Ask a Shiter

[M'coli]

"Sort out my Escort for the price agreed, you shyster!"

[ashmicro]

 

"Park your Polo across my driveway? Have some 7.62 long you VAG driving cunt"

[ashmicro]

You know things like the Freelander 1, the Cavalier 4x4 etc? You know the way if the front-to-rear tyre where is uneven it fucks up the gearbox, because it spins up the

 

What is that called. I simply cannot remember!

 

KTHX

[Des]

Viscous coupling?

[ashmicro]

I think that's the correct Term, Des, but I seem to recall a single word being used.

[Albert Ross]

IRD?

[ashmicro]

Cheers lads, one, other or both of you are undoubtedly correct, and my head's up my arse.

 

ta.

[face]

Does a car (carb fed) use more fuel if the airbox is removed?

[CreepingJesus]

If more air's getting in, it will theoretically put more fuel in. But without altering the jet sizes, it won't make much difference. It might develop a flat spot or two tho'.

I did reckon back in the day, that any drop in fuel economy was due to the leaden right foot of the driver, who felt or thought that the car (or bike) was quicker as a result of airbox removal.

A performance filter and bigger jets to suit, are a better bet!

[face]

Cool, thanks.

[willswitchengage]

I asked a similar question on the BX forum a couple of days ago RE replacing the airbox with a K&N cone - yes far more air would be getting in so you'd be running "lean" therefore you'd have to readjust the mixture settings accordingly.

[barefoot]

I've been wondering this for years...

 

How does overdrive work?

What happens when you flick the switch?

Where does the extra ratio come from?

 

Thanks

[M'coli]

Not so - the Land Rover mini-gearbox works in reverse, but a proper overdrive is ruined, burst, knackered if engaged while the gearbox is in reverse.

 

Edit: I thought you meant the twin-ratio gearbox bit, rather than a sepearate overdrive function - you are correct. An Overdrive unit will work in any forward gear, but not in reverse - they are usually limited to the upper gears as they are capable of transmitting a limited amount of torque.

 

An overdrive works in a not dissimilar way to the old 3-speed Sturmey Archer hub as found on many a Raleigh Chopper, but it only does the 2nd-3rdgear segment of the Sturmey archer hub, second beinbg direct drive in an SA hub, third being the overdrive - usually by 33% - and first being an underdrive, so-to-speak, of 25%. Guess who, 25 years ago, when bored in Maths drew a freehand exploded diagram of an SA hub for a classmate? (gets anorak!) The traditional 3-speed automatic transmission is very similar to an SA hub, too, using epicyclic gears to alter the ratios. (The centre gear, i.e. the one on the mainshaft/rear hub, is the "sun" gear, then around that are the planet gears which drive the "annular" outer ring gear - it is the ratio set up in these various gears that causes the overdrive effect.

 

Basically, when the drive from the gearbox enters the Overdrive unit and it's not engaged, the OD unit passes the shaft speed through the OD unit unchanged, but when the OD is engaged, it transfers the power to the epicyclic gears - and for the same input RPM, the epicyclic gears convert this to a certain % more than the direct drive.

 

Obviously, this does not mean that the car lurches up to a much greater speed, so it reduces the engine revs instead.

 

IIRC, due to the way that the clutches operate inside the OD unit it will break if reverse is engaged. Yes, a Sturmey Archer hub WILL allow the pedals to go backwards when one of the non-direct drives is engaged, as will an ovedrive if in a forward gear - but a bicycle hub has no reverse gear, unlike a car gearbox! I hope this helps to explain it rather than muddy the waters.

[barefoot]

That is excellent, thanks.

I had no idea. I also had no idea how a Sturmy Archer worked!

Was aware that they didn't work on first (or first & second) but didn't know why or about the reverse thing.

I'm guessing that it's electrically blocked when the lever is in one of the ratio's where it's not wanted & presumably it was heavy, complex & expensive in comparison to just bunging a fifth cog in the box, or is there other reasons why they're not used any more?

[RobT]

Should the rear silencer on an exhaust cancel out any noise created by a slightly dodgy intermediate baffler/muffler wotsit? I reckon I've got a duff new centre section on the Montego as it makes an annoying noise at certain speeds that wasn't there before. All the joins are leak free.

[autofive]

I've been wondering this for years...

 

How does overdrive work?

