520R SV build has commenced

[JohnCh]

One year, five months, 6 days and 14 hours after placing my order, the crates have arrived.  Not that I've been counting...

 

Despite the order sheet identifying the car as a 420R SV, it won't reach the road in that state of tune.  The engine, built around an Esslinger 2.4L short block (thread here), should be good for around 260hp -- probably a little under while still using the 420 exhaust and little over when replaced with something larger.  Given the engine is so different, calling the car a 420R doesn't make much sense to me, so I've applied Caterham's naming convention which doubles the stated horsepower to arrive at the model name and dubbed this the 520R.  

 

For the purists among you who don't like my rename, you'll like my planned modifications even less 🙂

Those deviations from stock are listed below.  Some are pretty straightforward, but others will add to the timetable as I attempt to figure out the best approach and likely ponder why I didn't take the simpler, factory route.  i.e. this is gonna take a while.

 

• 2.4L Duratec
• Emerald K6+ ECU 
• External fuel pump with return-style plumbing and Holley Hydramat
• Traction control 
• Cold air intake (likely via the intercooler duct in the 620R nosecone)
• Blank carbon fiber dash (from Westermann)
• Aim MXS 1.2 Strada display
• Freewheel programmable steering wheel mounted controls for horn, turn signals/hazards, high/low beam, and possibly single wipe function
• 620R toggles for the remaining switching needs
• CORE single adjustable dampers (Front: digressive valving w/linear springs; Rear: normal valving in rear w/ progressive springs)
• Removable scuttle
• Relocated WB O2 bung
• Assorted other customizations I'm still pondering

 

 

 

 

Next step is to go through the parts to see if anything obvious is missing
 

-John

[S1Steve]

That’s a cool color… Enjoy your build..🍻

[JohnCh]

The color is Roulette Green which was a factory color several years ago.  As a pearl paint, the color morphs a bit under different lighting conditions, which makes it difficult to accurately capture in photos -- particularly when I'm taking them.  In person, there is a hint of gold that isn't visible above. 

 

-John

[11Budlite]

Congrats John, looking forward to your updates.

[KnifeySpoony]

Awesome build. TC on a 7 though... doesn't that kind of defeat the purpose?

 

 

[JohnCh]

The TC has 4 user-definable settings, one of which will be fully off.  With the amount of torque this engine will produce, I want to ensure I can put it down on a narrow bumpy road when passing someone without going sideways in a straight line.  This "should" give me options.  We'll see how well it works.

 

-John

[lg2k]

I'm really looking forward to this build. I hope to make a similar purchase one day. Love the other cars in the stable especially the 993. 

[JohnCh]

2 hours ago, lg2k said:

Love the other cars in the stable especially the 993. 

 

Thanks, that's the only car I've ever purchased which has appreciated.  Typically, the market for a car plummets as soon as I buy one.

 

Yesterday after work, I attempted to do a preliminary inventory.  Based on things I have read elsewhere, I figured a Guinness would help the process. 

 

 

Surprisingly I haven't yet found any obviously missing parts, but Caterham hasn't made it particularly easy.  There is a half-hearted attempt to group things in sealed bags or labeled boxes, but unfortunately it doesn't appear the people doing the packing are very good at the childhood game "which of these things is not like the others?"  For example, one wing stay was in the front suspension parts box, while the other was in the box with the half shafts and exhaust manifold.  There was sufficient room for both stays to have been in either box.  The sealed bag that contained the tie rod ends and steering rack brackets also had one additional item: the dry sump dipstick/cap.  Interestingly, a second dry sump dipstick was screwed into the dry sump tank.  If you're kit was missing one of these, it appears I have it.

 

Hopefully I'll have time later this week to make actual build progress.

 

-John

[BruceBe]

John - glad we've got it here and delivered in one piece. The Roulette Green is a winner.

-Bruce

 

[John B]

Congrats John! 

I look forward to following the build. Love the color, and good call on the inaugural Guinness 

 

FYI - Caterham's naming convention is more complicated than merely 2x HP. It's based on the power to weight ratio, specifically HP/Tonne.  A metric Tonne is 1,000 kg or 2,204 lbs. So a 260 hp 420R SV that weighs 1235 lbs would more appropriately be a 464R.

