Temple Cloud

Eric at Millwood has fitted a new fuel pump and I have to admit that I seem to have greater torque at lower revs than before which is what should be happening with greater fuel pressure, so let's hope it's real rather than a placebo. Whatever, the car does drive really well now and I'm very happy with the current state of the car. Eric also changed my steel rear arch protectors as the original ones were quite pitted by stone chips. Car looks a lot better as well as driving better. Great stuff.

A quick update. As an ethanol resistant fuel pump appears to be really difficult to get hold of, those good guys at Millwood have told me they can fit a new one pretty quickly so as soon as I return from the south of France in a couple of weeks I'll book her in for a new pump...

So, today I finally managed to get my 7 onto the rolling road at Interpro. It was one of the hottest days of the year and for some reason the roads were chock a block, mainly lorries and white van men. There comes a point when the temperature is so high it's better to have closed car with good air conditioning than an open one, particularly one with a transmission tunnel you could cook a meal on. Nonetheless it was a nice drive up to Thornbury in South Gloucestershire and Dave Griffiths greeted me with his usual smiling self. He's going through an exceptionally busy time at the moment so it's been almost a month since I booked myself in and the car has now done around 1400 miles since the rebuild and boy have they been great. I've done a couple of blats with local club members and got around five others to join me at the Haynes Motor Museum for a Sunday breakfast club which they have on the first Sunday of every month. Plenty variety of cars to see there and it was a great morning. And overall my rebuilt 7 has been totally transformed. A big thanks to GP Sevens and Boss engineering who did the head.

Anyway, Dave first did a compression test, which showed that things had obviously changed considerably. They were now 190,190,185,190 which is much better than the original 185,180,175,135. After checking the carbs and timing Dave got on with the power test which showed she's producing 143bhp at around 5900 and 129ftlbs of torque at around 5800. The original spec of the car shows she should produce 135bhp and 123ftlbs so my figures top them both. He was slightly concerned about the torque figure as the max figure should really be seen at much lower revs, more like 4500 to 5000. Torque delivery relates to acceleration and bhp relates to top speed. So he decided the carbs may benefit from slightly different jets in order to create the max torque a little earlier. However my twin Weber 40s didn't want to play ball and whilst the max torque did indeed arrive earlier it was at the cost of the max bhp. Dave felt this was possibly due to low fuel pressure and on measuring it it appeared it indeed was a little lower than he would have preferred. So back came the original jets which restored the original curve (which you can see in the image below).

Whilst we're both pleased with the success of the rebuild Dave has suggested that I get a new mechanical fuel pump (that I currently have) but one that is not affected by the ethanol that current fuels have. These engines were designed prior to our current range of ethanol fuels and the ethanol creates havoc with anything rubber. The problem is finding such a pump. Burton power are developing one but it's not ready yet and there is a company in the US that have one, as the Americans have a longer history of ethanol fuels than us. So Dave is sourcing such a pump for me and if he doesn't turn up trumps he suggests I convert the car to an electric fuel pump which involves slightly more work. Either of these solutions Dave considers necessary for all crossflows as the current fuels, especially E10,  can create issues which I'm sure many crossflow owners already know better than me. And he does suggest I only run on 99 or 97 octane fuel, or even the 102 BP Ultimate.

So, it's reassuring to see that all is well and I now look forward to getting the icing on the cake with a new fuel pump. Watch this space

I've finally got the car back after the rebuild and I'm now doing 500 miles to run her in. She goes very well, sounds much healthier, indicating there was obviously something wrong before and now I've polished the ali with Mother's Mag and Ali paste she looks stonking. Mother's looks similar to Autosol and does a similar job but it's certainly better and comes in a nice pot, so there's much more to go round. I've also added a smaller front number plate which I think looks a little more discreet.

I'm off to the Goodwood FOS on Saturday 25th so the run down and back will see the 500 miles done. It'll be interesting to see how she fits in with all the other hypercars that  she'll be sharing the Performance Car Park with. Should be quite funny. Then it'll be off to Interpro to their rolling road and get her tuned properly. GP Sevens and Boss Racing did a great job on the rebuild but inevitably after an extensive rebuild there are a couple of flat spots that can be tuned out quite simply by a bit of timing and carburettor tuning. After Interpro she'll be off to Millwoods to have two new rear wing protectors fitted together with either a respray of the wings or some new ones fitted depending on whether or not they're actually available. Apparently Millwoods tell me Caterham have real supply issues for almost everything at the moment. This seems to be a recurring theme.

Well, the rolling road session at Interpro wasn't quite as successful as I'd hoped. In fact a rolling road session never really got underway at all. Dave always likes to do a compression and leakdown test prior to putting the engine under strain but the results weren't quite what were expected. Three of the cylinders were fine but number four was quite a bit down on pressure at 135. The rest were in the correct ball park at around 185. After the leakdown test it appeared to Dave that I had a leaking inlet valve on number four and therefore a rolling road session was probably not a great idea. What a bummer, especially with the best of the summer months fast approaching.

As the car was still under warranty I sent her back to GP Sevens who agreed to take a look and do the remedial work. They removed the head and sent it to another Dave, this time at Boss Racing. This Dave, just like the one at Interpro, has a vast history of working on these engines and so I was confident that once he had renovated the head all would be well. I decided to install stronger exhaust valve seats at the same time to accommodate for unleaded petrol. Boss Racing were under pressure at the time so the work wasn't carried out for a couple of weeks but once completed GP Sevens tried to re-install the head only to notice that it wasn't going to be as simple as they'd hoped. Apparently I also had a cracked piston in cylinder four. I gather this is a well known issue with cross flows as the cast pistons weren't really designed for the high compression ratios Caterhams were built with. So the decision then was forged or cast replacements ? The big issue with forged replacements is that they're not made for the Supersprint 1700 as these crossflows were over bored by 90 thou but they were available at +100. However, talking to Dave at Interpro he advised me that overboring by another ten thou could potentially cause issues with the water jacket which, if badly rusted, could burst through with dramatic effect. I therefore decided to stick with the Hepolite cast pistons which Dave assured me were really good, underrated pistons. In the end I've decided to renew a few other bits and bobs in the block to lighten and strengthen the engine and effectively rebuild it. So I'm now waiting for it all to be put together and hopefully get the car back by the 18th June. Touch wood....as I miss her a lot....

I've booked the car in with Dave Griffiths at Interpro to look at the engine to make sure everything is fine and dandy with the engine and that's it's producing the best it can in it's current configuration. We'll then discuss what the possibilities are for upgrading if he thinks that's a good idea.

I'm also going to book the car in at Williams Caterham to have the immobiliser removed. It's a complete pain in the arse as it's sometimes reluctant to let me turn the car over and I'm worried that it may give up the ghost entirely one day and leave me stranded somewhere like many others have done in the past to other Caterham owners.

I've also bought some Toyo R888R tyres all round and will pick up and fit them next week. The fronts will remain 185/60/13 but the rears will widen to 205/60/13.