520R SV build has commenced

[JohnCh]

Progress has been slow thanks to other priorities getting in the way and some level of procrastination born from frustration with the car, some vendors, and a realization that some things I had planned were too much effort to achieve during the initial build.  There are, however, a number of updates.  I'll break them into a few posts, but don't worry, I promise to sprinkle a little bitching and moaning into each one.  

 

The engine and transmission are in.  I've removed and replaced the Duratec in the Westfield a few times over the years.  I've always done it solo and without a load balancer.  It's a pretty straightforward process.  Not so with the Caterham.  Clearances in this car are extremely tight.  The process was made more challenging by the fact the rear suspension and driveshaft were already in place, and I opted not to drain the factory installed oil from the gearbox.  I'm not convinced I could have done the job solo without the load balancer.  It also took more swearing than I'm used to, but that extra effort certainly helped.  

 

 

After confirming crank and chassis centerlines aligned, the driver's side engine mount had to be shimmed 4mm away from the block.  

 

 

Next hurdle was the alternator getting in the way of the steering shaft.  The solution was easy (although someone else had to point it out to me): rotate the steering rack forward to raise the u-joint and steering shaft.  I'm not sure if this need is down to more production inaccuracies or if the taller 2.3/2.5L block has the alternator mounting holes in a slightly different location, but my OCD went on overdrive as the top of the rack, which is emblazoned with "Caterham" no longer points straight up.  

 

 

Then was the discovery of a really poor steering u-joint.  The welds and design were done in such a way that a socket won't sufficiently grip the head or nut of the pinch bolt to tighten it down, and switching to an open-ended wrench meant tightening could only be done 1/3 of a turn at a time.  Additionally, the hole for that bolt was drilled really far from the groove in the shaft.  I never clamped it down (see above) so I'm not sure how much meat of the bolt was still in the groove as a safety measure for preventing pull out, but it would have been much less than I've seen with my other cars.  Before heading down to the hardware store to pick up a socket head bolt and try again, I checked the spare u-joint for the Elan's steering to see if it has the same ID and spline count.  Turns out it's a perfect fit, and although it looks the same as the Caterham part, it is made to much better tolerances.  There is no issue using sockets to tighten the hex head bolt and the bolt shaft fits perfectly into the groove.  Although that may not make a functional difference, it did inspire more confidence in the part.  The Caterham u-joint is now a paperweight.

Guess which U-joint came from RD Enterprises and which came from Caterham:

 

 

-John

[JohnCh]

Attempting to install the oil and coolant plumbing was fun due to product quality issues.  First, unbeknownst to me (i.e. user error on my part) there are two versions of the rear coolant junction that bolts to the back of the Duratec's head.  One has a port for the coolant temp sensor that feeds the ECU and the other has that port blocked off.  I purchased the wrong one months ago but didn’t discover this until trying to install the sensor.  The replacement arrived, but it had a manufacturing fault that prevented the sensor from seating.  The third one was the charm.  

 

Turning to the dry sump plumbing, I discovered the oil tank arrived with a poorly threaded 1/8 NPT port for the temp sensor.  First the threads were full of aluminum shavings, and second, the sensor blanking plug and sensor could only be screwed in 1/2 turn by hand.  Using a wrench to turn the sensor a further 1/2 turn cut a groove in the threads.  Bruce Beachman had me bring the tank to his shop so he could run a tap through it, but quickly discovered the tap was actually a little loose.  The theory was the first thread had a little damage at the beginning from the factory screwing in the tapered tap too far.  My sensor was still a little off when attempting to screw it in after the cleanup, so Bruce switched to a spare which screwed in better.  It was still hitting a spot of increased resistance in part of the thread, but it was far less than with my original sensor. 

 

 

 

With both of those sorted, most of the plumbing was installed.  Rather than use the factory coolant expansion tank which mounts under the nosecone where access requires nosecone removal, I'm using a Radium Engineering expansion tank mounted to the firewall.  On the positive side, it looks great and is easy to access.  The negatives are an additional 1-1/2 lb of weight and a stupidly large price tag.  

