I am assuming your 2005 4/4 will have a Zetec engine? I have certainly seen 4/4s of this era fitted with the blue springs but they were originally specified by MMC for the +8.
The +8s from 1997 to 2004 (beginning of the long door to the end of the run) used the "blue spring" in order to give a "softer" ride that Charles Morgan thought was deterring some potential customers. Most folk think these are too soft for the +8 and rebuild them with one rated at a higher rate.
Sorry but I cannot find the reference to the numbers right now , but I am sure others will know them.
Spring rates are a matter of personal preference and ideally you should do some and trial and error testing.
My memory of Norwegian roads outside of the E6 is that they are not very good, (no offence just an observation) , especially after the winter snow and ice has melted, so you probably benefit from weaker springs to absorb the bumps and very good shock absorbers with weak bounce but strong rebound absorption.
Last edited by MOG 615; 09/12/1510:42 PM. Reason: omission
Andy G 1999 +8 , Indigo Blue. Ex-John McKecknie/Mike Duncan 1955 +4 racer.
As I recall Plus 4 Black Springs are 160 in/lbs Plus 8 Blue Springs are 140 in/lbs 4/4 Eisbach springs are 120 in/lbs
To confuse You more Plus 4 Black Springs were used on +8's as well as +4's The Blue Spring came on late model +8's and Roadsters. Many of these +8's were converted to the Black Springs for better handling. I have used the blue springs on My +8. Now using the Suplex kit. On My '61 DHC with Zetec engine I am using the Blue Springs. Zetec is lighter than orig TR engine. The 4/4 spring is a little longer than the +4 and +8 springs and a bitch to get into place even though that are softer springs.
My 2005 4/4 has a Duratec engine DHE418 ( see picture). It feels like a little trimmed. The blue Plus 8 springs are marked Elbach 05/05. Engine and springs are originally fitted by Morgan. The shock absorbers in front are Rutherford AVO, adjusted 3 clicks. With more than 4 clicks it becomes much up and down activity in the front. At the rear end there are KONI.
Is this then a straightforward configuration, or are there other things I should look at?
My car was built in 2005 and also has the blue springs (but not as clean as yours). I’ve always suspected my front end was a bit on the hard side. You can barely move it by pushing down at the front. A couple of months back Peter B got underneath with his tape measure and concluded my lowers had about 20mm of compression I think he said it was comparable to the stiffness of an F1 car! So I’m eagerly awaiting my kingpins to developed slack so I get in there and play.
My car was built in 2005 and also has the blue springs (but not as clean as yours). I’ve always suspected my front end was a bit on the hard side. You can barely move it by pushing down at the front. A couple of months back Peter B got underneath with his tape measure and concluded my lowers had about 20mm of compression I think he said it was comparable to the stiffness of an F1 car! So I’m eagerly awaiting my kingpins to developed slack so I get in there and play.
Not being able to manually move the front much is totally normal, try any other car and you will see the same. As for measuring the lower rebound spring....little exercise for you, if you have a front bumper grab the stays and do your best impression of a weight lifter and try and raise the car, or use a jack in the middle. Let it go and measure the lower springs.....now push the front down and repeat and you will find there is a considerable difference. The cars 'stick' either high or low by at least 20mm depending on how it was parked, did you roll to a stop, did you dab the brakes, did you power into the parking place more? Its all down to the 'stiction' in the kingpins and bushes and if you saw a car with kingpins and no stub axles and wheels assembled you would see the angle the pins sit at (corrected in geometry by the stub axle face not being parallel to the bush tube)....all a normal part of the geometry. Don't let a characteristic of the car sway you into thinking the rebounds are under load, an excellent video posted on here (somewhere) of a car driving down the road showed the rebounds have a massive gap above them most of the time anyway making a bit of a nonsense of this worry about preloading the rebounds. Of course you want smooth interaction between the kingpins and bushes but if it ain't broke why fix it?
Thanks Colin I will give it a go although my weight lifter impression will not be up to much. I do agree re the stiction as I think I have the hygroscopic Devol bushes as well so very relevant. If you leave the car for a long period I get the impression the front feels tighter. It’s not a great problem to me, more a curious observation and I’m always pondering what to do next.
Thanks Colin I will give it a go although my weight lifter impression will not be up to much. I do agree re the stiction as I think I have the hygroscopic Devol bushes as well so very relevant. If you leave the car for a long period I get the impression the front feels tighter. It’s not a great problem to me, more a curious observation and I’m always pondering what to do next.
