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The machine shop called today and said the block cleaned up at stock specs. Still going to bore it to 84mm, and purchased pistons today. Ended deciding on Supertech 84mm 11:1 compression slugs and Wiseco rings. It felt odd following SMs advice on almost everything except slugs, so I closed my eyes and went for it. The builder wasn't too bothered by the choice either, so that's good.
Funny how you and Option both got major updates from your machine shops within the same couple weeks. Can't wait to see the high-comp BP sing like Nate said.
Measured their weight to compare to stock and out of curiosity. Lightest Supertech is 340.0g, heaviest 340.5g. Stockers 332.0 lightest, 333.0g heaviest. About 8g gain per piston.
The rods though. Stock rods weigh between 573 and 574g. The carrilos are 427g. 146g loss per rod.
Bearings should arrive in a couple of days. I’m going to ask the shop to fly cut the pistons for more valve clearance in case they need to skim the head or deck the block a lot.
Those Carillos are light! Are you going to get the rotating assembly rebalanced to match?
Crazy light. And yep, they are going to balance the pistons, rods, pins and rings. Also going to balance the crank, flywheel and clutch assembly if needed.
I had to tell Ricardo to stop being such a weight weenie, considering those pistons have so much more dome and are barely heavier than the stockers, that's a win! Not to mention the strength vs OEM stuff.
This engine is going to be very cool.
Last edited by Fireindc; Feb 24, 2026 at 02:36 PM.
That's some DOME baby! You gonna set the rev limiter to the moon with all that shaved rotating mass? Can't remember if you mentioned anything about that in previous posts.
Took bearings, crush washers, pistons and rings to the shop today. We had a talk about valve to piston clearance concerns and he said fly cutting these pistons with the coatings is a pain the behind and he doesn’t want to do it. Fair enough.
After some questions about compression height and headgasket choices it seems this may not be an issue if I let the compression drop to 10.5 or 10.8 with these pistons. It’ll depend how much down the hole the pistons end up, and will have to use a headgasket to compensate and keep the squish somewhat happy. Basically, we’ll figure it out later. Another idea I’ve toyed with is machining a pill that slots into the VVT phaser and mechanically limits how much advance it can provide. The Honda people use this when going to bigger cams. Here is an example from TracTuff
I’ve got other news. In 2020 I drove a Caterham 485s in the mountains and since then I’ve not stopped thinking about it. The fizz of this car made my Miata feel numb afterwards. In January I was unfortunately lucky to drive said 485 at the track and two other Caterham 420s and in a nutshell it, was one of the best days of my life. It was one of those moments when you realize you’ve found a new path you must follow. Some friends of friends conversations later leads to today:
God damn. That’s with half a tank of fuel.
This is an older Caterham. 2007 build with a Ford Focus SVT motor rated at 170 crank HP and 1300lbs to move around. Ford Type 9 5 speed and sport suspension package with LSD. Got work to do before it’s track ready, but I feel like a kid right now.
That car is so sick! Can't wait to experience it for myself. I don't know how to explain it, but that car fits your personality way better than the stealth.
Also, I gave your post a cat, because the pic of a cat in a Cat.
Guess I can let the lack of major engine updates in that last post slide. Congrats on the new ride, thing’s sick!!
I posted some engine updates too! Just no pics, sorry. The machine shop will be actively working on the block and head this week and requested I get 3 shims of different sizes for them to get started on that side of things.
Haha so cool that he bought it back! Thanks for the link, I will be following the progress on it. I was somewhat planning to buy an MK Sportscar and build it with a Miata drivetrain, but this Cat showed up at a good price, and I enjoyed how the DeDion axle made things exciting.
Awesome pick up with the Caterham. They're always in the back of my mind and if I had a little more garage space I wouldn't be surprised if I had one as well. I've only ever driven them in simulators, but they're always a joy to throw around.
Thanks Simba. They're great little cars and I strongly suggest you find a way to drive any type of Seven. You travel a fair amount right? I've heard that Caterham dealers in the UK give joy-rides to future monk initiates . By all means, let someone talk you into one.
We have an older guy who's built a couple "LoCost" 7's in his garage, his latest one being powered by a turbo rotary. I've debated on picking up one of his old ones. He's older so he still uses the ECU's he's been tuning since the 90's and unfortunately he never seems to have the car running quite right. If my wallet get's too heavy I might have to start chatting with him
A good mate built a Locost - B6 and all - turbo-compound with both blower and turbo, because too much power is never enough. The gearbox is not at risk, it just lights up the tyres.
He still has it, but I don't think it is roadworthy atm.
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. By all means, let someone talk you into one.