 

 

My hope was to finalize the install this weekend, but then I discovered Caterham supplies 3/4" ID hoses for the dry sump breathers but supplies 5/8" ID hoses for the coolant plumbing.  This isn't an issue for the 5/8" metal tube they supply which houses the coolant temp sensor for the dash gauge, but it is an issue for the connectors Ford uses on the rear coolant junction and water pump which are both 3/4".  Interestingly, Caterham supplies a T-connector to plumb the expansion tank and this too is 3/4".  For the heck of it, I lubed up a hose and the T-connector to see how hard it would be to seat, and more importantly, how hard it would be to remove.  It took a little effort, but it would seat.  Removing it was another story.  It was simply not feasible without a hose pick and even then, it was difficult.  Not sure I could do this with limited space in the car.  More worrying was the outer barb of the T-conne ctor made a cut along the inside of the hose.  It was not subtle and didn't give me comfort for longevity.  I'll order properly sized hoses this week. 

 

-John

[JohnCh]

Firewall cleanup has begun.  With no need for the factory airbox, the brake/clutch fluid reservoir was moved to that side, freeing up space to mount the fuse box so it pokes through the firewall, making it easy to change/check fuses and relays.  The factory positions this on the back side of the firewall under the scuttle and requires a contortionist to check.  In my experience, a fuse is most likely to blow on a rainy night in a dimly lit parking lot.  This new position will make those situations far less frustrating.  I'll wait to cut the firewall until I finish the under scuttle electrical work to ensure it's optimally positioned.  

 

 

One surprise -- OK, not a surprise, I'm used to looking at aspects of this car and asking no one in particular what the hell the factory was thinking.  Anyway, one surprise was the heater block-off plate.  The firewall has a large section removed for the heater box.  When no heater is optioned, that opening is covered with a block-off plate during the build.  There were a couple of problems.  First, they size this plate so the top covers a portion of the scuttle rivet holes.  Since I am doing a removable scuttle, this is problematic.  Second, and the part that made me mutter "Um……"  the plate has a number of drilled holes that match up to the mounting holes drilled in the firewall.  It makes sense for the factory to reuse the mounting holes, right?  Except they drilled the holes in the plate for 1/8" rivets which are juuuust a bit smaller than the firewall holes drilled for M6 bolts.  Fortunately, the fix for both issues was cutting 15mm from the bottom, then drilling new holes in the firewall to match the 15mm lower holes on the plate.

 

 

 

-John

[JohnCh]

The Antigravity Lithium-Ion battery doesn’t fit the factory battery holder, but it seemed a shame to toss the stainless steel base that fits over the ECU.  Rebending the rear lip to accommodate the extra length of the AG battery when on its side, then replacing the side straps with shorter aluminum versions and 3D printing a new top clamp, it fits well.  I just need to print spacers to fill the gaps between the side straps and the battery.  According to the scale, the lithium battery saves over 11 pounds which offsets the weight gain from the bigger engine.  BTW this was my first time trying to bend or drill sheet stainless steel.  Wow, this is a hard material!

 

About this time, I discovered my kit included the correct number of battery cables: three.  Kudos to the QA person for their counting skills!  Counting all the way to three can be hard!.  Unfortunately, rather than supplying one red positive cable and two black ground cables, my kit came with three ground cables.  Apparently counting to three is much easier than differentiating between the colors black and red.  Since I am mounting the battery slightly differently than factory, this served as an opportunity to correctly size a new positive cable for my installation.

 

The factory all SS battery holder:

 

 

The replacement for the smaller battery:

 

-John

[JohnCh]

Next up was progress on the DRLs.  The 620 nosecone has a Euro sized license plate bracket glued into the bottom that I repurposed for DRL mounts.  Simply drill out the 1/4 turn fastener nuts, bolt on 3D printed brackets, and attach the DRLs.  The pic of the 3D printed part shows the final version, which differs slightly from the version used in the other photos (an extra rib and some cosmetic chamfers.)

 

 

 

 

 

 

The laser engraving on the horn button is finally done.  Other than a smeared E, it looks good.

