A few more replacments (heavy clutch)
 

Swapped the alternator out today as the old one was showing signs of failing. New one charges properly at 14v.

Replaced the blue temp sensor in the hopes of fixing occasional warm start issues, but that will need more testing. It was fine after filling it up.

Replaced the Silkolene Silk Tran Syn 5 in the gear box with Fuchs ATF 3000 which has smoothed out the gear changes a lot (no more crunching, even from cold) gear box is still a bit stiff though.

The clutch in the car is very heavy, anybody got any thoughts on modifications to lighten it up a bit?

I think the problem is the Marlin pedal box design. Not much you can do about it except get bigger muscles in the left leg!

The original BMW design was quite fancy with a spring to assist the action. Now we know why!

Someone on this forum actually reused the BMW pedal box - you could think about that route but it would be a big mod to so.

Robin

PS yes I am making progress but painfully slow atm.

On my Cabrio I modified the Sierra pedal box to incorporate the BMW clutch pedal 'helper' spring assembly (although I'm sure the Marlin pedal box could also be modified in a similar way). This gives an 'over centre' type action whereby you work against the spring when initially depressing the pedal (ie its even stiffer to push down) but when over half way the spring helps to reduce the pedal effort.

Hopefully the picture on the enclosed link will explain it alot better:

Simon
http://www.flickr.com/photos/marlin_...7603834512041/

Thanks Simon very nice work there :D I'll have a dig through my boxes of stuff I still have all the springs from the original pedal box. May even have some of the metal too.

My woosy left leg is used to the clutch in my E46 :lol:

I've been getting problems changing gear now. Slowly its fine but if I'm going for it I change and it won't go in to the next gear for a short period. I've got just under 2k on the car.

Originally I suspect the thrust bearing or the syncro mesh on the box as it does have 113k on it now.

I think I've worked out why now. The whole side of the pedal box flexes when you push on it (this is by hand me looking to see what's going on. The master cylinder which should be stationary moves a good 5mm left to right and forwards a bit.

Now I suspect when I move the pedal quickly with my foot it flexes a lot more - the flex means the piston is not pushed in far enough to disengage the clutch completely.

I've got several thoughts:

1) Weld a thicker piece of metal over the clutch site with a bend to re-enforce it (may as well do the accelerator pedal as well as it floats about too when you use it)

2) Drop the clutch pedal completely from the box and use one of these: http://www.wilwood.com/Products/005-...smcp/index.asp

3) Bin the whole pedal box and go for something a lot more substantial. Issues here are all the racing boxes don't have servos which means it would need one or two remote servos which makes the whole thing very expensive.

No. 1 is a good short term solution.

If there is enough room No 2 I think might be a good solution

No 3 is a bit drastic, but with the master cylinder inside the cabin it keeps the heat away from it.

My pedal box flexes too. I am surprised though that none of the other builders have reported this problem if it is a general one. How was the day at Uxbridge?

Robin

Mine flexed when i first installed it so I used a strengthening bar across the top of the bulkhead and bolted through this and the top of the pedal box it almost eliminated all the flexing.

Stuart

I ended up not going to uxbridge due to wisdom tooth issues robbing me of my sleep! I was not happy as I was looking forward to seeing Peter's car.

I'll go with option 1 and see where it takes me to start with. I've got some spare steel knocking about :)

Your probably right but, you might try bleeding the hydraulics before making too many changes. You might have some air in the system and that can have strange effects on clutches as it compresses under pressure.

I hope the tooth is better now!

Peter

Good idea I will try that first :)

With the aid of ibuprofen its manageable thanks :) Maybe we could meet up outside of a show as some point as were not that far away from each other?

I've done the same (see previous posts and web site) It certainly eliminated some of the flexing - but not all.

Robin

mine was ok for about 1500 miles, I guess is slowly flexing more

Are you sure that you haven't got some air in there somehow? I wouldn't have thought that any flexing would get worse that quickly - steel generally doesn't behave that way.

If it were me:

1. I would double double check for air in the system.
2.Did you use new slave and master cylinders - if not I would think about replacing these.
3. Brace the top of the bulkhead where the pedal box is bolted as Stuart suggested and I have already done. (I found that the bulkhead was flexing more than the pedal box itself)

Robin

I used new master cylinder and slave cylinder :) Air is certainly the easiest this thing to check so I will do that first. I'm wonder if my bolts have loosed up a bit as well over time. I'm going to check them all again.

Patrick

I was concerned about the flimsyness of the pedal box, so I added a stiiffening bracket to the clutch master cylinder - see
http://www.flickr.com/photos/mikes_b...7604100777863/

[QUOTE=Patrick;12723]I've been getting problems changing gear now. Slowly its fine but if I'm going for it I change and it won't go in to the next gear for a short period. I've got just under 2k on the car.

Originally I suspect the thrust bearing or the syncro mesh on the box as it does have 113k on it now.

I think I've worked out why now. The whole side of the pedal box flexes when you push on it (this is by hand me looking to see what's going on. The master cylinder which should be stationary moves a good 5mm left to right and forwards a bit.

Now I suspect when I move the pedal quickly with my foot it flexes a lot more - the flex means the piston is not pushed in far enough to disengage the clutch completely.

Regards
Mike

thanks :) wish I'd done more originally now!

I bolstered my pedal box on the clutch side, mostly due to the fact that I had a new wilwood master (supplied my Marlin) that wouldn't fit.

http://www.greatoldone.co.uk/Sportst...ylbracket1.JPG
http://www.greatoldone.co.uk/Sportst...lbracketon.JPG
http://www.greatoldone.co.uk/Sportst...lutchcylon.JPG

After mounting it in the car, and filling and bleeding the clutch line, it flexed a lot. So I put these braces in, and it seems to have cured it.

http://www.greatoldone.co.uk/Sportst...chbracket1.JPG
http://www.greatoldone.co.uk/Sportst...chbracket2.JPG