The following warnings occurred:
Warning [2] Undefined variable $search_thread - Line: 60 - File: showthread.php(1617) : eval()'d code PHP 8.1.28 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/showthread.php(1617) : eval()'d code 60 errorHandler->error_callback
/showthread.php 1617 eval




Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Engine still knocking....
#11
Many thanks for all your interesting comments, trust me they are all very much appreciated.
I did try rotating the flywheel in both directions and the noise was there in both directions.
I was fairly happy it was not a valve/cam follower/ spring issue as I had spent a lot of time cleaning these and resetting the tappets and oiling them once complete.
So following Ruairidh’s comments I went out to have a closer look at the gears whilst turning the flywheel and marking each of the teeth where the noise occurred. It happened at the same teeth I’d marked on the cam gear every time, although there was no pattern at the spacing between marked teeth. Looking very closely, I could actually see the cam gear “snap” shut and hear the noise simultaneously at every point I’d marked on the cam gear.
At the point where the gears snapped shut I could feel backlash on the cam gear but at all points in between I could not feel any movement. Using a thin piece of 0.005” shim steel I could get this in between some of the teeth but not all but nowhere was this a loose fit, not exactly a perfect check but a reasonable indicator of the backlash. These are the gears that came with the car and have been in all the time I have had Ruby, would this backlash be an issue??
Again following Ruairidh’s comments I applied a liberal coating of engine oil to the crank gear and just like magic, after a couple of rotations of the flywheel, the noise disappeared and was followed by a deep sigh of relief! Quite embarrassing really ……………
So once again many thanks for your contributions and any advice regarding the backlash would be appreciated
Cheers Denis S
Reply
#12
Most people live with the backlash. But as you've seen (or felt with a.005" guage) due to the uneven load around its rotation, the cam wheel doesn't wear evenly. If you cut a new keyway in the cam gear at 90 degrees to the existing one, the hard work will be done by relatively unworn teeth. Obviously, this makes 'dialling in' the cam timing a must. IMO, even without a mod like this,  it's worth checking the cam timing with a 360 degree protractor rather than relying on the 'dots' lining up; not least because after many decades of tinkering, the gears in any motor may well not be a matched pair from the factory.
[Image: 51200572413_607a9bed6e_k.jpg]

[Image: 51134820384_555fe7ad84_k.jpg]

[Image: 39854797775_c62695b08f_n.jpg]
Reply
#13
Stuart, cannot say that the timing gears I have installed are original, my guess is they are not as the crankcase is marked 1, the cam gear is marked 1.5 and the crank gear is 0.5 and if they were original, I assumed the gears would be marked 1.0 like the crankcase?
I also guess finding new or serviceable matched pairs of timing gears is a bit like searching for hens teeth and then would anyone want to part with them??
I have the makings of a three bearing engine but both of the timing gears have lost teeth.
I also have the makings of a spare two bearing engine which I hope to begin after Ruby is back on the road again, but will need to source a set of timing gears.
If anyone knows of a source I’d love to hear
Cheers
Reply
#14
Hi Dennis

Dave Dye sell them. “Austin in the shed” on this forum.  Can’t recommend them more highly.

Cheers

Howard
Reply
#15
Are the new timing gear copies cut to allow for all the various meshings ?
Reply
#16
Hi Tony

I believe Dave makes just the standard 0 / 0 sets but he should confirm.

Cheers

Howard
Reply
#17
Tony have fitted several sets of Dave's timing gears to various engines and they all have acceptable tolerance compared to trying to match a pair from used gears. Terry.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)