 

 

 

-John

 

[windsurfer]

Hi John, your build seems to be going well! Did you figure out how your gonna fit the airbox. Mine will be even more challenging since it is the tinier S3 frame... I just brought back a new bonnet without any cuthole for air filters but side vents form de UK, along with some carbon front wings. I got no clue if the air box of Caterham actual design won't restrict too much air flow ( and it will need to be on the right side since the pedal box is on the way in our driver side)

Regards!

[JohnCh]

Wow, this thread is way out of date.  I'll try to post some updates with pictures later.  Regarding the airbox, the original plan was to build a cold airbox fed by the 620 nosecone scoop.  I eventually gave up on that for two reasons: space and potential AFR issues.  Between the dry sump tank and its hoses, the coolant hoses, and the chassis triangulation, there is not a lot of space to snake sufficiently large ducting from the front to the throttle bodies.  It's solvable, but it just creates more problems down the road with access.  More importantly, I found some flow tests on airboxes that convinced me there was a reasonable chance AFR across the 4 cylinders would be very uneven.  A single WBO2 sensor would average out those differences when tuning, meaning some cylinders could be overly rich, or worse, overly lean.  It seemed much safer for the engine if I bit the bullet and stuck the filter out the bonnet; nose levels be dammed!  Cutting the aluminum scares me but blowing that engine scares me more.  That work is still about a month out so I can't tell you how not to do it  .  I special ordered an ITG sausage filter without the logo and was told to expect arrival in April or May.

 

Based on results from online calculators, the bonnet side vent is sufficient for 420 levels of power. Those same calculators say the 620 shouldn't work, but it clearly does. Perhaps those formulas change with a supercharger, or there is more going on with high pressure in that area that offsets the size of the opening.  That said, I also noticed that the opening in the air box itself is smaller than in the bonnet, but again, it seems to work.

 

-John

[JohnCh]

The Radium coolant expansion tank is in and plumbed with a hose covered with nylon braid to provide a little more abrasion protection where it runs into the mass of hoses in front of the battery.  I also plumbed the cooling in that area with correctly sized 3/4" hoses. Because I am not using the second coolant temp sensor that feeds the gauge, I don't need the submarine which is 5/8" diameter, and is my guess for why Caterham supplies the smaller hoses (see my rant about this several posts up the page).  I ended up using a combination of rubber hoses and Silicone hoses given availability.  We'll see how it works.

 

 

The location for the windscreen wiper reservoir on current cars is in the boot, which is not my preference.  Taking up valuable real estate in the small boot to locate a container of liquid does not make a ton of sense to me.  To be fair, the factory 420 air box takes up a lot of space, so finding an under-bonnet location means they would need to be creative or use a different form factor, but still…  My initial plan was to locate this part on the firewall.  However, given I'm running ITBs with a sausage air filter, another option presented itself: under the filter.  A simple aluminum bracket to dop it a few inches that repurposes two rivets that hold the side skin to the frame, and it's in place.  It does mean I need to remove the air filter to fill it and work round an air horn, but the filter attaches with three 1/4 turn fasteners, and even if I have to remove the air horn (two socket head screws) it's not a big deal to me as I will likely only fill it before a tour when there is a chance of rain.  Otherwise, I won't use it and won't bother it keep it filled.

 

 

The scuttle is now removable to make behind dash repairs/work significantly easier.  To minimize the air gap between the firewall and scuttle, low profile M4 rivnuts from McMaster Carr were used.  These have a flange thickness of 0.4mm vs. 0.8mm of a standard rivnut.  The only challenge was installing the rivnuts that mount to the dash tube and hld the sides of the scuttle in place.  On my car -- and it may only be my car -- they drilled the hole for the rivet at an angle pointing rearward rather than forward as needed to place the hole perpendicular to the side of the scuttle.  When using a rivet, the hole angle doesn’t matter, but a rivnut is a different story.  Given it's a round tube, you can't simply enlarge the hole in one shot and need to walk up on it with increasing larger drill bits.  Ok, no picture, but if you look at the photo of the Radium you can see the rivnuts in place.  

