valve timing

[ronnie]

i stripped the timing cover off tonite to change my front oil seal and gasket because of a leak . Ive never been happy with the performance of the moggy as you all might have read in the past and tonight i think ive (again ) found the cause . The valve timing is at least 2 teeth out , i assume this has got to cause lack of power ?? . My question is , how do i remove the camshaft sprocket and crankshaft sprocket to re-align them without causing any damage , again , would the car start and run ok with 2 teeth out ??? all help gratefully received

[bmcecosse]

I would be very surprised - but it's possible. BUT - are you SURE?? Can you set #1 piston exactly to TDC and then show us a picture face-on of the timing gears??

[ronnie]

hi bmc , so correct me if im right , take no. 1 to tdc and the timing gear pulley and the cranshaft pulley dots should be lining up right through the centre .I will try and get a pic and post it . Im hoping its out and might solve my lack of power problem

[bmcecosse]

Yes - that's it, although you may have to turn the engine 1 rev to get the dots lined up. Obviously you need to get the piston EXACTLY at TDC..... There is method to check the valve timing -slightly complicated, but not by any means difficult. I can go over it if you wish........

[ronnie]

bmc , just been out to the garage to check what you asked . With no. 1 at tdc ( even if i was slightly out ) with the dot on the crankshaft facing the camshaft , the camshaft dot is about 2 teeth out , the dot on the camshaft is before the meeting point of the two ??? help

[bmcecosse]

Hmmmmm. Well - here's the check method. Rocker cover off, turn the engine clockwise only (DO NOT turn it back..) so #1 piston is at TDC (put a drinking straw down the spark plug hole and watch it bob up/down as you turn the engine)and both rockers are tight -ie the valves are both lifted (in other words - #1 is NOT firing, but # 4 IS). Now without turning the engine - slacken back the adjustments on these rockers (just the 2 for #1 cylinder) and set both the gaps to say 10 thou. Now turn the engine 1 revolution so # 1 IS now expecting to fire - and measure the gaps at that point. They will be large (maybe 40 thou..) - but the point is - they should both be identical (within a couple of thou) if the cam shaft is timed in correctly. Let us know how you get on!

[ronnie]

bmc , tried to send a pic but wont go . I will try tomorrow night the routine you said and get back to you . Do you not recommend i try adjusting any timing meanwhile ?? . Im not ASOLUTELY positive but pretty sure the two dots on the pulleys will not line up . As ive said in the past lack of power since i bought it . Had it in a local garage last week , old guy like myself ( 21 ) showing 130 to 140 psi across the 4 cylinders , new carb , new dizzy , crap power , thought i thiught i had cracked it when i found this

[bmcecosse]

130 to 140 is pretty low - but of course it could be caused by incorrect valve timing. It only takes a few minutes to do the check, so i suggest you leave well alone meantime......

[ronnie]

thanks will do , i nicked out again just to have another look but theres no way i can get the dots to line up and just as you say with no.1 valve on the rock and no. 4 firing the marks are a couple of teeth out , Is it not possible in your opinion for an engine to run timed like this ( bearing in mind i could still be wrong ) will try and upload a picture tomorrow

[bmcecosse]

It's entirely possible - has the engine been in bits in living memory? I have in the past run an engine with the cam intentionally timed one degree advanced. It ran well at the top end, but was a bit flat low down......

[ronnie]

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bmc this is the pic of the timing and as you can see the marks are approx 2 teeth apart

[ronnie]

2nd pic

[ronnie]

bmc , tried what you said but to get the 2 valves on the rock at the same time but i had to take the crank past TDC by about the same as you can see the timing marks are out to get the 2rocking at the same time , so does that mean the timing is out ?? and if so whats the best way to go about getting the crank and timing gear wheels off without causing damage do i need a puller or just prise of

[M25VAN]

Wouldn't slipping the chain off, lining up the gears and putting the chain back on cure this?

[ronnie]

hi , sounds great but how can you slip the chain of , theres no link and the chains relitively tight ????

[brucek]

Unfortunately, you cannot remove the chain without first removing both the cam and crankshaft sprockets and, from the look of their positions in your photo, this is what you will need to do.

Remove the camshaft end nut and lock tab so that the larger sprocket can be removed from the camshaft. Also remove the oil thrower from the crankshaft so the smaller sprocket can also be removed. Removing both sprockets is sometimes difficult and you will need some patience. Insert 2 large screwdrivers behind the larger sprocket making sure these are 180 degrees opposed. Carefully lever the sprocket off the camshaft. Be careful how much force you use here and try to resist whacking the screwdrivers enndlessly with a hammer! Whilst you may need to give the some encouragement - go easy on the force. Plenty of WD40 will help here. You may, at the same time, need to use the same technique on the smaller pulley too.

Once you have both sprockets off their respective shafts, make sure you don't lose the two woodruff keys (semi circular tabs) as these are needed to locate the sprockets back on their shafts in the right position. Take the opportunity to clean everything including the channels of each sprocket, their keyways and the ends of the cam and crankshaft.

Now turn the engine until you have No1 piston at TDC and the 1/4 mark on the flywheel is pointing upwards. It is essential that the piston remains at TDC throughout this process so keep checking it hasn't moved. On the bench, re-assemble the timing chain on its sprockets ensuring that you have the correct alignment (see diagram)

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Now replace the assembly back on the cam and crankshaft retaining the relationship between the marks on each sprocket. You can see from the diagram where the crankshaft keyway will be when No1 is at TDC and also where the camshaft keyway should be to ensure the two timing marks align properly. You may need to tweak the position of the camshaft keyway slightly to ensure it fits correctly.

Drift the sprockets fully back into their positions and check that TDC has not moved and that, once on postion, the timing marks still align correctly. If so, replace the cam locktab and nut and re-assemble the rest of the timing cover, not forgetting to put your oil thrower back on the right way round!! Good luck

[ronnie]

many thanks will be doing it tonight , will post results

[Declan_Burns]

Ronnie,
Loosen the camshaft nut and use tyre levers to ease the sprockets off.
Regards
Declan

[bmcecosse]

Well - it does sound like the cam is running retarded - it would have been useful though to measure the valve gaps etc as I advised.. You don't need to take the crank sprocket right off - just ease it forwards. The cam sprocket should just wiggle forwards with fingers - be aware - the edges of the cam sprocket are VERY fragile - do not ever lever against them.. Then turn the cam and shuffle the chain round the two teeth - and then refit the cam sprocket so the dots align. Turn the engine over two turns - and check the alignment again before you close everything up. Obviously - you then need to retime the dizzy......

[M25VAN]

hi , sounds great but how can you slip the chain of , theres no link and the chains relitively tight ????

Sorry Ronnie, all the ones I've replaced have had a split link and I couldn't see all of your chain in the picture.