Fitting a rev counter

[youngun]

Can a rev counter be fitted to your bog standard 948 engine? And if so, how? And, is the 948 fitted with any kind of rev limiter?

[Packedup]

Can a rev counter be fitted to your bog standard 948 engine?

Yes. All you need is an electronic counter of the right polarity (most cars will now be neg earth, but factory spec was pos). There are other options (mechanical, electronic from the dynamo), but they're not really likely to happen due to price, rarity of parts, and simple pointlessness when electronic counters are plentiful and can be had cheap if you keep an eye out.

And, is the 948 fitted with any kind of rev limiter?

It's called valve bounce. It's also natures way of telling you to change up a gear... ;)

[bmcecosse]

Why do you want to count the revs ?? Just listen for the valve bounce.

[IslipMinor]

Youngun,

Valve bounce used as a regular 'rev limiter' will seriously damage the engine!! I'm sure the suggestions were made very tongue in cheek!

Std 948 = around 5,500 revs maximum. In good condition, good quality oil etc., then can cruise around 4,000 rpm max.

[bigginger]

I KNEW I'd read that somewhere - see a previous post where I was ridiculed for saying it

[bmcecosse]

Aye the standard 948 may just get 5500 if the valve springs are not too knackered. Fit the higher lifting (more spring compressing!) 1098 cam and double springs - and it's ok for 7000 (more if brave) - but do fit a crankshaft damper. The 1098 engine is much more 'fragile' - it's the longest stroke A series - longer even then the 1275. And the 1098 crank has a nasty frequency it doesn't like at ~ 6000 rpm - but again with crank damper fitted (which BMC were too miserable to fit on the NS engine - but did fit on EW version) - it can be revved to 7000, but not for long - and the cruise is best kept a bit down from 6000.

[youngun]

Yea, i distinctly get the impression that the 948 is actually the better engine, even if its not as powerful!
I wanted to fit a rev counter to act as a visual aid to my well tuned engineering ear! And it looks good.......

[bmcecosse]

Potentially you will be able to get more power from a '948' engine (bored to 998 or even more with Mini flat top pistons - genuine 100 bhp is possible) because the shorter stroke crank can be revved harder. The 'rev counter' is really not necessary - anyone doing competition driving has no time to look at a 'rev-counter' and it's certainly not needed for any other purpose!

[badobsession]

this one can be programed to flash at a per set limit .

[youngun]

Now that, I like!

[badfelafel]

valve bounce? wouldn't you have been deafened by the sound of the engine anyway by then, so you wouldn't hear it!

[Packedup]

You don't hear it so much as feel it...

Or so I've been told

[bmcecosse]

I would like to see the A series engine that can do 11,000 rpm on that revometer!

[badobsession]

cant do 11 but can get it to do 7.lol
mark..

[RogerRust]

What does valve bounce feel like?

[paul.kissick]

What does valve bounce feel like?

Dont know what it feels like, but it sounds terrible. you just think the engine is going to explode, which it probably could, so you would be better to only rev it to 4500 to 5000 rpm

[bmcecosse]

Valve bounce - just a sudden flatness in the engine power with a rattlyzzzz noise. Not a good idea to maintain it for more than a fraction of a second!