V8S Suspension
Discussion
Just got my springs back from Maldon Shotblasting Powder Coating and they look better than new. The powder coating is Plascoat ppa 571 and has produced a deep lustrous smooth black finish which is flexible and so shouldn’t crack when the springs move about.
This product is also available in red and white so give Trevor Lodge a call if you’re interested in finding out more. Trevor has been very helpful and while I was there he had my rear dampers blasted while I waited.
These will now be going off to be refurbished once the primer has dried. I've got some new dampers for the front
so when the rears come back the whole lot will be built up and put on the car – watch this space.
This product is also available in red and white so give Trevor Lodge a call if you’re interested in finding out more. Trevor has been very helpful and while I was there he had my rear dampers blasted while I waited.
These will now be going off to be refurbished once the primer has dried. I've got some new dampers for the front
so when the rears come back the whole lot will be built up and put on the car – watch this space.
Just noticed something odd……..according to the Suspension Wiki every set-up has heavier springs on the front, which seems to make sense given the weight of the engine. However, on the original set-up the rear spring has a larger diameter than the front. Also, the diameter of the steel coil is 13mm against 12mm on the front. Given they are the same length, doesn’t this mean that the original rear spring is a higher poundage than the front? Thoughts?
v8s4me said:
Just noticed something odd……..according to the Suspension Wiki every set-up has heavier springs on the front, which seems to make sense given the weight of the engine. However, on the original set-up the rear spring has a larger diameter than the front. Also, the diameter of the steel coil is 13mm against 12mm on the front. Given they are the same length, doesn’t this mean that the original rear spring is a higher poundage than the front? Thoughts?
The reason the front springs are stiffer is primarily because of the 'motion ratio', or the lever arm effect. For example, my car weighs in at around 250kg per corner. I have 450lb/in springs on the front and 375lb/in springs on the back. At the WHEELS, the spring rates are almost identical at 145lb/in front and rear. The original springs are rising rate, and their stiffness will vary with compressed length as the tight coils close. Nevertheless, I thought the front WERE stiffer than the rear. You can check using one of the many spring rate calculators on the interweb - all you need is wire diameter, coil diameter and number of free turns (not free length). Note that the sums are very sensitive to wire diameter, and if you don't discount the coating thickness you will get a seriously wrong answer...
G.
By an amazing coincidence, this afternoon I also picked up my old springs freshly powdercoated by Chicago Coatings of Mossley, just N.E. of Manchester.
Reasonable cost at £30 for this lot....
They also stripped, blasted & powdercoated my old sump pan, it was in a lot better condition than I thought before I got it replaced. A lot of light pitting, but nothing too serious, it's a perfectly serviceable item now, in case a spare is needed.
They do tend to leave large bricks laying about on French motorways to catch the unwary, don't they Stew ?
By the way, thanks are due to Phillpot for his idea for a fancy spring compressor method to strip the coilovers.....
Cheers Mike, works a treat.
Reasonable cost at £30 for this lot....
They also stripped, blasted & powdercoated my old sump pan, it was in a lot better condition than I thought before I got it replaced. A lot of light pitting, but nothing too serious, it's a perfectly serviceable item now, in case a spare is needed.
They do tend to leave large bricks laying about on French motorways to catch the unwary, don't they Stew ?
By the way, thanks are due to Phillpot for his idea for a fancy spring compressor method to strip the coilovers.....
Cheers Mike, works a treat.Edited by glenrobbo on Wednesday 12th March 00:11
I’ve used one of the online spring rate calculators using these values
Front Rear
Free length 288 285
Coil diameter 82 90
Wire diameter 12 13
Active coils 11 10
But because I don’t know the thickness of the powder coating or the type of steel used for the spring so the values are just relative. The result was F: 302ft/lbs, R:343ft/lbs which means the heavier springs are on the rear. Does this make sense?
Front Rear
Free length 288 285
Coil diameter 82 90
Wire diameter 12 13
Active coils 11 10
But because I don’t know the thickness of the powder coating or the type of steel used for the spring so the values are just relative. The result was F: 302ft/lbs, R:343ft/lbs which means the heavier springs are on the rear. Does this make sense?
glenrobbo said:
By an amazing coincidence, this afternoon I also picked up my old springs freshly powdercoated by Chicago Coatings of Mossley, just N.E. of Manchester.
Reasonable cost at £30 for this lot....
They also stripped, blasted & powdercoated my old sump pan, it was in a lot better condition than I thought before I got it replaced. A lot of light pitting, but nothing too serious, it's a perfectly serviceable item now, in case a spare is needed.
They do tend to leave large bricks laying about on French motorways to catch the unwary, don't they Stew ?
By the way, thanks are due to Phillpot for his idea for a fancy spring compressor method to strip the coilovers.....
Cheers Mike, works a treat.
