Hi,
In trouble again!!
Fitted the camshaft and followers and all works ok both move, set TDC, fitted cylinder head and rocker box cover and set the valve clearances.
When I turned the engine through 360 and checked the valve clearances again the inlet is solid, no matter how lose you leave the rocker it is solid when the engine turned through 360.
Took the rocker box off and turned the engine over but only the exhaust rocker push rod seems to move, thinking is the cam shaft not working correctly ?
Thanks,
One of the problems you always get with unit singles is that it can be hard to locate the end of each pushrod in the top of its follower. You have to do it blind normally which can sometimes be a challenge. However, if the rocker box is off, you should be able to look down the pushrod tunnel (with the push rods removed) and check whether the followers move up and down when you rotate the engine and to also check both followers are still present.
I had a similar issue on my B44 engine after re-build. Basically the cam didn't have enough end float after new bushes fitted so the follower 'foot' was binding on the cam pinion.
That's very interesting.when I first had the issue I removed the gearbox to check the cam and followers, all ok so I set the valve clearance turned the engine over a dozen times and all was fine when I fitted the gearbox turned the engine over to check again bingo I have the same problem again the inlet valve is solid. So perhaps I am getting a similar issue as you did. How did you overcome it ?
You can dress the outer edges of the follower with an oilstone.
Quote from: jumbo12 on 24 Oct, 2022, 08:34
That's very interesting.when I first had the issue I removed the gearbox to check the cam and followers, all ok so I set the valve clearance turned the engine over a dozen times and all was fine when I fitted the gearbox turned the engine over to check again bingo I have the same problem again the inlet valve is solid. So perhaps I am getting a similar issue as you did. How did you overcome it ?
Basically I machined the outer cam bush flange (took about 0.010" off) if I remember correctly. I'm not familiar with the Ceefer outer timing cover, but assume similar to the later B44, so does your outer timing cover have a thrust flanged cam bush? Did you replace it? If so, is the bush fully pushed home? The bush on mine was fully home but the flange thickness was a little overspec.. HTH
If there is a question mark over camshaft free play, I would tighten down the inner timing cover (internals not required to be place) and see whether the engine turns over freely - removing the followers first would make this easier to test. You can also use the auto advance unit bolt screwed into the camshaft to feel for the necessary free play by pulling and pushing it.
If the camshaft free play is ok, it might be sensible to fit the followers and check the engine still continues to turn over freely and there isn't a problem with them binding together or against the camshaft pinion. I would have thought from the history of the engine rebuild that there shouldn't be a problem with the camshaft at this stage as I'm sure you haven't touched the camshaft bushes?
I have removed the gearbox and both valves and rockers work fine so fitting the gearbox does seem to lock something up. I will now try what has been suggested. Not sure if it's relevant as I did not look before but the is a score mark on the back of the cam shaft where the inlet cam follower is.
I assume you mean on the rear of the inlet camshaft lobe? Given that it's hardened steel, it would take quite a bit to score it. A light scratch is probably nothing to worry about but if it a deeper score would be a little more concerning although probably wouldn't affect the way the engine ran?
As well as checking camshaft end float, it would be a good idea at this stage to check the length of the pushrods (7 5/16") and to check you have curved foot (not flat foot) followers which are inserted the correct way round with the holes in the stems facing backwards. As said earlier, you should be able to see both followers rising and falling at the bottom of the push rod tunnel if everything is working correctly.
Hi
Quick update. I have now checked the various items and ways suggested, it still pointed to when I fitted the gearbox it seemed to lock up the inlet valve. Blued up the outside cam follower edge and it did show some blue on the inside face of the large cam driving gear, so, wrongly or not I have ground off 0.010 thou off the outside edge of the cam follower and all seems well now. Everything is fitted and bolted up and the valves now work fine. As the cam followers were new ones perhaps, they were pattern ones and slightly out?
Again, many thanks for everyone's help and advice. MW.