jbcollier

The S3 has a swirl pot hooked to a standard thermostat cover by a hose. Sealing should be fine. Did yours run hot at all with the stat in place?

Crossflows in Lotus Seven S3s did not have thermostats fitted. Supposedly if you fit a thermostat they will overheat. I'm a retired, 35 year mechanic and I like thermostats. They provide quicker warm up and better heat dispersion while doing so. Can anyone confirm this is actually true? If so, any idea why?

I am, unfortunately, also retired. Had I known how busy it would get, I would have stayed working!

PS: thanks for your assistance! Now to cut it up so I can fit a small-block Chev in there... :-)

All settled. It's a Universal Radiator made chassis and they used fusion welding, not brazing. John had it already in his system and is moderately confident it is the real deal. I think moderately is about as confident as you can get with any Seven, so I'm happy.

Things are getting curiouser and curiouser. There is no stamping where in the usual S3 location beside the brake master. I figured, in for a penny, in for a pound, so I cleaned off the top of the upper rear shock mounts, cleaned off the top of the cross tubes in front of the seat bases, and cleaned off a one or two joints in the front compartment. First there are no numbers at either of those locations. Second, the chassis is welded, not brazed (!!). So it is not an Arch Motors chassis. Any thoughts?

Guilty as charged. I also have a Europa S1. Thought I would like a roadster again so bought this Seven when it came up a month ago. I've explored both sites but they looked fairly dated and thought they might be no longer maintained. I'll ping Mr Watson. Thanks.

First post! I've just bought a Lotus Seven S3. Serial number is LSB2383 but there is no body number that I can find. To me, the CBU looks like it has been changed but I would appreciate other more expert opinions. I'm not worried either way as both original and properly triangulated later production have their pluses. Here's a link to my photo album on the car. All the car shots are from the seller. Mine are the last three with the VIN plate, the place where the chassis number is supposed to be (by the master cylinder), and a photo of reinforcing by the lower a-arm mount which I have also posted below. Does the VIN plate look original? Couldn't call it legible that's for sure. Any idea if the CBU is a replacement and, if so, by whom? Other places I should be checking? https://jbcollier.smugmug.com/Lotus-Seven-S3/