Hi Roger, yup I had an 02 +8 on Devols and for sure they swell and the 'stiction' was very noticeable. Not sure when they stopped fitting them though? One clue I was told, not tested for 100% accuracy but it makes sense, is to look at your top bolt, DEVOL cars had a plain top bolt, in other words no grease nipple or oiler pipe. Apart from that its a case of pulling it apart to be 100% sure. I am sure your aware of this but the recommended course of action if you ever replace the pins is to go for Hardchrome and Phosphor Bronze bushes, they have to be oversized O/D as the stubs have been machined to a larger internal diameter, these are readily available from Peter Mulberry, new top biolts and grease nipples will soon cure that stiction, have a read what Phil Royal wrote recently ;-).
My car was built in 2005 and also has the blue springs (but not as clean as yours). I’ve always suspected my front end was a bit on the hard side. You can barely move it by pushing down at the front. A couple of months back Peter B got underneath with his tape measure and concluded my lowers had about 20mm of compression I think he said it was comparable to the stiffness of an F1 car! So I’m eagerly awaiting my kingpins to developed slack so I get in there and play.
Not being able to manually move the front much is totally normal, try any other car and you will see the same. As for measuring the lower rebound spring....little exercise for you, if you have a front bumper grab the stays and do your best impression of a weight lifter and try and raise the car, or use a jack in the middle. Let it go and measure the lower springs.....now push the front down and repeat and you will find there is a considerable difference. The cars 'stick' either high or low by at least 20mm depending on how it was parked, did you roll to a stop, did you dab the brakes, did you power into the parking place more? Its all down to the 'stiction' in the kingpins and bushes and if you saw a car with kingpins and no stub axles and wheels assembled you would see the angle the pins sit at (corrected in geometry by the stub axle face not being parallel to the bush tube)....all a normal part of the geometry. Don't let a characteristic of the car sway you into thinking the rebounds are under load, an excellent video posted on here (somewhere) of a car driving down the road showed the rebounds have a massive gap above them most of the time anyway making a bit of a nonsense of this worry about preloading the rebounds. Of course you want smooth interaction between the kingpins and bushes but if it ain't broke why fix it?
I am a bit confused by your statement "the rebounds have a massive gap above them most of the time anyway making a bit of a nonsense of this worry about preloading the rebounds". My understanding is/was that standard rebounds are always under load and this is quite excessive as they are around 375lb springs, and that only when the top spring is under load and compressed through hitting a bump or during hard cornering does the bottom rebound spring become unloaded. This as I understand it produces a non linear suspension effect where the initial suspension is at the total of the rebound 375lbs plus the lbs force of the top spring, so that when the rebound becomes unloaded the suspension effectively immediately drops to the lbs force of the top spring becoming much softer and this can then effect the handling of the car. So the suspension goes from hard to soft and back to hard when going through a rough time or hard cornering. One approach as I understand it to address this issue is to replace the top springs that are around an inch shorter and to then shorten the rebound spring so that when the car is at rest the rebound spring is just touching the bottom of the stub axle and is not compressed. By shortening the top spring the ride height remains the same and all the suspension is now linear due to the top spring being the main component and and bottom spring now truly acting as a rebound spring. Obviously rebound is also controlled through the the shock absorbers as well depending on what they are and how they are tuned. My understanding is that this approach is/has been used on race and road cars to some success. In fact it is an approach I will be taking with mine when I come to replace the king pins, I will raise the top spring rates by about 20lbs with 1 inch shorter springs, shorten the rebounds having assembled them and measured the amount to remove. and I will then tune the shock absorbers for the rebound rate, possibly using Quantums if I can afford it, or maybe with some minor mods to the AVO adjustable for bump and rebound.
Please tell me if I am missunderstanding something here?
Last edited by AJSki2fly; 10/12/1511:45 AM.
Adrian
Buggered Off, to a modern none leaky car, heart's still ticking
Not so much misunderstanding just there is more information following someone's posting of a link to a Video, just wish I could find it???
I was under the same impression as you, however my thinking was changed somewhat after fitting a Suplex kit to a car (owner on here) and we observed the affect of having the rebound under load or free depending if we lifted the front or pushed it down....and this was after fitting new pins and bushes and yes I had got the clearance between pin and bush correct, as demonstrated to the owner dry pins would fall through the stubs but oiled pins would support their own weight. Anyway this had me looking at 'stiction' more and over several king pin jobs and a few removal of Suplex jobs I was able to observe the same condition. From that I struggle to see how much load the rebounds actually impart on the mains in real life conditions. I understand the theory and have heard the presentations and cant fault the logic or maths but wonder at the effect in the 'real world'....and then the vide was posted on here. It showed the front suspension during a road test, I think the car was a Roadster but that may be wrong, what it showed was as the car was driven into and round bends and even on the straights the rebound springs spent more time free and without any effect on the mains whatsoever....that has me thinking that the whole subject needs more consideration than just measuring or observing a static load that is dependant on how the car was parked up anyway and can be changed by lifting or pressing down on the front?.....maybe?
I think he said it was comparable to the stiffness of an F1 car! So I’m eagerly awaiting my kingpins to developed slack so I get in there and play.
