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…


Gosh! Never mind the impending world doom of Corvid-19, the real tragedy of 2020 is that the Mantis still hasn’t moved since it died on Christmas day. Well… that’s not strictly true, as it was pushed out of the garage (thank you Tilly & Sam!) to allow a thorough inspection of the fuse box, then pushed back in again. From which, dear readers, you will have correctly assumed that the root cause of the electrics failure is still not found.

Sooo… what’s next? There is obviously some kind of electrical fault but I don’t know of anyone local who I am confident would fix it. Options would appear to therefore by taking the car to Joe at Redline, or Jay at Chariots to get the wiring checked out (it cannot be a coincidence that everything stopped after a good soaking when the car was being thoroughly cleaned!). \neither one is local so that is going to be hard on the trailer costs. On the other hand… I have saved two months of fuel so far! Checking the fuses has also made me realise the pedal box really needs a refurb & the fuse box needs replacing. The heat dissipation from the LS3 has never really been resolved & I am mindful of Guru Chivers comment last year that the factory saw a 10 degree reduction in engine temperature with no mesh fitted to the front bonnet vents, so I am also minded to get a less dense mesh fitted. Finally… do I swap the fast road cam for a standard cam to get better mpg & get the ECU remapped to a more normal config (less extreme advance etc). OK so this would drop the car from the magic 500 plus BHP (530 BHP) to a slightly-more-modest 480 BHP, but I have come to the conclusion that I can live without the bragging rights.

I am also going to hand over the reins of the North West club organiser to the Morrisons. Uncertainly about job, the car off the road so much, the end of Marcos at Tatton Park & so on have meant I am no longer as enthusiastic as I used to be & the other owners need someone with more Va-Va-Voom. After around 20 years there is a good case to be made for new blood, & the Morrisons are both extremely passionate about the marque & all round ‘good people’!

Diff fix and, erm, an 8,456 mile service

Time to get the worn differential fixed & try improving the heat dissipation from the LS3 engine. And I know just the man for the job, almost just round the corner too! 😎 Well, kind of!

I headed off this morning to drop the Mantis off with Jay at Chariots near Lewes in East Sussex. A mere 260 miles away but hey, we’re in the middle of the hottest summer since ’76 so that should make for a lovely drive… What could possibly go wrong!

Debris on the motorway added a little time but it was the endless bloody 50mph speed restrictions that put another 90 minutes on the journey. 😡 However, I arrived in beautiful sunshine under a clear blue sky so all was well (despite the nearside door mysteriously opening on the A27 roundabout 😯).

Always a pleasure to catch up with Jay, & having talked through the job list (which, strangely, grew as we talked!) we had a quick look at his Mantis before he kindly dropped me off at the station. I will come back down to collect the car in a couple of weeks, & looking forward to seeing some new holes in the bonnet. No, really! Watch this space…

How was it for you?…

So things have been building up to my triumphant collection of the car. What’s happened in the intervening few weeks? Well… quite a lot! Generation III of my Mantis has had an eventful birth, & best described after the dust has settled.

