Over Rev
Posted: Sun Aug 12, 2012 9:29 am
I had an incident were the throttle return spring migrated across and caught on the side of the rear carb bracket. I have Weber 151's with that small bracket cast in the body. It was cut off but part of the stub remained. When in third under acceleration I decided to give the car more fuel (was at Lemans on the parade laps). Usually I am very light with the right foot. Unknown to me the above occurred so as I backed off the throttle and put the clutch in, to change gear, I heard the motor rev and Tacho whiz round. I think the action shocked the sticking bit loose as I went straight for the keys and turned the engine off. I am no fast draw gun slinger in getting to the keys, that quick, so feel sure if it had stayed stuck the motor would have been damaged. I coasted and wondering had I done any damaged. Needed to get off the circuit so decided to try the engine and it started without a problem, engaged gear and carried on. Upon slowing down and coming off the track (and a further 500 miles later) the only thing that has changed is an annoying metallic click when pulling off.
I have been around everything I can think off.
Engine and gearbox mounts. Touching exhaust etc.
It sounds like it is coming from the clutch bell housing area. I have checked the prop? shaft joints (new anyway). Has new TTR sliding spline drive shafts and just redone the diff hangers.
Ross, if you?re reading this, the diff hangers cured the light passenger side rear clicking when in right hand bends at low speed.
Any way, I fitted a new boot on the clutch arm as I thought that was rattling, also heat wrapped the exhaust "Y" piece and changed the clutch slave cylinder rubbers as the boot on that had hardened and come off. I even thought that had caused the slave adjuster rod to rattle.
Yesterday I removed the chassis cross brace as the roll bar drop links touch it. Noise still there!
When pulling off after you have taken up drive there is a click from the bell housing. Not like an engine mount as you are doing it but after. Sometime in second it happens. I got my son to drive it and he agrees and says he can feel the click come through the clutch pedal.
So, I think I did not get away with it! Anybody have any thoughts (Rohan). What could break up in the clutch? I am limited here, no experience of this. Could the spring petals on the pressure plate be breaking up? I am thinking I need to haul the motor out to find out and get a new pressure plate etc. Could I have sheared a fylwheel bolt?
My gut feeling is that inadvertently breaking load with the clutch has shocked something.
PS. Weber 151 casting filed off in France and an Electrical connector put on the waste part of the return spring. Can not go anywere now. Yes, I am going to get a rev limiter for this and the project car. Scary thought of the possible damage to the beloved twin cam. I note that the Accuspark guys have a new product soft limiter adjsutable 2 ? 12K RPM unit for ?29.00 on the eBay web site.
Advice Welcome.
Mike
I have been around everything I can think off.
Engine and gearbox mounts. Touching exhaust etc.
It sounds like it is coming from the clutch bell housing area. I have checked the prop? shaft joints (new anyway). Has new TTR sliding spline drive shafts and just redone the diff hangers.
Ross, if you?re reading this, the diff hangers cured the light passenger side rear clicking when in right hand bends at low speed.
Any way, I fitted a new boot on the clutch arm as I thought that was rattling, also heat wrapped the exhaust "Y" piece and changed the clutch slave cylinder rubbers as the boot on that had hardened and come off. I even thought that had caused the slave adjuster rod to rattle.
Yesterday I removed the chassis cross brace as the roll bar drop links touch it. Noise still there!
When pulling off after you have taken up drive there is a click from the bell housing. Not like an engine mount as you are doing it but after. Sometime in second it happens. I got my son to drive it and he agrees and says he can feel the click come through the clutch pedal.
So, I think I did not get away with it! Anybody have any thoughts (Rohan). What could break up in the clutch? I am limited here, no experience of this. Could the spring petals on the pressure plate be breaking up? I am thinking I need to haul the motor out to find out and get a new pressure plate etc. Could I have sheared a fylwheel bolt?
My gut feeling is that inadvertently breaking load with the clutch has shocked something.
PS. Weber 151 casting filed off in France and an Electrical connector put on the waste part of the return spring. Can not go anywere now. Yes, I am going to get a rev limiter for this and the project car. Scary thought of the possible damage to the beloved twin cam. I note that the Accuspark guys have a new product soft limiter adjsutable 2 ? 12K RPM unit for ?29.00 on the eBay web site.
Advice Welcome.
Mike