The special is now on the road and the only unknown is the engine, it performs well but it is very noisy and it seems to be coming from the front of the engine and sounds like badly meshing gears. Here is a video I put on Youtube of me rocking the pulley with the timing gear cover off, there seems to be a lot of play in the crankshaft to cam gear and also cam gear to generator gear.
The link to Youtube is here https://youtu.be/Wnd33CtfXq4
Teeth on the intermediate wheel look very worn. Looks like a relic from the recent Dynamator episode, qv. Perhaps been run with no oil trench to feed the gear.
(14-10-2018, 09:54 AM)Bob Culver Wrote: Teeth on the intermediate wheel look very worn. Looks like a relic from the recent Dynamator episode, qv. Perhaps been run with no oil trench to feed the gear.
Hmm that does look worn, a lot of backlash too. And you've got to ask yourself where all the wear debris went to...
Sorry but I would strip and investigate.
(14-10-2018, 09:54 AM)Bob Culver Wrote: Teeth on the intermediate wheel look very worn. Looks like a relic from the recent Dynamator episode, qv. Perhaps been run with no oil trench to feed the gear.
I was wondering how the oil gets to the gears as when I ran it with the inspection cover removed virtually no oil sprayed out, it is not dry but not very oily either. You speak of an oil trench is this in the camshaft bush?
The oil comes along the gallery in the crankcase and feeds the oil jets. It then carries on across the front of the crankcase to the front camshaft bearing bronze bush. It feeds the bush and there are slots on the back of the camshaft gear/front of the bush to feed oil onto the gears.
The feed hole in the bush can get blocked which starves the bush & gears of oil.
Usually the feed to the front bush is excessive so there should be plenty of oil. It is a common practice to reduce the size of the feed hole on the bush and also the bush at the back of the camshaft. This raises oil pressure a bit as well.
This shows the front bush, with the threaded hole for the fixing bolt from the top of the crankcase, together with the oilway which matches up to the oilway in the crankcase. You can just see the "trench" on the inside of the bush. This runs all the way front to back. The backlash you're looking for in the geartrain is .004" and the endfloat for the camshaft is .002". Lapping the gear onto the camshaft to give 10 to 12 thou will produce this once the camshaft nut is nipped up.
14-10-2018, 10:21 PM (This post was last modified: 14-10-2018, 10:25 PM by Mark McKibbin.)
(14-10-2018, 12:45 PM)AustinWood Wrote: The oil comes along the gallery in the crankcase and feeds the oil jets. It then carries on across the front of the crankcase to the front camshaft bearing bronze bush. It feeds the bush and there are slots on the back of the camshaft gear/front of the bush to feed oil onto the gears.
The feed hole in the bush can get blocked which starves the bush & gears of oil.
Usually the feed to the front bush is excessive so there should be plenty of oil. It is a common practice to reduce the size of the feed hole on the bush and also the bush at the back of the camshaft. This raises oil pressure a bit as well.
Thanks Jim, it now makes more sense, as it's getting so little oil I assume a blockage or the bush has been located using the oil hole.
(14-10-2018, 12:51 PM)Colin Wilks Wrote: This shows the front bush, with the threaded hole for the fixing bolt from the top of the crankcase, together with the oilway which matches up to the oilway in the crankcase. You can just see the "trench" on the inside of the bush. This runs all the way front to back. The backlash you're looking for in the geartrain is .004" and the endfloat for the camshaft is .002". Lapping the gear onto the camshaft to give 10 to 12 thou will produce this once the camshaft nut is nipped up.
Colin, initially I thought "What Trench" but on closer inspection all was revealed, thanks for the picture. As I was waiting for my new crank to arrive anyway I think the car will not be used until the engine comes apart for that.
