Pokey

Thanks @MV8. Sounds like you agree that the pedal stroke increasing could account for the failure then? BTW, I bled using suction from the slave’s bleed screw after assembly.

Long story short, hydraulic fluid dumped from the slave onto the bottom of the bell housing. We replaced the slave, bled, and the same thing happened. The original slave's manufacturer is unknown, but the replacement was a Perfection Clutch 360062. The two look identical down to the first four digits of the number stenciled on the casting as shown in the picture below. The release bearing touches the clutch's fingers but does not look to be depressing them. When the clutch pedal is operated the release bearing does not move. That's the facts, now comes the random thoughts: I took the clutch off to inspect, and while it seems unlikely I installed the clutch disc backwards, and unlikely that I could have cinched down the pressure plate had I done so, and it isn't clear how doing so would cause the fingers to become unmovable, if the fingers were stuck in position then what could have happened is the slave cylinder seals failed as the hydraulic fluid had to go somewhere. Note that this thought does not explain why the original slave failed in seemingly the same manner. The clutch pedal does not have a stop, or more precisely the stop appears to be the bulkhead, which over the yeas has deformed outward by a centimeter or more. Assuming the master cylinder can move more hydraulic fluid than the slave can accommodate, and that the pedal-induced bulkhead bulging allows more pedal movement and hence more fluid leaving the master, then, again, the slave cylinder's seals would suffer as a result. This would also explain why the original slave failed, but it also requires that while bleeding the clutch I pressed down to where the pedal pushed on the bulkhead. I can't say that I did or did not as I wasn't paying attention. Operating the pedal now using only half of the pedal stroke still results in hydraulic fluid transfer onto the floor of the bell housing, so that either means the clutch fingers are immovable or the slave's seals are so utterly destroyed that the resulting pressure isn't enough to move release bearing against the fingers. Anyone every experience anything like this? And those with a Zetec/6-speed setup, do you happen to know what slave you have installed?

Not sure if I posted anything at the time, but I had one cylinder running colder that I eventually traced back to the ignition signal coming from the ECU. For me the symptoms were more binary than for you, all of a sudden I (partially) dropped one cylinder. Granted, symptoms were more or less acute depending on driving conditions, and I don't know if the MBE ECU in these 420's fails the same way every time but perhaps you are chasing this gremlin? The definitive test is to put your ECU into another car and see if the problem follows, but I got to that point in troubleshooting by using a logic probe starting at the coil and working my way back in the wiring harness until I was convinced it was the ECU signal.

Assuming COP, a logic probe tester at the coil is the easiest way to rule out everything electrical upstream.

I'm looking at two steering racks. The first was manufactured in the early 2000's and is stamped as shown in the picture. The second was recently purchased and has a different character string stamped in the same place as the other rack, plus another character string stamped on the opposite side of the circular hole. That other character string matches the Caterham part number for an 8% rack. I'm told that the older rack is a 22% ratio, but lock-to-lock they are identical at just shy of two full rotations. Right now the new 8% is installed but I'd like to replace with a 22%. I'm thinking that I was told wrong, that the older rack is also an 8% ratio but am wondering if anyone can identify why lock-to-lock isn't the best way to tell. Maybe I need to pull the rack on the car and bench them together to see if the tie rods move the same distance? That wouldn't seem likely as that would mean one rack can turn the tires more than the other, but?

An alternative to a dry sump that seems to fit the need is Raceline's low profile wet sump: https://www.raceline.co.uk/products/part_section.asp?SectionID=40&CategoryID=2.

Given it is a roller my pick are wheels.

I can't see any way to adjust - it has a single attachment point that is round, not slotted. Nevertheless, I did try backing out the bolt and wiggling the sensor to see if it would have any effect on idle and it didn't.

I've ordered a new sensor. The $25 will be worth it even if for ruling out one of the possible causes.

The thought had crossed my mind that the ECU hadn't cleared a code, but it has been sitting with the cutoff switch off. I wonder if the ECU has NVRAM...

I put mine right at the kill switch.

Got yet another weirdo for those so inclined to ponder. This time it is a circa 2003 Zetec SVT that was running fine on track one moment, and the next moment sputtered to a stop. After getting a push back to the pits I discovered that the crank position sensor, normally located on the LHS bell housing, was dangling from its wires. A few minutes later I had the sensor reinstalled but the engine runs rough. There are no markings that I can see on the sensor or the bell housing, nor is there any way to adjust the sensor's position when installed. I just backed the bolt out that attaches the sensor to the bell housing and tried moving it around while the engine was running with no effect. I also manipulated the wires and connector while the engine was running and, again, no effect. About the only other piece of information I can offer is the bolt was lost on track so I had to substitute. No reason to think the bolt is factor though as everything cinches down tight. Unless someone has a better idea I think my next step is to replace the sensor. Seems unlikely to be the cause though. Anyone care to offer an idea? Nothing is too whacky at this point. Greg

Here are before and after pictures having replaced the original 2019 rear lights with Caterham's LED kit.

While not part of a new build anymore, I thought someone might be interested in seeing one of many options available for installing a Signal Dynamics Backoff XP. I opted to install in close proximity to the brake light switch. The Backoff XP is attached with 3M Dual Lock. Note the white wire with the red stripe isn't attached, I've just terminated with a female blade connector that can be removed to make switching between the two modes simple.

@HUTCH, if the answer to the problem is to replace the ECU and you are having trouble finding that part, perhaps Raceline can help: https://www.raceline.co.uk/products/part_section.asp?categoryID=2 &SectionID=43. Presumably you need the Omex 600, but you would need to check with Raceline and you should also ask what, if anything, you need to do to plug your wiring harness into their ECU.