  1. Drive to Lewes in the Pug, stopping off in Bedford overnight to drop my daughter off. I will, Shhhh… miss it! (The car that is)
  2. Get to Chariots on the Tuesday, see Jay, see Mantis gleaming on the ramp, see about 20 Wedding cars, several Bentleys, a Model T, lots of vintage & not-so-vintage bikes and… a 50s Electric Milk float (with 1/3 pint glas bottles in wire baskets). Am hopeful my car is the quickest out of this lot.
  3. Car sounds lovely when started on the ramp & pleased with Start button. Connolised leather looks amazing in real life, & I am told the chap who did it spent an entire day masking off the piping before bringing the straw leather back to its original glory. Cool! The Dark Green Samco hoses are a remarkable match for the paint & look great.
  4. Go for a spin. Sounds & drives like I imagined 6.2 litres would! Very fast with bottomless torque & silly acceleration. Also unfeasibly pleased with the OSRAM Daytime Running Lights (combined DRLs & Fogs), which really update the front of the car. And gosh… it’s loud!
  5. Back to Chariots to catch up on the snag list. Frustrating after a five month wait but nothing terminal: Rev Counter only reading half actual value, Speedo not working at all, original LS3 A/C won’t fit around the steering column so retro-fit electric motor fitted, a few Samco hoses missing off expansion bottle.
  6. Spent Wednesday driving around Brighton & Eastbourne in blazing sunshine. Visit Beachy Head – holiday mode fully engaged! Stuff gets tightened/loosened etc as car shakes down over the day. Jay’s hospitality is faultless with beer & meal each night.
  7. Thursday is all about waiting for the new Speedo gauge to arrive from Smiths. I kill time taking the car out, but UPS have mis-sorted the Package & it has black-holed. The prominent fuel smell from the Generation II engine is still there, prompting some furtling with the fuel tank breather pipes & the replacement of a faulty one-way valve. At this stage in the day, I need to head back to Bedford as part of the paternal taxi service.
  8. Pay bill. The old alarm didn’t survive removal so a new one has been fitted. In the best traditions of Grand Designs, it has gone over budget… but, heigh ho!
  9. Off to Bedford – the M25 is a bitch & I discover how hard it is to drive an unfamiliar 500BHP engine in stop/start traffic for 50 minutes, knowing that the fast road cam isn’t helping. The car is also guzzling fuel so I bail off the M25 to find a petrol station, only to overshoot it & break down at rush hour in the centre lane of the A408 as it feeds onto the M25 & M4. Yikes! The car won’t start & has all the symptoms of having run out of fuel. I am not impressed!!! Under telephone guidance from Jay, I press the bleed nipple on the offside fuel rail & get air not fuel, which seems to support an empty tank & the fact that I am a pillock. Friendly copper pushes car to roadside & I await The AA, who arrive & thoroughly nice chap emerges from the van to announce he has worked on the LS3 engine before. Hallelujah! He does exactly the same trick with the bleed nipple but leaves it open a few seconds before fuel emerges. The car restarts & I am left a bit bemused until AA man explains this is a ‘vapour lock’ which is a new one on me… Journey to Bedford resumed.
  10. Taxi service from Bedford to Suffolk to Manchester and finally home.
  11. A couple of short local drives including one into work (bad standing traffic experiences again) where I take an ex-Marcos owner colleague for a spin, with very complimentary feedback.
  12. Home. Battery is dead when I go to take the car out for the weekend. Charge it up & it happens again. Then several hairy moments as I lose clutch pressure while reversing out of the garage. This is enough for me & The AA are summoned once again.
  13. The AA flatbed the car back down to Lewes to be worked on & it’s back to work with no car again!
  14. Several weeks later, I’m off back down to Lewes, collecting the car from Jay. Although the Rev Counter is still misreading, I have a smart new programmable electronic Speedo from Smiths. The centre console has also been rejigged with a much improved fit. The big improvement though, the ECU has been remapped with several significant changes to the factory settings (Fuel Trim from 39 to -1) which results in a much improved, smoother driving experience and a predicted 33 MPG(!). More M25 angst on the way back to Manchester but no hattrick with The AA & I only have to fill up twice before I ‘m home, achieving about 200 miles with 40 litres.

    Pete comes up trumps with this top notch LS3 badge to replace the original ‘Quad Cam’ one.

And now, so far so good except the oh-so-predictable rain every day. The plan is to get some more experience driving the car (albeit in grindingly sloooow commuting traffic) then wind up to the Tatton Park Classic Car Show in three weeks time, then the big one… Le Mans 24 hour & CBW!

Wish me luck!

A fleeting glimpse

So the Mantis is at JP Exhausts in Macclesfield & today I had arranged to work from a colleague’s house in the town then walk up to JP & see the car for the first time since it was kidnapped at the end of November 2016. I was quite excited as I would finally get to see the new engine in place.

We found JP easily (thank you Google Maps!) & wandered in to immediately spot the Mantis on a ramp. It wasn’t being worked on, so I introduced myself to one of the staff, Kyle (who it turned out would be making up my exhaust) then went over to have a look. The car was a bit grubby from being transported up but after a quick study of the driver’s seat leather repair (a good colour match) I was pretty keen to get the bonnet up & check out the LS3 in-situ. It looked… big! I was surprised at how few wires, hoses & pipes there were but have since found out that Jay has not fitted most of them to maximise access for JP when fabricating & fitting the manifolds & exhaust. Clever chap!


I also had the chance to physically compare the Audi, Nissan & after-market (Pivot) Engine Start buttons side by side for the first time. The Audi button is not flat which is unfortunate as that was my first choice. Not massively enamoured with either of the others & so will find an alternative, but this time without any reference to ‘Stop’ as I’m not going to get this functionality from the button.

Kyle kindly raised the ramp so I had the opportunity to view the car from underneath as well… Always a voyage of discovery for me! I got a great look at the engine & transmission, as well as the propshaft & the cleaned up chassis. It all looks very low but Jay assures me it’s higher than the old Ford Mustang engine. (I will find out pretty quickly when I park at work & have to navigate the prominent sleeping policemen in the office car park). Time was short however as my colleague & I needed to get back to work, so after a few more minutes peering round the car followed by a quick ‘Hello’ to the manager at JP we had to head off. Well worth it to see the car, but also to remind myself that it’s a 20 year old vehicle in regular use & not some pristine concours Marcos where everything to do with the new engine needs to be perfect or top-of-the-range.

