I’m getting ready to put the engine back together and have new timing chains and everything but new sprockets. I’ve tried to find info on the forum as to how to tell if the sprockets are worn and need to be replaced but couldn’t find the info. Can someone tell me how to tell if they need to be replaced or since all new parts are being used, to just buy new sprockets? The head was rebuilt by the old Coventry West machinist who said the valves are timed and just needs to be set on the block. The manual says that if new chains are used then new sprockets should also be used as the timing may have to be reset. What do you guys say? Thanks.
If the teeth have any semblance of being ‘pointy’ then replace them, but if everything else in the train is new is there a big cost to use new sprockets?
I agree but figured I’d check with you guys who know a LOT more than I do. I was ready to order them but then saw a post saying might not be necessary and we all know how quickly the money adds up on these cars. Here’s what they look like…
I agree but figured I’d check with you guys who know a LOT more than I do. I was ready to order them but then saw a post saying might not be necessary and we all know how quickly the money adds up on these cars. Here’s what they look like…
Just replied via regular email. All 5 sprockets are around 400 so no, it’s not too bad. Here’s the pics if the other email didn’t go thru…
They look to be in serviceable condition. How does the eccentric shaft look for wear?
He likely meant the tappets are shimmed to spec. Valve timing happens after the engine’s put at #6 TDC, the head is torqued down, the camshafts positioned and upper timing chain properly tensioned. It’s not uncommon for the camshafts to rotate slightly out of sync during the process of chain tensioning, requiring loosening the chain, tapping the sprockets off the camshafts and minor adjustment before tightening the chain again…
Ok, thanks, just concerned because some say if the gears are pointed, they need to be replaced. These are pretty pointed.
Yes, you’re right, that’s what he said.
| Nickolas Nick Saltarelli Regular
April 15 |
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They look to be in serviceable condition. How does the eccentric shaft look for wear?
homerboy:
The head was rebuilt by the old Coventry West machinist who said the valves are timed and just needs to be set on the block
He likely meant the tappets are shimmed to spec. Valve timing happens after the engine’s put at #6 TDC, the head is torqued down, the camshafts positioned and upper timing chain properly tensioned. It’s not uncommon for the camshafts to rotate slightly out of sync during the process of chain tensioning, requiring loosening the chain, tapping the sprockets off the camshafts and minor adjustment before tightening the chain again…
Those sprockets look ok to me. All the wear takes place down in the roots, where the rollers make contact, not at the tips.
Thanks. So installing new chains with the old sprockets won’t be an issue?
The only way to measure runout might be on a lathe and dial gauge but a rule of thumb is if you can delineate visually two distinct sheens with a definitive dividing line in the journal then the shaft is worn, and so will be the bronze bearing in the idler sprocket. Likewise the intermediate sprocket and shaft. But wear is inevitable in used parts. It’s a matter of deciding what’s still within tolerance. If you can’t measure it then the only sure move is to go new.
The peaks would only show wear if the engine was running a long time with a loose chain.
Look for severe wear in the roots. Lay a new chain on it. If the links are touching or nearly touching the sprocket, then the wear in the roots is too deep.
It’s pretty hard to see but it looks like the new (and old) chain is laying down in the sprocket not resting on the sides. There is NO movement of the chain while in the sprocket, it does not wiggle or have any side-to-side movement. Also the shaft is tight in the intermediate gear, no slack or looseness.
I am going to weigh in here on something I know nothing about. But I do know about bicycle chains and sprockets. It the tips are pointed, there is way too much wear. Wear will occur in the valleys first and only affect the points if the valleys are toast. Worn sprockets will also result in premature wear of a new chain. If the old chain shows wear, and particularly if it is stretched (longer than a new chain) the sprockets need to be replaced. The safe bet is to replace both sprockets and chains at the same time if there are significant miles on them and the engine is apart.
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