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Thread: My "new" 1987 Caterham 1700 Supersprint "SUPER7"

  1. #1
    Join Date
    Jan 2020
    Posts
    180

    Default My "new" 1987 Caterham 1700 Supersprint "SUPER7"

    I have posted a couple of threads on this, but have decided to journal my work.

    So when I purchased the Caterham there were a number of issues that needed taking care of:

    • It was very hard to start when cold
    • It smoked, primarily when letting off the gas
    • It used oil, related to previous bullet
    • It overheated if sitting idling in warm weather
    • It was pretty dirty, and has an oil film on the bottom shield
    • It spat out of the carburetor especially under low and medium throttle
    • It had air leaks in the carburetor to inlet manifold gasket, especially of any force was applied to the carburetors, a light push up or down on the carbs would change the idle.


    Based on the above, I decided to do the following:

    • Install a modern radiator fan
    • Replace the carburetor manifold gasket with a Misab gasket
    • Replace the supposedly unreliable Lucas electronic ignition with a complete Aldon Ignitor ignition.
    • Install a catch can to the crankcase breather
    • Replace spark plugs and give it a general tune-up
    • Do a thorough cleaning


    I also decided to install cycle wings on the front instead of the traditional wings. Just like the look better.

    So I got cracking:

    I installed a choke cable. Very simple, but it didn't do much to improve the starting

    The next thing I attacked was the carburetor spitting. I bought a timing light and discovered that there was little advance on the timing. I advanced it to optimal idle, between 10 and 12 degrees and it did wonders to the idle and the spitting is gone. I also decided to clean the K&N filters. They were filthy and after cleaning and oiling I needed to adjust the carb balance and idle mixture. Took it for a test run and was very pleased with the result.

    Since that test run the car has been on jack stands. Putting it on jack stands without putting your safety into jeopardy and risking damage to the car takes some care. Doing one side at a time didn't work. The first side worked fine, but when jacking up the other side, the jack stands started shifting. Doing one end at a time worked much better.

    After putting the car on jack stands I discovered that it had a coolant leak from the thermostat housing. Fixing that was one of the most frustrating things I have experienced. The old gasket had completely disintegrated and it was a pain to clean the remains from the surfaces. I couldn't get a gasket that fit from the auto parts stores, so I bought some gasket material and cut my own. Installed one, it leaked. doubled it up, and it leaked. At this point I was concerned that the leak hadn't been from the gasket, but from either the temperature sensor, or another, one wire, sensor on the other side. Assume one controls the fan and the other the temperature gauge. Finally I used a gasket in a tube, and behold, the leak was fixed. This took many days because the leak was small but persistent.

    I bought an Aldon distributor with an Ignitor. Replacing the distributor required removing the carbs. Needed to be done anyway in order to replace the carb manifold gaskets, not an issue. Getting it off was fiddly, mainly because access to the manifold nuts under the carbs is really fiddly. Took a couple of hours, but then it was off. With the carbs off I decided to tackle the catch can. Experts on this forum and and Lotus7.club had recommended running the crankcase breather to one end of the valve cover end and then from the other end of the valve cover to the catch can and finally under the car. The nipples were bought from MacMaster Carr and the catch can from Amazon. I wanted a catch can with at least a quart capacity and the ability to see the volume contained and also easy draining. The one I bough is pretty and big, but turned out to be un-baffled, so I'm going to stuff some steel wool into it to provide some surface for catching the oil droplets. Got some practice with my new pop riveter. There's a lot less room to install extra stiff along the upper side rails than you would think.

    I measured the radiator and decided that an 8" pusher fan mounted in front of the radiator would be the best. It came with an adjustable thermostat and probe that I decided no to use, but instead run the wires from the old fan to the new fan relay. The fan turned out to be a tad too big, and when I cut it back I had hadn't noticed that the fan blades were connected to a rim. The rim interfered with the reservoirs on the top and the bottom of the radiator and a 7" fan would have been better. I was able to mount the fan so that the blades would spin. Two of the cheap Chinese spring loaded mounts broke and I used tie wraps as temporary mounts until I can get replacements. The old fan was pretty useless. Small, far from the radiator and no shroud to ensure that it pulled air through the radiator.

    Next the ignition replacement. The car was built with a Lucas electronic ignition and it took some work to figure how to unwire the Lucas and wire the Aldon. Especially since I didn't want to make it a one way street in case I couldn't get the Alson working. After more trouble than I care to describe the Aldon was installed and after very careful checking I turned the ignition on and tried turning the distributor to check whether there was a spark. No spark! I then tried to see if I could generate a spark without the distributor by grounding the negative terminal of the coil and breaking the ground, simulating opening and closing points. No spark. By this time I decided to reinstall the Lucas system, and it sparked when the distributor was turned, so until I can figure out how to test the Aldon it isn't going into the car.