One month to go

Staying in touch with Jay, who has uploaded a couple more photos. Here we can see the engine being dropped in to confirm engine mount placement.

The Nissan Engine Start/Stop button is HUGE at about 80mm across (!) so I am going with the Audi one, which will look even nicer with a small black surround.

It looks like the car won’t be ready until mid-February now as JP have decided they need the actual vehicle to fabricate the manifold & exhaust, so it will need to be trailered all the way up to Macclesfield (about 15 miles from me) then back down to Clayhill (about one million miles from me) to be finished off. My cunning plan is to sneak over to Macc when it’s there though, & have a look at the car. Sadly excited at this prospect!

All I want for Christmas

It’s been just over two months without the Mantis, & with Christmas Day tomorrow I have to face up to the fact that Santa is going to struggle to fit it into my stocking! On the other hand Jay has been uploading a few photos of the engine & also the chassis (which will have to be tip top if it’s going to cope with all that power). I was relieved to hear it’s generally OK with only superficial rust in a few places – nothing some rust cure, Hammerite & Waxoyl won’t sort out.

Another New vs Old shot!


I’ve also been trawling the automotive world for a decent Engine Start button. Given it’s going to take up one of the holes from the Racelogic Traction Control on the dash, it will be highly visible & therefore needs to look right. I like the idea of something red, but also backlit so it can be seen at night. The aftermarket Engine Start buttons are either barnded, cheesy or both, so I’ve narrowed it down to the Audi S1 (below left) or the 370z Nissan OEM GT-R Push Start Switch combined with the 2015 Nismo Model Red Trim Cover Finisher (below right). I’m leaning towards the Nissan currently as I can’t get the surround for the Audi button plus there’s not much aluminium on the dash (other than the gear knob).


Then I’ve got to get the socket & loom which fits the button of course, and then there’s the small matter of how you wire up to achieve the ‘Stop’ function on the engine.

I swapped the Mantis for a Peugeot 307SW

No, I have not gone bonkers… the Pug is a loan car from Jay. (Getting the tram or bus into work while the Mantis is off the road is refreshingly different, but doesn’t help when I need to divert off to collect sproglets etc). Jay trailered it up from East Sussex where he is based. An hour later & after some impressive winching he disappeared off with the Mantis. Gulp! Actually it couldn’t be in better hands as Jay has his own Mantis & also knows mine is my baby!

I only ever see Jay at the odd Marcos rally or over at Le Mans so it was good to catch up with him before he left, & also ‘Talk Marcos’. Of course much of the discussion was around what was happening around the engine swap (which I continue to be very excited about!).

  • I am still minded to have an Engine Start button but have rejected the idea of going fully keyless due to all the bad press around security flaws such as radio jammers & code grabbers; so the conversation was around Engine Start vs Engine Start & Stop. Both are possible it seems, but I still haven’t decided! I quite like the Lexus one right now.
  • We also discussed how best to manage the solenoid lockout on the TR6060 transmission, which is required because 5th & reverse are located right next to each other, & ‘bad things’ would happen if you select reverse instead of 5th at 100mph! Having read up on this on a few US forums, one workaround is wire up the brake light so you can only get reverse while the brake pedal is depressed. Another alternative would be to put a momentary switch into the gearknob under the Marcos badge, but this would mean modifications to the gear shaft etc which seems to be asking for trouble. We’ll go with the brake option.
  • The new exhaust will be based on the one on Jay’s car which is racing spec & in all probability will be quieter than my current one. I’ll certainly miss the sound of the Ford V8 which had the most wonderful, wonderful lope… but my neighbours probably won’t! To be honest, it also killed off using the stereo & grated a bit on very long journeys like Le Mans where you’re driving for hours on end. A gorgeous noise though and… dare I say it… the nicest sounding Mantis out there (a few other Marcos owners have said the same thing though!).
  • Finally I have been looking at Cruise Control which (if you read far back enough in this blog) you will know I considered early on for the Mustang Cobra engine before opting for the Traction Control instead (subsequently uninstalled as it never worked properly). There are a few places in the US who have after-market CC for the LS series engines, & I like the look of the one at HotRodTherapy, however Jay has suggested he ask around more locally before I go ahead & purchase, so waiting to hear back on that one.

Jay texted me when they got back to East Sussex (what a nice chap) so now I just need to wait for the first photos to arrive. Am I nervous? Oh yes! (Especially if it tops 500BHP) But it’s still exciting stuff & fortune favours the brave etc etc!