Birkin S3 pedal box issue.

[JB455]

I just picked up a 2002 built Birkin with Zetec engine. Previous owner was on the smaller side and I'm on the bigger side. When I picked the car up the adjustable pedal setup was set nearest the driver seat and everything worked fine. I moved the pedals to the furthest spot of the three settings, to provide the most legroom. All seemed fine as I set off on a test run.... but it became apparent fairly quickly that the shifts were more difficult. It seems the clutch pedal was hitting the bulkhead and was not fully releasing. I moved the pedals back to the middle setting and all seems well again. 

 

My question is this- It would seems if Birkin had designed the movable pedals with 3 locations that the pedals should properly operate from all 3 locations. Is there something amiss with my clutch pedal? Something that could be adjusted to allow it full travel? Fluid reservoir is properly full, but I suppose it's possible that it might need to be bled. Aside from that, anything else I should be looking at? 

[wdb]

I'm not familiar enough with a Birkin to be of any help without some pictures showing what is adjustable.

[MV8]

A slightly larger bore clutch master or smaller bore clutch slave would bring the release point away from the firewall. You may also be able to fit/adjust the pushrod to be longer if the pedal can start the swing further aft.

[11Budlite]

There is an adjusment with the pushrod of the clutch M/C to move the pedal. I can't remember what position I had my pedal box mounted in on my former Birkin, but I was able to adjust everything to get the clutch to release properly. Here's a photo of the M/C pedal assy that shows the adjustable pushrod setup. Yours should be the same or similar, you just have to take off the black cover to access it.

 

Edited September 14 by 11Budlite

[JB455]

@11Budlite Thank you! That's just the info I needed! 

[pethier]

On 9/14/2025 at 10:36 AM, 11Budlite said:

There is an adjusment with the pushrod of the clutch M/C to move the pedal. I can't remember what position I had my pedal box mounted in on my former Birkin, but I was able to adjust everything to get the clutch to release properly. Here's a photo of the M/C pedal assy that shows the adjustable pushrod setup. Yours should be the same or similar, you just have to take off the black cover to access it.

 

That's the source of my Zetec woes.  I had a shop put the Zetec/T9 combo out of a Birkin into my Caterham.  It is now obvious to me that Steve, the builder of the Birkin, (who is now building it into an electric car) followed the Birkin instructions to set up the clutch.

 

The shop transferred the hydraulic clutch system into the Caterham which had used a cable system.  The action turned out to be quick, and there was a lot of pedal travel left after the clutch was fully disengaged. After over half a century driving standard-shift cars, I didn't know this was a problem.  The is a bolt with a locking nut on the aluminum bell housing which can be adjusted to provide a hard stop as soon as the clutch is disengaged.  This bolt was turned all the way in.  I assume that a stop was done on Steve's Birkin at the pedal end of the mechanism either by accident or design and Steve autocrossed the car for decades with no trouble.

 

Since I didn't know any better, and the professionals who should have known better didn't, that bolt on the bell housing never got turned out to block the throwout lever at the appropriate place.  I seized the engine by using the clutch in the normal manner.

 

I had by this time taken the car to a tuning shop, which had always been the plan.  When the engine seized, I brought it back to the tuner, who suspected I had rotory-welded the thrust washer (which I had in my ignorance assumed was a bearing).  Tuner suggested I get a junkyard engine to get me through the season.  As he dug into the engine, he was surprised to find that the oil pump, which is on the crankshaft on these Zetec engines, had taken the hit.

 

 

To clarify, it is not that the pump failed and the engine seized due to oil-pressure failure.  The pump itself seized and prevented the engine from turning. This is entirely a clutch setup problem which did not harm the clutch but harmed something on the other end of the engine.  This engine will come apart and be cleaned and balanced over the winter.

 

The junkyard engine is in the car with the Hayabusa injection working. The clutch throw has been properly limited with the bolt on the bell housing so this can not happen again.

[MV8]

JB, moving the pedals and adjusting will not cause engine failure. It is true that a fork stop will limit crank travel from the release bearing through the pressure plate and extend service to an engine with worn thrust bearings. Bottoming of the release bearing against the crank won't occur with a pushrod adjustment when the problem is that the pedal is hitting the firewall before it can move enough fluid to release the clutch.  

 

When thrust bearings wear too thin, the shoulder of the crank (where the machining for flats to drive the slide-on oil pump ends) can be pushed too far forward, loading the very hard/brittle pump gear. 

 

Thrust bearing wear can be checked without engine tear down or removal by pushing the crank rearward in the block with a lever/screw driver, setting a dial indicator, then pressing the clutch pedal.

[IamScotticus]

Omit

Edited September 20 by IamScotticus