 

-John

[JohnCh]

The underside of the wings have been coated with Herculiner to prevent star cracks.  I was initially on the fence about this as the Westfield wings have suffered no such damage since going on in 2004.  A closer look, however, revealed Westfield uses much thicker fiberglass.  Based on quick measurements, the Caterham wings are about 3mm thick, whereas the Westfield's are over 5mm thick.  Undoubtedly heavier, but I suspect this is why I haven't had issues.  

Rear wings are on, but the driver's side needs to come off to inspect a rivnut that I suspect may be a little loose.  Of course it was the last of the 10 fastener I installed on that wing. 

 

 

I'm currently in wiring hell.  Despite attempting to order the 620 switch loom since November, I've given up and am repurposing the 420 switch loom.  Before making cuts, I decided to reinstall the stock dash with the gauge and switch looms to confirm all those electrical components are working correctly.  This way, if an electrical issue crops up for the AiM, Freewheel, or toggle switches, I'll know it's my fault and won't need to test any of Caterham's work.  Once an issue with the factory supplied flasher was confirmed, it was time to perform a test install of the Freewheel without cutting the harness.  I wanted to wait for that no-going-back moment until I knew the Freewheel worked as expected.  Yes, that's a scary picture below, but it was taken after achieving success with the test.  I'm now in the process of modifying the switch loom -- wires have been cut! -- and will then tackle the loom for the AiM display.  If things go very, very well (they won't) the AiM and Freewheel wiring could be completed this weekend.

 

 

-John

[JohnCh]

One surprisingly hard part of this project was finding someone to TIG weld a stainless steel WBO2 bung on the stainless steel cat bypass pipe.  The factory bung locates the sensor so it's pointing upwards, which is bad for longevity.  Ideally the sensor should be mounted at least 10 degrees above horizontal to prevent condensation from settling on the tip and breaking the sensor after a cold start.  It seemed every place I called only did MIG and every lead I was subsequently given would have the same limitation when called.

 

I eventually found three places. A very high-end vintage race shop in the Kent/Auburn area who dismissed doing the project out of hand as too small, a high-end race shop in Bellevue, and a family-owned welding shop located next to an airstrip in Snohomish that's been around since 1972 and does everything from building custom exhausts to installing 5th wheel hitches.  The race shop said it would take 1- 2 hours at $225/hour and they couldn't get to it for at least a month.  In contrast, the welding shop wanted $58 to drill and TIG and could turn it around in a day.  I went with the family operation and was very pleased.  Friendly, clearly take pride in their work (even the person who did the weld wanted to make sure I was happy with the final quality), and very reasonably priced.  Anyone in Seattle's Eastside looking for this type of work, check out Airport Welding and Muffler in Snohomish.  

 

 

 

-John

[JohnCh]

A few days ago, I wrote "If things go very, very well (they won't) the AiM and Freewheel wiring could be completed this weekend."  Well, they didn't go very, very well, but things still went well, if not very well.  The Freewheel chassis wiring is done, and it works.  The final switch plate for the steering wheel hasn't been printed as I'm working through a couple of cosmetic revisions, so I simply shorted the transmitter wires, mimicking momentary switches.  A little troubleshooting was required, but nothing onerous.  I'm opting to keep the labels on the harness in place as well as some unneeded wires until the AiM harness is done and the combined harness is tested.  Top photo shows items removed thus far, and the second shows the current state of the harness as described above.

 

 

 

Rather than use Weatherpack connectors to tie the 14 wires from the Freewheel control module into the rest of the switch loom, I bit the bullet and bought a good crimper for solid pin Deutsch connectors.  It was so much easier and less frustrating than the stamped terminals used with Weatherpack.   When given a choice, I will never go back.  

 

One annoying discovery is that when upgrading the tunnel cover to the black leather version in the Signature catalog, they don't bother to install the heated seat switches, instead supplying them in a bag with the retrofit harness that isn't needed when the heated seats option is chosen at time of order (once again, Caterham supplies parts you don't need, which apparently they karmically believe offsets failure to supply parts you do need -- but I digress.)  It sounds simple, but this is upholstery work in a highly visible place.  It requires drilling holes, cutting the leather, wrapping it through the holes, gluing it to the aluminum structure, and hoping the resulting hole is sized perfectly for the switch.  Not too small that it won't push in, and not too big, that it rotates with little effort.  Not wanting to see my potential screwup every time I looked at the interior, and not really being a fan of the switches breaking up the aesthetic of the tunnel top, I took this as an opportunity to relocate them to the side of the tunnel.  After determining a location that was easy to access, wouldn't be accidentally bumped by errant knees, and was sufficiently removed from the multitude of cross braces in the tunnel, holes were drilled, the carpet was installed and then cut.  I like it.

