MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Front Springs

At the moment my heritage shell has no front wings, doors, bonnet or boot lid. It also has no windscreen or any interior trim, so I wasn't too surprised that the front suspension was fully extended and on the rebound stops.

But today I put in the engine and gearbox, two items of significant weight, and yet the suspension hasn't deflected at all. This seems odd to me - I would have expected it to depress a bit. The suspension is all new. New lower pans, recon dampers, poly bushes, and without the springs in it all moves smoothly up and down. Could I have extra strong springs? Or would you not expect it to deflect with only the engine and box for load?
Mike Howlett

Losen all the bolts near a piece of bush.
These should not be fully tightend until full load is applied.
And to settle the suspention needs some fwd and aft movement as the tyres don't just like to move sideways
Onno Könemann

All the bolts were already loose Onno, and I tried bouncing the car, but it remains firmly on the fully extended position. If I bounce it seriously with all my weight (only 65 kg it's true), the suspension moves a little, but not much.
Mike Howlett

>>And to settle the suspention needs some fwd and aft movement as the tyres don't just like to move sideways

Move the car 10yds forward, and then 10yds back... the suspension will settle.

What is the spec of your springs? IMO anything more than 330 lb-in is probably too much for road use... (maybe a little more for 1500s, but I have no experience of these).

A
Anthony Cutler

What's all this talk of suspension settling? I don't see Mike asking about that aspect at all.

To go back to mike's original query, I've just received brand new standard springs from the MGOC and they are rock solid. I can balance on one and not see any movement at all - I'm over 17 stone at the minute - the old springs would compress a little but not by much.

Graeme
graeme jackson

If you jack the front up, the wheels gain positive camber as they fall, and the lower part of the tyres move closer together.

When you let the car off the jack, the tyres contact the ground first, and then the suspension begins to deflect... but the grip of the tyres on the road keeps them in the 'closer together' position and this works against the suspension returning to its steady state; the car sits an inch (and sometimes more) higher than steady state.

If you move the car ~5 to 10 yards, the tyre contact patches move apart, the +ve camber disappears, and the car lowers itself to normal/steady state.

Mike mentions the suspension appears not to deflect when weight added to the font - ahead of this, the front would have been high with large +ve camber since susp on bump-stops, it's similar to jacking tyres off the ground.

(This doesn't happen at the rear, since there is no camber change; OTOH the rear leaves have stiction, so you can lift the back up, and it tends to stay a little higher and vice-versa if you press down hard).

The question 'do I have extra strong springs...' is best asnwered by putting the suspension into steady-state first.

A
Anthony Cutler

<<What's all this talk of suspension settling? I don't see Mike asking about that aspect at all.
>>
Mike is asking why his car doesn't settle under weight, Ant is explaining it !
David Smith

I've been doing some research. The A-series engine apparently weighs about 250 lb, but it doesn't say whether that is "dressed" or not. As I can lift the gearbox, and I'm not especially strong, it probably weighs around 100 lb, total of about 350 lb. The standard springs (1966 mark 2 midget), according to Horler, are rated at 271 lb in.

Even if the entire weight of the engine/gearbox was bearing on the front springs alone (which it isn't) that's only 175 lb per spring and the deflection would only be a bit over half an inch. So the small amount of movement I've seen is probably to be expected. I had visions of the springs depressing by 1 - 2 inches, but that obviously won't happen. Interesting isn't it? Well, I think so.
Mike Howlett

Mike, don't forget, though, that the suspension multiplies the number (I forgot by how much, Rachel has said it before and I wrote it down somewhere).


Norm
Norm Kerr

This thread was discussed between 27/10/2011 and 29/10/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.