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Caterhams built after 2003 (I think this is the year) use the front button programmable speedometer. There are no DIP switches in the back.

Skip, Pin 7 (oddly enough) is the low voltage (5 vdc TTL) input on Caerbont speedometers. You may be able to move the contact in the connector shell from pin 6 to pin 8. Unfortunately, I found the wiring diagram for a Miata here. It clearly shows the speedo sender as a variable reluctance AC sensor. Look at page 20 of the year 2000 diagrams. I have to call APT Instruments today to find out when my new OP and temp gauges are shipping. I'll question them about wiring up a Miata.

Skip, these are the instructions for the Caerbont speedo that Caterham uses. here Unfortunately, There may be some specific alterations made to the speedo just for Caterham's sensor. The programing instructions are the same. Looking at the Caterham wiring diagram, I see they are using pin 8 on the speedo plug. Caerbont calls this lead "not used" What you see with the multimeter hooked to the Mazda sensor has me puzzled. I would agree that it's not a simple reed switch. It may be a variable reluctance sensor that produces an alternating sine wave like a crank position sensor. As far as I know, Caerbont does not work with VR sensors. Maybe Keith knows what Mazda uses for a speedo sensor. If you repeatedly contact the speedometer input wires together at a constant rate can you get the gauge to begin reading speed? You may have to use the programing button to set the pulses/mile to a low enough setting to do this test. If you see speed, you at least know the speedo will work with a reed switch or other solid state switch. This does not answer the question of what the Miata sensor is however... Are there any aftermarket speedometers that work directly with the Mazda sensor? If we could find instructions for such we may be able to determine what kind of sensor Mazda uses.

Skip, I had some trouble posting to this thread yesterday as my router was untraining just about the time I was ready to post. See the related thread in the General section. As to the speedo situation; The stock Caterham speedo sensor is a two wire Hall effect device. I'm only guessing here, but the input to the speedo is probably pulled high ether in the speedo or in the wiring loom in order to provide current to the sensor. If you can figure out which wire is the actual speedo input, pulling it to ground through the reed switch should provide the signal you need. If this doesn't work, it might need to be pulled high through the reed switch. Maybe a simpler explanation would be; you won't be using both wires from the reed switch going to the speedo, only one. the other wire to the reed switch will go to ground or power depending on how Caerbont has configured the Caterham speedo. Since the Caterham speedo uses a hall effect sensor, you can buy one from Automation Direct and mount it to the front upright. The signal is then picked up off the disk bolts for a more accurate solution.(no wheel spin errors) The speedo will have to be recalibrated with the odo push button. -Bob

I may be the culprit. I was trying to reply to Skip's post on speedos in the tech section. Every time I got close to posting, Qwest would untrain my router. After a couple of trys, I gave up. My attempts were around 04:00 GMT, if that's any help. Here's what I think was happening; Even if you don't complete a post, the forum software still sends the Topic Subscription New Post Notification by e-mail if any members have selected that option. I've seen it happen in other forums that have the look of this one. Qwest fixed my router problem now and I can stay connected. BTW...You've done a fantastic job of making this forum work well. I hope I haven't thrown a spanner in the works here...

I finally found long wheel studs that fit Caterham hubs perfectly. For the record; The standard studs supplied by Caterham are 36mm long. Measuring over the splines reveals they are .509 (12.95mm) in diameter. I pulled various studs from the Dorman parts bins at the local CarQuest. Regardless of what the Dorman catalog says, the diameters are rather ambiguous. Only by actual measuring did I find the correct fit. The original Caterham studs are Dorman 610-294, cataloged at 12.95(.509in) diameter x 36mm long. To get 42mm studs, ask for Dorman 610-340. They are listed at 13.08mm diameter x 42mm long. In reality they are exactly .509 (12.95mm) diameter. they press in with just the right amount of force. The 42mm length meets the stud length requirements of most sanctioning bodies with all but the very thickest alloy wheel centers. The shoulder on the 610-340 is short enough to allow mounting alloy wheels without worrying about shouldering the thread on the nuts. If you mount steel wheels or use counter bored pickup truck style lug nuts you may want to check and make sure the wheel nuts are actually tightening with out hitting the shoulders. Also make sure you are not bottoming the threads if you insist on using bling type closed end lug nuts. Checker and Autozone carry Dorman products, however they may have to order enough of them from the warehouse if you need a full complement of studs. If you have the upgraded machined alloy sealed bearing hubs and stub axles, you may want to double check this data. I've only evaluated these studs for use with standard steel or cast alloy Caterham front hubs with the 4 x 108 PCD.

From another RHD Sevener, Sweet car! Very nicely done. I can see you took great effort to follow the Lotus Series 2 design. Certain details really make the car. I love the period tail light assemblies, placement of the instruments, and switches. It looks as though your rear wings are alloy. Did you form those up as well?

Works good now! http://www.usa7s.com/aspnetforum/upload/813623408_oops.JPG

Keep up the good work! I can imagine there's a fair bit of hair pulling involved. I'm still amazed at how user friendly all this web forum stuff is compared to trn...

Yup, I was making a reply to the last post in the thread.

Wot did I do wrong? This is what the grey button produces in a separate window. Server Error in '/aspnetForum' Application. Procedure or function 'yaf_message_list' expects parameter '@MessageID', which was not supplied. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Procedure or function 'yaf_message_list' expects parameter '@MessageID', which was not supplied. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [sqlException (0x80131904): Procedure or function 'yaf_message_list' expects parameter '@MessageID', which was not supplied.] System.Data.SqlCl

I can see again! Let's see if I can post an image. http://qualmach.com/C20XE/conclave/Image02.jpg Looks as though that works well. OK, now back to the mess in the garage...

