jbcollier

Electronics is not my specialty but LEDs do not work like incandescent bolts. They do not just dim with lower voltage. Below a certain threshold point, they simply won't light. You will have to experiment or just fit a lower output LED.

That particular Lucas electronic unit takes a standard AC Delco module commonly used in 70s GM HEI distributors. Test the inputs. If they are good, change the module. The inputs are 12v switched, tach feed and the two to the distributor. The two to the distributor can be checked using the AC voltage setting on a multimeter. You should get roughly 2vac when cranking. The pick up output in these systems is go/no-go. If it works, it works. If it doesn't work, there's no signal at all. The most common failure point is the module inside the box. The main reason for failure is the break down of heat transfer from the module to the box and the module overheats. This happens inevitably over time. Clean the box's mounting surface carefully and use the paste supplied with new module to ensure long life.

Yes, original latches. Good suggestions, thanks. I'll start with replacing/adding foam gasketing to give the latches more tension.

After a couple of short trips, and fettling the few final issues after a major refresh, I went for a proper 700 km round trip. Overall it went very well. Economy is not as good as my Europa but reasonable none the less. Suspension is as good as can be expected with the rear being quite firm on the big bumps. I did some experimenting and buffeting can be reduced to reasonable levels by either shrinking an inch or so, or by adding a small clip-on extension to the door frame. All well and good. However, I was alarmed to find that three of my bonnet latches “weren’t” upon arrival. They all stayed latched on the return journey but I’m afraid my confidence has been shaken. It’s a somewhat original 69 Seven S3 and I’m trying not to stray too far from stock. Any suggestions on how to keep the bonnet firmly in place while I further push back the Seven’s horizons?

Not sure what your question is. The choke is a restriction that creates the pressure differential to draw fuel in. The auxiliary venturi is the outlet for the case's main circuit. Both work together, along with other parts, to control when, and how much, fuel flows into the engine. Smaller chokes work better with low air flows and larger chokes the reverse. Choke selection is based on expected engine air flow and is a compromise either emphasizing low end torque or high speed power -- or something in the middle.

The stock system is a pressurized system. It is designed to be completely full at all times. As the coolant heats up, it expands and excess volume is released into the reservoir when the rad cap's pressure rating is exceeded. The correct cap is double sealed so that when the coolant contracts, coolant flows back in from the reservoir. Any leaks in the system will result in the coolant being pushed out but not drawn back in. The coolant level in the engine will drop leading to overheating. The same problem happens when people replace the sealed system cap with an ordinary cap. Again, coolant is not drawn back in leading to coolant loss and overheating. I would recommend making sure the system is worKing as designed before modifying it. YMMV

Dont 'run a car with 15 year old hoses, never mind 40.

You are right on the letters but I think the 2071 is just a number, not a date. This is a frame builder's number, not a chasis/VIN number. It was a factory build, sold in Canada in 1970 but most probably made in 1969.

160°F or 71°C

If there isn't an oil thermostat, fit one.

Long term update: Runs just fine with a 160° thermostat.

I removed the pedals as I'm fabricating a cover for the pedal box to help stem the flow of hot air into the passenger area. And, underneath, I found the missing chassis number:

My 69 Seven S3 has no roll bar and anemic rear lighting. As I drive my cars in all weathers, I added a rainlight with a brake light option: Here's a video of the rain light function: And the "third" brake light: The rain light also doubles as a hazard light. Both are INCREDIBLY bright compared to the stopck lights with LED bulbs.

He says, ignition off, sidelights on, and the new, high-level, lights (with sidelight function) go off when he steps on the brake. What is happening is that the non-powered, brake light circuit is providing an alternate path to ground for the side light voltage. Not quite shorting it to ground but enough to lower the voltage below the LEDs active threshold, extinguishing the light. You could wire in diodes but, really, does it matter that much? You have sidelight function and brake light function and when are you ever parked up, sidelights on, ignition off and your foot on the brake?

Just want to make sure that no no one thinks that more timing always results in more power. At a certain point, on some engines, it still won't ping but it will start to have some retarding effect on the piston. Also, increasing advance increases the heat load imparted to the piston crown.

I also have a '69 S3. I'm happily running the 3.9. I added a Quaife diff so it wouldn't just spin up one tire. Now I can spin both in second under hard acceleration. There's also 3.7x, etc, and even a 3.3x ratio available but I find the 3.9 to be just about right with a stock-ish crossflow and the stock gear box ratios. Bit buzzy on the freeway but nothing a short stroke engine can't handle with aplomb.

Plate diffs can be set up in a myriad of ways from virtually fully-locked to fairly "slippery". This makes direct comparisons and definitive statements problematic. For the track, with a good experienced crew and a bucket full of spares, I think you can get more out of a plate diff. However, just like everything else on a race car, set-up will change with different tracks and different conditions on the same track. An ATB diff is just plain fit and forget. I have fitted ATBs to three cars now and am a big fan of them for road use. While not tuneable for the ultimate performance, the ATB is a consistent performer. I find it especially helpful when "dancing" with the limits in poor conditions. For obvious reasons, I simply do not drive to the limit on public roads in clean, dry conditions. YMMV John

The sender just bolts up. You have to make a thicker cork gasket as the thread inserts sit a little proud. The tank itself is slightly lower but the rubber elbow still reaches.

Better:

Not enough experience to say, sorry.

The new tank requires a 3/4” spacer at the front lower edge to lift the tank slightly, and significant bending of the fuel sender’s lever (make it shorter to reduce total travel). It will all work though you couldn’t call it drop in.

Well, it “fits”. I have to redesign the axle brace as it extends too far into the tank’s space. It was actually rubbing against the original tank and had worn through the 1/8” wall brace !!!!

I'm ordering one and will report back.

Big shout out to Caterham. After my enquiry, they have added a photo with dimensions to to the listing.

Just heard back, Arch says a Caterham crossflow tank will fit!