The Ford Barn - View Single Post

SAJ · 12-22-2014, 03:42 PM

Thanks for the follow ups. Answering them in the order they came:
Colin, I will check the crank gear when I get to work. I still find it hard to believe such a heavy knock can arise from backlash of a fibre gear.
George.I left the car for Diff work with someone.They reset the timing by ear and it was very retarded and the engine seized while driving it back to my workshop. No damage to bore or rings after it cooled, but I surmise the No. 3 valve overheated and warped. I didn't find anything else to cause it. New valve tip not ground. I have adjustable lifters etc. Cam thrust plunger already replaced by an adjuster bolt etc, and this does not remove the knock. Replacing the timing pin with a Polythene bolt does remove the knock with little pressure exerted on the rim of the gear. see videos attached, (which were in the wrong order and have just been fixed!).
Distrib. shaft etc all free - first things I checked. Can't be "cam walk" anyway since the adjustable thrust on the front cover would remove or at least improve it. I would love to find it was something I did, actually, so then I could fix it! I do not profess to be an expert on these engines in any way. I learn each time I mess with anything.
LARRY. Front cover is off, Gear nut tight. Will remove the gear anyway and get in a standard and oversize one from Snyders for trial fitting.
PC/SR. have tried .003 end float (DTI on gear) and screwing it in full tight while running ( dangerous because the front cover flexes a lot!) and neither changed the knock , whereas a slight twist on the poly bolt in the timing pin hole immediately removes the knock. I agree the gear does seem to wobble, and in time with the knock. But turning slowly by hand crank, it seems stable. Backlash 0.008 was measured at 4 points at 90 degrees. but the gear looks eccentric in the videos nevertheless. I will take it off and measure over pins in teeth to be sure.
As you say, I would expect more of a rattle than a synchronized knock with fibre gears, so I have to suspect the gears themselves.
Thanks again for all the advice
SAJ in NZ

12-22-2014, 03:42 PM	#14
SAJ Senior Member Join Date: Jul 2010 Location: Auckland, New Zealand Posts: 515	Re: Timing gear knock Thanks for the follow ups. Answering them in the order they came: Colin, I will check the crank gear when I get to work. I still find it hard to believe such a heavy knock can arise from backlash of a fibre gear. George.I left the car for Diff work with someone.They reset the timing by ear and it was very retarded and the engine seized while driving it back to my workshop. No damage to bore or rings after it cooled, but I surmise the No. 3 valve overheated and warped. I didn't find anything else to cause it. New valve tip not ground. I have adjustable lifters etc. Cam thrust plunger already replaced by an adjuster bolt etc, and this does not remove the knock. Replacing the timing pin with a Polythene bolt does remove the knock with little pressure exerted on the rim of the gear. see videos attached, (which were in the wrong order and have just been fixed!). Distrib. shaft etc all free - first things I checked. Can't be "cam walk" anyway since the adjustable thrust on the front cover would remove or at least improve it. I would love to find it was something I did, actually, so then I could fix it! I do not profess to be an expert on these engines in any way. I learn each time I mess with anything. LARRY. Front cover is off, Gear nut tight. Will remove the gear anyway and get in a standard and oversize one from Snyders for trial fitting. PC/SR. have tried .003 end float (DTI on gear) and screwing it in full tight while running ( dangerous because the front cover flexes a lot!) and neither changed the knock , whereas a slight twist on the poly bolt in the timing pin hole immediately removes the knock. I agree the gear does seem to wobble, and in time with the knock. But turning slowly by hand crank, it seems stable. Backlash 0.008 was measured at 4 points at 90 degrees. but the gear looks eccentric in the videos nevertheless. I will take it off and measure over pins in teeth to be sure. As you say, I would expect more of a rattle than a synchronized knock with fibre gears, so I have to suspect the gears themselves. Thanks again for all the advice SAJ in NZ