[JohnCh]

Thanks John.  Guinness is always a good call  

 

BTW the naming convention you mention was correct in the past, but Caterham changed that when they went with the 360 and 420.  Caterham lists the starting weights for the 360 and 420 at 560kg, and the 620 at 610kg.  Their respective horsepower ratings are 180hp, 210hp, and 310hp (half the model name).  For the names to follow the HP/Tonne formula, they would each need to weigh 500kg.  Using the old formula names and the published weight and power on their website, the model names would be 321, 375, and 508 -- although I'm sure the marketing people would round up the first and last models to 325 and 510  

 

Cheers,

John

[John B]

Thanks John, I hadn't realized they had "slipped" so much. 

I recall the Superlight R500 as a friend has one and I drove it, which is what led me down the whole Caterham wormhole in the first place.

 

     Superlight R500 (2008)   263hp/506kg = 520 HP/Tonne - 14 above "500"

     620R (now)                       310hp/610kg = 508 HP/Tonne - 113 below "620"

 

 

 

 

 

[JohnCh]

Caterham is not the only company that has morphed away from their original model designation convention.  The last two digits in a BMW model used to indicate the engine capacity in liters: 320i was a 2.0L, 325i was a 2.5L, but then things changed and sometimes a 328i was a 2.8L and sometimes it was a 2.0L turbo.  Then there is Porsche.  The turbo designation meant it was, well the version with a turbo.  But now it just means it's the highest performing model.  The base 911 has two turbos as does the 911 Turbo, then there is the Taycan Turbo that doesn't even use an ICE.  Marketers never let the truth get in the way of a good name...

 

-John

[JohnCh]

I made some progress today, and as expected, ran into some minor issues.  Most of them are known and well documented in other build threads and blogs.  So instead, I'll focus on things I haven't seen elsewhere and will simply confirm that, yes, getting the washers to fit the lower front control arms is frustrating, and it's annoying that bolt placement for both the upper front shock mount and upper forward front control arm try to occupy the same space as the painted side skin.  

 

Unfortunately, in my initial inventory I missed the fact that the fastener pack for the steering rack and column assembly is still at the factory.  This required a trip to the hardware store.  They didn't have exactly what I needed, so temporary fasteners are holding the steering rack in place for now.  

 

As noted earlier, I'm using CORE dampers from Meteor Motorsport in lieu of the factory Bilsteins.  The CORE's bolt spacers are 0.6 mm narrower than the Bilsteins.  When coupled with factory tolerances for the mounting brackets, this resulted in gaps ranging from about 0.8mm to 1.2mm.   That meant another trip to the hardware store to buy washers, then some time with a file turning them into proper width spacers.  This would have been a far more tolerable tasks with a Guinness, but alas it wasn't 5pm anywhere, let alone Seattle.

 

 

Next, the nut that holds the bottom of the upright to the lower wishbone, doesn't fit as expected. I'm not sure if I screwed up somewhere, if the nut is wrong and too thick, or some bigger issue is afoot. The instructions state that for the R-pack cars, you need to bookend the lower wishbone's spherical bearing with two different spacers. Those are both fully seated, but with the nut torqued, the threads of the stud aren't protruding from the bottom of the nut. Pics below show the spacers, the correctly(?) seated spacers, and the bottom of the nut.  A thinner nut, as provided for the wing stays (same thread size) would resolve the issue.  I'm hoping that's the answer rather than something more annoying.  Anyone know?

 

 

 

 

 

 

Before calling it a day, I attempted to install the driver's side wing stay only to discover, there isn't sufficient room to install it with the CORE dampers in place.  Unlike the Bilsteins, there are fitted upside down and have larger diameter coils, which conspire to leave insufficient space to slide the wing stay onto the upright.  It's a simply fix -- remove the lower damper mounting bolt and rotate the damper inward -- but by this time I had already exceeded time allotted for the build today and will need to pick it up in the morning.
 

-John

[KnifeySpoony]

Pretty sure you should have some half-height nuts for the lower wishbone. At least your spacers fit together. Mine were an absolute bear. I've read online people having to heat/freeze to get them together. I had to sand mine...

