SafeChav

This is something i've been meaning to start a topic on for a while now, and i'm hoping it'll turn into a good thread.

In the time ive spent messing around with cars and the people i have met as a result, i have heard numerous people talking about "timing an engine by ear".........saying you can buy fancy timing lights etc but the best way is to do it by ear.

Having watched someone do it i don't see how that conclusion is reached, i really wasn't convinced myself how revving an engine and spinning the dizzy back and forth can be more accurate than equipment? Ignition timing if im not mistaken, is crucial, and it doesn't need to be out a lot to have disastrous results.....

Your views please

DROPTOP

is that over the phone?

SafeChav

DROPTOP

nevermind

SafeChav

antony215

Your never going to have it 100% right tho are you if you do it buy ear so i cant see how it's the best way to do it id rather use a timing light and know that it's spot.

foreigneRS

even if you get it 'right' at idle or off load, it probably won't be 'right' on load.

who still has a car without mapped ignition these days anyway?

Graham S1

I still know a few old school mechanics that can do it by ear, but still check with a timing light.

AlexF

tell them to buy mapped ign!


[cough]MegaJolt[/cough]

COMEDY DAN

Done by a really helpfull guy, over the phone?

Chip

iTrader: (3)

You set an engine to book figures with a timing light, if you want to actually set it up properly with the weights altering the shape of he ignition curve and different stops etc, then your ears are all you have, same as when you map a cossie you use your ears.

GARETH T

does he go out of his way for you?

COMEDY DAN

For free?????

foreigneRS

or the torque figure on a dyno

D.K.

My mates old man does it by ear its never spot on tho even tho he swears it is untill proven wrong with the timing light.

Phil

iTrader: (1)

I think you need a combination of things to get the timing right on older cars...

You can set them up by the book figures using a timing light, but this is never going to be optimal as the book has to allow for different fuels and tolerances within the engine build. In real life you can release more power and torque by setting the timing for your exact angine and the fuel you are using (e.g. has the head been skimmed and the compression ratio upped?)

If you set it up by ear basically you are advancing the timing at idle by spinning the dizzy until you hear pinking then knocking it back just a touch and then going for a drive to see if it pinks, and knocking back the timing a touch if it does until you can hear no pinking.

The downside to this is that running the ingition just on the verge of pinking whilst giving you a couple more BHP can lose torque, which is where a dyno/RR comes in and you can advance/retard the timing to suit the purpose of the car to get the best graph

GARETH T

Chip

iTrader: (3)

Indeed, what a load of bollocks

HOW can it Phil?



given that the fundamental definition of BHP that is utterly cast in stone is:
Torque * RPM / 5252 = BHP

How the hell at any point in the rev range can an increase in Torque result in a decrease in BHP?

Chip

iTrader: (3)

Indeed, and then in the maufacturers case (particuarly on older engines with not knock sensor) the trick (which utterly cannot be done on a "live map on the road") is to then keep backing the timing off until you find the point at which it starts to dip again, so that you get the minimum advance required to get within a specified % of that figure, this then gives you your "safety margin" for if someone runs old fuel etc

Rossco

The way i set my ingition timing on my Nova 1.4 SR (on the carb), is advance the timing to fooook, drive it then back it off untill it stops pinking!

foreigneRS

yes, but that involves changing the weights, vacuum advance etc. not practical imo, and megjolt or similar is a much better proposition

Mark_w

My mk1 mexico with standard engine is a good example of how this works ...if i set it up to factory spec with a timing light,it runs rough and is down on power...if i advance the ignition until i start to get pinking under load,and then back it off a couple of degrees it completely tranforms the car...when i then check the timing with a strobe,it is about 15 degrees different to what it should be

regards mark

GARETH T

mark rs

does it idle ok once advanced?

what you might find is you coudl change the bob weights, get the idle ignition advance back to standard figures, but still have the performance

SafeChav

well as i hoped there is some interesting replies!

basically where this stems from is my friend has just bought a Mk1 Golf Cabrio with a Mk2 16V lump, and after getting the mechanic at her dads garage to fit a new cam belt and getting it back it would barely run.

Turns out he also decidied to adjust the ignition timing, and consequently timed it up by ear, so i thought i would pose the question to see peoples views on it.

So as i can see from this there are mixed views on it, but i get the general opinion its not a good way of going about it? Mappable ignition isn't an option for this car, so thats out of window unfortunately

Phil

iTrader: (1)

I didn't say at the same RPM you spaz

If you advance the timing right up to optimal peak BHP output (at the top of the rev range) it is known that you will loose some torque further down the rev range, as with cars like these you cannot set it up quite so easily for what the advance is at each RPM point (using 205's as an example from my experience)

GARETH T

ah right,,,, we are the spaz

Chip

iTrader: (3)

The only way thats going to be true is if you advance it so far that you get pinking lower down.

Providing you stay away from det, more ignition wont lose you torque.

If its well known it does, its well known by people who havent a clue what they are on about

GARETH T

i dont agree chip

Chip

iTrader: (3)

well i dont agree with your disagreement

GARETH T

are you sure you wont agree with my disagreement?

Chip

iTrader: (3)

ah, go on then, its only a shitty 205, no one cares anyway, lol



Seriously though, its actually very application specific in terms of the peak cylinder pressures versus the point in the cycle etc, but its certainly not safe to make sweeping statements about it one way or the other.

GARETH T

i agree

Chip

iTrader: (3)

DROPTOP

sounds good! if only there was an after sales team that came and took it off your drive in the early hours to give it a test run

ivorbiggun

Don't tell me he set the points with a fag paper as well....

ECU Monitor Enthusiast

iTrader: (1)

All engines are tuned by ear.........


Using det amplifyng headphones of course (unlike one famous tuner I know )

SafeChav

ok.....when i say timed by ear, i'm talking WITHOUT det cans......