Duplex chain end float

[philthehill]

Mowog
Whilst there is a small difference in the measurement i.e. 0.85mm in the depth of the main boss of the camshaft sprocket/gear I would consider that difference to be not unacceptable as the depth of the boss does NOT have any bearing/relationship on the lateral movement of the camshaft as the boss DOES NOT & SHOULD NOT contact the camshaft locating plate. If it does it will wear the plate as the plate is not designed to take thrust on both sides. Also see sectional drawing above.
Note:- There is a gap between the camshaft locating plate and the camshaft sprocket/gear.
Any difference in the alignment between the crank sprocket/gear and the cam sprocket/gear can be rectified by removing or adding shims on the crankshaft which are located behind the crank sprocket/gear.
The difference in the ring diameter again is not significant.
To reiterate the camshaft sprocket/gear does not have any bearing/relationship on the amount of camshaft lateral movement.
Do you have the distributor drive shaft fitted when you are checking the end float?
Going right back to basics - there is NO reference/specification or measurement for camshaft end/lateral float in the official BMC wksp manual AKD530E or subsequent editions. Where are you getting your reference to camshaft end/lateral float/clearances from?
Tolerances/clearances are taken into account in production.
So with that in mind the camshaft is fitted in the block, the front engine plate/gasket in place and the camshaft locating plate
fitted, the camshaft sprocket/gear installed and fully home. The oil pump fitted (with gasket) at the rear, the distributer drive fitted - you are home and dry.
The camshaft just sits in the block and the thrust is taken by the camshaft locating plate.
Clearances/end float/lateral movement of the camshaft on a production engine (even with a duplex set up) are not required to be taken into consideration UNLESS when assembled you find that something is fouling and/or restricting the movement of the camshaft/timing sprocket/gears.
Mowog - as you having now measured the camshaft sprocket/gear and given the measurements above & which differences I consider are not excessive and importantly will have no bearing on the camshaft end float I believe that you are looking for something that is not required to be looked for.
My final advice is to assemble the engine and if it turns over freely you have cracked it.

[bmcecosse]

To try to explain how it all works I took some pics today - in the lovely sunshine!
Ignore the camshaft - it's just an old standard shaft - badly worn/corroded and never going back in an engine !
[frame][/frame]
Here you see the parts involved.[frame][/frame]
The sprocket (duplex or simplex) fits on the cam - right up against the journal boss - leaving a small gap[frame][/frame]
The triangular plate fits over the boss of the sprocket - leaving a very small amount of the boss sticking through - this is what controls the 'endfloat' - so - if the float is too much , and the triangular plate is not excessively worn - then the protruding boss must be filed down until the endfloat is correct, Equally - if the endfloat is not enough (or you file off too much..) then a thin shim can be fitted between sprocket and camshaft.[frame][/frame]
And finally everything together - the triangular plate is 'loose' in the gap by the amount of the endfloat. QED

[LUR759H]

Oh God I hope i never have this problem it is a complicated problem - but now i undestand that this car is not so simple....

Alan

[philthehill]

bmc
I am sorry to say that you appear to misunderstand the purpose of the camshaft locating plate.
Firstly - What is the specified end float and where did you find that end float specification?
It is not quoted in the official BMC wksp manual of which I have several editions.
Secondly - The location plate only controls camshaft thrust in one direction and that is FORWARD. What the locating plate does NOT want or need is the camshaft sprocket/gear bearing against its front face. The locating plate and the camshaft sprocket/gear were designed never to come into contact; the working clearances being built in during production.

Regarding the depth/height of the ring which I gave above as 2,8mm (min) & 3.0mm (max) Mowog did not advise in his post above that the depth/height on his sprocket/gear were outside those tolerances. Of all the measurements that is the most important one as it controls the working clearance between the camshaft locating plate and the camshaft sprocket/gear.
The overall depth of the camshaft sprocket/gear boss is not that important; what is important is to get the sprockets/gears aligned and that is done by shimming the sprocket/gear on the crankshaft.
As to shimming the camshaft sprocket/gear to get the right clearance - in all my years of repairing and modifying the 'A' series engine and over those years have done quite a few I have never had to shim between the camshaft and camshaft sprocket/gear.
Mowog it is up to you as to whether you file the boss or not but personally I would not put a file anywhere near the camshaft sprocket/gear.

