Ride Height

Technical advice Q&A

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basilruler1234
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#1 Ride Height

Post by basilruler1234 » Fri Mar 15, 2019 6:02 pm

I know the common wisdom is to retain your original springs as the repro stuff gives the wrong ride height, but I didn't have this option as the spring/shock set-up must have been taken from a tank judging by the damping or lack there of.
So with a new pair of shocks and springs I have suffered with the dreaded ride height problem, last week I made a set of these split collets with a longer section in an attempt to drop the back end back to where it should be. I also made a new set of the rings with a much closer ft on the spring bore size and around my new collets.
I think my theory is sound, but I shall rebuild the shocks tomorrow as I'm waiting for my RAF blue grey paint to dry. Just thought this might be of interest
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James Guest
Series 1 4.2 '65

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Simonpfhc
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#2 Re: Ride Height

Post by Simonpfhc » Fri Mar 15, 2019 6:16 pm

Hi James,

Wow, that’s a big drop! Your theory is sound though, it will lower the ride height. As long as the spring is clear of the lower swing arm, it should be fine.
Simon
62 3.8 FHC
91 Porsche 928GT

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mgcjag
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#3 Re: Ride Height

Post by mgcjag » Fri Mar 15, 2019 6:18 pm

Are they laserjet printed plastic?....will they stand up to the job?.....Steve
Steve
1969 S2 2+2 & Building a C type replica

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basilruler1234
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#4 Re: Ride Height

Post by basilruler1234 » Fri Mar 15, 2019 6:28 pm

No I turned them from solid steel bar and every corner has a 0.8mm radius so there shouldn't be any stress points.
I took a bit of a guess with the height but the car was at least 1 1/2 inches too high, and making a packer to take it up again is much easier than not having gone far enough and making new collets....
James Guest
Series 1 4.2 '65

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Jeremy
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#5 Re: Ride Height

Post by Jeremy » Fri Mar 15, 2019 6:33 pm

I bought replacement rear springs from CMC during my restoration, and with Boge shocks and standard collets the ride height is spot on. CMC started having them made specially for their own restorations as they were not happy with anything available on the market. That was about 2 yrs ago - things may have changed since.
Jeremy
1967 S1 4.2 FHC

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basilruler1234
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#6 Re: Ride Height

Post by basilruler1234 » Fri Mar 15, 2019 6:40 pm

That's interesting because I spoke to CMC after seeing their springs and after a bit of discussion the chap said their springs were specifically for the roadster and fittings them to a FHC would put the car much too high. I see in your signature you've got a FHC so either I was given duff information or they've stopped making them.
James Guest
Series 1 4.2 '65

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Dawnpatrol
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#7 Re: Ride Height

Post by Dawnpatrol » Sat Mar 16, 2019 12:39 am

Hi James,
Very interesting solution to your ride height issue. I say that as that is exactly what the factory did to 4WPD to lower it an inch all round. The fact that the car was lowered is well documented but not how they did it. They also had much shorter and stiffer springs such that they needed wire straps under the wishbones so they didn't drop out on full extension. Only 4 WPD had the mods.
I have the same set up on my car as we copied the originals in the 90's.
Recently appendix K now excludes adjustable ride height (platform) dampers, so this mod may come back in fashion🤔.

Michael
Michael
1961 OTS LWE, 1965 OTS, 1966 FHC.

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PeterCrespin
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#8 Re: Ride Height

Post by PeterCrespin » Sat Mar 16, 2019 11:59 am

basilruler1234 wrote:
Fri Mar 15, 2019 6:40 pm
...the chap said their springs were specifically for the roadster and fittings them to a FHC would put the car much too high.
Sounds a bit ‘iffy’ to me...
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 79 S2 XJ12L; 97 XJ6L

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mgcjag
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#9 Re: Ride Height

Post by mgcjag » Sat Mar 16, 2019 12:10 pm

Dosnt sound right to me either......I dont know for sure but would expect a fhc to be heavier on the rear so sit lower...here is a quote from a previous post a few years ago.....for a fhc...."I checked with CMC what they thought would be the correct set up before fitting up my rear end. They recommended their springs which they believe to be the most accurate to the original performance, and they also recommended fitting a spacer top and bottom"

It is all a bit subjective though as there is no specified ride height for S1/S2 cars......Steve
Steve
1969 S2 2+2 & Building a C type replica

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jag68
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#10 Re: Ride Height

Post by jag68 » Tue Mar 19, 2019 1:59 am

Rear spring part numbers from Jaguar for the Ser 1 4.2l DHC and FHC are identical, so CMC's advise doesn't make sense. Your spring extenders will work to lower your car, I used them on a car that I used to autocross. Yours look quite long. If they interfere with the central tube on the lower control arm you'll know it when you try to mount them at full droop. With the rear of your car being 1 1/2 inches too high you've got a significant problem The manual sets out specs for the springs - that is height at rest, number of coils, and wire diameter. Replacement springs have been an ongoing problem. I suspect yours are too high and / or too thick wire diameter. There are numerous threads on this Forum and the US forum on the subject.
1967 E Type coupe
1968 E Type OTS
2007 XKR

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