About a week ago I bought a 1987 Caterham 1700 Super Sprint from a friend of mine. I first saw at a summer party at his home a couple of years ago and thought that would be a fantastic car to own. We had just bought two Porsche Boxsters, so the time wasn't right, but I kept lusting for it. A year ago my friend brought it to our local autocross venue, a closed military airport, and saw it in action. More lust. I did notice that it emitted a cloud of smoke whenever he lifted the throttle, so I knew something was worn.
The car has pretty much sat for the last decade and needs work. My first priority is the engine. Make sure that it gets a good tuneup, and then evaluate whether any kind of rebuild is needed.
Finally all the pieces fell into place. I was able to get spousal approval and my friend realized that the car needed to go to someone who would use it. Pricing was a little tricky. We finally left it as he would decide how much he was willing to sell it to be for and I would pay him that amount if I could afford it. No dickering. He worked out a price and I accepted it, so the deal was done.
A week ago I drove it home. The temperature was right around 40 degrees F and it was a bit hard to start and needed both starting fluid and choke, a two person job since the car didn't have a choke cable. First time I drove it in traffic. Pretty rough in the 1000 to 3000 RPM range. Lots of farting out the exhaust and popping out the carburetors. As soon as it hits 3000 RPM it smooths out and pulls like a champ.
My plan is to give it a thorough tune-up ASAP and then decide whether there is a need to rebuild any component. This weekend proved ideal to get the project going. Yesterday was in the 40s, today and tomorrow in the mid 60s. Terrific for Massachusetts in January.
Yesterday I started out having the car inspected. I registered it earlier in the week and got the license plates Friday. The state inspection is similar to the UK MOT. It was a hoot. Everybody was really interested in what it was and took a lot of pictures. The inspector insisted on driving it in and needed instruction on how to get in. Once in, I had to show him how to test all of the controls. Everything worked as it should and the car passed and got its sticker.
After I got home I started by installing a choke cable. Once I get it tuned right I suspect it won't be needed, but right now it is. My plan was to tune the Webers, but as soon as I started I noticed that any push on the carbs make the idle speed change and the manifold mounting nuts seemed really loose. Tightened them a bit and then decided it was prudent to get some expert advice. Glad I did. Didn't realize that the manifold mounting is flexible to reduce frothing in the carbs. End result was that I ordered the parts to replace all of the mounting hardware.
Today started with a carburetor tune after replacing the spark plugs. The carbs turned out to be balanced perfectly. The idle mixture was not right with the air filters off. I did set them as described and it ran fairly well, but after putting the air filers on it was clearly off. That prompted me to get a K&N filter cleaning kit. Used it, and now have the filters drying inside the house, so no more carb work. Next was a compression test. I did it dry and found that the cylinders all are very close to 150 PSI. Cylinder 4 is a tiny bit lower. I need to find out whether this is good. I was relieved, however, to find them so close.
Tomorrow I'll put some oil in the cylinders and do a wet compression test. That should tell me if there is any piston blow-by. I will also do a road test and see how it feels.
At this stage I suspect that both carbs would benefit from service at a specialist and also that the head also should be given a rebuild. The valves seem to seat well by the compression test, but the smoke at lifting indicate that the valve guides and/or the valve seals may be worn.