tompollock

And it's a 1991 car with the Ford Crossflow 1700 Supersprint motor, not that should affect matters.

Just digesting the replies received so far. Thanks so much. Very, very helpful. I should just add that the engine is dry-sumpted, but it is the after market Neil Brown Engineering one, and I expect the car still has the standard Sierra CRB setup fitted.

Eight months in to Caterham ownership and I'm still chasing this illusive clangy rattle coming from somewhere in the middle of the car. It's on a 1700 Supersprint / 5 speed Sierra box / De Dion rear, with 20k miles on the clock. Apologies for the long thread but I'm running out of ideas. The clutch (original AFAIK) works perfectly, no slip, good bite point, and the pedal lines up with the brake pedal. Took the rubber boot off the bellhousing and was puzzled (and horrified) to find a good 50mm of rattly slack in the clutch release mechanism before the CRB touched the clutch diaphragm. How long it has been like this I've no idea. Perhaps it had a new clutch some time before I had the car and was never adjusted correctly afterwards. Shouldn't the CRB be pre-loaded against the diaphragm spring so that it is always spinning at engine revs, or is this particular design/application different from the usual? Either way do you think the rattly slack in the mechanism, amplified by the acoustics of the bellhousing, is likely to be the source of my clangy rattle, ? Proof of the pudding would be to find a bit of broken tarmac that sets off the rattle, preferably downhill, and drive across it both with the clutch engaged and disengaged. If I'm right what is the correct amount of pre-load to apply to the CRB when adjusting the clutch cable? i.e. Adjust until the CRB touches the diaphragm, then 1/8th more of a turn on the cable adjustment to pre-load? Too little pressure and the CRB could get hot spinning against the diaphragm, too much and you could end up overloading the bearing. Thanks in advance, Tom.

Thanks for the swift replies. Googled and found 2 more forum members happy with the way the TR1's performed on their 7's so that's good enough for me!

I need to replace the very old Toyo T1-S and T1-R tyres on my C7 1700 Supersprint which runs on 15 inch rims. Road use only and with cost in mind. Not worried about longevity as I don't do enough miles, just driveability, in all conditions. Are any members using Toyo TR-1 tyres and how have they found them? Other lower priced recommendations welcome! Thanks in advance.

Thanks Paul. I saw your original answer but didn't realise the petty strut went that far forward.

Hi Everyone, Thanks for all the suggestions . My C7 is a 1990 1700 Supersprint (no honeycomb in those days!) with competition manifold. There is no centre exhaust support bracket on this model but that's just down to poor engineering in the first place.The system really needs extra support. As I said I've just had the silencer front pipe re-welded to the main box after the weld failed. I'm amazed the manifold itself hasn't failed somewhere considering all the loads placed upon it. A little job for me to rectify in the future. I think I'll revisit the underside next and look around the gearbox mounting area for the source of the rattle. Meanwhile here's the MYSTERY BOLT. Lhs door card. Not one on the other side. Still no ideas anyone?

Thanks for all the suggestions. I'll rule out the silencer for now because I've just had it off to get the front tube re-welded where it had parted company with the box itself - absolutely sound as a pound inside there with nothing loose, surprising after so many years. It's also just been through the MOT and I know what a stickler the tester is, he lets nothing through. I'll check the screen wash bottle though and anything else fastened with rivets. It's not going to get the better of me!

Lots of happy Protech customers out there. And they do look very shiny!!!!! I'll give them a call tomorrow and see what they come up with. I've only had the car since October so I'm still getting to know the handling. I'm sure the shocks are the main cause of the bad manners on bumpy roads, after all they're 32 years and 20k miles old. I'll get the shocks sorted first then get the geometry sorted afterwards. Looking forward to the warmer weather

Thanks Geoff. I'll try the seat fixings anyway but its a definite rattle, not a buzz or a sizzle, and is dependent on the depressions in the road surface and not on engine revs/hf vibrations.

Ditto the re-valving. Surely they come off the shelf from Protech already suitably valved as they are Caterham 7 specific? Did you use them oem spec. before having them re-valved, and if so what difference did it make? Thanks.

My Seven sits on its original Spax Gas shocks (adjustable spring platforms). The piston rods are corroded and the car gets quite lively accelerating at speed on narrow bumpy tar. I chicken out at around 75 mph unless the road is quite wide! I suspect the dampers aren't doing much. Can members recommend the best bang for buck adjustable dampers. I would like to use the original springs to save costs. Replacement Spax are reasonable but are there better out there for not too much money?

Mine doesn't have a heat shield.

Yes, its bright cadmium plated and shiny. Haven't taken it out to measure diameter but similar to the bolts that used to retain an old fashioned seat belt swivel bracket, the one mounted on a saloon B post. The rattle occurs with a passenger strapped in so don't expect it to come from the seat belt or fittings.

I've been trying to find the cause of a rattle coming from the passenger side on lumpy blacktop. Its not coming from the front or rear suspension and sounds like its coming more from the middle of the chassis, but where? The exhaust mounting is sound with a new bobbin fitted, and the windscreen frame screws are all tight, as is the heater box assembly and the dry sump tank. Not much else to rattle. Then came across the Mystery Bolt (11/16 AF with a short head) on the inside of the "door" card adjacent to the lower edge of the dash. Could this be the culprit? This was a little loose and took nearly a full turn to tighten up. What does this retain? There isn't a corresponding bolt on the driver's side. Thanks in advance, Tom.