 

 

I also did a bunch of other work, including rerouting the handbrake cables, fixing the buggered rivnut for one of the rear wing bolts, working out the DRLs, identifying the wires in the gauge loom and how they will plug into the AiM analog harness, and a number of other little things.  Not the massive progress I hoped for, but more than I expected.  Before calling it a night, I installed the tunnel cover and steering wheel, and tried out the seating position.  It's getting there...

 

 

-John

[JohnCh]

I decided to do a temporary install of the DRLs so I could build the harness and get that out of the way.  This is the redesigned bracket.  Very rigid but will need to be reprinted in carbon fiber nylon to deal with the heat from the radiator.  Hoping to do a big print day this weekend to get all parts done using that filament.

 

 

The wires were run under cover of the license plate bracket the factory glued into the nose cone, then run up the side using adhesive zip tie mounts and finished with a Deutsch connector.  I decided to place this on the exhaust side since there is more room on that side of the engine bay.  It's very easy to undo the connector before removing the nose cone.
 

 

 

 

These guys are pretty bright.  First photo is taken off axis to highlight the location.  Next photo is head on.  Speaking from experience, I don't recommend looking straight at them from only a few feet away  

 

 

 

-John

 

[Alex-Ks1]

OMG, 225$ for 5 minuets of welding??   I have a TIG and a MIG, both are super easy to use.  15 minuets of practice is all you need . serious 

and months to wait,,   wow, shops sure know how to screw people now days ..

 

[JohnCh]

Just a few updates. The final versions of a several prototype parts were printed and installed: revised steering wheel switch plate and hub extension, redesigned battery hold down, throttle cable plug to accommodate the smaller ferrule in the Jenvey's throttle cable, DRL brackets, and fuel rail spacers. I also printed a prototype for the fuse box housing that allows access to fuses and relays from the engine side of the firewall.  First version came out well, but seeing it the flesh has given me some ideas for V2, which I'll work on this week before posting pictures.

 

With the steering wheel parts done, I could finally solder the push buttons to the transmitter wires.  The initial switch plate design had grooves in the back to route the wires from the transmitter to the pushbuttons.  The plan was to hide the wires with small covers on either side of the hub, but I decided to simplify by moving the grooves to the front of the plate and covering the wires with the back of the steering wheel spokes.  The wires then poke through small holes to reach the back of the pushbuttons, which are then covered with small caps.  I forgot to take a picture of the wires in place before attaching the plate to the wheel, but these two photos illustrate how it works.  

 

 

 

When testing the completed wheel, I had a bit of a scare: the horn was blaring regardless of the horn switch position.  After troubleshooting to see what I screwed up between the last testing session and soldering, I discovered that first turning the key, then attaching the temporary ground for the Freewheel receiver would create havoc for the electronics.  If the ground was attached before the unit received power, then all was good.  I had an esteemed visitor from the East in the garage on Saturday to check my progress who was accidentally treated to this phenomenon when I showed him the wheel.  Oops.

 

The Freewheel auto-cancels the indicators using a configurable timer that can be set anywhere from 6-30 seconds long.  This eliminates the need for the obnoxiously loud indicator beeper Caterham fits to the loom.  Rather than cut it out, I topped it with a small dab of adhesive putty and covered it with heat shrink.  Much better…

 

 

The Schroth harnesses and driver's seat are installed.  The passenger seat is waiting on backordered sliders from the factory.  It looks like variations in production tolerances are to blame for the outer driver's side shoulder harness bolt not fitting under the rollover bar lower brace.  The outer passenger side barely -- and I do mean barely -- fit, but the driver's side has about 3mm less clearance according to the calipers.  I've temporarily used a shorter, spare lap belt mounting bolt, that I'll replace with something a little longer before finishing the car.   

