Sierra 5-speed & Hydraulic Clutch Issue

[Monty-4]

Hi,

A chap local to me with an all important piece of equipment - a car lift - is having a go at fitting a 5-speed kit to my Minor. It's the Sierra 5-speed with the hydraulic concentric clutch and roller release bearing. I have what I believe to be the appropriate spacer and slave/lifter on the nose of the gearbox as they came from another Minor with it fit.

Problem is, the guide tube for the release bearing appears to foul the thrust surface that the bearing is supposed to push on. I thought it was possible to use the existing 1098 clutch cover with this conversion, but perhaps not without machining the internal diameter of the part to be wider? Ditch it and drill the flywheel for a Ford clutch?

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[philthehill]

http://www.frontlinedevelopments.com/pa ... cc-engine/

http://frontline-developments.s3.amazon ... -speed.pdf

[Monty-4]

The PDF linked states the tube needs to be shortened on 948cc cars - this also applies to the 1098 then?

[philthehill]

You will have to do what I did when fitting the Ford gearbox to my Minor - mate the gearbox (without the Ford release bearing guide fitted) to the Minor engine with Minor clutch fitted and see what needs to be done through the release arm access hole.
It took me a couple to goes to get it right - got there in the end but ultimately decided that the Ford 7.5" dia clutch assy was a better option anyway.

[philthehill]

Further to above as the ability to edit now appears to be removed after a certain period.
It quotes in the link above that there should be a min of 4mm and a max of 10mm between the end of the Ford release bearing tube and the clutch release bearing pad.
So if the tube will not go through the release bearing pad then the tube will have to be shortened to suit the pressure plate.

[Monty-4]

Thanks Phil. It's good to have a definitive answer, especially one that doesn't necessitate waiting for different parts to arrive.

[Monty-4]

Gearbox is in and road tested. The guide tube has ~1mm clearance from the clutch cover. I wonder what happens as the clutch wears; will the release bearing be in danger of falling off the shaft with this setup?

Still need to tidy it all up as the handbrake fouls the gearstick as expected and there are no carpets. I'm unsure as to whether I want to move the whole handbrake assembly back or trim the lever. Also, would adding a clutch return spring help or is relying on the hydraulic action to return the pedal fine?

[philthehill]

As the clutch wears the release fingers will lift and ultimately the clutch carbon release pressure plate will hit the Ford release bearing tube and cause the clutch to slip.

1mm clearance is not enough - there should be at least 4mm - 10mm.

No need for a return spring as the hydraulics/clutch will push the release bearing away from the clutch carbon release plate.
I have never felt the need for one on my hydraulic clutch system and one was not one fitted to the MG Midget hydraulic clutch system.

[Monty-4]

An update to my saga - I've been running it for a few months with the slightly bodged combo of the cut down nose and standard clutch cover. After taking the car for wheel balancing and to have the toe-in set I find the clutch is slipping a bit... I suspect they revved and slipped the clutch a lot getting it onto their alignment machine. Of course I'd prefer to think that it has started slipping due to my continued tuning and tweaking with the mighty engine I built - but that may be unlikely!

Fortunately since my last post I have sourced a recon flywheel drilled to accept the Ford clutch cover, a Ford clutch kit, an uncut bearing shaft w/ gasket and oil seal, the special spigot bearing, plus the relevant new bolts and locktabs.

When the weekend arrives I plan to have a go at fitting it. A couple of questions to be sure...

After some reading of this forum it seems the easiest route for me to do it without access to a car lift will be to unbolt the engine (plus rad, starter, carbs, lcb exhaust, alternator & horn) and then rotate it in place on a jack to access the clutch assembly. Correct?

Can I use the Ford friction plate or must I still use the friction plates sold for Sierra conversions for some reason - the latter being £90!?

[philthehill]

So long as the driven plate is the right I.D./O.D. (match against the pressure plate drive surface) and has the right number of splines all will be ok.

