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setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 8:00 amby bert one
As the Avanti head is recessed, & the 2mm squish band sits inside the bore, does this mean my desired btdc timing of 17° (which equates to 1.6 mm) should read 3.6mm on the dial gauge, or am I spectacularly wide of the mark?
Also I noticed on another thread, that when setting the squish, solder was played across both the piston crown & measured, then some across the cylinder head squish band & measured again. Is that just a belts & braces affair, or could there be a difference?
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 8:35 amby rossclark
If you zeroed the the gauge with piston at TDC your timing mark is still 1.6mm before, it's just the piston travel you're measuring.
The solder is used to measure the squish which is entirely separate from the timing and basically checks the piston won't hit the head and the compression / combustion will be OK. You should always check this.
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 10:17 amby hullygully
Good reply Ross, I was sweating & couldn't type any quicker after reading the question
............... phewee
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 1:59 pmby Blaginit
Hi I thought 17 deg ment put arrow on tdc and count back 17 degrees mark and this becomes new timing mark can any one help clear this up am I write or wrong please help
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 6:59 pmby coaster
Blaginit wrote:Hi I thought 17 deg ment put arrow on tdc and count back 17 degrees mark and this becomes new timing mark can any one help clear this up am I write or wrong please help
That is correct, what they are talking about above is the slightly more accurate but more fiddly way of measuring the timing with a dial gauge on top of the piston. mm of piston travel rather than degrees of crankshaft rotation. Either way is fine tbh.
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 8:58 pmby rossclark
Yes, piston travel is arguably more accurate than a degree wheel. Accuracy with a small degree wheel that fits the flywheel is down to about 0.5 of a degree. With a dial gauge you should be able to get down to 0.01 of a mm which is about 0.1 of a degree in this area (17 degrees).
We all assumed you are using a standard crank 58/107mm for 17 degrees at 1.6mm
For a 60/107mm that would be 1.67mm
For 60/110mm that would be 1.69mm
For a 58/110mm it'd be 1.59mm
Re: setting Avanti timing with dial gauge
Posted:
Fri Oct 23, 2015 11:09 pmby bert one
Yes, it's a standard 58 / 107 set-up.
Thanks for the replies. Much appreciated.