Cam timing wildly out

johnk

johnk

Member
I bought a 2000tc last summer, a previous owner had for reasons unknown put a sc head, carb and exhaust on it. It has never ran right, always lacking in power and running rough to the extent it burnt a valve in September. A friend and I replaced the valve but couldn't find the locking pin on the crank so we just put it back as we found it rather than mess about with the timing adjustment. Feeling brave I started on it yesterday and with the markings on the crank at tdc, the piston on the top of its stroke and the no 1 exhaust port open it was about 30-40 degrees advance. I disconnected the chain but couldn't rotate the cam enough before it locked up. I assume another valve was hitting a piston so I put it back together, backed off the crank until the cam was tdc and locked in position with the key, disconnected the chain and rotated the crank but again it is hitting something solid before it reached tdc, I would say about 10-15 degrees before.

Interestingly I think it is the valve that was replaced that is hitting the piston. Is it an interference engine? Are the heads interchangeable? Have I fitted a valve that is too long? It seemed the same as the old one from memory.

Help!!
 
AARGH !! The cam is not to be timed at TDC but at the other mark on the flywheel which is called EP ( which as far as I know stands for "Exhaust Peak " ) . With the No 1 exhaust valve fully open it should then be possible to insert the locking key with its leg vertical into the slot in the back of the chainwheel. I am not quite sure where you are now , but if you can, restore the setting you had, put the chainwheel and chain back on, and turn the crank very gently and slowly until you can see the EP mark in the window low down on the right side of the bellhousing are, and then reset the cam timing from there. If you meet ANY resistance at all, STOP
 
You can interchange the SC and TC heads without problems. You can't fit a 2.2 head to a 2000 block though.

You need to peg the crank in position using the pin into the flywheel. You can see where this should be by looking in the access plate on the top of the bellhousing on the drivers side and turning the engine over until the pointer lines up with the EP mark. Once that peg is in place take the cam cover off and see how far out the camshaft is. The camshaft locking peg should fit when the rearmost cam lobe is pointing directly upwards. If it doesn't then you need to adjust the camchain until it does, either by moving the chain round on the teeth of the sprocket, or by using the vernier in the chainwheel.
 
Ok, I see where you are coming from, my mistake. However, before I took the head off in September a friend and I spent an hour moving the crank round with a pry bar looking for the hole in the flywheel and the EP mark, neither of which we could find. I did the same yesterday before starting again, I made the mistake of thinking it was timed from tdc. Oops! So, with no mark or hole, how do I check how far out it is? It seems to be the only thing to stop it running properly as the ignition timing has been set and the carb re built but still a lack of power as if it is being strangled.
 
There will be a hole, you just need to find it. Start by finding the EP mark through the inspection plate in the bellhousing. Once you've found that and got it in line with the pointer, then the pin will go through and lock into the hole in the flywheel.
 
This is what you're looking for



Mine doesn't quite line up with the pin fitted but it's close enough.

Dave
 
Thanks for all the advice. I reset everything as was and started again. I ended up rotating the flywheel one tooth at a time and rubbing the flat section with some emery paper over the end of a flat blade screwdriver. And low and behold I eventually found the marks under a load of crud, almost invisible to the naked eye but not to the camera phone... Great invention!! I don't have a pointer like in the pic, more a nub that comes off the backplate I think. Anyway, both got a lick of tipex to make them easier to find again. Still no hole in the flywheel though unfortunately, I even tried a smaller diameter Phillips screwdriver in case the hole was gummed up but nothing... Just waiting for the battery to charge to see if there is any difference. Fingers crossed.
 
johnk said:
I don't have a pointer like in the pic, more a nub that comes off the backplate I think.
Click to expand...

Most of them are smaller than the one in the pic.

johnk said:
Still no hole in the flywheel though unfortunately, I even tried a smaller diameter Phillips screwdriver in case the hole was gummed up but nothing.
Click to expand...

Are you using the proper pin to try to lock it? You may have to move the crank backwards and forwards a bit to locate it.
 
As Harvey says you might have to rock the crankshaft around the EP mark whilst pushing on the pin to find the hole. That pic of mine is with the pin fitted in the hole.

Dave
 
As Harvey says you might have to rock the crankshaft around the EP mark whilst pushing on the pin to find the hole. That pic of mine is with the pin fitted in the hole.
Click to expand...

yes, using the proper pin but still no luck. I tried a smaller diameter as I thought that might make it easier to find the hole. i'll have another prod around on Wednesday evening and see if I can find it.

Thanks for the advice.
 
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