- Is there a possibility of dropping the chain off the jackshaft or crankshaft sprocket and either having trouble getting it back on or getting things out-of-sync? That's my biggest concern. Suggestions for how to handle this are appreciated.
-How about re-installation? Might I expect any difficulty associated with depressing the valves/springs when reinstalling the camshaft?
Hi Vince,
It's a long time since I did mine but I think it went something like;
You've already got the clearances, but write it up on a clipboard, rotate engine a couple of times, have a coffee and double check the numbers.
Remove cam cover & spark plugs and rotate engine until timing marks are aligned. I'm incredibly cautions so I also check it's really are on TDC firing stroke from the distributor position. I use a mirror at the front of the engine to see the cam marks easier.
cable tie the cam sprockets to the chain in a couple of places. Not necessary but makes life that bit easier.
slacken the chain tensioner
Remove camshafts. I do one at a time and I can't recall for certain if I did this with the sprockets still in place but I think I would probably have taken them off because it makes removing the cams easier and it's only one bolt. Because it's cable tied to the chain, putting it back is straightforward.
If you leave the cam sprockets in place then you'll probably need to split the chain to get the cams out. The chains on my cars have a split link so that's easy to do, but generally I prefer to leave the chain intact and around the crank sprocket.
Remove shims, measure, get new ones or swap around the old ones between valves if you're extremely lucky. As you seem to be on bottom clearance throughout, that's probably not an option for you although you should be able to reduce the number of new ones required.
Because this isn't a regular job I'd consider replacing the oil seal at the end of the camshaft. It's probably fine now but you've disturbed it and might just damage it. They are cheap enough and if you put it back together and it leaks, you've got a lot of hassle to replace it.
And as all good workshop manuals say, replacement is the reverse of the disassembly procedure.
Once done, lube up cam bearings slot the cams into place. Replace cam caps, tighten up very slowly & evenly. There will be some spring pressure of course but any significant resistance before the cam caps are fully seated might mean somethings not aligned properly. Don't force it, that's how I broke an inlet cam in my young and arrogant youth....
Once all back together rotate engine, measure clearances, find you've got one out, scream, kick the cat, drink several beers, sit in the corner of the garage mumbling to yourself.......
OTOH, in the real world, it's all gone perfectly.
Make a note of the valve number, final clearance and shim that you've put in. If you ever have to do the job again then you'll be able to measure up and order new shims so they are ready for when you pull it apart. Unless you're a high miler it's not likely you'll need to touch them again.
To be honest if everything is in clearance, even at the end of the range, I'd leave it until the job needs doing or the head is apart for some other reason. It's not difficult but it is a fiddly job and takes much longer than you might think.
Brian