Also... cheers Mike for the spring compression method. I struggled for ages trying to get my spring clamps on and when I did, I couldn't get them off again! All done now though, using the tie-down method - works very well... Reasonable cost at £30 for this lot....
They also stripped, blasted & powdercoated my old sump pan, it was in a lot better condition than I thought before I got it replaced. A lot of light pitting, but nothing too serious, it's a perfectly serviceable item now, in case a spare is needed.
They do tend to leave large bricks laying about on French motorways to catch the unwary, don't they Stew ?
By the way, thanks are due to Phillpot for his idea for a fancy spring compressor method to strip the coilovers.....
Cheers Mike, works a treat.Edited by glenrobbo on Wednesday 12th March 08:55
Glen – another question for you. In the photo above of your rear dampers it looks like the tighter coils are at the bottom of the damper but on mine they are at the top. Originally the tighter coils were at the top on the fronts as well but when the garage re-assembled them after the chassis work in 2010 they put the tighter coils on the bottom. Does it matter? I didn’t notice any difference.
Common sense says the more open coils should be at the bottom so that they compress more on the initial bump and then as the force travels up the spring the tighter coils slow the compression down to reduce body roll.
Picking up on my other point above about front and rear spring rates, why are all aftermarket set-ups arranged with the heavier spring at the front and the lower one at the rear ie the reverse of what TVR designed?
Any engineers out there like to suggest what’s going on here?
Common sense says the more open coils should be at the bottom so that they compress more on the initial bump and then as the force travels up the spring the tighter coils slow the compression down to reduce body roll.
Picking up on my other point above about front and rear spring rates, why are all aftermarket set-ups arranged with the heavier spring at the front and the lower one at the rear ie the reverse of what TVR designed?
Any engineers out there like to suggest what’s going on here?
Looking at Glen's springs, they don't look progressive to me. I believe TVR changed spring specs quite frequently, so this wouldn't surprise me.
It doesn't matter which way up the springs go - they won't know the difference.
See what happens if you change your wire diameter by half a mm, then ask yourself how reliable your spring rate estimate is...
I recall going through the same exercise with those springs before choosing the spring rates to go with my Nitrons, and ended up concluding that the originals were too soft anyway. But I don't remember the fronts appearing to be softer than the rears!
Have fun,
Graham
It doesn't matter which way up the springs go - they won't know the difference.
See what happens if you change your wire diameter by half a mm, then ask yourself how reliable your spring rate estimate is...
I recall going through the same exercise with those springs before choosing the spring rates to go with my Nitrons, and ended up concluding that the originals were too soft anyway. But I don't remember the fronts appearing to be softer than the rears!
Have fun,
Graham
v8s4me said:
Glen - from your photos it looks like your springs are the same as mine so presumably you have the larger ones on the rear as well?
Hi Joe, Sorry, only just got back on the forum & seen your post.
Pic of my rear damper, straight after removal, alongside new firmer Gaz replacement ( which looks much less beefy ):
And the whole set for comparison:
The old springs were progressive ( rising rate ) & yes, the larger dia were fitted at the rear. They were not standard, but uprated Konis fitted by the second owner a few years into Austin's life.
The dampers are still in good working order but springs were too soft for my liking, even though they look so much chunkier than the Gaz replacenents.
ETA Open coils of old springs were fitted towards the top.
Edited by glenrobbo on Thursday 13th March 09:33
Here’s the re-assembled units awaiting fitting. The pair on the left are the new front dampers and the re-furbished rears are on the right all fitted with the re-furbished springs. The second picture shows for comparison the bushes on the new dampers with the old ones which have done about 40,000 miles. They made them to last!
I’ve set them up with maximum damping on rebound compared with the minimum setting which is the way TVR sent them out of the factory. I know Glen is desperate to bounce on my back end to see how tight it is.
Once they’ve been fitted I’ll update the WIKI. Is there any point in putting ride height on? I will if anyone is interested but let’s face it, if the outriggers have been repaired they aren’t going to be in exactly the same place as when new and tyre profile and wear will make a difference as well.
I’ve set them up with maximum damping on rebound compared with the minimum setting which is the way TVR sent them out of the factory. I know Glen is desperate to bounce on my back end to see how tight it is.
Once they’ve been fitted I’ll update the WIKI. Is there any point in putting ride height on? I will if anyone is interested but let’s face it, if the outriggers have been repaired they aren’t going to be in exactly the same place as when new and tyre profile and wear will make a difference as well.
v8s4me said:
Once they’ve been fitted......
By 'eck Joe you don't like rushing a job do you? v8s4me said:
if the outriggers have been repaired they aren’t going to be in exactly the same place as when new
Unless you've let some cowboy bodgers loose on your car I'd hope they're no more than perhaps a millimetre out!Gassing Station | S Series | Top of Page | What's New | My Stuff