Lotus Elan

Clutch Weight

PostPost by: vincereynard » Mon Jun 22, 2015 4:27 pm

I've tried a couple of +2s now and, as MrsR has a dodgy back, the clutch weight could be a problem.

How does the 5 speed compare and does a MT75 conversion have a lighter clutch action.

Perhaps having a master cylinder with a smaller bore would lighten it a bit.

Or is it a "Lotus" thing. Some were light and others not?

Cheers

Vince
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PostPost by: mbell » Mon Jun 22, 2015 6:39 pm

I wouldn't have described my clutch as heavy but compared to a new hatch back or similar it might be a bit harder.

vincereynard wrote:
Perhaps having a master cylinder with a smaller bore would lighten it a bit.


It probably would but the standard master is 5/8" which is the smallest diameter of that type of master cylinder commonly available. So it wouldn't be easy to find a smaller one. Then there is the question if a smaller master would move enough fluid to fully operate the clutch.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: Orsom Weels » Mon Jun 22, 2015 6:42 pm

My +2's clutch is quite heavy, much more so than the elan. I can't say for certain, but I put this down to having the wrong slave cylinder fitted. When I put the car back together in the late eighties, I was missing the bellhousing & couldn't find the correct item. I ended up using a cortina item, with the smaller clutch/flywheel/slave etc. I eventually found the correct bellhousing & swapped it over, fitting the correct clutch/flywheel, but continued to use the 3/4 bore slave instead of changing to the 7/8 bore. I've not found it a big problem, so have never bothered to change it, but Mrs O struggles with it now, so it's on my 'to do' list. In fact, if sue had a slave in stock when I spoke to her the other day, it would probably have been done already. As everything else is the same spec as the elan, it's the only thing I can think of that would make the difference.
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PostPost by: jimj » Mon Jun 22, 2015 9:39 pm

I have the Voight conversion, Sierra box, and the first time I depressed the clutch I thought it wasn`t connected. It`s much lighter.
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PostPost by: stevebroad » Tue Jun 23, 2015 9:43 am

Which slave cylinder is fitted? If it is 3/4" (originally fitted to Anglias and Cortinas), then replacing with the 7/8" version (normal Elan size) may well make the difference.

If that doesn't work, options are limited.

Look for a clutch with ligher clamping springs (may cause slippage issues).

Redrilling cluch pedal so the master cylinder rod can be moved slightly nearer the fulcrum.

Get slave cylinder bored out to 1". This will also entail getting a piston machined up to fit and finding suitable seals.

Change wife :-)
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PostPost by: vincereynard » Tue Jun 23, 2015 8:28 pm

Thanks for the learned replies.

I shall check the slave cylinder if there is a problem and possibly investigate a small master? I know in bike circles there is a practice of sleeving the master cylinders to A/ correct corrosion and B/ give lighter action.

Jim - Sierra box is the T9 ??

Changing wife could give financial repercussions that could result in long term bus travel. Forget having a toy Lotus.

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PostPost by: stevebroad » Wed Jun 24, 2015 12:37 pm

Sleeving is an option, just a little more complicated than boring. But if that is the only solution............
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PostPost by: prezoom » Wed Jun 24, 2015 4:28 pm

I have re-sleeved several Girling style slave cylinders with good results. The clutch slave cylinder for the Elan being the easiest, as all the work can be done on a lathe. I sleeved them with stainless, and hopefully they will last longer than the original. As far as boring to restore the internal surface, even when taking out a minimal amount of material for a sleeve, I have found inclusions in the casting, that was not a part of the corrosion. On one "new" slave I purchased had exposed inclusions and leaked like a soaker hose, and required re-sleeving.
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PostPost by: vincereynard » Wed Jun 24, 2015 4:55 pm

prezoom.

You are obviously the man to contact with advice as to how then!

The idea was to sleeve the master, with stainless, to reduce the bore and lighten the clutch.

Can you for see and problem with that?

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PostPost by: prezoom » Wed Jun 24, 2015 10:56 pm

As stated before, reducing the slave's diameter, while retaining the existing master, will reduce pedal effort, but will increase pedal travel.

The nice thing about the Elan slave was, even with its lumps and bumps, I was able do the job in my 13 inch lathe. To be able to chuck the slave up, I took a piece of aluminum round stock I had on hand, that was just larger in diameter than the entire slave. I cut a piece that was thick enough to match the area of the slave that fits through the loop on the bell housing. Then bored a hole in the round stock that was a snug fit over the loop area of slave. I used a saw to cut a slot through the side of round stock to the newly bored hole. With the slave inserted in the hole, the slot allowed the lathe's chuck to clamp down on the round stock and tighten its grip on the slave.

For the stainless material, I used some 416 round stock I cribbed from a friends cutoffs bin in his machine shop, who just happens to own several Elans. Visiting a metals dealer, a machine shop, or utilizing one of the online metals dealers that will sell you what ever length of whatever you need, should get the material required. I have done this with some hex stock, I got from a dealer I found in the magazine Home Shop Machinist. Purchasing some tubing stock of the right size would have reduced some of the machining time, but free is free. I also have a very nice metal supply shop in San Diego, Industrial Metal Supply, that sells all kinds of pre-cut pieces of metal when I need something quickly.

I bored the slave, so the diameter was about .060 inches larger than the existing bore, enough to clear up any damage. The slave cylinder bore size can be anything you want, as you will machine the outer diameter of the new sleeve match what you have bored in the slave. This allowed for a sleeve with a wall thickness of about .030 inches. Thick enough to support a press fit. I bored the stainless to the .750 diameter of the original cylinder, and slightly deeper that the bore in the slave cylinder. Then I cut the stainless down to a diameter that was .0015 inches larger than the diameter I had bored in the slave, this cut was also just a bit longer than the full length of the slaves bore. The additional length allowed the sleeve to just sit just proud of the bore when installed. Then parted off the sleeve.

I stuck the sleeve in the freezer for a while, and when ready to insert the sleeve, I heated the slave cylinder with a heat gun. Applied some locking compound to the sleeve and used my press to lightly push the sleeve into the cylinder. After cooling, I drilled a new hole through the port for the fluid to enter the cylinder and cleaned up the drilled hole on the inside of the bore. This hole is deeper in the bore than the slaves rubber seals can reach, so being exact is not an issue. Re-fitted the re-assembled cylinder to the bell housing, attached the fluid line, added some new fluid, bled the cylinder, adjusted the rod, and drove away with no more leaks. I use speed bleeders on all hydraulic pieces, makes the bleeding task a bunch easier, a one person job, and keeps my wife much happier, which is a very good thing.

Two other clutch slaves I did were of a shape that they had to be bored on the milling machine, so a new holding jig was needed, which took a bit longer.
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1964 Elva Mk4T Coupe (awaiting restoration)
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1954 Nash Healey LeMans Coupe

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PostPost by: prezoom » Wed Jun 24, 2015 11:02 pm

Whoops! Got the first sentence backwards. What I described was work on the slave. Have yet to do any masters, but have three awaiting renewal. All of which, will require making a jig for boring on the mill. The basic process will be the same.
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1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe

Owning a Lotus will get you off the couch
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