Tornado
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- Joined
- Dec 5, 2017
- Messages
- 4,863
Well into my first dive into timing chest of my '74 850.
Had no success using a deadblow rubber hammer to release the cover but found razor blades tapped into the gasket edges at strategic locations made short work of it.
Used the AN intermediate shaft holding plate sourced from OldBritts and rear brake locked and in top gear, was able to release the cam nut using a deep 1" socket. Nut is too shallow for a spanner. Came loose with a good amount hump on an 18" breaker bar, thankfully not needing heat nor impact rattle gun. A three leg puller was able to get the cam sprocket off without much trouble. Evidence DPO had used a thread locker product on cam nut.
New chain (AN) put on as described in shop manual. I used this post to set tension:
https://www.accessnorton.com/NortonCommando/cam-chain-tension.13575/#post-192235
Basically using a socket ratchet on the cam nut to rotate cam anticlockwise to take valve spring loads off the top chain run, then set full up/down movement of top run at tightest area to between 1/8-3/16". This was the only statement I had come across mentioning a min-max slackness for the chain, something that makes much sense to use rather than just the max amount listed in my books.
Spent a good hour scraping off gasket and its hardened black sealant from DPO. I plan to just use Hylomar on new gasket.
Next comes the oil pump flatting. Though it has visible scoring on side plates these cannot be felt with fingernail so very minor.
Had no success using a deadblow rubber hammer to release the cover but found razor blades tapped into the gasket edges at strategic locations made short work of it.
Used the AN intermediate shaft holding plate sourced from OldBritts and rear brake locked and in top gear, was able to release the cam nut using a deep 1" socket. Nut is too shallow for a spanner. Came loose with a good amount hump on an 18" breaker bar, thankfully not needing heat nor impact rattle gun. A three leg puller was able to get the cam sprocket off without much trouble. Evidence DPO had used a thread locker product on cam nut.
New chain (AN) put on as described in shop manual. I used this post to set tension:
https://www.accessnorton.com/NortonCommando/cam-chain-tension.13575/#post-192235
Basically using a socket ratchet on the cam nut to rotate cam anticlockwise to take valve spring loads off the top chain run, then set full up/down movement of top run at tightest area to between 1/8-3/16". This was the only statement I had come across mentioning a min-max slackness for the chain, something that makes much sense to use rather than just the max amount listed in my books.
Spent a good hour scraping off gasket and its hardened black sealant from DPO. I plan to just use Hylomar on new gasket.
Next comes the oil pump flatting. Though it has visible scoring on side plates these cannot be felt with fingernail so very minor.
