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SAJ · 12-22-2014, 02:24 AM

Thanks Larry, Vince and T'BIRD During the tests the front cover was removed, a clamp put on the gear and the proper spanner put on the nut and I exerted about 60 ft lb on it before the clamp slipped. There was no movement. I know it should be tighter than this so I may re-test to a higher value, but I saw no signs of looseness.
TBIRD, funnily enough I used to manufacture Formica DF105 Phenolic Fabric for gears, so I know the quality can be very high if well-made. We pressed and cooked 8ft X 4 ft. sheets in various thicknesses at 2400 psi and the gears for Fords etc were cut from this. A very good self-lubricating material for bushes as well as gears etc.
This was woven cotton fibre impregnated with a Bakelite-type resin and layered up to required thickness. I was Technical manager at Formica here in charge of all formulations, processes and engineering for many years in the 60"s and early 70's.
The gear I have looks OK. I will wash it off and look again.
Larry the clicking noise is definitely not the polyethylene bolt moving over the indent. It is quite a lot bigger than the indent and I took 1/2 and1/8 speed videos of the bolt being screwed in to check this. Videos do play tricks and the knock is only when the bolt is clear of the gear and goes completely when it contacts the gear.
My thoughts were that the poly bolt can either eliminate end walk, which the thrust bolt in the centre should also do, or damp the backlash by friction or damp wobble from a loose gear. I have another video where I leverd on the gear to observe looseness with a DTI attached and I saw only about 0.010 flex axially at the rim of the gear. I am left with backlash as the cause. I could imagine an ally gear knocking at maybe 0.010 backlash. But 0.008 inch seems rather small to produce the level of knock I hear at Idle with an absorbent fibre gear. Am I wrong here? It cannot be heard when driving, but I love to listen to a quiet idle next to buses at traffic lights etc!
In view of Vince's advice i will check tightness again, and remove the gear to examine the pins. And get an 0.003 gear from Snyders too.
Re Schwalms, I have done 10,000 miles since they reco'd it and 9000 of those did not knock. And I do not think Ora Landis will want to hear about it in view of that. The engine is a real performer and the burnt valve was caused by my letting someone else work on it while I was too busy running my own company here.
Thanks again fellows for your advice.
I will post when the problem is solved.
SAJ In NZ

12-22-2014, 02:24 AM	#4
SAJ Senior Member Join Date: Jul 2010 Location: Auckland, New Zealand Posts: 515	Re: Timing gear knock Thanks Larry, Vince and T'BIRD During the tests the front cover was removed, a clamp put on the gear and the proper spanner put on the nut and I exerted about 60 ft lb on it before the clamp slipped. There was no movement. I know it should be tighter than this so I may re-test to a higher value, but I saw no signs of looseness. TBIRD, funnily enough I used to manufacture Formica DF105 Phenolic Fabric for gears, so I know the quality can be very high if well-made. We pressed and cooked 8ft X 4 ft. sheets in various thicknesses at 2400 psi and the gears for Fords etc were cut from this. A very good self-lubricating material for bushes as well as gears etc. This was woven cotton fibre impregnated with a Bakelite-type resin and layered up to required thickness. I was Technical manager at Formica here in charge of all formulations, processes and engineering for many years in the 60"s and early 70's. The gear I have looks OK. I will wash it off and look again. Larry the clicking noise is definitely not the polyethylene bolt moving over the indent. It is quite a lot bigger than the indent and I took 1/2 and1/8 speed videos of the bolt being screwed in to check this. Videos do play tricks and the knock is only when the bolt is clear of the gear and goes completely when it contacts the gear. My thoughts were that the poly bolt can either eliminate end walk, which the thrust bolt in the centre should also do, or damp the backlash by friction or damp wobble from a loose gear. I have another video where I leverd on the gear to observe looseness with a DTI attached and I saw only about 0.010 flex axially at the rim of the gear. I am left with backlash as the cause. I could imagine an ally gear knocking at maybe 0.010 backlash. But 0.008 inch seems rather small to produce the level of knock I hear at Idle with an absorbent fibre gear. Am I wrong here? It cannot be heard when driving, but I love to listen to a quiet idle next to buses at traffic lights etc! In view of Vince's advice i will check tightness again, and remove the gear to examine the pins. And get an 0.003 gear from Snyders too. Re Schwalms, I have done 10,000 miles since they reco'd it and 9000 of those did not knock. And I do not think Ora Landis will want to hear about it in view of that. The engine is a real performer and the burnt valve was caused by my letting someone else work on it while I was too busy running my own company here. Thanks again fellows for your advice. I will post when the problem is solved. SAJ In NZ