BE3 3rd and 4th Synchromesh worn

Unread post by **CitroJim** » 04 Jun 2007, 17:31

Third and fourth synchromesh on my 205GTi garbox are showing signs of wear

They've always been a bit bulky but in recent months they have got steadily worse and I've had to re-learn the old art of double-declutching to make the change smooth and quiet

I've ruled out oil and clutch as being the fundamental cause of the problem and the linkages are all fine.

The strange thing is that the gears only crunch on upchanges. Paradoxically, downchanges are OK

I've never been into a gearbox in my life (about the only automotive component I have no experience of whatsoever) and I don't know if it would be best to source another 'box, given that 1.6 GTi BE3 'boxes are like rocking horse manure as they are in demand for 205 Mi16 conversions or repair what I have which is in otherwise excellent condition.

So, can anyone shed any light on what the problem is and how amenable it is to being repaired by me. I'm assuming it's worn synchro rings. Are gearbox spares available from Pug at an economic cost?

AndersDK · Unread post by **AndersDK** » 04 Jun 2007, 18:12

Whats so special about a '1.6 GTI' BE3 g/b ?
The BE3 is about the most common basic type gearbox you can find on the scraps - given the vast model range from PSA with XU/XUD's - including vans !

If you cant find genuine parts at any PSA dealer, ask around at motor factors. Its GOT to be easy to source bits for such a common automative part

Unread post by **CitroJim** » 04 Jun 2007, 18:30

AndersDK wrote:Whats so special about a '1.6 GTI' BE3 g/b ?

Fundamentally nothing Anders, except that the ratios are unique to the 1.6 GTi. It is a close-ratio box with a relatively low final drive to complement the revvy nature of the engine

You're doing over 4000rpm at 70mph

Most you find in a scrapyard will be worn-out after a lifetime of being thrashed. The 1.9 GTi box has an entirely different set of ratios that don't suit the 1.6 at all. The 1.9 is an altogether more lazy engine with a considerably more torque.

The 1.6 'box is most favoured by the 205 conversion lads for use with the Mi16 engine, hence why good ones are in short supply and are expensive. The Mi 16 has a similar power delivery characteristic to the 1.6 although of course much higher.

fastandfurryous · Unread post by **fastandfurryous** » 04 Jun 2007, 20:25

While the overall ratio may be different, you'll probably find that the gear ratios themselves are exactly the same as some other application, just with a different final drive ratio.

One nice thing about BE gearboxes is that other than the ratios, everything else is pretty much the same, so the synchro hub from any other BE will fit. If you can get hold of any other BE box (from free to not much more) then you can strip it (thus learning how a BE box comes apart) and use the 3/4 synchro hub in your own BE box.

I think I even have a stripped BE somewhere in the garage, so may well have a spare 3/4 synchro hub if you want it.

Unread post by **CitroJim** » 04 Jun 2007, 22:40

Thanks F&F, excellent and most valuable information

I really like your idea of stripping another 'box first for practice.

I shall now post a wanted ad

AndersDK · Unread post by **AndersDK** » 05 Jun 2007, 01:56

Sorry about that Jim : "Whats so special about a '1.6 GTI' BE3 g/b ? "

I should have known that statement would move focus from the point I was trying to explain : the BE3/BE1 g/b would be one of the most common g/b's to source, and hence bits for it likewise easy to source.

Thanks to F&F we got back on track

Unread post by **CitroJim** » 05 Jun 2007, 06:17

AndersDK wrote:Thanks to F&F we got back on track

I'm shocking for wandering off-topic Anders

Back on-topic again, I hear rumours it is possible to replace the 3rd/4th synchro without removing the 'box from the car or disturbing the clutch or final drive. Looking at the Orange 205 BoL it looks like it is possible to remove the fifth gear assembly from the end and then remove the main gearbox casing and then lift out the layshaft with the synchro hubs complete.

Is this correct? It all seems too easy

AndersDK · Unread post by **AndersDK** » 05 Jun 2007, 12:30

Well - the outermost (towards LHS in car) housing part on the g/b contains the 5.th gear bits. The lower gears are successive located moving inwards into the box on the input and output axles.

Haynes is in fact pretty good here, as its got many detailed images together with good dismantling explanation. It also takes the DIY'er by hand avoiding a few traps AFAIR.
I'm referring to the early (grey/brown) BX Haynes edition.
My guess there would be much the same info - even complementing the BX info - in an early Haynes 205/309/405.
Later Haynes with the 'famous' tool ratings are crap. Much info is left out and images are scaled down to almost useless info. (Errrr ... getting off topic here

...)

