Spitfire front suspension set up.

[Black Cat]

Hi,

Trying to sort out my front suspension. The chassis is supported on blocks so there is no weight on the suspension at the moment. With the shock bolted in place the spring doesn’t sit flush with the upper mounting plate, I suspect when the weight of the car is fully on the shocks and spring there may well be a slight bend in the spring, would you say this is what I should expect or am I doing something wrong here?  

The parts are from Moss and the shocks are telescopic Spax adjustable. Ref. TT3301PR and the springs are uprated fast road. Ref. TT4301PR.

Many thanks

[Clive]

Looks fine to me. The top fixing on the shock allows movement so when weight is applied ll will be well. (you don't see this with std springs as they are under tension and will have a slight bend. It is what springs do!)

 

[Nigel Clark]

1 minute ago, clive said:

Looks fine to me. The top fixing on the shock allows movement so when weight is applied ll will be well. (you don't see this with std springs as they are under tension and will have a slight bend. It is what springs do!)

 

+1

That spring top looks as I would expect without load on it. Try placing a jack (with rubber pad or wooden block) under the trunnion and applying some load to the suspension. The spring should then 'square up' to the top plate.

Nigel

[Black Cat]

Gents, thanks for your reply's.

As there is no weight on the spring at the moment, there is some play between the top and bottom of the spring on the shocks. How tight should the center top bolt on the shock be, hand tight or is there a torque setting and if the spring is loose on the shock when the center nut is tightened up will there be any knocking as there must be times when there will be no weight on the springs,  such as if the wheel is not in contact with the road at some point. lastly, should I fit a spacer to take up the slack or don't you think this would be necessary?

Many thanks

 

[Colin Lindsay]

I wouldn't fit a spacer until I see how the car is when back on the wheels; the suspension will compress due to the weight of the car and certainly more so once a driver is in it. In normal road use it will probably never extend like that again unless you're lifting off.

Tightening the top nuts of the shock is something I've always done with fingers crossed; I tighten them until the rubber bushes are gripping the top mount firmly and just starting to distort. I've never seen official figures or any manual method for doing it; they may be there in black and white but never when I need them...

[Nick Jones]

Technically that is an MoT fail as it stands as the spring should be secure in it's cup.  If that's the 330lb Moss spring, they usually are - just barely.  Should be 10" free length IIRC.

Doesn't look to me as though the centre nuts are tightened fully?  There is no torque setting, but the rubber (poly?) bushes should be fairly well compressed without being mashed.  This may gain you just enough to hold the spring.  Also possible to get nylon spacers to sit under the spring.

In practice, the only time you are likely to risk unseating the spring is "getting air" over hump-backed bridges.

Nick

[Clive]

My solution to the "loose spring" was to weld some 3" diameter (that is from memory) exhaust pipe as an extension collar around the spring top mount.  The other option is to modify the shock top mounting area, to effectively shorten the open length. 

Of course, if the ride height turns out to be too low, a spacer which fits with the spring (as opposed to above the top plate like the thinner ones tend to be) will do the trick. I have used original TR4? spacers bought at the show last year, 2 pairs for £10. Cut them down to the length I required, and then found a little attention was required to get a satisfactory fit. I wonder if the current springs supplied are a fraction smaller diameter than orignals? But nothing here to compare.