This weekend Saturday 17th October 2020 and after 3528 miles saw the Caterham 7 420R return to South Coast Performance for its year 2 annual service. As per the unofficial PBC I was able to help out during the service, picking up tips about the Seven from the years of experience that proprietor Paul Dangerfield has on Sevens.
The car was given a thorough looking over totalling 4 hours on the four-poster ramp. Thankfully we found only one issue, a slight amount of play in the steering column lower universal joint. I'll come to that shortly.
As with any service the engine oil was addressed. Oil was removed from the dry-sump tank, the dry-sump lines were removed from the sump itself and the residual oil drained. The finger filter was removed and inspected. There was nothing notable present, it was cleaned and subsequentially reused. The engine oil filter was replaced as expected using the recommended Mahle unit. The car then received Motul Sport 5w50 Ester as now specified by Caterham Cars, approximately 6.5 litres.
Engine coolant and brake fluid were all deemed fine and so left for another year.
Through service we inspected the entire Seven which including the rear where the DeDion tube was inspected for any signs of fatigue. Due to an ongoing debate on BlatChat concerning life expectancy of the Titan differential unit, we spent a few minutes discussing the issue and visually inspecting the differential. Paul expressed a view the only real way to check the diff was to remove it. Although he did later give the Seven a hard road test and stated the differential felt fine and the 420R handled great. Any noise I was experiencing was normal. He seemed quite impressed with the 420R, although he did comment it would benefit from a brake upgrade. He recommended an Alcon kit which retained the current disc size..
As I stated earlier we did find an issue with the lower steering universal joint (sorry I forgot to video or photograph the issue). There was a very small amount of play which Paul felt unhappy about. He attempted to tighten the fixing but doing so didn't remove the play. As a result, Paul removed the bolt and found it had bent very slightly, plus some surface damage was present.
We didn't have an M8x40mm 10.9 bolt to hand, so an M8x40mm 12.9 was used. I've ordered a 10.9 to replace the 12.9, I wasn't aware that the stronger bolts were more brittle.
The Seven also got a set of new ZZS tires on the front. In truth only the front nearside tire was get close to the wear limits, but the Isle of Man Roads Policing unit are pretty hot on tread depth so I didn't want to take any chances.
That's pretty much it. It's probably not that interesting to read, but an important step within the life and thus diary of the 420R.
I had some emails with Tony Mills at Caterham this afternoon. Their view is that they only fit the spacer if people are having vibration problems from the gearbox, which I'm not. But it solved the clunking problem for Chris even though he wasn't expecting it to.
If you email me directly at david@berclas.co.uk I'll forward the emails to you (I don't have your email address otherwise).
I also checked the diff preload in case it was low - which would have indicated early failure. It was the opposite - set to quite a high torque setting.
So my plan is to wait until Oakmere have seen the car on the 30th - and then depending on the outcome I…
Mark - did you ever resolve your clunking diff problem ? I completed my 420R build in June and have driven about 600 miles so far, and it's clunking a lot. Exactly as you describe (and I can hear on the videos). Worst at low speeds when taking up torque. Even worse when cornering at low speed. I've read the blatchat thread (>500 posts) so it's clearly a problem experienced by many, and still is.
I purchased my car from Oakmere and it's going back in on 30th Sept with this as number one problem. Did they offer to change it out under warranty ? If so what did they recommend - a rebuild ?
Seems a big and problematic…