    Reinstalling the carbs with the Misab hardware was one of the most fiddly things I have every done. For one, the rubber "springs", their caps, the steel spring washers and the nuts barely fit on the studs when not compressed and I kept dropping parts on the floor. The top studs weren't too bad, but the bottom ones were very hard to access and the middle ones were too close to the bracket joining the carbs to allow a socket to go on to the nuts. So here's how I did it. Rubber "springs" and caps on top studs, nuts on the two upper, outer studs to prevent the cabs from coming off the top studs. Then the same on the bottom studs. A magnetic pickup and a screw driver and a flashlight helped get them on and deep enough to not fall of. Nuts on the two bottom outer studs and off the two upper studs and then the steel spring washers. Nuts on to again and off the bottom and springs on the bottoms, and then nuts on the bottom outers again. Now for the really difficult part, getting all nuts on and tightening them. The only order I could to the top ones were first the outers and then the inners. Bolts had to be pushed into the barely large enough gap and pushed and aligned with a screw driver while fastened with an open ended wrench. If more than one to two threads holding the nut, the gap for the other nut was too narrow for the nut to go on to the stud. The bottom was worse. Outer nuts fine. Enough room to put the nuts on by hand and then tighten with a socket. The inner nuts were really hard. No room for a wrench, no room for a socket, so how to get the nuts on. After much trial and error I thought of carefully banging a screw driver blade into the top of the nylock nut and then use the screw driver to align the nut, push on it to compress the spring and then tighten it. Phew. I forgot to mention that I gave the carb a good clean with carburetor cleaner before mounting it. The new mounting is much better than the old one. Really pleased with it.

    While all of this was going on I had ordered a set of front cycle wings, wing brackets, headlight brackets and a cycle wing mounting kit from Caterham US. Getting the old wings off was simple. Getting the light brackets off was not so simple, because the wires to all the lights had to be cut. I ordered automotive connectors from McMaster so I can put the old wings on again without as much work. The wing brackets and new light brackets were easy peasy to install and with a wheel mounted the wings were trial fitted, Will work with all my rims, 13s, 14s and 15s. The connectors will arrive on Tuesday and then I'll rework the light wiring and install the lights. The wings will go on last after I figure out exactly where to drill the 4 mounting holes in each wing. I did look up on lotus7.club and found the measurements, so I am ready.

    Then an oil chance, brake and clutch fluid flush and last a though cleaning and polish and my Caterham should be presentable and ready to use!

    I'll also check and adjust the lifter gaps before doing any serious driving. The gaps on cylinder 4 seem to be too small just from comparing them cold with the others.

    Next fall and winter I will do a deeper analysis of the condition of the engine. I suspect the valve guides and seals are worn and hope the rings and pistons still are in good condition. Bought a leak down tester and will find out how much work is in store.

    No time to be bored with the lockdown!
    1987 Caterham 1700 Supersprint
    2002 Porsche Boxster
    2004 Porsche Boxster S
    1941 Dodge Luxury Liner
    2009 Mercedes CLK 350 Cabriolet
    2017 Chevrolet Volt

  2. #2
    Join Date
    May 2018
    Location
    Albany, NY
    Posts
    422

    Default

    Bump. Hows the progress been?
    2001 Caterham Superlight R

  3. #3
    Join Date
    Jan 2020
    Posts
    180

    Default

    The big news is that I was unhappy with hesitation between 2 and 3 K RPM. I tried working on timing, new spark plugs, carburetor balancing and adjustment, but no significant improvement. Not being willing to tear down Weber carburetors I took it to a specialist who determined that the idle jests were too small. After they replaced the jets the hesitation was gone. So was spitting out of the carburetors and explosions out of the exhaust. It made a huge improvement to the drivability of the car. The only thing remaining is to deal with some smoke. Today was the last autocross of the season, so my plan is to pull the head, check the valve guides and seals, and take a look at the cylinders. What I can afford to fix I will fix over the winter.
    1987 Caterham 1700 Supersprint
    2002 Porsche Boxster
    2004 Porsche Boxster S
    1941 Dodge Luxury Liner
    2009 Mercedes CLK 350 Cabriolet
    2017 Chevrolet Volt

  4. #4
    Join Date
    Jan 2020
    Posts
    180

    Default

    You may have seen the YouTube review just posted in this forum. It is may car and it is great as is, but I want to make it as perfect as I can!

    https://youtu.be/xR2rjh-D6LM
    1987 Caterham 1700 Supersprint
    2002 Porsche Boxster
    2004 Porsche Boxster S
    1941 Dodge Luxury Liner
    2009 Mercedes CLK 350 Cabriolet
    2017 Chevrolet Volt

  5. #5
    Join Date
    Apr 2018
    Location
    Ft Lauderdale
    Posts
    232

    Default

    Great write up thanks
    Life Can Be Cruel

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