JimD

I have an intermittent fault on my 2010 Caterham Supersport 2L SV. Now wont start! Need an electrical fault finder in Essex (Billericay) Can tow to garage if necessary. Recommendations please.

Sigma BC1009 is my recommendation - cut the wire and extend its length - fit the magnet with an electrical tie wrap to the output of the diff. Fit the pick up to a small home made bracket and attach to the diff locking tab, run the extended wire along the tunnel, under the dash and mount the Sigma base in centre of dash below and between the oil pres and temp gauge. Remove the semicircular handlebar mount from the base to give a flat rear surface and drill two small holes in top corners of Sigma base and attach to dash with small self tapers. Twist in the computer and a nice neat job is completed. Measure circumference of wheel in mm and put in computer. I zero mine each time I fill with fuel which is every 200 miles.

The only (easy) way to reduce the chamfer to give a wider gasket land is to machine the whole face. I found a small machine shop who milled the face by about 1mm. Care must be taken not to remove too much as the gearbox input shft will enter deeper into the flywheel bearing by the amount removed. My careful measurement indicated adequate clearance and as proven by the last 5000 miles of trouble and drip free driving. This is a topic I think should be taken up by the technical guys at Caterham as it is a design/manufacturing/machining problem they have built into this bellhousing. I hope this helps. Jim

Sorry guys, I could have got the engine and gearbox out in the time its taken to get these three descriptive photos to you! They are in Picasa and in the public domain. I think they are impotant as IMO are the root cause of the problem to many of you guys. This is the route to my album: https://picasaweb.google.com/118358463285944574343/CaterhamDuratec5SpeedGearboxToBellhousingOilLeak# Edited by - JimD on 20 Oct 2011 14:20:11

photos https://picasaweb.google.com/118358463285944574343/CaterhamDuratec5SpeedGearboxToBellhousingOilLeak# here

Edited by - JimD on 20 Oct 2011 14:24:12

here

For photos try: https://picasaweb.google.com/118358463285944574343/CaterhamDuratec5SpeedGearboxToBellhousingOilLeak# Obviously a novice with computers, will try again tonight to include photos! Edited by - JimD on 20 Oct 2011 14:26:07

This is the root cause and a guaranteed cure to the oil leak problem which I posted with photos last year. Quoting JimD: Leak can only be cured by sealing the gasket area around the gear change rod. Sealant has to be applied on the gasket face to have any chance of working, which is an engine out job! Sealant around the underside of the box is a botch job which won't work! The Caterham made aluminium bell housing for the Duratec to the Ford Sierra type 9 standard five speed box has insufficiently width around this hole and is the root cause of the problem. IMO this is a manufacturing / machining fault as the chamfer around the hole is so deep that it has removed half of the sealing face. The only way of increasing this land is by machining the face down to remove most of the chamfer. In theory there should be no oil pressure forcing its way out, but as its a blind hole the rod enters, the quicker the gear change from 1st to 2nd or 3rd to 4th increases the squish pressure causing the gasket to fail. My 'proven' solution has not been discussed with CC. For photos see later posting or try: https://picasaweb.google.com/118358463285944574343/CaterhamDuratec5SpeedGearboxToBellhousingOilLeak# Edited by - JimD on 19 Oct 2011 23:50:22 Edited by - JimD on 20 Oct 2011 14:22:09

Yep you're quite right, I need to keep off the A12 and give it more welly and plenty of opposite lock to even out the wear!

From my experience you need a new rack! Because the car spends most of its life driving in the straight ahead posion, the teeth on the rack wear more in this position resulting in a loose or sloppy steering feel. This can be removed by tightening the large nut on the rack but results in tightness, as you describe, when the steering goes away from the worn straight ahead position to the relatively unworn turning position. I replaced my rack at about 48,000 miles on a 1998 1.6 K. I stripped the rack down to see if it could be rectified but the wear was not obvious and regrinding the teeth would, I suspect, have been too expensive. Could this be a bad batch of racks with insufficiently hardened teeth made around this era, or is it a common problem with high mileage sevens?

I've 'hopefully' attached photos to show the leak path here

here

Leak can only be cured by sealing the gasket area around the gear change rod. Sealant has to be applied on the gasket face to have any chance of working, which is an engine out job! Sealant around the underside of the box is a botch job which won't work! The Caterham made aluminium bell housing for the Duratec to the Ford Sierra type 9 standard five speed box has insufficiently width around this hole and is the root cause of the problem. IMO this is a manufacturing / machining fault as the chamfer around the hole is so deep that it has removed half of the sealing face. The only way of increasing this land is by machining the face down to remove most of the chamfer. In theory there should be no oil pressure forcing its way out, but as its a blind hole the rod enters, the quicker the gear change from 1st to 2nd or 3rd to 4th increases the squish pressure causing the gasket to fail. My 'proven' solution has not been discussed with CC. Photos hopefully attached here

Built my Duratec 175 with type 9 five speed box and had a small oil leak between box and bellhousing. Removed engine and found it to be from the gearchange rod which drags throught the oil into the blind hole in the bellhousing. This gets hydrauliced by the rod and squishes back into gearbox or if your unlucky, across the gasket face which is only about 2mm wide due to the deep chamfer. It then drips from the bottom of the gearbox. I cured it by having 2mm machined off the bell housing face to increase the width of the gasket face to about 4mm. Reassembled it with gasket sealant around this area and 2000 miles later all OK. What I also did was change the gearbox internals from the standard wide ratio box as supplied by CC to the BGH heavy duty long first. Not an easy DIY job but well worth while.