I've never done a BE box myself. Years ago I did a BLMC 1750 sump mounted gearbox, while the engine was overhauled anyway.

Unread post by **CitroJim** » 05 Jun 2007, 13:03

The orange Haynes for the 205 is the early one and thick too! It really is very detailed on the gearbox (and everything else). It is, in fact, not a BoL at all

The only gripe I have is the use of photographs rather than line drawings

I had a "spanner" one once and gave it away, it was so useless

I've been doing a bit of research in my tea and lunch breaks today and found this:

http://www.rallyparts.co.uk/cwp_change/

Here is a set of very good pictures showing how to dismantle the 'box. It shows how to remove the output shaft and gears complete without disturbing the crownwheel. Unfortunately (or perhaps fortunately?) the 3rd/4th synchro hub sits on the input shaft at the top just below the taper roller bearing so it should be possible, after removing the output shaft assembly, to pull this bearing off and replace the synchro without further dismantling of the gearbox and I see no real reason why it cannot be done on the car. One question I need answering is how tight that taper roller bearing is on the shaft as I can see a risk of pulling the input shaft right out of the clutch centre plate and causing lots of "fun" as a result

I'll practice on another gearbox off the car first I think. I have an ad posted for a practice 'box.

I'm enjoying this!

Unread post by **CitroJim** » 10 Jun 2007, 18:01

Update:

I had a scrap BE3 gearbox delivered to me today and it is sitting on my bench

I've already taken the fifth gear pinions off and and now, for the first time in my life I understand exactly how synchromesh works

Gearbox oil is horrid stuff

makes me feel sick

The learning process of stripping and reassembling begins!

fastandfurryous · Unread post by **fastandfurryous** » 10 Jun 2007, 18:50

I have to say, I wouldn't try and strip/rebuild the gearbox in situ in a car. The risk of getting dirt & detritus in it is very high, and if it's left open for very long, you may end up with corrosion etc. Plust of course there's the restricted access issues.

'ave it out. Much much easier to work on it on the bench, and be sure it's right. You know it makes sense.

Unread post by **CitroJim** » 10 Jun 2007, 19:55

fastandfurryous wrote:I have to say, I wouldn't try and strip/rebuild the gearbox in situ in a car. The risk of getting dirt & detritus in it is very high, and if it's left open for very long, you may end up with corrosion etc. Plust of course there's the restricted access issues.

'ave it out. Much much easier to work on it on the bench, and be sure it's right. You know it makes sense.

Spot on! It now makes total and perfect sense to me!

I have my practice 'box apart now, input and output shafts out

I reached the conclusion that it was not really feasible to do in-situ as soon as I pulled the main housing off to expose the main gearset and reverse pinion fell out! And how I'd drive out some roll pins and getting that huge "C" bearing retainer clip lying on my back under the car I couldn't imagine

Still, it was worth a go to see and I can now pull a gearbox apart

Not only that, I reckon I can put it back together again too!

I'll be taking mine out of the car and doing the clutch whilst I'm at it, wether it needs it or not!

I reckon it would only be realistic to replace 5th gear synchro with the gearbox in place and even then there is a surprise in the form of a spring and detent ball on the selector shaft to fly off somewhere!!!

Unread post by **CitroJim** » 10 Jun 2007, 20:22

Forgot to say, the Orange 205 BoL does a tremendously good job of showing how to strip a BE gearbox

The main part shows how to tackle a BE1 and in the supplement for later models they cover the minor changes to the BE3.

Unread post by **CitroJim** » 11 Jun 2007, 20:13

This evening I pulled out the 3rd/4th synchro assembly from the input shaft from my practice gearbox.

The person who gave it to me told me the synchros were a bit weak. He was not wrong. The cone on the 3rd gear side of the baulk ring was completely worn out and would not provide any friction whatsoever with its pinion. The 4th gear cone was a little better but not perfect.

The cones on the baulk ring appear to be made of an alloy whereas the mating surfaces on the pinions themselves are of hard steel and don't appear to wear.

Here is a picture, you can just see the wear (as high spots on the synchro cone). They should have lines on them!

It appears the synchro hub/cone assembly is available as a spare part separate from the pinions. I wonder how much it costs?

Unread post by **CitroJim** » 13 Jun 2007, 17:43

I queried the cost of a new synchro hub from Pug today. £121

But it did include VAT