Ford clutch... technical question

[jonnytuna]

sorry if this is in the wrong forum - but I couldnt find the technical questions bit that morninggents told me to look for....

anyway, here is a nice simple question I am sure someone can answer.

we are in the process of piecing together a lotus twincam for a mk1 cortina with a variety of spares accumulated over the years.

we have a lightweight bell housing BUT the aperture for the slave cylinder is only 28mm, which, from looking for spares, appears to be for a non-lotus model. The questions are ..... was the lotus one a different clutch and required a different or heavier duty slave cylinder and rod? Can we fit this bell housing, with a 28mm slave and rod, onto a lotus clutch plate (if indeed there was such a different part).

I appreciate this is probably a real dumb and novice question so cut me some slack - just trying to get some answers before we go sourcing any parts.... or do we have to stick with one of the steel bell housings we have (with the larger slave housing aperture (about 33mm? or such like).

many thanks - hoping we can get some help!! or at least be redirected to post or move this to the correct forum.

[GORDON STREETER]

Most of the twin cams fitted with the 2000E type 3 rail boxes used the 105E bell housing at least in the Elan and as far as I know also in the Cortina Mk 1.
The external diameter of the slave cylinders were all the same and the only difference was the internal bore that was larger to ease pedal pressure.
Joe will see this and no doubt be on to sort you out in the morning if not tonight !

[jonnytuna]

Thanks Gordon. We have two steel housings - one broken - with the larger hole , and one with a smaller 28mm in alloy. Looking at spares on eBay it looks like the 28mm one is for a 105e - I contacted seller and confirmed this was a 28mm one.
http://www.ebay.co.uk/itm/Ford-Angli...-/221015462024
Am I in trouble for posting in the wrong forum? Or due to be told more details in response to my question?

[zefarelly]

small hole is MK1 Cortina and Anglia, the slaves come in 2 bore sizes, the larger bore size is for the twin cam ( elan and Cortina) use a jubilee clip as well as the circlip to hold it in.

throw the larger holed iron one away, its from a MK2 Cortina and you won't get the bits without getting your leg lifter right royally, and they're a bit crap anyway.

next thing is look at the bellhousing . . . the ally one ( and an iron twin cam one) is larger and radiused as the twin cam runs (or should/did) an 8 1/4") clutch. the standard Anglia and Cortina comes away from the flange/block at 45 degrees in a straight line, its for a smaller 7 1/4" or 7 1/2" clutch

If you fit a big clutch with a small bell housing you'll need one hell of a starter motor, I've taken a few calls from people building 'kit cars' saying their engines seized in the past . . . . worse still an engine came back for a rebuild with chunks of dynamically balanced clutch cover sliced off with an angle grinder!!!

use all the mechanism and twiddly bits from a MK1/Anglia . . .it all works perfectly well if its in good nick.

[GORDON STREETER]

We used to use a diaphram clutch pressure plate from one of the Rootes Group vehicles Hunter/Avenger that worked with the bigger clutch Ford center plate,the only mod was to cut some of the bearing carrier nose off.

[zefarelly]

the Commer van had the same 8" clutch a twink uses!

Harrington had one . . . . some have thrust pads, some don't, flat or round faced release bearings . . . .that'll confuse 'em!

[MartinH]

Hi there, I can confirm that what Zeff says is correct (as ever !!) & can also add that this ebay sellers part is what you need ; I bought 1 from him 2 months ago & is what is currently in our race car.

One important thing is that over time the 28mm hole becomes oval due to the sideways force of the slave cyl on it & results in a loose fit of the slave which will lose you some pedal travel. Best is to sleeve the bellhousing if possible, or use a 2nd circlip at the base of the slave cyl before you pass it thru the bellhousing to create a tighter fit, though this does mean that the actual retaining circlip becomes quite difficult to fit.

Hope this helps.

[jonnytuna]

Thanks everyone. Have also spoken to the race mechanic. All this info will no doubt help morninggents when he sees it all and if we need to clarify anything. Thanks again. Amazing quick and helpful responses.

[jonnytuna]

Though I am easily confused. Are you saying that the ally 28mm hole bell should fine BUT the 28mm slave comes in two designs, one that has a larger internal bore to ease foot pressure for using a larger clutch?

[GORDON STREETER]

Originally Posted by jonnytuna

Though I am easily confused. Are you saying that the ally 28mm hole bell should fine BUT the 28mm slave comes in two designs, one that has a larger internal bore to ease foot pressure for using a larger clutch?

That's what I said but obviously you won't get as much movement with the bigger bore.
It all depends what clutch you're using if it's a sintered single plate you don't need that much movement.
If you are using a big "normal"clutch you may find that the release arm will bend and eventually break that's why concentric slave cylinders are used as an Anglia release arm that could be 50 years old will only put up with so much, it was only designed for use with a weak spring pressure plate in it's day.

[GORDON STREETER]

Originally Posted by zefarelly

the Commer van had the same 8" clutch a twink uses!

Harrington had one . . . . some have thrust pads, some don't, flat or round faced release bearings . . . .that'll confuse 'em!

We used to use the one with a thrust pad on the diaphragm with the std Anglia release bearing.
Obviously it all depends on what you are allowed in the type of car you are building.

[morninggents]

Thanks Gordon. The car is an App K Lotus Cortina and it's all about whether we can use the smaller 28mm diam slave cylinder with the 7.25 single plate heavy duty clutch.

[GORDON STREETER]

I see no reason why not. I personally have only had one arm break and that was on my Anglia van that I used for towing my Hot Rod about, that was fitted with the biggest strongest clutch that I could fit in it.
My Anglia is fitted with an alloy bell housing with a small 6 inch single plate race clutch and the small diameter slave cylinder that is very hard on the pedal to push down and it has had the same operating lever in it for over 20 years, and that was an old one even then.

[zefarelly]

same as Gordon, I've got 2 engines:

1: heavy duty 8" TC clutch with thrust pad and flat faced release bearing

2: 7 1/4" AP race clutch, spacer and round faced release bearing

both run the std clutch arm, 28mm slave, 3/4" bore and a 0.75 bore master cylinder to make it all work.

only trick is making sure the slave is secure, they do pop out. everything else is standard and nearly 50 years old, and still working.

obviously thats not expensive enough to be competitive for some, but it works for me!

[GORDON STREETER]

Originally Posted by zefarelly

obviously thats not expensive enough to be competitive for some, but it works for me!

[morninggents]

Thanks Gordon and Joe. I think we'll go with the smaller set up.
PS Joe - you can't say that after Snetterton! Congratulations.