Off to Chariots for a bunch of fixes

Today I headed down to Chariots, 250 miles away to get various things sorted out. Top of the list was the cooling fans & anything else related to keeping the engine temperature down. Also I have bitten the bullet & the fast road cam originally added when the LS3 was fitted and pushed the car past 500BHP is going, to be replaced by the standard cam. That will come along with an ECU retune of course. Whilst it was fun to have the 500BHP bragging rights, I never really had the chance to drive it in a way which really utilised the extra power. The fast road cam doesn’t even get out of bed below 2500 RPM & realistically the majority of my driving in our wonderful UK traffic meant I rarely hit that threshold. I am putting it all down to experience – it was fun but I’m looking forward to a more drivable (& less thirsty!) car. Definitely pleased I gave it a go though. I think that just leaves Jay’s converted Challenge car as the only road legal Marcos Mantis with over 500BHP.

Also on the hit list is a somewhat overdue refurbishment of the pedal box. This has been slowly suffering from moisture ingress over the last 24 years plus some organic growth & get-me-back-on-the-road fixes to the electrics & fuses.

Other stuff… the chassis protection from a couple of years ago is flagging in a couple of spots so that will be refreshed. I had asked for the hood seal rubbers to be replaced as part of my futile battle to make the car vaguely waterproof with the hood up (don’t know why I bother, much more fun with the hood down!). However, Jay had some great ideas about replacing the flange on the hood that should form a seal with the window. It’s about 0.75″ at the moment & will be replaced with a much deeper version. I’ll be delighted if this works as I’d assumed any changes to the hood meant a complete new hood. Fingers crossed…

As ever it was great to catch up with Jay. His place is like an Aladdin’s cave of interesting cars & I was particularly impressed with the bright red London double decker bus. Cool! I also got to see the vent covers that he has fitted onto his ex-Challenge Mantis, courtesy of Eurotech. These are the ones used on the race cars & they look mighty mean!

The drive down was OK & no issues with the car overheating (Hurrah). Coming back on the train was a bit weird with Covid, but even the Tube wasn’t that crowded so I felt pretty safe all the way. I will be counting the days until I pick the Mantis up…

MOTd for another year

Back from the garage with a shiny new MOT. The offside rear light has been rewired as a temporary fix so happy days. Just need to drive the thing around a bit to figure out if the coolant system has been fixed. Shame about the weather forecast 😢

Oh… and fit my shiny new radiator cap… because the other one actually rusted so much it broke apart.

Aaaand… it doesn’t live 😢

Overheated today a couple of miles out from home & lost lots of coolant. Topped up with water but only made it half a mile before it went again so wasn’t going to get home. Inevitably the only time I have ever gone out without my phone… D’oh! 🙄 Fortunately the chap in the house I had pulled up (aka broken down) by came out to talk, & kindly lent me his phone to call The AA. What a thoroughly nice chap who turned out to own one of the local butchers. The AA then informed me I had no MOT… nightmare. The downside of cycling to work instead of driving… out of sight, out of mind 😮. Anyhooo… The AA won’t attempt to fix anything without an MOT but agreed to recover me home. Nice chap rocked up in a low loader a few minutes later (really… I have waited longer than that for the kettle to boil!). Very complimentary about the car & really looked after it loading it onto the flatbed. A few minutes to get back home then a hard-to-disguise-from-the-neighbours-with-all-the-flashing-lights unloading of the car.I drove it into the garage shortly before midnight.

A little disappointed I got one day’s driving before the car broke down again but c’est la vie. I now need to figure out how to clear the airlock (if that is what it is), & get the car MOTd before the tax is due at the end of the month.

Another Marcos adventure! 🤣


Beautiful weather & not driven the Mantis for a few days so decided to nip over to Stockport this afternoon & the 🤬ing cooling fans aren’t kicking in. Cue 90 minutes in a McDonald’s car park trying to figure out what’s going on. The mega-fuses are all fine & can’t see any loose wires. The ever awesome Torque confirmed the temperature gauge is reporting true. Argh. 🙄😠😡.

Finally let the engine cool down then made it home with the interior fan maxed out. On the bright side nothing boiled over! But… the weather is stunning… I really want to have the car running. Bugger. Bugger. Bugger.

Pre Le Mans cooling

The two Spal fans arrived at SP Automotive yesterday, so with three days to go before leaving for Le Mans 24 hour, I headed over there this afternoon with the car & some 50A Maxi-fuses to get the overheating sorted out. The plan was to swap out the single Spal straight blade fan for the two curved blade models, fit the additional in-line fan controller & remove the blanking plates from the rear bonnet vents to give somewhere else for the hot air in the engine bay to escape through.

Ryan talked me out of replacing the shaped vent grills with the less aesthetically pleasing (but more more efficient) grill that matches the front vents – so the originals have been retained. We agreed to locate the two new Spal fans in parallel at the top of the radiator rather than offset them; this required some minor grinding of one of the fan frames to squeeze them both in side-by-side, but the end result looked very good (below). The offside fan would continue to be controlled by the ECU (kicking in at 95 degrees), whilst the nearside fan would be controlled by the new Revotec in-line controller, set to about 99 degrees. I left the team to it while I went for a stroll down the country lanes of Cheshire with my daughter, ending up in an Ice Cream farm (not entirely by accident, to be fair!). There was a steady drizzle by this point, but we had a couple of hours to kill so got on with the very British family activity of playing in the rain. Upon returning to SP Automotive, Ryan had finished removing the blanking plates (I can’t watch people with chisels attack my car!), & was sealing the vents back in. In the meantime the fans were fitted & the wired up but I was surprised & a bit annoyed to see a standard 30A fuse fitted, despite my supplying parts & specification for a 50A fuse. The justification for this was that the fan controller was only rated to 30A, and the fan itself was only showing as drawing 2A, but upon pointing out that Spal’s data sheet showed max draw around 33A, I was informed ‘they must be wrong’. Given the time available we agreed to disagree, but I have since found out that SP err on the side of caution in this area, having encountered several fire damaged TVRs, arising from under-specced wiring combined with high amp fuses which have overheated & ignited.

The engine was run to fine tune the point at which the second fan kicked in, with airflow judiciously managed by Ryan armed with a large sheet of cardboard to limit throughput. Cunning! Who needs a wind tunnel or computer simulation eh?… Finally with work finished the car was all set to go; bonnet down & a 50 minute run back home to see how things went. No standing traffic encountered, so natural airflow kept the engine temperature down & the fans weren’t triggered. Despite this, the rear grills were extremely hot to touch which goes to show how much hot air there is in the engine bay. I may yet need to get some circular vents drilled into the rear bonnet face. Le Mans of course will be the big test.