 

 

-John

[JohnCh]

I had hoped to wire the AiM this weekend, but after looking at the required Binder 719 connectors and remarking to myself, "Holy crap those things are tiny" I checked the specs and confirmed they require 24-gauge wire to fit inside the hollow pin.  I had cheap 22 gauge on hand that is known for being undersized which could be persuaded to fit after a few tries without stray stands sticking outside the pin.  However, that approach didn't seem prudent. Good quality 24 gauge is on order.  Although not the outcome I had hoped for this weekend, I was able to confirm which wire goes where for the various gauges and warning lights, and I also powered up the AiM to ensure it works.  
 

 

 

Aside from the AiM, the electrical is finally done.  The fuel pump controller was changed for a second relay controlled by the ECU, the AEM wide band O2 controller was wired up, the engine loom connector for the TPS was swapped for one that works with the Colvern TPS fitted to the new engine, and DRL relay is connected and working.  
 

Factory fuel pump controller:

 

Replaced by a relay still controlled by the ECU:

 

With that work done, it was time to clean up the wiring a bit -- wires for some unused circuits will remain to ensure future flexibility -- and to work on the new mount for the fuse/relay box that provides access from the engine side of the firewall.  The prototype was printed in PLA and the test cuts and installation was done using a spare sheet of aluminum the same thickness as the firewall.  The factory fuse box will slide in from the rear then bolt to the mount similar to how the factory attaches it to the firewall.  To keep things watertight, a Nitrile cord is glued into a groove printed into the top of the frame with a matching, but slightly shallower groove printed into the back of the lid.  Black thumbscrews from McMaster Carr will hold the lid in place and provide quick access.  I may make a few more tweaks to the design before printing in the carbon fiber nylon and may also add a mount to the back of the lid to hold a small fuse puller, but it's pretty close to final.
 

 

 

 

-John

[JohnCh]

I forgot to add the picture of the AEM wide band controller in the last post.  This is attached behind the battery and ECU.  Easy to see the status lights, but out of the way.

 

 

-John

[CBuff]

John,

 

The 520 is coming along nicely. I plan on installing the Schroth Harness on my, in progress 420R (with track day roll bar). Other than the rogue bolt fitment issue, how are you liking them? Any insights on installation and how they are working out would be greatly appreciated. I believe there are some options on how the shoulder straps are mounted to adjust the spacing on the shoulder width (for HANS use etc) - but I am not really sure. I plan on using them with the standard leather seats. The car looks amazing!

 

Charlie

[JohnCh]

I like Schroth's ASM technology and run their Profi II ASM harnesses on both the Westfield and Miata.   My harnesses came set up for snap in connection, which I changed to bolt-in using the B24 bracket with matching SG11 shoulder bolt for the lap belts and the B23C bendable bracket with S65 pivot sleeves on the shoulder belts.  Wavy washers and flat washers were also used as shown on the HMS site.  https://www.hmsmotorsport.com/products/hardware-Harnesses

 

I didn't do anything with shoulder belt spacing.  Another nice feature of the Schroths is the ability to configure the lap belts for either pull-up or pull-down tightening.  I have the Westfield setup for pull-down on the driver's side, but pull-up on the passenger side since I've occasionally had to help a passenger belt in.  It's much easier to tighten their belts in that situation when you can pull up. 

 

-John

[CBuff]

Great to hear you like them. Yes I was thinking the profi II asm ones. I like your idea on pull up pull down (I feel like my passengers are going to be somewhat captives so being able to strap them in will only add to the experience ). 
 

When I was shopping online some places had the bolt in option (vs the clip in). And I heard the leather seats would need the longer (longest) crutch straps to make it all the way back. 
 

Thanks for the feedback 
 

Now I just need the car. Impatiently waiting…

[JohnCh]

38 minutes ago, CBuff said:

I feel like my passengers are going to be somewhat captives so being able to strap them in will only add to the experience

 

Yes, leaning over the passenger then pulling up hard on the belts to strap them in definitely helps with the message to "sit down, shut up, and hold on!"

 

When is your car due to arrive?

 

-John