Skip, Cody used to keep wipers in stock. I see you are located in Erie. If he ships them regular UPS you'll have them next day. It looks as though you're getting close to test drive time. If you'd like another Caterham or two to explore some local roads with, drop me an e-mail. If my car is not in scattered bits at the time, maybe we could go for a blat. -Bob

What's the knurl diameter? -Bob

I need longer wheel studs for my '94 Caterham. Does anyone have the dimensions for the knurl required? I know they are approximately .500" in diameter. I looked at the ARP catalog and it seems the only choices are Honda .485" and Miata .507". Part numbers would be helpfull. TIA -Bob

"trailer-specific tires" V-important. Trailer tires have sidewall design considerations for safely transmitting weight to the road, same as truck tires. Car tires are simply not up to the task. I might add that trailer wheel balancing is often overlooked as well. Trailers need wheel balancing just like a car.

"Towing isn't to be taken lightly" Well said. Sorry, I wasn't implying that one should haul at 3 digit speeds. I was trying to make the point that trailer dynamics need to be carefully calculated to provide for vehicular stability. I guess better wording would have been appropriate. Single axle trailers are inherently unstable and require extra thought. Tongue weight becomes critical. Even with a perfectly tuned single axle towing setup, a drag axle blowout at speed can eat your rig post-haste. Many times there will be nothing you can do about it. Tandems don't react as violently in similar situations. Personally I won't have a single axle trailer anymore and I won't drive trucks equipped with super single tires either.(although DOT deems SS's to be perfectly safe) Just my $.02 worth... Now, back to our regular programming...

Having had some bad experiences with single axle trailers, I opted for tandem axles. Single axles and non-equalized tandem axles (torsion bar type) are wishy-washy to say the least, especially when negotiating drain pans, pot holes, and speed bumps. Just too damn bouncy. My current trailer is lightweight all steel construction with tandem equalized axles and 13" wheels. The frame structures are folded sheet steel and rectangular structural tubing. The deck is 72" X 120" and only 10" off the ground, a little small, but adequate for a Seven. 8' aluminium ATV ramps load the car nicely, but I do have to put a couple of turns into the landing gear to drop the back low enough to clear the bell housing. The trailer can remain hitched during this maneuver. Weight is around 1200 lbs. In tight turns the trailer wheels apex about 6" inside the rear wheels of the Tahoe. It tows like a dream even at three digit speeds. http://www.usa7s.com/aspnetforum/images/emoticons/eek6.gif You have to constantly remind yourself that you are towing something as there isn't even the slightest influence transmitted to the tow vehicle. Well, OK maybe acceleration suffers a bit.http://www.usa7s.com/aspnetforum/images/emoticons/rolleyes5.gif I disabled the original surge brakes. I could never manage to get the surge brake back-up feature to work properly. I had to get out and pin the coupler manually to back up. Newer model surge brake couplers have much better back-up functions from what I understand. Unfortunately, I can't remember the make of the trailer. I do recall that it was built by a commercial mass producer of boat trailers. I picked it up at a farm sale for $300. A few hundred dollars in parts and a shake-n-shine BRG paint job made it into a Farmer John Lotus. http://www.usa7s.com/aspnetforum/images/emoticons/thumbsup.gif

http://www.mitchellsoftware.com Pretty good stuff, although 500 clams might be a bit out of range for most of us. You can get a no-save demo version with Warren Rowley's book "An Introduction to Race Car Engineering" at; http://www.rowleyrace.com/publications.htm If you are serious about suspension design, the Rowley book is a great resource to have around. A bit more detailed than Van Valkenburgh's work.

As for a central meeting place; The Colorado/Wyoming Rockies have some of the most Se7en appealing roads in the country. As those that drove USA2005 can attest, the fall colors are quite brilliant. Additionally there are a couple of National parks available for touring. Just watch out for the park rangers...http://www.usa7s.com/aspnetforum/images/emoticons/angel_anim.gif In addition, there might be a possibility some type of participation from the local Lotus club and Se7en dealer/distributor if we were to hold an event here. I can do some recon if there's any interest. Hmmm, maybe we need a topic change here...

Just a thought, Has anyone put together a promo sheet or membership form that could be handed out to potential club members? If we could get this into the hands of Seven specific dealers and suppliers, we would get free exposure to a lot of LSIS enthusiasts. -Bob

Has anyone here had experience with centrifugal oil/air separators? I refer to the type bolted to the back of multi-stage external dry sump pumps. The reason I ask is; wouldn't this make oil/air separation in the tank unnecessary? I'm trying to squeeze an oil tank into a dedion chassis without removing the passenger's extended foot well. There's not enough space between the foot well and the exhaust primaries to place an Easy-Clean type tank. I can fit a custom oil tank, but it's got to be small, only oil. NASCAR and drag racers have used centrifugical separators with great success for years. I just haven't ever seen one on a sports car. I understand there is a balance between atmospheric breather air pressure and scavenge oil pressure that's critical to proper operation. Get it wrong and the sump scavenges onto the track. ?? -Bob

I'm just floating an idea here... If the electrics stay on but the engine cuts in high G situations, I'd suspect the fuel pump inertial safety switch. Jumper around it just to make sure it's not clapped out. -Bob