The Crocodile Hunter

Is there an easy way to convert an st170 from the standard dual mass set up to a solid flywheel and sprung clutch plate?

Can you just use the flywheel and clutch from a normal black top zetec 2 litre focus? (I assume they are solid like a silver top zetec is?)

Thanks

zippyobrien

iTrader: (2)

Black top flywheel will fit but the clutch won't work with the box.

The st170 clutch has 23 splines same as a vauxhall. Zetec has 21. ( or other way round. Either way it don't fit lol )

You can get solid kits from the states.
I've heard a rumor some one used a vauxhall clutch plate and a modes zetec flywheel. Dunno if it was just pub talk or fact

Straight_4_N/a

Either buy a solid flywheel for the st170 or do a full swap to mtx75 setup.

The Crocodile Hunter

Interesting!

Just did a quick bit of research and it appears the vaux f28 box fitted in the LET turbo cars has a 25mm x 14 spline input shaft. I think this is the same as the st170 box?

They also have a clutch diameter of 230mm which is the same as the early st170's?

Maybe there is an easy conversion?

The Underdog

iv read of vauxhaull clutches being used but theres very little info on it. i assume you could only use the vaux clutch plate and not cover plate as that woldnt bolt to a 170 fly or zetec surely?? also the dual mass is thicker than a single fly so if you used a zetec flywheel with vauxhaull clutch would the gearbox shaft reach the clutch?? i dunno the answer but iv have thought it through before and i now have a ttv solid flywheel (not fitted) and its made thicker it seems to replicate the thickness of a dual mass.

i did think once would a zetec solid flywheel with a zetec cover plate but st170 230mm clutch plate combo work? no one seems to have ever done it so i can only assume the clutch would not reach the box shaft. i may be totally wrong though.

The Underdog

https://passionford.com/forum/techni...mm-clutch.html

The Crocodile Hunter

I was thinking a zetec flywheel and cover plate with an LET F28 vaux centre plate.

Didn't think of the flywheel thickness before, this could put a stop to the whole 'easy conversion'

If you used the zetec flywheel and cover with a 170 solid centre plate there would be no give anywhere. Don't think that this is a good idea on a daily driver?

The Crocodile Hunter

Beginning to think that if it was as easy as I'd hoped it might have been loads of people would have posted about how to do it by now?

neilnewboy

iTrader: (1)

I'm selling an Spec stage 2 complete setup flywheel and clutch(Kevlar disc with steel backing) a direct replacement for the dual mass setup on an st170. Cost a fortune to import from the states. Done 25,000 miles only, melted a valve on engine back in the day and this has sat on a shelf ever since.

Plate, clutch and flywheel faces are superb, so much so original manufactures facing off marks still visible on pressure plate, there is no wear on matting surfaces!! Centre spline aperture on clutch unit does however have engagement marks.

http://www.specclutches.com/618909/s...s-sf30s-537795

http://www.specclutches.com/651542/s...s-sf002-523795

Ł450 collection only West London

The Underdog

yeh the thoughts have gone through my mind many times but there has to be a reason why no one has done it or at least posted it online somewhere. the thickness of the flywheel is the only reason i could think it would not work but thats just a guess.

unless i find a cheap alternative il be using a standard 230mm clutch on my solid flywheel. it will be unsprung but its on my track car and iv asked around and been told it will be ok, i hope lol

wombat76

ok surely its basic.. the engine and gearbox bolt together as normal mainshaft locates in the crank spigot so using a concentric slave type space this 5mm closer to the flywheel cover assembly.. i reckon the ring gear is same distance on a zetec 1.8 f/w as it is on the d/m 170 one if not space the starter out. and use the c20let clutch and a decent zetec cover.. some who have done it dummied on the bench say reverse the plate to catch the splines however i know a man who can make me up an equal distance one and rivet it like a new one ..he does many conversions and refaces clutches as well.. seems this mod really lights up the st mill.. will

big_wasa

The ring gear is fine, main shaft does not locate in the crank spigot bearing. ( I would love to know why the st has a spigot bearing and a Zetec does not ? ) I haven't measured it yet but you will need to space the thrust bearing more than 5mm. The Vauxhall clutch plate is 228mm and the Zetec 1.8 fly' is 220mm so you will want the 2.0 fly', 240mm

wombat76

Big Wasa,, could you please measure what the spacer needs to be as i would like to do this all over a weekend and that measurement would be useful as otherwise i would need to have my d/m flywheel out and compare the differences on the bench where otherwise i could have a spacer made up and ready to fit.. as to the clutch size i aim to lighten and balance the 1.8 and i think there's enough meat in it according to my machine shop guy to get it out to 230mm overall.. will

big_wasa

There is no way a 230mm clutch plate will fit in the 1.8 cover. When fitting the clutch to a standard Zetec you have around 1.5mm around the plate. If machining the fly to fit the 228mm vauxhal cover then I havnt done it so I couldn't say. But a spacer will depend on the bits your using.


Trouble is the dmf is mocked up in the engine and box at the moment.

For the track I planned on using a lightened 2.0 Fly' and clutch cover with an unsprung 240mm st plate and spaced thrust bearing. But..... I then found a billet fly' and paddle clutch so lost interest in the conversion.

Shaun Barratt

I thought that I would add an update to this thread (just in case there are still any hardcore ST170 fans)

RTS Performance does a direct bolt-on kit which you can find here:

https://www.rtsperformance.co.uk/pro...t-with-clutch/