DJ.

Useful thread thanks My speedo has always over read by about 4mph, not a lot at 70, but a higher error proportionally at 30. The error was 13% at 30 and 6% at 70. I don't want to risk it under reading so I added 5% and trying it this morning it is approximately 2mph over at 30, 50 and 70 so I'm happy with that. The original figure was 39199, tyres are 185 x 60 x 14 Rain Experts and thenew figure 41160. Duncan

Tyres does seem a good shout as they will have been affected by the lock down much more than bearings and propshaft. Certainly worth getting all the wheels re-balanced as the next step. Duncan

Or you can cut some planks to drive onto and lift the car enough to use your current jack.

Driving an old Fiat Abarth onto ramps scared me to death in 80s, my brother reported the ramps were a few inches in the air by the time I stopped . Never again! They came in useful for my build as my garage is tiny and my drive slopes, so I needed to level the drive to roll the car out before installing the engine and gearbox: I'm not sure health and safety would have been impressed, but I wasn't under it and if the wood broke, it would have just dropped a few inches Duncan

I do use four axle stands if bleeding the brakes, changing pads etc. If I'm going under the car, I'm happier to have some blocks of wood I have made under the wheels, it seems much more stable.

I found a leaking damper last winter and as they had done 42000 miles, I decided to do all four. I repeatedly tried phoning Bilstein UK and would be put through to the service department only forit to ring and ring. I never got a price for rebuilding them, but decided in the end to buy four new dampers as unless they charge well under £100 per damper, by the time I added postage both ways, the saving wouldn't be more than £20 a damper. I can definitely feel the difference! Duncan

I mounted two 12v sockets on the bulkhead behind the dash. They are quite easy to reach and it would be a lot less stressful than cutting a carbon dash. Duncan

Hi, I was in the yellow Seven going the other way. Sorry I didn't wave, I was a bit slow on the uptake Duncan

You really can't have any mechanical sympathy if you want the best 0-60 times. The testers do things like side stepping the clutch at 5000 rpm, not using the clutch and over revving the engine to avoid changing gear depending on what's required. I don't think you'll do much better than 5.5 seconds...................... in your own car anyway

In my experience, no But the Ford fits the chassis without a heavy steel cage and also has an alloy housing so is lighter (I assume) than the BMW diff. The Ford diff also has proper taper roller bearings whereas the BMW has twin ball races and has a reputation for not lasting well in BMWs, the Sierra diff seemed to cope well with extremely powerful turbo Sierras back in the day and the noise problems seem to have appeared around the time the metric chassis appeared, and the requirement to drive the top diff bolt in with a club hammer because the bushes aren't in the right place................ Duncan

The early Lotus De Dion tubes were curved and included the wheel bearing mounts without using ears. I believe they also used inboard rear brakes which would reduce unsprung mass considerably. They also had a larger diameter, but I presume a thinner gauge steel. I found a photo of an Eleven, but I've seen similar fitted to a Seven chassis. http://www.britishracecar.com/GlennStephens-Lotus-Eleven/GlennStephens-Lotus-Eleven-DE.jpg

That sounds an interesting modification

A much lighter DeDion with better location would be more than halfway to IRS with a lot less bother. I fitted a powerflex bush to my DeDion and it reduced the rear wheel steer quite a lot.

There are plenty of Seven designs with IRS out there. I think designing the set up to suit some existing hub carriers from Westfield for example would speed up development. Having previously built and owned an independent Westfield SeiW, I have to say, I much prefer the way my DeDion Caterham S3 drives. There are theoretical advantages to IRS, but I would prefer a well developed live axle or DeDion chassis to a poorly designed IRS every time. Duncan

I'd be interested to hear more about that

If you re-torque the bolts now, it may disturb the thread lock which will have set in the meantime. If you plan to adjust the torque, I would undo them, re-apply lock tight and then torque them up to the new figure. I always apply paint to mark the flange and bolt head, so I can visually check for movement while under the car without re-torquing each year. Duncan

Sometimes this can be caused by a slightly corroded brake disc or binding brake. I wondered if my diff was ok one winter as moving one wheel didn't move the other all. Swapping sides to get the second wheel moving seemed to get things back to normal

I recently changed my standard front springs with Sealey motorbike compressors and I found them easier than the rears as there was no circlip to struggle with.

It's not very elegant, but the best solution I can come up with is to buy some rectangular aluminium tube. The tube width would be the width of the chassis tube plus enough space to reach a little behind the seatbelt mounts, and high enough to just cover the seatbelt bolts. It would be fiddly, but you could cut out the front and lower portion of the tube so it can fit onto the chassis tube and cover the four seatbelt mounts. Then you could attach the press stud bases to the top of the tube with longer screws into the chassis tube. The front of the boot cover would have to higher than normal, but you would still be able to unfasten the front edge. The alloy tube should prevent water getting under the cover and into the boot, and painting it black would make it less obvious. It shouldn't involve cutting the boot cover or damaging the chassis further, so if you don't like it, you could remove it and just bolt the belts through the cover as most Sevens have. Duncan

Looks like you have that very well set up I've fixed two laser spirit levels to a plank of wood, one with a pivot mount and adjustment bolt. I place it close to the wall to mark where the beams hit and then move it three feet away to check the beams are parallel. I then place it on blocks a measured distance in front of the front wheels. And used a marked piece of (high tech) cardboard to read the distance of beam to the wheel rims. I set the front rims parallel, because that's how Caterham set them initially and it drives nicely, plus it is easier The disadvantage over your system is I suspect it wouldn't be accurate enough to do all four wheels (lucky I have an S3). It does have the advantage of being quick to set up, and after adjusting, I can roll the car backwards and forwards to get the suspension settled again without disturbing the beams. Duncan

A few years back, I took my S3 sigma car to Dunsfold and a chap with a Vauxhall engined car asked me if I had an engine in my car as he couldn't see the sump! The sump is below the chassis, but I'm pretty sure it is higher than duratec Sevens as I know a chap who went from a Sigma car to duratec, drove a favourite route and cracked his sump on a bump he hadn't noticed before.

I had to change the centre bush under my De Dion, because the diff oil was getting to it. Changing it was a pain, so only do it if you really think it needs it. Attempts to remove the bush using sockets and threaded rod failed. I managed to remove it from the DeDion after lowering the A Frame by cutting the centre tube with an electric saw, cutting out the rubber with a fret saw and then gently hacksawing through the outer metal. Installing the powerflex bush was easy after that. Duncan

That sounds a good tip, thanks Geoff Duncan

That looks nicely engineered. I like the way you have avoided welding or damaging the chassis as far as I can see. It also maintains your ground clearance as you said. It's always difficult to decide which is better to sacrifice, the chassis or sump. My Sigma 125 is pretty much standard Ford, so I'll take my chances with the sump. Reducing ground clearance by completely covering the sump isn't a great idea, I have a friend who added a substantial guard below his very low sump. He went over a badger corpse, the sump guard lifted the front as planned, but at the crucial moment he couldn't turn into a corner and went off the road! Duncan

That looks good to me