Thread: Timing by ear?

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Sometimes respectable engine guys tell me they time all thier motors by ear and by the looks of it, it works good. So for everybody that times by ear what exactly do you lissen for and/or do?? Thanks

Originally Posted by tweaked250r

Sometimes respectable engine guys tell me they time all thier motors by ear and by the looks of it, it works good. So for everybody that times by ear what exactly do you lissen for and/or do?? Thanks

Well, you find the guy with the best ear, and I'll bet all my money on my timing light for accuracy....

Setting by ear at idle only works for a start. When the advance comes in, you may need more or less timing. If it pings on accelleration, retard, if it bogs, advance.
Timing lights and book specs can't take into account the effects of age, wear and tear, and many small variables we introduce ourselves when we modify engines. I get them to run the way I want, then put the light on them and record the setting for future use.

Tuning by ear isn't a great way to set up an engine for optimum operation. First and foremost, you cannot always hear detonation (ping). This can cause damage as minor as a cracked spark plug to as major as broken pistons and bent valves - and you can't always hear it hapening. Secondly, todays gasolines are seldom consistant in antiknock (octane) compounds from one truck load to another and can be a deterrant to good mileage, detonation reduction and overall performance. A timing light and vacuum gauge along with known tuning specs are your best tools for good overall performance.
And yes, I do tune by ear, but only as my starting point for my light and gauge.

If it's timed by ear,should it be stroked by hand? Seriously,I always use a vacuum gauge as Denny described. Hank

If you don't have a timing light or vacuum gauge, nor the well-tuned ear, why not time the engine statically?

Commonly done on fresh engines.

You won't be able to get an exact read on the vacuum advance end of things, but you can tell if the vacuum advance is working.

Timing lights and book specs can't take into account the effects of age, wear and tear . . .
why not time the engine statically . . .

Not to discount anything that has been said to this point, but this question did spark an old memory.

Back when we had no tools or money we would -

Find #1 TDC using some down hole device like a wire or screw driver.
Set the point gap at the highest cam point.
Put a cigarette celophane between the points (while closed).
While pulling on the paper, rotate the distributor (counter clockwise?) until the paper 'just' released from the grip of the ponts.

That was the starting timing point to check rotor alignment etc.
From there - easy staring and no bogging under accelleration by ear.

Of course these were old tuners - not expensive 'built' engines.

Originally Posted by C9x

If you don't have a timing light or vacuum gauge, nor the well-tuned ear, why not time the engine statically?

Commonly done on fresh engines.

You won't be able to get an exact read on the vacuum advance end of things, but you can tell if the vacuum advance is working.

My find on initial statically tuned engines is that my timing is generally way advanced as they all seem to idle very nicely 'way up'. I then need my light and gauge to put it into specs.

As far as checking vacuum advance operation - you are correct on GM engines that use full intake vacuum. Ford uses ported(timed) vacuum from above the throttle plates which has no bearing on idle advance.

I remember some of the older tuner garbage. So and so could set the points, timing, and idle mixture by ear and when he was done you could stand a nickel on edge on the top of the air cleaner!!!!

When I get one of the real "pounders" put together, and set on front and mid engine plates with a urethene mount at the frame the engine usually thumps so hard a 3/8" drive socket won't stay on top of the air cleaner at idle, and when ya blip the throttle it's tough to keep your hand there!!!!!

Anyway, I set everything with my timing light with advance knob on the back, a tachometer, and an exhaust analyzer. Is vacuum even any kind of tuning device on the high performance stuff? Not sure I even have a vacuum gauge anymore. I just set my initial timing so it will start, sometimes with an ignition cut off switch to let it get cranking before the spark hits.... Then tune in my vacuum advance (if used), set the rate and point of the mechanical advance, then get the total timing where I want it. Only thing left after that is a couple pulls on the chassis dyno and a bit of tweaking on jets and timing.... Without power brakes (I much prefer twin master cylinders and a proportioning valve) where or what am I missing that a vacuum measurement would be an issue?????

http://www.secondchancegarage.com/public/186.cfm
There is alot that can be done with a vac guage and as a matter of fact I will have one in the dash hooked up at all times.

So when you time engines by vacume do you use the manifold or ported vacume? What if it dosnt change very much at all? Also, let me get one thing that I have been confused on for a long time... Vacume advance hooks up to manifold OR ported??? thanks

Manifold vacuum is the only way to go - ported is ABOVE the throttle plates therefore will show little or no movement without a constant throttle opening - like driving down the road. And then it will only move in relationship to that throttle plate relationship position to full or partial opening.

Ford uses ported vacuum, GM's use manifold vacuum. Usually!!

I've put together a lot of small block chevs in my day. most of the time I
set the timing by ear. Just did so on my chev 350 trk and runs great. I also
have a big blk in my hot rod which is advanced 36 degrees. I used a light
on it, but on stock engines I generally just go by ear. To be safe, use the
light.
rd

I'm with Dave up at the top. give me a timing light and a TDC tool of some sort and the timing will be spot on. Some hotrod motors run so rough at idle that it is hard to set the timing under the best of conditions. You have to set them at a point well after maximum advance. How do you know where this is?? If you have had use of a Sun Distributor machine and run distributors and with mag adaptor magnetos you will be able to find exact advance curves (if any) and be able to set the timing correctly and be prepared to make tuning adjustments.

Magnetos are set with a buzz box which works off the points and you can set them very accurately with these. For a long time it was the only way they were set. Today you can get timing lights that will work with mags.

Originally Posted by tweaked250r

Sometimes respectable engine guys tell me they time all thier motors by ear and by the looks of it, it works good. So for everybody that times by ear what exactly do you lissen for and/or do?? Thanks

Timing by ear is a good way to loose hp or blow holes in the tops of your pistons.