What happens when you flick the switch?

Where does the extra ratio come from?

 

Thanks

 

lots of info and diagrams here: http://www.buckeyetriumphs.org/technica ... 1/JOD1.htm

[tonedepear]

Proper stupid question, but I want to check my working before I tell her the wrong thing an asplode her car -

 

(ex)mrs_tone just called all of a tizzy, as it's been shitting down with rain, and she went through some big puddles, and her car (206 1.9d) spewed a load of white smoke (steam, one assumes?) out the exhaust, and misfired/chugged it's way back home. Just.

 

The fact it's still running must be good, right? Assuming it's not hydro-locked, will running it back up to temp now it's had a rest clear the water through, or should she be not running it and seeking expert assistance instead?

 

(Details are hazy, but this is roughly what I think she said)

[scaryoldcortina]

Yeah, the fact that it kept going is good news! I'd change the airfilter though, that won't have faired well.

 

On the way home tonight I came across a 2 foot deep river across the road. While I was deciding what to do a peugeot taxi drove into it at 20mph and then stopped dead with an appaling sounding bang. I drove the sierra through very slowly and drove round him.

[KruJoe]

306td's, ZX's etc are really bad for sucking up floodwater and buggering the job up, these might be the same. Might have had a lucky escape, or will it only run on three now? I reckon the damage has been done if there is any, I'd prolly try taking it for a blast and see what happens...

[Pillock]

Yeah I know a chap with a ZX TD that went through some fairly shallow water, sucked some up and hydro-locked the engine. Are those air intakes stupidly low or something? It went over the bridge after the nice man in the oily overalls explained the concept of a bent conrod, pointed to where it was in the engine, and drew a diagram of his hourly rate.

 

It's an ideal time to be buying Cat C salvage if you have an engine crane though.

[tonedepear]

Thank you!

 

Right. I'm 120 miles away, and I'm pretty sure changing the air filter is beyond her abilities, and me trying to talk her through it would probably be even worse. Urgh.

 

Might have to have a go though. She won't be able to get a newun til tomorrow, but she could take it out at least just to see how it runs.

[scaryoldcortina]

I could pop over tomorrow sometime and have a look for you if you like.

[autofive]

On the way home tonight I came across a 2 foot deep river across the road. While I was deciding what to do a peugeot taxi drove into it at 20mph and then stopped dead with an appaling sounding bang. I drove the sierra through very slowly and drove round him.

 

you didnt go through Lanchester then?

 

i thought i would get some petrol on the way home.....

 

 

 

[tonedepear]

I could pop over tomorrow sometime and have a look for you if you like.

Thanks mate. Panic over, hopefully.

 

Well, I told her not to start it and to have a look at the air filter, she got as far as not being able to find the lever to open the bonnet, got in a huff, started it anyway and after 30 seconds it's running clear. She's now convinced she's a mechanic.

 

Nice to hear from her, at least!

[KruJoe]

Are those air intakes stupidly low or something?

Yes, just in front of a front wheel aren't they?

 

Glad to hear Tone's one seems ok. I hope his lass has learnt something today...

[scaryoldcortina]

I could pop over tomorrow sometime and have a look for you if you like.

Thanks mate. Panic over, hopefully.

 

Well, I told her not to start it and to have a look at the air filter, she got as far as not being able to find the lever to open the bonnet, got in a huff, started it anyway and after 30 seconds it's running clear. She's now convinced she's a mechanic.

 

Nice to hear from her, at least!

 

Fair enough! The air filter will almost certainly (ime) block up in the next day or two, best case loss of power worst case the turbo will suck it up the inlet pipe and grenade itself. Paper doesn't take kindly to water.

[Ross_K]

Even Land Rovers aren't immune from morons driving them into floods:

[Albert Ross]

If that's BER and going for scrap, I know a good home for it!

[dollywobbler]

Our Mini is rubbish at starting. I'm wondering if it's fuel starvation as it just churns over and over until it suddenly catches and runs beautifully.

 

It used to do it if left for more than a week, but it now seems to do it all the time. Is there a non-return valve somewhere that's past its best?

[Ross_K]

If that's BER and going for scrap, I know a good home for it!

 

They any good for anything apart from sending over the bridge?

 

Presumably they take the armour plating and ballistic glass out before they put them through the auctions?