Australian Jensen Forums

For owners of Jensen Cars from Australia and around the world.

Leaf Spring Sag

Keep it pinned to the road.

by Paulio » Tue Jan 20, 2015 8:27 am

How do coilovers affect ride/control/feel Nig?
User avatar
Paulio
 
Posts: 119
Joined: Thu Feb 17, 2011 12:59 pm
Location: Melbourne

by Interceptor3 » Tue Jan 20, 2015 9:47 pm

I'll tell you once they are in. Main thing is they do not sag, and you can adjust them so the car sits at the right height. Not that I have this problem. Handling is meant to improve, especially when combined with the 17" wheels and decent rubber (which I have).

I just bought an NA8 MX-5. Man the Jensen was strange to drive after that. Steering so slow. So big. Hah.
Nigel Honey
Hobart, Tasmania
'72 Jensen Interceptor Mk3 128/4633
'08 Mitsubishi Lancer Evolution X MR
User avatar
Interceptor3
Site Admin
 
Posts: 495
Joined: Thu Feb 03, 2011 7:46 am
Location: Hobart

by dinofritz » Thu Aug 13, 2015 12:57 pm

Hi everyone,

Well, mid winter so it's time to get the leaf springs looked at properly (and I'm so glad that I did).

Took it to a leaf spring specialist here in Sth Oz (Robert Fish), and started by making a few measurements first. Whereas the passenger side had dropped 1/2 inch lower than the drivers side, now the driver's side was slightly lower???

After I had them off the car, the reason was obvious - one of the leaves on the drivers side had broken clean in two.

After having a chat with Robert and disassembling both spring packs (hey, Trev, here's some good news - he originally worked at Southcott Engineering and showed me a spec sheet for a MK III that he reset in the late 1990's which had an LPG gas tank fitted.........), we think that trying to reset my 40 y.o. leaves would be marginal at best, so the best course of action may be to actually make up a new set.

Well, this may end up costing a bit, but I'm glad that I opted not to fit the coil overs (I'd rather fix the broken leaf problem than to try and mask it).

More to come as things progress.

Dino
User avatar
dinofritz
 
Posts: 78
Joined: Wed Nov 16, 2011 2:08 pm

by dinofritz » Fri Oct 23, 2015 11:53 am

Progress!!!

Well, after finding the passenger side main spring bent, and a cracked leaf on the drivers side (see below), I oped to do the "safe and proper" thing and remanufacture a set of rear leaf springs, so this should last for another 40+ years.

Image

It's taken an while, but the good news was that the manufacturer (Industrial Springs) were actually able to track down the correct sized material for the leaves (most manufacturers were going to use metric sizing, which would have caused problems with thickness and how much the springs would have deflected), and the staff actually travelled to the Bay to Birdwood to stick their head under some Interceptors to try and improve the design and eliminate the rear spring sag problem. Note that thy increased the length of the top two springs to help support and strengthen the main (top) spring:
Image

I must say that I was extremely impressed with how they look, even with the dimples made into the bottom of the springs, making them look OEM!

Image

Looking forward to getting them on the car in the next week or so.

Dino
User avatar
dinofritz
 
Posts: 78
Joined: Wed Nov 16, 2011 2:08 pm

by stephenw » Sat Oct 24, 2015 1:00 am

Hi Dino
How far did the you get with the composite idea, must admit I was eagerly awaiting the results, although i must say the new leas look great.Its a pity they couldn't be coated with some durable flexible coating to keep them nice.
Steve
stephenw
 
Posts: 94
Joined: Wed Jul 25, 2012 9:40 am

by Paulio » Sat Oct 24, 2015 4:02 am

Nice! Are you tempted to grease them up and wrap them so they are quieter and contaminant free? Can I ask how much this set cost you? I think they may be in for a few orders of the same......
User avatar
Paulio
 
Posts: 119
Joined: Thu Feb 17, 2011 12:59 pm
Location: Melbourne

by dinofritz » Sat Oct 24, 2015 10:26 am

Hi guys,

Unfortunately, I had no luck tracking down a spring specialist here in Australia who would do anything using parabolic springs, or composite materials. However, in the last week or two, I read that there were some advanced manufacturing companies in Geelong who do some cutting edge work in carbon fibre who may be worth a try (e.g. http://www.carbonrev.com/ ). Seems that none of the spring manufacturers were willing to invest around $1m into the new technologies for old-fashioned leaf spring technology, and the government weren't going to chip in any money to help them either.

Unfortunately, I couldn't find anyone in the UK that would also be willing to design rear parabolic leaf springs for the Jensen either. Owen Springs weren't interested, but there was another UK company which I found a day or two ago that claims to do parabolic one-offs http://www.jones-springs.co.uk/ . This was really a way that I would liked to have gone - Google "Land Rover Parabolic Springs" - suppliers have made parabolics to retro fit onto the old Land Rovers, and many owners have claimed improved ride quality almost equal to the later coil spring fitted cars. And they'd ne heaps lighter too!

As to how much for the set, let's just say that after buying new bolts, etc., there wasn't much change left from $1,000. Ouch!

Started to fit them on the car today, about 1/2 way through the job, but seems to look okay so far.

Cheers, Dino
User avatar
dinofritz
 
Posts: 78
Joined: Wed Nov 16, 2011 2:08 pm

by dinofritz » Thu Nov 05, 2015 11:16 am

The Jensen curse strikes again.......... :(

Fitted the new rear leaves on the car, and was I surprised when I saw the result - the car is virtually sitting 40 mm higher than standard, and on the drivers side the shock absorbers have pulled the leaf springs into place (virtually a locked suspension)! I have a photo, but you'll be on the floor in laughter if I posted it :lol:

So, some final fettling is required to get the correct ride height - but I thought to have a little fun with the car before I pulled them off to test how the car would drive.

OMG the new leaves have really stiffened up the rear end, transforming the entire car's handling!!!

I always thought that my car "floated around" a little too much previously compared to other Jensen's, and while I knew the rear seemed soft (especially under acceleration), I thought that the front would really need some attention too (I've been reading about the thicker front sway bars on the UK forum with interest). But these new stiffer leaf springs have really stabilised the body roll on the car, making it so much sharper and surefooted both around corners and at speed.

The guys at Industrial Springs have offered to reset the rears for me (lovely guys), and suggested that I give the car "a bit of stick" under acceleration to try and settle the rear a bit more. What surprised me here too was that there is so little squat under hard acceleration (unlike the past), and a few squirts on the accelerator at a few lights actually had me settle the rear end by another 10mm!

I must say that if I can get the rear ride height correct and still retain this level of stiffness, I'll be a VERY HAPPY man!

More to come in the coming weeks.

Dino
User avatar
dinofritz
 
Posts: 78
Joined: Wed Nov 16, 2011 2:08 pm

by Paulio » Thu Nov 05, 2015 12:28 pm

How long did they suggest to leave it until you take them for the reset? Did they give you a rough figure of how much they'll settle? Sounds like your on the right track though. Can't wait for your next installment!
User avatar
Paulio
 
Posts: 119
Joined: Thu Feb 17, 2011 12:59 pm
Location: Melbourne

by Lyn » Wed Nov 11, 2015 8:30 am

If you need extra ballast for the passenger side i would be happy to help. The furthest i have been in mine is to the letterbox so far.
Lyn
 
Posts: 8
Joined: Sun Feb 02, 2014 5:50 am

PreviousNext

Return to Suspension

cron

Who is online

Users browsing this forum: No registered users and 1 guest

View new posts