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RV8 Ignition Timing
Posted: Fri Mar 02, 2012 9:35 pm
by timnutt
Hi,
The new thermostat housing I bought to fit my Edelbrock carb touches the vacuum advance, so I decided to turn the the distributor round so the vacuum is on the other side. This is what I did, but what have I missed...:
- Rotated crank until No.1 cylinder is TDC.
- Removed distributor
- Turned distributor round ready to put back so vacuum is on other side.
- adjusted the rotor arm (and rotated oil pump slot) so it lines up with No 1 on dizzy cap when its dropped in
- Re-labelled the dizzy cap with correct cylinder numbers ready for when I add spark plugs and leads
Will this be OK when I finally finish putting the rest back together and try to start the big lump...or have I missed something.
Thanks
TimN
Re: RV8 Ignition Timing
Posted: Fri Mar 02, 2012 11:39 pm
by DEVONMAN
timnutt wrote:Hi,
The new thermostat housing I bought to fit my Edelbrock carb touches the vacuum advance, so I decided to turn the the distributor round so the vacuum is on the other side. This is what I did, but what have I missed...:
- Rotated crank until No.1 cylinder is TDC.
- Removed distributor
- Turned distributor round ready to put back so vacuum is on other side.
- adjusted the rotor arm (and rotated oil pump slot) so it lines up with No 1 on dizzy cap when its dropped in
- Re-labelled the dizzy cap with correct cylinder numbers ready for when I add spark plugs and leads
Will this be OK when I finally finish putting the rest back together and try to start the big lump...or have I missed something.
Thanks
TimN
All ok provided no 1 was on the firing stoke when you removed the dizzy.
Regards Denis
Posted: Sat Mar 03, 2012 11:39 am
by timnutt
Thanks! I did check by lifting on one of the rocker covers - although not needed as the TDC marking on the crank pulley shows TDC compression for No.1
Thanks
Posted: Sat Mar 03, 2012 12:01 pm
by sidecar
timnutt wrote:Thanks! I did check by lifting on one of the rocker covers - although not needed as the TDC marking on the crank pulley shows TDC compression for No.1
Thanks
Remember that the TDC mark on the damper will also line up when No1 piston is at the end of the exhaust stroke!

Posted: Sat Mar 03, 2012 12:05 pm
by SimpleSimon
sidecar wrote:timnutt wrote:Thanks! I did check by lifting on one of the rocker covers - although not needed as the TDC marking on the crank pulley shows TDC compression for No.1
Thanks
Remember that the TDC mark on the damper will also line up when No1 piston is at the end of the exhaust stroke!

Just because you are at TDC does not mean you are on the compression stroke on No1 cyl

but you will be at No1 TDC but could be anywhere in the cycle.

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Posted: Sat Mar 03, 2012 12:14 pm
by timnutt
Yes, sorry, I'm being a numpty, you do need to check that both valves are closed to ensure No.1 is on its compression stroke.
Thanks
TimN
Posted: Sat Mar 03, 2012 1:40 pm
by sidecar
SimpleSimon wrote:Just because you are at TDC does not mean you are on the compression stroke on No1 cyl

but you will be at No1 TDC but could be anywhere in the cycle.

Er, at TDC you can not be "anywhere in the cycle" There are two places you can be in the cycle when the marks line up at TDC, either at the point where the plug has just fired a few degrees earlier or you are at the end of the exhaust stroke and at the start of the induction stroke with the valves 'on the rock'
Anyway, Tim has done it right, he has checked the valves and that way he can be sure that his timing is at least 'in the ball park'
Posted: Sat Mar 03, 2012 11:05 pm
by SimpleSimon
sidecar wrote:SimpleSimon wrote:Just because you are at TDC does not mean you are on the compression stroke on No1 cyl

but you will be at No1 TDC but could be anywhere in the cycle.

Er, at TDC you can not be "anywhere in the cycle" There are two places you can be in the cycle when the marks line up at TDC, either at the point where the plug has just fired a few degrees earlier or you are at the end of the exhaust stroke and at the start of the induction stroke with the valves 'on the rock'
Anyway, Tim has done it right, he has checked the valves and that way he can be sure that his timing is at least 'in the ball park'
You know what I mean

not perfectly worded I grant you
