tompollock

Still refurbishing my 1990 C7 1700 Supersprint. Been to Arch to have the chassis leg repaired. Lovely job, lovely people. Thanks for the good advice to go there rather than anywhere else. Heater motor and ballast replaced - very toasty now! Replaced all the dodgy old dash switches which was well worth the effort. Repainted the corroding instrument bezels while I was at it so it now all looks as new. Does anyone recognize the make of this dry sump system fitted to my C7? I'd like to get the definitive instruction on oil filling level as advice seems to vary according to manufacturer. Another thing, when I did the oil change, the positioning of the holes in the baffles seemed to prevent the suction tube of my vac pump going right to the bottom of the tank, leaving some old oil still inside. Not ideal. Are you meant get the last bit out by splitting the top and bottom halves of the tank? Thanks in advance, Tom.

Heater motor to replace first, then the indicator switch and all the rocker switches, two of which are now non functional this week, the car having passed the mot only a few days ago. The joys of re-commissioning a 32 year old car that has been OTR, stored in a garage about 50 metres from the beach.

Thanks Andrew. I'll keep the book in mind. My car is a 1990 S3 Supersprint 1700, and afaik so far is completely standard in the jetting/timing department. Took it out for it's first run today (I'm new to C7's) and though the engine ticks over like a train it smells like it is running very rich. Though very tractable, it spits back on a light throttle between 1750-2500. Its eager for revs on full throttle and is still pulling at 6500 when I chicken out. How high is safe with the 1700 Crossflow? Plenty of sexy popping and banging on the overrun, and as the cam in this engine is reasonably mild, it seems to confirm it is running very rich. I'm sure a carb rebuild will give me a good base to start on, then I can try the different jetting recommended over the factory spec.

Thanks Stephen, I've looked at the carburetor section of Part 3 of the most excellent "Get to know Your Seven" guides and it seems pretty comprehensive. If I get stuck I'll take you up on the offer. Thank you. First things first though, the chassis is my immediate priority and hopefully that can be addressed this coming week.

I'm a very happy bunny. Passed first time, with the only comment being that the n/s headlight was a touch low! Also did a compression test and was overjoyed to get readings of 161/161/158 and 166. Happy days. After Phil at Arch deemed the corrosion not bad enough to make the chassis structurally unsound I took the executive decision to employ a bit of cosmetic subterfuge. Looked perfect afterwards. I will be off to Arch to get it fixed properly as soon as we get a couple of guaranteed dry days for the drive, but meanwhile I've saved myself the possibility of some unnecessary and expensive trailering, Thanks for all the advice from the forum. Next job is a carb rebuild and setup. The usual spitting back between 1750-2250 rpm, particularly when cold, though it ticks over like a train. Seems there's plenty of archived material to get me pointing in the right direction.

MOT tomorrow! Fingers crossed.

Phil at Arch Motors is hopeful that the tube can be replaced without taking the engine out. Wonderful! And he thinks my theory about how the corrosion started is very likely. Now to get the MOT done so I can take it there. I found the diff, drain plug. Trouble is that there's less than 25mm clearance between the drain plug and the de dion tube, not enough to get a socket with hex bit in there. Difficult! Thanks for all the your help and suggestions. You're all stars and it's very encouraging for a new member.

Spoke to the very helpful Phil at Arch Motors at lunchtime and sent him the picture. Just waiting on the verdict now. Said they may be able to repair without taking the engine out! Fingers crossed.

Strange. Pic shows on my laptop. Will re-post pic. TP.

Thanks for all the valuable info received so far. Just so you know the problem I have. Not pretty is it? (The bottom of the picture is the front of the car). Interesting that the failure going forwards is pencil straight, so it looks like the round tube manufacturing weld line itself failed initially, allowing moisture in to start the corrosion along that line. The bronze welding of the round to square tubes is sound. Good thing is the square section longtitudinal (which I assume is the most important load bearing element for the engine mount?) is completely sound, as is all framework fore and aft. Will keep you posted when Arch get back to me. I imagine other Caterham chassis may have failed at this point.

Refurbishing a 1990 Caterham 1700 Supersprint, 5 speed Sierra XR4i gearbox, with De Dion rear suspension. Numpty questions from a 7 novice. In the limited crawl space underneath with the car on stands I have not been able to locate either the gearbox or diff filler plugs to change the oils. Where are they? Secondly, there is no fuel filter fitted on this particular car, which seems a strange omission. I am considering fitting one of those clear nylon jobbies with the visible paper filter, immediately before the standard Ford pump. Any problems with this? Finally this motor, though standard, has been dry-sumped, as much for ground clearance as anything else. The tank would probably hold about about 5 litres. Information on the web about fill levels seems a bit vague. Should I check the level with the engine running around 3000rpm and how much above the top baffle should it be? Currently 3 litres in the system which seems not a lot and the fill level is about 3/4 inch above the top baffle at tickover. Thanks in advance.

Thanks for the replies. I'll send some pics to Arch over the weekend. Hopefully it won't be an engine out job. Unfortunately the MOT has expired and I'm not sure how Mr. Plod would view the 160 mile journey across to them for the repair. Fingers crossed.

Hello, The Caterham 1700 Supersprint I am refurbishing has some nasty but localised chassis corrosion on the joint immediately underneath the rhs engine mounting. The perforation in the 3/4 inch round tube is about 7cms in length. Can anyone recommend a garage nearby that can do a repair for me. Thanks in advance, Tom.