Good job there isn't a woman around...;)
Discussion
Sometime last year I aquired a Jaguar airflow meter to experiment with on my 390SE (larger bore than the standard item).
Sadly it proved to have a sticking flap (ooer missus) that no amount of fiddling, ultrasonic cleaning or anything else could cure.
So I decided it was time to bite the bullet and pull it apart. As you do
I got the plastic cover off and studied the workings, made a few sketches and photos. Then I removed the pot wiper, resistor pack etc. and proceeded to drill out the 'rivets' that secure the lower cover.
With this removed the flap came out and I could study the problem. It quickly became apparent that the thrust washers are worn, allowing the preload spring to pull the flap up into contact with the inside of the casing. Easy enough to cure, so I'll source some new bearings and assorted washers and rebuild it.
Ah, you say, but what about the precision helical spring that determines the response of the flap. Well, don't you worry, I've got that figured out as well... watch this space!
I've taken the opportunity to use a die grinder on the castings, to round off some of the edges, clean up casting marks etc. and some abrasives to clean up the internal walls where the flap had been scraping (that's how bad it was!). Probably won't make any difference, but you never know
I was surprised to note obvious signs of leakage at the main casing joint as well, where the sealant hasn't (been sealing), and air has been drawn in BEHIND the flap
One to watch out for on reassembly. Something to check, incidentally, is that the plastic cover is completely sealed, since a small leakage potential exists there as well. I found I could suck air past the flap spindle bearings....
If this works I may have found another sideline...
Ian
Sadly it proved to have a sticking flap (ooer missus) that no amount of fiddling, ultrasonic cleaning or anything else could cure.
So I decided it was time to bite the bullet and pull it apart. As you do
I got the plastic cover off and studied the workings, made a few sketches and photos. Then I removed the pot wiper, resistor pack etc. and proceeded to drill out the 'rivets' that secure the lower cover.
With this removed the flap came out and I could study the problem. It quickly became apparent that the thrust washers are worn, allowing the preload spring to pull the flap up into contact with the inside of the casing. Easy enough to cure, so I'll source some new bearings and assorted washers and rebuild it.
Ah, you say, but what about the precision helical spring that determines the response of the flap. Well, don't you worry, I've got that figured out as well... watch this space!
I've taken the opportunity to use a die grinder on the castings, to round off some of the edges, clean up casting marks etc. and some abrasives to clean up the internal walls where the flap had been scraping (that's how bad it was!). Probably won't make any difference, but you never know
I was surprised to note obvious signs of leakage at the main casing joint as well, where the sealant hasn't (been sealing), and air has been drawn in BEHIND the flap
One to watch out for on reassembly. Something to check, incidentally, is that the plastic cover is completely sealed, since a small leakage potential exists there as well. I found I could suck air past the flap spindle bearings.... If this works I may have found another sideline...
Ian
danny hoffman said:
I might regret asking - but are you going to post any pictures?
Not of the kitchen, but I might get some of the meter in bits tomorrow. My £30 digi camera has no flash and doesn't work well in fluorescent light.
At the mo I'm frantically scoffing a plate of spag bol 'cos I'm meetng a mate for a beer in 26 minutes... and I haven't even had a shave yet!
Ian
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