Vacuum advance take off
Discussion
Just in the process of recommissioning the Chimaera, following 14 months of non-use.
Whilst changing the oil, I found the 90o bend from the plenum to the dizzy vacuum advance pipe, to be perished, which I've replaced. However, I thought I'd give the take-off port from the plenum a clean, I assumed that it travelled straight down into the plenum, I can't seem to blow through it and I can't get a pin through either (this is with the throttle wedged open too). Does the take off tube turn 90o within the casting?
Cheers.
Whilst changing the oil, I found the 90o bend from the plenum to the dizzy vacuum advance pipe, to be perished, which I've replaced. However, I thought I'd give the take-off port from the plenum a clean, I assumed that it travelled straight down into the plenum, I can't seem to blow through it and I can't get a pin through either (this is with the throttle wedged open too). Does the take off tube turn 90o within the casting?
Cheers.
Ok, I popped in to see Dan at Taylor TVR today after (passing 
) the MOT and he happened to have a spare plenum laying around, with which he showed me that the pipe does travel straight down, up-stream of the throttle, which I didn't expect.
The hole is tiny though, so may explain why I can't feel it from the inside. The skinny wire I tried to feed through, should have passed through though. I'm pulling the plenum off soon, so can have a proper look then.
) the MOT and he happened to have a spare plenum laying around, with which he showed me that the pipe does travel straight down, up-stream of the throttle, which I didn't expect. The hole is tiny though, so may explain why I can't feel it from the inside. The skinny wire I tried to feed through, should have passed through though. I'm pulling the plenum off soon, so can have a proper look then.
peaktorque said:
Ok, I popped in to see Dan at Taylor TVR today after (passing ) the MOT and he happened to have a spare plenum laying around, with which he showed me that the pipe does travel straight down, up-stream of the throttle, which I didn't expect.
The hole is tiny though, so may explain why I can't feel it from the inside. The skinny wire I tried to feed through, should have passed through though. I'm pulling the plenum off soon, so can have a proper look then.
Thanks for this post, I'll check mine's ok when I get home this afternoon. ) the MOT and he happened to have a spare plenum laying around, with which he showed me that the pipe does travel straight down, up-stream of the throttle, which I didn't expect. The hole is tiny though, so may explain why I can't feel it from the inside. The skinny wire I tried to feed through, should have passed through though. I'm pulling the plenum off soon, so can have a proper look then.
I pulled the plenum off yesterday and sure enough I found the take off port completely blocked. I couldn't clear it with any thing other than a 1mm drill bit in my grandad's old hand drill (didn't want to over cook it 
).
Once that oriffice was clear
, I thought I may as well see if the other end actually works, it doesn't 
, I can draw air straight through the diaphragm. This may explain why the port was blocked, unfiltered air has been drawn in through the faulty diaphragm and dirt has built up in most restrictive part of the passage.. I've no idea how long it's been broken, I've had the car over 5 years and haven't ever noticed a change in running characteristics, for all I know it may have been this way for years.
New vac advance ordered (hoping for great things once it's all fitted and operating again) and I should be all set for the annual trip to Le Mans in a few weeks
). Once that oriffice was clear
, I thought I may as well see if the other end actually works, it doesn't , I can draw air straight through the diaphragm. This may explain why the port was blocked, unfiltered air has been drawn in through the faulty diaphragm and dirt has built up in most restrictive part of the passage.. I've no idea how long it's been broken, I've had the car over 5 years and haven't ever noticed a change in running characteristics, for all I know it may have been this way for years. New vac advance ordered (hoping for great things once it's all fitted and operating again) and I should be all set for the annual trip to Le Mans in a few weeks
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