Dwell Meter And Timing Light

[mnaka]

Hi guys ive searched the forum but coudnt find a answer, im looking for a dwell meter and a timing light combo to buy, does anyone got any leads? thanks

[Rumesh88]

Why not search in ebay? You can find things like http://www.ebay.com/itm/SUNTUNE-TIMING-LIGHT-DWELL-METER-SET-TUNE-UP-Kit-Sun-CP7717-/181650232620?hash=item2a4b32952c&item=181650232620&pt=Motors_Automotive_Tools&vxp=mtr

The timing light in this sample is xenon but there are ones based on LEDs too if you take time to search. Is it for professional use or just DIY jobs?

[mnaka]

Just for diy jobs RUMESH

[Rumesh88]

Just for diy jobs RUMESH

Well in that case why not use a WYSIWYG method to check dwell and use a simple timing light for other purposes? Whenever I wanted to check dwell angle (in fact it is the symmetry and uniformity that matter most) what I used to do was to use a small buzzer (even a LED made to work at 12V would do if the ambient light permits) in parallel with contacts and manually turn the crankshaft very slowly and only in one direction. Keep in mind that the crank speed is twice that of distributor shaft speed. Then you can mark the crank pulley as the buzzer goes on and off for each cylinder. The angle you get here is twice the actual dwell. By simply observing the marks you can determine the extent of irregularities between cylinders (If the cam lobes are unevenly worn out, shaft bent etc). The only thing you wouldn't catch here is the uneven contact bounce that can happen at high revs. A bit of a messy method but fr me serves the purpose better than a dwell meter. Edited February 2, 2015 by Rumesh88

[mnaka]

Well in that case why not use a WYSIWYG method to check dwell and use a simple timing light for other purposes? Whenever I wanted to check dwell angle (in fact it is the symmetry and uniformity that matter most) what I used to do was to use a small buzzer (even a LED made to work at 12V would do if the ambient light permits) in parallel with contacts and manually turn the crankshaft very slowly and only in one direction. Keep in mind that the crank speed is twice that of distributor shaft speed. Then you can mark the crank pulley as the buzzer goes on and off for each cylinder. The angle you get here is twice the actual dwell. By simply observing the marks you can determine the extent of irregularities between cylinders (If the cam lobes are unevenly worn out, shaft bent etc). The only thing you wouldn't catch here is the uneven contact bounce that can happen at high revs. A bit of a messy method but fr me serves the purpose better than a dwell meter.

Yeah thats a great idea Rumesh, maybe ill give it a shot, btw what is this method called? so i can read more regarding this before approaching it right? and this is the same method used for static timing right?

[Rumesh88]

Yeah thats a great idea Rumesh, maybe ill give it a shot, btw what is this method called? so i can read more regarding this before approaching it right? and this is the same method used for static timing right?

Well that's not a big deal if you understand the engine mechanics. I cannot identify the method with a particular name and don't think you would find it on the net either. Find a 12V buzzer and connect it in parallel with the contacts so that you can keep your eyes freely on the cam pulley while listening for the buzzer sound. Remove the spark plugs if you find it difficult to rotate the crank. For every rotation of the crank the distributor cam would rotate half a turn. In an engine with 1-3-4-2 firing order, get the distributor finger to just pass the 2nd plug so that you can begin with the 1st cylinder. Now rotate crank clockwise until the buzzer sound just disappear. Mark the point on the pulley with something like Tipex against a fixed point on the engine like timing mark tab. When detecting the point always keep the movement in the clockwise direction b'cos if you back up in reverse you will not get the correct point. This is because of the play in timing belt and cam gear. Then rotate until the buzzer sounds again and mark the point. In a vehicle with a 50/40 degree dwell (example only) you must now read 100 deg between the points b'cos crank is twice as fast. You need not read the angle but go on doing the same for next plug which is No. 3. Now ideally the four points you marked should be at 0,100,180 and 280. Now when you do the same for cylinders 4 and 2, the points should coincide. but practically they will deviate by a small amount. Of course you can improvise this method by pasting a 360 deg protractor template on the pulley.

[mnaka]

Well that's not a big deal if you understand the engine mechanics. I cannot identify the method with a particular name and don't think you would find it on the net either. Find a 12V buzzer and connect it in parallel with the contacts so that you can keep your eyes freely on the cam pulley while listening for the buzzer sound. Remove the spark plugs if you find it difficult to rotate the crank. For every rotation of the crank the distributor cam would rotate half a turn. In an engine with 1-3-4-2 firing order, get the distributor finger to just pass the 2nd plug so that you can begin with the 1st cylinder. Now rotate crank clockwise until the buzzer sound just disappear. Mark the point on the pulley with something like Tipex against a fixed point on the engine like timing mark tab. When detecting the point always keep the movement in the clockwise direction b'cos if you back up in reverse you will not get the correct point. This is because of the play in timing belt and cam gear. Then rotate until the buzzer sounds again and mark the point. In a vehicle with a 50/40 degree dwell (example only) you must now read 100 deg between the points b'cos crank is twice as fast. You need not read the angle but go on doing the same for next plug which is No. 3. Now ideally the four points you marked should be at 0,100,180 and 280. Now when you do the same for cylinders 4 and 2, the points should coincide. but practically they will deviate by a small amount. Of course you can improvise this method by pasting a 360 deg protractor template on the pulley.

Thank you Rumesh very informative, i will try it, and yes protractor template thing has to be done first, thanks again for the time taken to explain/write this all

Edited February 2, 2015 by mnaka