timing question

[fairspares]

[ With a dial gauge, for ignition timing, there is no need to find true TDC so it's accuracy here is irrelevant.[/quote]

so how do you know were the firing point is if you dont find tdc first? this is a new method to me.

[victor]

[ With a dial gauge, for ignition timing, there is no need to find true TDC so it's accuracy here is irrelevant.

so how do you know were the firing point is if you dont find tdc first? this is a new method to me.[/quote]



The disc MUST be more accurate due to the play you have around the TDC. Positive stop will give you the EXACT centre i.e. TDC

[bazza3004]

Thanks for the replies/debate. I don't have a timing disc at the moment so I will have to use a dial.

[firekdp]

so how do you know were the firing point is if you dont find tdc first? this is a new method to me.

The disc MUST be more accurate due to the play you have around the TDC. Positive stop will give you the EXACT centre i.e. TDC

MUST it
The dial gauge is measuring piston travel NOT degrees. As the piston isn't moving during the dwell the gauge can be zeroed anywhere during this period. You'd have to be pretty dumb to try and find exact TDC to zero it when it will read zero wherever it is in this period, wouldn't you? .
So zero the gauge when the piston has reached uppermost travel, turn the flywheel back past the required mm needed and then in the correct direction to it, mark the mag housing adjacent to the arrow.
ONE mark needed, one margin of error, due to parallax etc, not FOUR.

[Muppet]

so how do you know were the firing point is if you dont find tdc first? this is a new method to me.

The disc MUST be more accurate due to the play you have around the TDC. Positive stop will give you the EXACT centre i.e. TDC

MUST it
The dial gauge is measuring piston travel NOT degrees. As the piston isn't moving during the dwell the gauge can be zeroed anywhere during this period. You'd have to be pretty dumb to try and find exact TDC to zero it when it will read zero wherever it is in this period, wouldn't you? .
So zero the gauge when the piston has reached uppermost travel, turn the flywheel back past the required mm needed and then in the correct direction to it, mark the mag housing adjacent to the arrow.
ONE mark needed, one margin of error, due to parallax etc, not FOUR.

[Yanker]

this disc its easier.I also use it to find the TDC by the positive stop method described in the stiky's book.

A few seemed to have missed or misinterpreted this part of the post?: I think "Pepot" is saying 'find TDC by positive stop, align the disc and mark-off ignition point.' I like the positive stop method for TDC determination (due to the 'dwel' factor), and like his disc as it will be more accurate than one bolted to the end of the crank. But each to their own.

[Pepot]

this disc its easier.I also use it to find the TDC by the positive stop method described in the stiky's book.

A few seemed to have missed or misinterpreted this part of the post?: I think "Pepot" is saying 'find TDC by positive stop, align the disc and mark-off ignition point.' I like the positive stop method for TDC determination (due to the 'dwel' factor), and like his disc as it will be more accurate than one bolted to the end of the crank. But each to their own.

Well,at least for me it's a relyable sistem.The image of the timming disc I posted has a very poor resolution.I have a better one in PDF,but don´t know how to post it here.

[victor]

A few seemed to have missed or misinterpreted this part of the post?: I think "Pepot" is saying 'find TDC by positive stop, align the disc and mark-off ignition point.' I like the positive stop method for TDC determination (due to the 'dwel' factor), and like his disc as it will be more accurate than one bolted to the end of the crank. But each to their own.

Well,at least for me it's a relyable sistem.The image of the timming disc I posted has a very poor resolution.I have a better one in PDF,but don´t know how to post it here.

I'd love the pdf version can you mail it to me? I'll pm you my address.

[Pepot]

I'd love the pdf version can you mail it to me? I'll pm you my address.

It´ll be a pleasure!