8 replies to this topic

[Russ528]

Morning chaps, and Happy Monday. Hope everyone had a good weekend. We had one of our forum meet ups on Saturday, which had a good turnout (between 70 and 80 cars) as the weather was good.

So, speedo issues (as I've described in this thread here), and the more I am thinking about it, the more I'm sure that the speedo dials in mine are the original Sprite ones, thus calibrated for a 1275 engine/gearbox.

So, the solution to (a) the bouncing needle and more likely (b) the speedo reading being incorrect, and getting more and more incorrect the faster you go seems to be to buy a new set of dials that are already calibrated for the same engine as mine.

Now the fun bit.

As far as I can tell, from looking up my engine number on the web, my 998cc lump is a 99HE67 unit that runs merrily on unleaded, which according to the MGcars engine listsing , a 99HE engine (no number stated) is a "Metro 1 ltr 1985 onwards".

However, this site says that the 99HE67 engine is a 1989 onwards metro engine, which I'm more inclined to believe, as it's given the full number in it's listing.

(*check that* - just had a look at a whole load of other sites that agree it's a 1989 onwards engine)

I have spoken to Minispares, who have some Nippon Seiki dials (same make as mine) for sale which are calibrated for the 'last' lot of 998cc engines with a final drive ratio of 3.1

It's about at this point that it all gets a little over my head!

Anyone know what final drive my engine has, and the likelyhood of these other dials working? I'm desperate to get this sorted now but I am wary of just throwing money at loads of different options.

There's some dials ending shortly on ebay, or I could get these others delivered next day - hence the request for a quick response if at all possible.

As usual, your help is greatly appreciated chaps and chapesses.

I do like this forum, there's always loads of people online and the information given always appears very correct - spent hours searching for stuff.....the missus had a pop at me last night because of it.

Edited by Russ528, 11 June 2007 - 08:48 AM.

[Guess-Works.com]

It's not the dials which is the problem, it's the speedo take off in the gearbox... there are a number of ratios which can be used which then match the FD to the speedo... Most Nippon Seiki dials run a 1242 tpm, and this can be checked by removing the dials and then removing the speedo head from the dial cluster... there's a coloured pinion which goes from front to back for the odometer which has the TPM imprinted onto it..

It's quite likely that the 998 engine has a 3.44 FD, and your old 1275 had a 3.1.. which if using the same speedo drives would means it would no be reading fast.

The only reliable way of discovering the FD is to use a GPS speedo and electronic rev counter (the analog one may be accurate enough)

Driving along @ 60 in 4th check the actualy speed against the RPM, and also the given speed on the speedo... then use the ratio calc to find out what's nearest your results..

http://www.guess-wor...ox/index_R.html

[Russ528]

Would this different ratio also explain why the speedo needle bounces up and down, rather than giving a steady reading?

I haven't got a rev counter either......so I need to buy one first I guess.

I've head that company "speedycables" do re-calibrations - could i simply send my dials off to them and say 'recalibrate these for a 3.44 FD"?

Or is replacing the speedo drive clobber fairly easy - bearing in mind I can't get the engine out on our driveway, so it'd be a stretching down the back of the engine with zero visibility exercise?

I've had a look on minispares and can't see any speedo drive bits listed?

Edited by Russ528, 11 June 2007 - 09:29 AM.

[Guess-Works.com]

Changing speedo drives is best done with engine out, but in theory can be done engine in...

The bouncy needle can be cause by a number of things ( usually it's the cable but you've ruled this our by fitting a new one - which I hope is of the correct type, should have a white plastic/metal end going into the speedo )

The other alternatives is the cable is spinning in the speedo drive at either end, or the worm/pinion the the gearbox are worn/slipping.

To remove the speedo drives you'll need to remove the radiator and the ns engine mount, mount bracket and connection block to the gearbox (which means supporting the engine on something ) and then removing the pinions ( never done it 'in car' so don't know if there's enough room )

You will also need the information required to select the correct drives...

Speed TPM
Tyre size
Final Drive Ratio

You can then use the ratio calc above to select the correct drives..

[Russ528]

ugh...what a ballache. So £60 to get the dials recalibrated is sounding a lot easier

With regards to the correct cable, I'm a bit confused to be honest.

I had read on here that the cable needed to have the white collar for nippon clocks, but I've been told by both Minispeed and Minispares that the cables now all come with the grey plastic connector at the dials.

My original, perfectly un-damaged as it turns out, cable had the white collar end - but that didn't work.

I suspected the reason for this was because I'd also read on here that the Sprite's had a different sized speedo drive gear to other engine/gearboxes. but on closer inspection, the little white plastic cable tip that fits into the dials had a crack in it, so whilst it stayed on the cable end, I couldn't see it gripping when the cable was whizzing round - so that could have been the cause.

Either way, I tried both cables in the dials using a drill, and both seemed to operate the dials fine, despite the new one having.......hang on, I've seen some cable pics on here, I'll find them and put them up to help explain.

Edited by Russ528, 11 June 2007 - 10:00 AM.

[Russ528]

Right...

OLD is what came out.

NEW is what I've put in.



At the gearbox end, the old speedo cable is square. Whilst the new one is an oval shape.



Now, the old cable had a white plastic tip on it that made it from a round end to a square end.

The new cable doesn't have the plastic tip, but the end of cable that fits into the dials is already square.

Edited by Russ528, 11 June 2007 - 10:30 AM.

[Russ528]

Just to confirm, Guessworks....(sorry!)

It's quite likely that the 998 engine has a 3.44 FD, and your old 1275 had a 3.1.. which if using the same speedo drives would means it would no be reading fast.

My dials are reading slow. So when they say I'm doing 50mph, I'm doing about 65ish, indicated 30mph is actually 40 ish.

So the minispares dials will be the same gearing as my current dials, and thus won't solve the problem...correct? But if I can source a set from another mini, set up for 3.44 FD ratio then they will work.....yeah?

Any ideas on how I can tell which minis had these 3.44 FD geared dials?

How does everyone that does an engine conversion get around this problem?

Edited by Russ528, 11 June 2007 - 10:56 AM.

[Guess-Works.com]

It's not the dials which are wrong, there are some which are different, but the reason you have the alternate ratios in the speedo take off is to get the same set of dials to work with alternate diff ratios and wheel sizes...

In general 90mph Nippn dials are 1242 tpm, there are reputed to be some which are different, but I've yet to find one...

The 110mph Nippons (as fitted to the coopers) are 1300 tpm

As for the speedo cable... not sure what's going on but... http://www.minispare....aspx?pid=32957 is the one you want if you have nippon dials

[Russ528]

Just rung Minispares again, and they've told me (again...embarrassingly) that the white collar type do not exist anymore and that they've been replaced by the grey capped type.

I'm minutes away from saying balls to the current dials and buying a digital speedo & rev counter.....as it all seems a little more complicated due to the engine having been swapped.

Edited by Russ528, 11 June 2007 - 11:44 AM.