Morris Minor Owners Club

I have assembled a 1098 engine with a duplex gear -the end float is 3 mm ( it should be 0.003 -0.007"). This appears to be poor parts, but I don't have the luxury of a lathe to correct the problem. I will send it back but I would like to get one that works

I think there are a few different suppliers ones on the market -can anyone PM me of ones that are manufactured to the correct tolerances?


Thanks

Sure you have assembled it correctly?? 3mm is ridiculous... The Mini Simplex chain with proper tensioner is a MUCH better option if quiet running is your aim... Duplex is for high lift cams/rockers and stupidly strong springs! Not something you will ever have on a 1098......

I cannot see anything wrong -I have found the details in the mini forums about having to do this. I was hoping that one of the suppliers might supply parts to the correct tolerances.

I would prefer to run a duplex as I suspect they are less likely to stretch. The mini tensioner might be quiet but i am sure i have read somewhere that a stretched chain can be up to 10 degrees out. I would prefer more accurate timing.

How are you measuring end float?
The timing chain doesn't play any part in the amount of crankshaft end float, that's controlled by the thrust bearings.

As important as how you are measuring the play - where are you measuring?
The end float of the camshaft is controlled by the camshaft locating plate (Pt No: AHU2379) which sits between the front face of the front camshaft journal and the back face of the camshaft timing gear/duplex gear.

Plate must be missing surely? Make sure its bearing face goes towards the camshaft.

Perhaps the title in not correct here. The movement (2-3 mm) is on the timing gear. This is with the plate fitted the correct way around (with no visible wear) and the gear bolted down.

I would suggest that the dimensions of camshaft timing gear are correct.
If the cam location plate is worn that would give you the 2 - 3mm play that you are experiencing.
Whilst you say there is no visible wear to the cam locating plate a photos of both sides of the cam locating plate being used and of it as fitted to the engine without the cam shaft timing gear would be helpful.
Does the cam timing gear when fitted to the camshaft go fully home against the end of the camshaft?
Grasping at straws - have you put any shims between the end of the cam shaft and the timing gear to get the gears aligned.
Any misalignment is corrected by shimming behind the crankshaft timing gear.
Attached is a photo of the thrust side of a new unused camshaft locating plate for comparison.[frame][/frame]

The camshaft timing sprocket may be jammed on the key if it has partially lifted out of the keyway. I suggest you remove the sprocket and refit temporarily without the key to check what's going on... 10 degrees stretch ??? Where do people get these ideas.... ?

If you have the simplex with the rubber rings disintegrated and a stretched chain in all probability you could get up to 10 degrees of timing difference. I have seen timing chains where the slack side is near enough hitting the chain case cover and the drive side on over run had marked the inside of the timing cover; but that is in the extreme and was very noisy but still ran.

Given that Mini Spares sell a 9 deg offset woodruff key that shows the variability in camshaft manufacturing even before taking timing chain stretch into account.

http://www.minispares.com/product/Class ... .aspx|Back to shop

Whilst It may be OK (but not to me) I do not like the idea of off-set woodruff keys as there is an inbuilt fracture point where the offset begins and ends.
Better to buy a vernier adjustable cam gear and do the job properly.
Good quality cams are usually spot on with the woodruff key position in relation to the cam and gear. Re-profiled ones may be a different matter and there is a good chance that they will need to be adjusted; but I never buy re-profiled cams only new and then they must be ground from a billet.
As usual you pays your money and takes your chance.
Good quality camshafts are not cheap.

People buy these offset keys so they can 'fiddle' with the camshaft timing. I have NEVER found any significant variation on the timing of any BMC camshaft. Buying in the open market - you take your chance. But unless you have a dyno - how do you KNOW what the best timing is for any particular engine - and it's intended use... As for 10 degree 'slack' on a chain - well it would indeed need to be 'desperate' as described by Phil... If an engine was in that state -I doubt 'timing' would be a significant factor Duplex is ok - but not immune to stretch or rattle. MG /Rover were well aware of the duplex - fitted to Cooper S and various others including the MGB - yet they decided to develop the simplex with tensioner for the A + range of engines.... Must have been a good reason !

A standard/original BMC/BL camshaft WILL NOT need timing but a reground or special camshaft may/will need the timing degrees/relationship between the crankshaft and cam-shaft to be confirmed/corrected to bring it into line with the camshaft manufactures specification. That is where the vernier camshaft adjustment comes into its own.
To ensure manufactures timing specification is correct will require two dial gauges and a timing degree disc fitted to the front of the crankshaft and infinite patience.
Whilst a dynamometer is required for overall engine performance the cam manufacture (if reputable) will have done the donkey work for you and issue a basic timing setting relative to the cam being used. You can then advance or retard the camshaft to suit your engine requirements.

We have drifted off the 'end float' problem......any progress with that mowogg ?

I never fail to be in awe of the technical knowledge and expertise of these people!God knows how we would manage without them.Keep it up!

You do know Phil that you can check the cam timing using feeler gauges and a chop stick....

tysonn wrote:....God knows how we would manage without them....

Easily. One would learn by experience, which is always more satisfying

Well at 64 yaers of age and having classic cars for a lot of those years nothings happened yet LOL!

Saves time and money (and scarred knuckles) if you can benefit from others' past experience !