jbcollier

Just a couple of points: - no one can accurately tune carbs by ear and eye. Take the case of the famous tuner (multiple Isle of Man winner) who set up his bikes for a sweet mid-range hit. With a modern A/FR gauge, they found he tuned in a flat spot to create the "hit"! - collector is the right spot, use a bit of sealer to make sure no false air is drawn in. - the sensor wire needs to go up if it is a permanent install. Just for testing a warm engine, it does not matter that much. - DO NOT SET THE MIX TO THEORETICAL PERFECT (14.7:1) That is way too lean. Very low 14s to high 13s for light throttle. Low 12s for WOT. Lots of info online. Older engines (insert Lotus TC and Ford crossflow) will especially not tolerate lean mixtures.

Mechanical tachs are not more accurate than electric/electronic ones. Had a Climax powered Turner come in with the owner saying there was no power. The problem? His mechanical tach read 3k low. Get a tach repair module for the tach you have. It will be fine.

We’re all built a bit different, true.

Can’t comment on a Birken but I have several 3 hour+ trips in my Lotus Seven S3 with no problem. I’ve done 5k trips in my Europa S1 with no problem. Most comfortable car I’ve ever driven. The Seven’s not bad but need to change the seat foam over to something more supportive.

IF: - the bore is clean, smooth, free of any signs of scoring, and; - the piston is perfect, no marks whatsoever, and no measurable out-of-round; then, by all means, rebuild the cylinders. If the rubbers in one went, then all three are due. Any signs of wear on the bores or pistons, replace them instead.

Interesting, sounds like yours and mine are closely related. Mine was sold in Toronto, built-up, LHD, and GT engine. I'm also the third owner as well. Must have been the first owner who fit the triangulated gearbox mount. Unfortunately he had dementia at the end and some of its history is unknown. It's certainly a joy to me. I'll drive it until too frail or demented as well, long may that be.

In earlier Sevens, the heater recirculates passenger compartment air. It does not draw in outside air. The heater control is also a "throttle" valve that opens and closes, it does not bypass.

Fitting a removable steering wheel makes a huge difference in ease of entry and exit.

And, if you split the calipers... https://www.pegasusautoracing.com/productdetails.asp?RecID=1144 https://rimmerbros.com/Item--i-17H7679

If you split the calipers, please replace the square sealing ring between the two sides with the correct part. Do not simply use an o-ring. I have split the calipers and replaced the sealing ring, and I have rebuilt them without splitting. Both methods work out just fine.

There actually isn't much similarity at all, thank goodness. The Ducati has its valves set at an 80° angle IIRC (ie: not good!). The exhaust port is ok but the intake port is awful with the incoming charge flowing across the valve head. It takes a lot of work to make the intake port simply bad rather than unbelievably horrible. In contrast, the twink valve angle is much smaller (mid-30s comes to mind but I can't remember for sure) and the ports are beautifully laid out. Things have moved on, for sure, but the twink head was state of the art at the time.

You’re correct that it is the time to peak combustion pressure we can’t change easily. We move the ignition point earlier to keep it happening at the same time. However, other things are going on as well. That is the amount of heat the piston is exposed to expressed in degrees of rotation. As we add more degrees to keep the ignition happy, more degrees of rotation are having the piston exposed to heat and less without heat. This means our piston temperatures go up. We have to balance “ideal” ignition timing with piston heat load. This is where timing by feel can catch people out. Yup, maybe you can make more power with your timing further advanced but you might hole a piston as well. Engineers and tuners can change combustion chamber design to increase turbulence and reduce area, this can decrease combustion time, increase efficiency and require significantly less ignition advance. My Ducati 250 has a classic hemispherical combustion chamber. With higher compression rations, the combustion chamber gets very long and thin. Total Ignition advance has to be in the range of 38 to 40 degrees — pistons lead a hard life. However, add a second spark plug into the chamber and the same engine will happily run 32 degrees and not have any piston issues.

JohnCh: Your curve is fine for a street driven TC that does not see much sustained WOT. If you do steep, long, mountain passes or track days, I would knock it back a bit to a maximum of 26 to 28 degrees total to reduce WOT heat load on the pistons.

I don’t like setting the static point to TDC and then doing everything electronically. I prefer to static time using the actual desired static timing point. This gives consistent timing during slow cranking speeds. So, if you use a static timing of 10 degree BTDC, you would subtract that from the timing points kindly shared by JohnCh. 500 - 0 1000 - 4 1500 - 8 2000 - 13 2500 - 22 3000 - 23 This would be good curve for a crossflow!

The seal kit will work just fine. Caliper dimensions are nominal not precise.

Ok, I’m travelling and do not have access to my books so I can’t suggest any curves for you. That said, your current curve is not good. You have 37 degrees of “mechanical” advance. That’s a LOT. That is added to your initial advance setting so you could easily be rocking 40+ degrees of total advance! Those kind of numbers are reserved for engines with poor, slow-burning combustion chambers from the 50s and early 60s. I’ll post a better curve when I get home mid-week — if someone else doesn’t come forward with one before then.

Do you mean wheel cylinder kits? 12.8mm is 1/2 inch. Do you have brake shoes and drums? Or brake discs and pads? Wheel cylinders from that era would all be in imperial, not metric.

Occasional toots from the horn won’t go amiss either. Seven horns need to be LOUD.

“death grip on the steering wheel” A set-up good for the track is going to be no fun on the road. Mine tracks straight and true. There’s just too much going on for me to actually fall asleep at the wheel but my mind can wander any time it likes. How visible you are to other road users is a very serious issue. Never thought I could drive anything less visible than my motorcycles but a Seven in traffic is virtually invisible. I have had people pass me pointing and staring, only to cut me off 50 feet later! You should NEVER be beside another vehicle in traffic, always ahead or behind.

They are as reliable as the person preparing them. On long trips, do bring a few spare a-frame bushings though. They have a short life even if there are no oil leaks.

My 69 S3 is actually pretty comfortable. I have added side-screen extensions and plan to change the seat foam but have no problem doing 350+km rides. My plan is to drive it to Vancouver (2300 km round) and Toronto ( tad under 7000 km round) in the next year or so.

Mid-50s and you are having an existential crisis? What are you going to do when you really get old? Drive it and enjoy until you don't, and then sell it. When? Who knows? Everyone ages differently.

At one point in its life, my Seven had its riveted-in mount removed (holes are still there) and square tubing welded in to support the gearbox. They also did some bracing in the front. Everything fits together very nicely so I think it was a reinforcement kit from either DSK or Arch -- they both offered "update" kits back in the day. I have the early style tail housing -- or did, dropped on the floor and broke (insert sobbing emoji). I have an alloy replacement coming but may just weld it back up.

Thanks for the suggestion but, unfortunately, not the same as what I have.

Apparently, it's a mount from a Ford Anglia (105E), Consul, Zephyr, or Zodiac mk2.