Noises - Various?

[Guest wizas]

I have just refurbished a Series 3 that has been off the road for 4 years. It has passed its MOT and is rearing to go!

However, when driving it I can feel the body flex slightly. The floorpan to the rear of the foot pedals seems to move around (only very slightly!) Is this normal? Also the engine seems to move around and sounds as if it is knocking on the bodywork somewhere. Is this normal? How stiff should the engine mountings be? Apart from that it is a hoot to drive! Mine has a 2 litre Pinto.

 

[Guest Gary]

I'd be interested to see some answers to this. I have a 3a with a 2ltr pinto, engine is solid, not really any movement in the mounts. I'd be quite worried myself if the engine was moving enough to knock on the body but maybe mines the strange one for not moving? I do however have a fair bit of movement in the gearbox and i think that knocks a bit.

 

Definitely no movement in the floor though if that helps!

[Guest crwoodford]

Is it 2 pipe or 4 into one exhaust? The reason I ask is because the 2 pipe system on my Sub K did not have any 'Rubber' mountings at the silencer end, and the two pipes were also tight going through the opening in the offside body panel.

 

The upshot was that I would occasionally hear subtle knocking. Once I had fitted a rubber mount at the silencer end (done recently) the knocking stopped. I think it was the vibration of the two pipes tapping the bodywork when the engine was revved or laboured?

 

I'm not sure about your floor movement though? Sorry to say that sounds a bit more serious? Silly question but have you had it up on ramps to check underneath? Floor panel fixings etc?

 

Cheers

Col (Taunton)

[Guest chris brown]

Even though it has gone through MOT I would look very closely for cracking particularly in the engine bay (remember the tester may only see one 7 a year never mind a monocock hood). Jim and others will be able to tell you better where to look as he has had several goes at overcoming the problem which I now believe he has done. There definitely shouldn’t be any detectable twisting or flexing of the monocock.

[Guest micky bigthumbs]

I have no twisting or knocking...if the floor pan is flexing it will crack if the engine mounts are ok it must be the box section they are bolted to check for small cracks in the stainless and cracks in the welded joints..if it is moving it will crack..post some pics..and fill in your profile information might be someone near

[Big Jim]

The monocoque cars do "flex" and can sound like Rolf Harris's wobbly board!

Obviously you don't want this, as it does lead to premature cracking, I say PREMATURE CRACKING, because it will suffer cracks sooner or later,

I've made a couple of stays that support from the top box section on the chassis to the bottom section, these go into the engine bay to stop the sides flexing.

The seat mountings need strengthening, or the floor will flex. Once you know where the holes go through the floor, you can strengthen the area up, at a push use bloody large flat washers, put it's best to plate it to spread the load.

The earlier engine mounts didn't move, but the later ones are just like bobbins, and allow the thing to rock around like crazy, although there are some variation in "wobblyness" from different models of Sierra (don't ask me which to get, I don't know, as I'm on the early ones)

The cracking to look for initially is in the engine bay, up each vertical weld in the corners. Then where the angle iron that supports the rear shockers, fixe to the body, this is totally inadequate, will twist and tear out of the chassis in time.

Then where the front suspension top wishbone pivots in the chassis. you're holding the whole corner weight on the car, and subsequent forces, on 2 pieces of 2mm stainless - not good enough.

If you've got tie-bars fitted, then you need to run a piece of angle iron across the bottom of the engine bay to pick up where the anti-roll bar used to fix, as that gives the front end some ridgidity.

 

Jim

 

PS. Col, they didn't sell that crappy twin exhaust with the monocoque, you got the best crappy stainless silencer, with either the 4-1 manifold, or a single pipe that attached to the sierra cast manifold.

[Guest wizas]

Thanks for speedy very helpful replies. I'll get the car onto ramps tomorrow and check it out. The engine mounts do resemble bobbins and do allow me to shake the engine about. The exhaust doesn't seem to touch the bodywork at any time. The car does not have tie bars, it still has the anti-roll bar. I have fitted new rubbers.