[Monty-4]

Unfortunately 190mm/7.5" 23 spline clutch plates are like hens teeth outside of complete kits for the Sierra, but I've found one a little cheaper.

Fingers crossed for Sunday.

[Declan_Burns]

We fitted a Frontline kit+FordT9 to a Midget two years ago and also a HI-Gear kit + Ford T9 to my MG TD. In both cases the Ford guide tube needed to be cut back to 1cm before fitting. Neither of the cars have had issues with the clutch slipping.
Regards
Declan

[philthehill]

Declan

Do you have a picture of the finished article. Interested to see your clutch release mechanism within the bell housing.

Phil

[Monty-4]

We fitted a Frontline kit+FordT9 to a Midget two years ago and also a HI-Gear kit + Ford T9 to my MG TD. In both cases the Ford guide tube needed to be cut back to 1cm before fitting. Neither of the cars have had issues with the clutch slipping.
Regards
Declan

It's both dripping the stinky semi-synthetic oil at the front and slipping so my issue is either the guide tube is not cut down enough AND/OR the front oil seal has gone. Either way I need to have a look at the same area and will have the parts to do both jobs.

[Declan_Burns]

Phil,
Sorry I don't have a photo of the finished article but it uses the original TD clutch fork, shaft and release bearing. We will be doing an MGA Hi-Gear conversion in the next two weeks and I will see if I can get some photos.
The only other photo I have is with the cast bell housing fitted. The Hi-Gear kits are really good-much better than Frontline.
Regards
Declan

[philthehill]

Declan
Many thanks for the photos.

My clutch release bearing/carrier is activated by the MG 1275cc Midget release arm which had two pegs welded to it which act in a annular groove of the release bearing carrier. The release bearing itself is a ball bearing type similar to the Marin/Ital release bearing. The release bearing carrier rides/slides along the Ford carrier tube so remaining concentric to the diaphragm clutch release levers.
The MG Midget release arm and the carrier are not locked together but free to articulate as the release arm moves in an arc motion whilst the release bearing carrier acts is a fore and aft motion. Some conversion kits have a slotted release arm pivot pin hole to allow the arm and carrier to interact,
It works very well with the ARP race spec Ford 7.5" pressure and driven plate but you do need large leg biceps to press down the clutch pedal.

Phil

[Declan_Burns]

Phil,
Just extend the clutch relay shaft by 1" and that will solve that problem and fit the weakest return spring that will bring the pedal back to it's upper position. I did that on my car after all the leg problem I had (have) and it makes a hell of a difference.
Regards
Declan

[philthehill]

Declan
Thank you for the above.

The gearbox now fitted is a Quaife SC/CR so I cannot improve the Minor linkage which has been done away with and replaced with a hydraulic set up but which still requires Herculean left leg biceps.

When I had the Midget SC/CR box in place I modified the Minor linkage in a similar manner to yourself. The only down side was the rubber bush in the chassis leg which was eventually replaced by a Minor Mania plastic bush.

Below is the clutch pressure plate fitted to a re-faced and modified 1275cc Midget flywheel which was previously fitted to my Minor

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It is the largest clutch that will fit in a BMC/BL 'A' Series bell housing so care must be taken to ensure that it does not foul the inside of the bell housing. That pressure plate was able to cope with well over 100bhp.

Phil

[Declan_Burns]

Phil,
My mate actually started the MGA conversion today so I caught him just in time. Here are the photos with the release bearing fitted. Again the Ford flange is cut back to 1 cm. I notice my mate mounted the bracket for the clutch fork with the bolt head facing down. I would do it the other way even when using a nyloc.
Regards
Declan

[philthehill]

Declan
Thank you for the photos.

My release mechanism is virtually the same as regards the release lever. The lever is mounted on and pivots on a similar fabricated bracket.

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To enable the bolt to be fitted downwards I made a suitable size hole in the alloy bell housing through which the bolt was fitted.

Phil