Coil Spring Herald clutches (6 Spring vs 9 Spring) and gearboxes

[Tim Bell]

Me and my buddy Jon bought a 948 convertible. All in good order apart from the fact that the engine was shot, so we have taken it out and will keep it (Y27736HE), and replaced it with a good, early 1147 Herald unit from Bill Davies (GA126935).However, the clutch also needs replacing (it was badly worn) and we also have an assortment of gearboxes. The 948 box (G95320) drops out of first easily but otherwise seems OK, an 1147 gearbox (GA17522) that needs syncro on 2nd seeing to and also, what is believed to be a gearbox out of a 1600 Vitesse which seems to have the number FD6_3145 (the D, if that is what it is, is raised higher and then the _ is either a gap of you can't see the number / letter any more).

 

The 1600 is the best of these and Jon was thinking he could use this (changing the bell housing because one is deeper than the other I understand....also heard mention of 'input issues?'). So, first thing is, can the 1600 box be used?

 

I have had a look through various threads and googled re the clutch and read on a Club Triumph thread that the 948 had a '6 Spring' Coil Spring clutch and that the early 1200s and Mk1 Spitfire had a '9 Spring' Coil Spring clutch.

 

Rimmers only sell a 6 Spring Coil Spring clutch as does a chap on Ebay, MEV Spares (Jumblemaster). Heard that Coil Spring Clutch is more durable (was used on tractors) but gear change not as smooth as diaphram type. Question was whether 6 Spring would be OK for 1147 engine (some suggestion not really strong enough?). Not sure whether the Club Shop sell 9 Spring Coil Spring Clutch kit or not as Garth is not back in until next Monday, so thought I'd 'unload' on the forum and see what advice folk may be able to offer.

 

Believe can't change to diaphram as bolt holes are different (Canleys and James Paddock's only sell these I think). Just want to get Lizzie (for that is what she is known as!) back on the road whilst the sun still shines, so thought I'd see if anyone could offer the benefits of the accumulated wisdom on any of the above?

 

Thanks

 

 

Tim

 

[Pete Lewis]

1600 will have very different input shaft than any 4 cyl car you cant swap this ,  depending on age and tooth profile and count the teeth swap a 1600 input shaft witha 4 cyl one 

 

FD is Mk3 spitfire box    1600 is HB   !!!

 

coil clutches use a thicker disc than diaphragms so designs must not be intermixed,  

you will find a diaphragm has same hole centres but different dowel locations

 

I converted my 1600 from coil to diaphragm and whilst this is crap engineering i added a pipe olive to the fixing bolts and nipped the cover on the flywheel ,  there is no way to accurately check all is concentric but took a chance the 6 bolts aligned the cover equally about the fixing holes ,, then drilled the flywheel to take a new dowels     (do  remove the olives ),    and its works fine for years .,

 

its worth looking at .

 

Pete 

[Tim Bell]

Thanks Pete. Jon has also owned a MKIII Spitfire, so this probably came for that and has been lying around in his man cave! 

 

Does anyone have any feedback on the 6 Spring / 9 Spring re coil spring clutches and whether the 6 Spring would be up to the job?

[Colin Lindsay]

I had read some time back that the 6-spring coil clutch - the version I had purchased a few years ago NOS, wrapped and sealed off a stand at Stafford, believing it to be a 9-spring - wasn't up to the 1200 engine but was more suited to 948s and Standard cars, and I really needed a 9-spring version to cope with my 1200. Consequently I may use the clutch plate but refurbish an old 9-spring cover by replacing the springs.

The alternative - to prevent me finding out the hard way - is to use all the other components off a later Herald and convert to diaphragm.

[Herald948]

Over the years (and I've been around these cars forever), I've always "known" that 6-spring clutches were 803 and 948cc, and 9-spring clutches were earlier Herald 1200 and Spitfire with the 1147cc! I'd worry the moment I bolted a 6-spring clutch into a Herald 1200, let alone a 12/50 or Spitfire 4!

[Tim Bell]

Does anyone have a view as to whether there is there a way of testing the springs on the 9 spring clutch plate that we have for spring strength because logic would dictate that, if its OK we can use it with just a new clutch plate?

[Pete Lewis]

on the 9 spring cover there are 3 dark blue coded  @ 90/100lbft  and 6 red coded @ 75/85lbft    see attached spec sheet  there is no clues at what lenght this load applies .

 

you can check the release height with 3 home made buttons to simulate a new compressed plate @ 0.305" thick

 

the clutch disc must have less than 0.035" runout if spun on a shaft, it says you can prise it into place to meet the runout spec  ??

 

theres a goos few clues in the workshop manual but dont see any spring test data

 

Pete

Scan0002.pdf

[Tim Bell]

Hmm. Thanks Pete. Where can you buy springs I wonder, if at all? Came across a web site http://www.asbg.com/products/springs-overview/torsion-springs-torque-coils-clutch-springs.aspx but guess there may be other places too?

[Pete Lewis]

we used to check some dodgy remanufactured truck clutches  on our warranty  a dial indicator to measure the travels and a load cell to record the loads  to plot the hysterisis 

some amazing awful stuff was put in a nice box and smart label

on some we had 16 springs all different  lengths ....what judder !!  

 

Firstline make the borg and beck designed units now.

 

Pete

[Colin Lindsay]

Same as valve springs, it's just a case of the strength required...

[Pete Lewis]

On all cluthes the clamp load reduces as the disc thins , and the pedal load increases

the diaphragm pedal loads are similar depressing and releasing where as a coil is heavier depressing

and lighter releasing , which is why a diaphragm has a more even feel .

 

I wouldnt worry about the spring loads but check they are all the same, make a simple rig to depress a fixed amount on the bathroom scales , you want them all the same

 

If you convert to diaphragm you need to look at the changes in the throwout mecanism and bearing

 

pete

[Tim Bell]

Thanks Colin & Pete. The springs on the 9 spring clutch cover we have are blue and yellow rather than blue and red? What lbft do yellow springs signify (or don't they?). Jon is going to test the spring loads via a ball bearing to depress via the central disc that spreads the load onto the springs to see that they all depress evenly, if that makes sense (you can tell I'm no mechanic!).

[Tim Bell]

Hey all. Breaking news. I emailed First Line who make Borg and Beck clutches and they replied;

 

Hi Tim , Unfortunately we only do the six spring clutch kit at the moment HK9704,  but later this year due to demand we will have the 9 spring one available.  

 

This was sent by Peter Hughes, Senior Clutch Product Engineer

Tel.  +44 1869 329 716

First Line Ltd, Chalker Way, Banbury, Oxfordshire, OX16 4XD, UK

 

So, good news for anyone who might wish to access one of these as a Christmas present!

[Herald948]

Hey all. Breaking news. I emailed First Line who make Borg and Beck clutches and they replied;

 

Hi Tim , Unfortunately we only do the six spring clutch kit at the moment HK9704,  but later this year due to demand we will have the 9 spring one available.  

 

This was sent by Peter Hughes, Senior Clutch Product Engineer

Tel.  +44 1869 329 716

First Line Ltd, Chalker Way, Banbury, Oxfordshire, OX16 4XD, UK

 

So, good news for anyone who might wish to access one of these as a Christmas present!

 

Well, I guess THAT explains why so many vendors were "passing off" the six spring clutch as suitable for early Herald 1200 and Spitfire (about which I have my doubts): it was the only one available!

 

Glad to hear that there will soon be a nine spring version available again! It's getting so hard to find good deals on eBay on NOS bits.