stopped the wind up. It produced creaking which I found irritating, so now has PTFE strip between the "second" and the half leaf.
Not sure whether this helps as you have tried Gaz, but as I say removing all damping was the start point for me.
FWIW I notice when the fuel is low or if I put a weight in the boot, that the ride changes.
When researching I came to the conclusion that most of the anecdotal evidence related to cars wanting to improve performance handling as opposed to my requirement-comfort handling. Short of trying all different types of damper, I lived with it until a pal who had a standard car but with Gaz let me drive it. Then the call to Gaz technical.
I have heard that lever arms can "froth" as parabolics "move more". Sounds doubful to me. I note your suggestion about lateral movement but I'm not sure teles offer much more!
You might have a point there regarding "frothing" in relation to parabolic movement. and lever arms Not sure about the frothing but It is known that Armstrong's performance goes off as they warm up, it's quite noticeable on a longish journey. My 1800, cart sprung, B suffered this drop off, but using synthetic motor cycle fork oil improved matters no end.
My use of Gaz was on the single RV8 parabolic springs. According to Spax their RV8 dampers were tuned to suit that application which I concluded would also be suitable for my B roadster, although the bottom bracket has to be modified.. Damping seems fine it's just the clattering valves and i can't understand why Spax can't cure that problem.
|Does the clattering valve change depending on the setting?|
Never gone down that road (sorry about that) as I experimented until I got them right, also the clatter is only really intrusive with the hood up, hood down it's more like chattering teeth. I do work with Steve Newton at MGV8 parts and he says it's a common fault but he's not sure whether it is a setting issue, or indeed whether it is a universal fault. I'm going to try some "Yellow" Konis. These were supposably an improvement on the OE "Orange" Konis, universally recognised as a cost cutting fitment by MG Rover to the RV8.
I haven't tried Avo, Munroe, KYB or any of the others yet but they may not have a suitable product.
|Are there any definitive specs for what you currently have? That might narrow down your need to try so many.|
I thought I was going to have to try a lot of makes (and rather baulked at the cost!).
If it was a universal Spax issue, I would have thought it would be well documented. I can't see why it should chatter (but there again I have never taken a tele apart). The main reason teles got popular was that they were cheaper to produce than hydraulic dampers, so I suspect the valve mechanism is pretty crude. Perhaps Steve has a dead Spax you could open up!?
I suspect the issue is one of valve seat material. By the sound of these it could be metal to metal or at least metal to another hard material. As for specifications, not sure where you go there. Presumably car weight, suspension necessities of model, spring rate and range of movement? I have a feeling that the after-market, "upgrade" tele dampers, because they are adjustable, are deemed "universal" which I think completely ignores specific applications.
I believe Spax did, at least, borrow an RV8 to "tune" a damper to that application, which explains why they do actually work reasonably well apart from the noise that is!
Maybe I'll walk off an E-mail to their techs.
|At the risk of stating the Bleedin' obvious: what makes your rear suspension so different to mine-other than the RV8 springs vs. modified paras? In terms of ride comfort. The weight is the same: probably unsprung and sprung weight too. So why do Gaz work on mine and not yours? Doesn't help you I know, but it does rather beg the question. At the risk of repeating myself I'd try disconnecting the teles and see what the spring alone does for the ride!|
|Further to the above, that should read WACK not walk of an E-mail, not many calories in an E-mail. predictive text again!!!**|
I have just been Googling Spax, it seems since it went into new ownership the technical dept is no more!! So I may just have to stick with dampers which work and only drive with the hood down or ear defenders on!
I have a set of Gabriel Classic shocks on the rear of my 69 roadster. Been on now for probably 14 years. They work really well for the day driver/local area touring around the ACT that I do. Comfortable (loaded boot and empty) and silent.
Looking through my file I think they are Factory part #739001, catalogue part #82001, for Volkswagens of the late 50s through to the 70s. I chose those for the weight approximations to the B.
Their website had a range of information to aid choice eg extended and collapsed lengths, stroke length and eye size and form selection (mounting codes). You may be able to determine lengths and stroke by direct measurement of your existing shocks. I had to get under the back end and construct all the relevant measures for my car as I was changing from levers.
Remember, different conversion kits may have different distances top bracket bolt to bottom bracket bolt, and you have to allow for travel of the bump straps.
|Thanks Roger, will check that out.|
I should have added the referenced shocks were described as 'slim design for limited environment application'. They are slim in comparison to others and I recall that installation was quite easy in the limited space above the axle.
Can't find Gabriel on this side of the world. Can you remember which 70's 80's VW vehicle?
Roger said 50s through 70s rather than 70s to 80s. So, wouldn't that pretty much narrow it down to the original VW Beetle? I suppose the bus was made in the 50s, but Roger probably would have specified bus if that was the case.
|C R Huff|
A quick grab from my computer files. Taken from a Gabriel catalogue downloaded in the past somewhere. From memory the R and F reference rear and front.
Have you tried to locate their webpage? IIRC they had a comprehensive one in the past.
Classic Shock Absorbers 82001
R 67-68 VOLKSWAGEN TYPE I +
F 52-65 TYPE I +
R 52-65 TYPE I +
F 66 TYPE I + 1200
R 66 TYPE I + 1200
R 66 TYPE I + 1300, 1500
R 69-77 TYPE I + Exc. 1976-77 Convertible, Super Beetle, & ''The Thing''
R 74-79 TYPE I + Super Beetle & Convertible
R 73 TYPE I + Super Beetle Sedan with 2 bolt lower mount
R 71-73 TYPE I + Super Beetle Sedan with 3 bolt flange-type lower mount
F 68-69 TYPE II +
F 56-67 TYPE II +
R 56-67 TYPE II +
R 69-73 TYPE III +
F 69-73 TYPE III +
F 62-68 TYPE III +
R 62-68 TYPE III +
I attempted an edit but it failed. Had added the following:
They have been retailed through the Supercheap auto chain here over some years in the past - up to a year or two ago at least. Five or six years ago they had an office contact here in the region of Melbourne. I'm not sure of their home base, though their catalogue employs both English and French subject headings - Canada perhaps?
Sorry missed your "bleeding obvious" post. Answer.......don't know! The only difference could probably be age of units, expectations or supplier I suppose. As I said with the noisy Spax on, the ride is very good so little to be gained by disconnecting them, Apart that is from discovering it is actually my teeth chattering or the ball bearing in the tin in the boot!!!
This thread was discussed between 18/04/2016 and 23/04/2016
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