[MV8]

I'd check the nut major clearance at full droop, then shave the lower, big end of the lower spacer so the threads protrude from the full height nut lock. As long as the nut "teeth" clear the lca boss at full droop, it's fine. A socket would not be used at full droop.

I would not swap for the half height/strength/engagement fender stay nuts but it probably works well enough.

How thick is the nut? SAE 1/2 inch grade 8 nylock nuts are typically 0.593" thick.

Older models have a specially made lower spacer/nut versus two pieces.

[JohnCh]

Someone sent me a photo of his 420R lower wishbone. His lower nut fitment is the same as mine which tells me this isn't an assembly issue.  The nut is 0.606" thick and the shorter nut for the wingstays is 0.469".  

 

This morning I found an extra pair of the shorter nuts in a random, unmarked bag that appears to have front anti-roll bar fittings and a couple of other random suspension parts.  I suspect these are the correct nuts to use and it's simply skipped in the Build manual.  I'll use these for now.  

 

Thanks,

John

[KnifeySpoony]

This is what mine looks like. 

[JohnCh]

Thanks @KnifeySpoony, mine now looks like that too.  

 

Ran into a minor snag doing something simple: removing the headlight bowl trim ring so I could access the innards.  All the online build blogs referenced removing the allen screw on the top of the trim ring, however, I only had two screws on the bottom.  I figured this was a running change and the trim ring would still pop off with a little pressure.  Except it wouldn't.  Now wouldn't in this case is code for me being afraid to force it beyond what I considered to be normal pressure for this job. I opted for the painted headlamp bowls and had visions of the trim ring flying off from me ham-fisting it and damaging the finish, so I was proceeding very cautiously.  After taping it up with painter's tape, I pulled out a plastic trim removal tool, sanded down the edge until it was very thin and burr free, then proceeded to wedge it between the trim ring and bowl and carefully work my way from bottom to top.  It took a fair amount of force for it to finally release.  The reason was pretty clear after it was off: thick paint on the tabs creating very tight tolerances for the friction fit.  You can see where the paint came off one tab revealing the standard black finish beneath.  The other tab was about the same.  Fortunately, no scratches.  Of course, I still have that opportunity with the second headlight.

 

 

-John

[JohnCh]

I made some minor progress this week; front suspension is completed, and headlight assemblies are installed.  

 

Reading various build blogs, many identify the headlight assembly as the worst job in the build.  Not sure if they've written that after completing the car, or if that's simply their opinion immediately after finishing that assembly.  I will admit it was fiddly.  In part because all these builders opt to redo the wiring assembly from stock.  They eschew the factory PVC tube that covers the headlight wires and instead use heat shrink or a combination of heat shrink and braided wire covering to protect the wires.  The reasoning is the factory apparently suggests -- and I say apparently because none of this is covered in the Build Manual -- cutting a slit in the PVC tube which runs from inside the headlight bowl, through the headlight bracket, and into the engine bay, then inserting the wires from the indicator with the negative running up into the bowl and the positive joining the other wires going down to the engine bay.  This slit is then sealed with electrical tape.  Some people think that approach is a little hokey.

 

I was sucked into that vortex and wasted a bunch of time trying to figure out which of the various approaches I preferred.  I went with heat shrink for better sealing and cleaning properties.  However, in hindsight, I wish I had attempted a modified version of the PVC tube as I think that is the most aesthetically pleasing.  It might have proven too difficult to get right or even fit -- it's a much larger diameter than the heat shrink wire bundle -- but without trying, I don't know if that's true.

 

The other part of the job that annoys many, including me, is the poor fit of the headlight bracket to the chassis.  It slides over the upper front suspension arm bracket and has a locating tab that fits under that bracket.  The suspension bolt then goes through both brackets and the A-arm bushing to hold everything together.  Problem is when pushed over the chassis bracket, the headlight bracket's bolt holes are severely misaligned with the chassis bracket's bolt holes.  Some people bend the tab down to alter the fit and achieve bolt hole alignment, others enlarge the bolt holes on the headlight bracket.  I had to do both.  But it's done.  Time for a Guinness.

 

 

 

 

-John