LUR759H
There are no problems/complications with fitting the simplex or duplex sprockets/gears it is people who make it complicated. The task is simple - you do not have to be a highly qualified motor engineer to fit the sprockets/gears.

[bmcecosse]

No - I don't misunderstand at all! I've been assembling A series engines for 50 years now! The endfloat is just a few thou - same as crank end float - no idea if it's quoted anywhere, but I have certainly never seen the '3mm' quoted at the start of this thread. This subject is often discussed on Mini forums - and the solution is to file (or 'machine' if you have a lathe..) the protruding boss if the endfloat is considered to be 'too much'. Yes - the thrust is one way - to the white-metalled surface of the triangular plate. And yes - the chain alignment must be checked/set after cam installation. My pictures are only intended to simplify the subject for viewers. You always seem determined to have the final word!

[philthehill]

bmc
No I don't always like to have the last word I just like things to be done properly.
As regards length of time repairing and overhauling 'A' series I started before I was 16 years old and I am fast approaching 67 and I served my time in a BMC garage stripping and overhauling 'A' series engines so have a little bit of experience as regards the 'A' series.
And a tail-script as you are a railway man:-
And so as you can see I have not always restricted myself to 'A' series.
Attached is a photo of me (in orange coat) having carried out a post major overhaul engineering acceptance inspection on a Andrew Barcley locomotive at the FAUR Locomotive Works in Romania.
And a good Scottish locomotive to whit.[frame][/frame]

[alexmcguffie]

LUR759H,
You won't get a much easier engine to work on. Don't let forums confuse or complicate things.

As for the 3mm end float, maybe the cam sprocket is passing through the trianguar plate and may not have the correct 'step' as expected on a standard sprocket. We don't know...

As for using a file on a rotating part it is just bad practice in my book. Each to their own though.

[les]

We all get things wrong sometimes, I got the parcel shelf fixing screw thread wrong the other day! Agree about filing Alex, not very precise in circumstances

[katy]

Firstly - What is the specified end float and where did you find that end float specification?
It is not quoted in the official BMC wksp manual of which I have several editions.

Workshop manual AKD530, page GD 12: Camshaft end-float...... .003 to .007 in. (.076 to .178mm)

Correct me ifn I'm wrong.

[MarkyB]

I've got AKD530 K and section G is about the propshaft!

[les]

I don't know how the end float is determined by those who have not seen the specification! However for those that would now like to see it in print, follow the post from Katy--in general date 12

[bmcecosse]

Well done Phil on that Loco...although I fear it is a dodgy diesel and not a proper 'steam' engine ! But I do also drive diesels....certainly a less physical task!
On the cam endfloat - I've never had to 'adjust' it - but these days some parts don't seem to be quite so accurately made. The boss just buts up to the camshaft - no relative rotation - so 'filing' if done correctly of course is perfectly reasonable! Few of us have access to a lathe - I used to be able to use the Toolroom at work - but not these days...

[philthehill]

Les/Katy
Many thanks for pointing out where to find the camshaft end float.
I had scoured the different editions of the BMC Minor wksp manuals I have to find and quote the definitive specification but to no avail.
So a trip to spec savers is in the offing
Strangely enough though - the BMC wksp manuals AKD530 do not specify an end float specification for the camshaft until the 10MA engines are fitted. There is no different between a APHM/APJM/9M and a 10MA as regards controlling end float but of course the 10MA has 3 camshaft white metal bearings. So why? As they all use the same camshaft locating plate.
I still maintain though that the Mowogs camshaft sprocket gear is still within tolerance and will not affect camshaft end float and that he should be looking elsewhere for wear.
And bmc this will be my last utterance regarding this matter
Phil

[bmcecosse]

[mowogg]

Thanks for all the input on this topic. i thought it would be good to feedback on how i solved this issue.

I bought a new duplex kit which was vastly superior in terms of fit, and end float. I did make have to make some adjustments to create the correct end float, but once aligned and reassembeled it works perfectly.

the engine has never been so quiet in the car.

If anyone wants details of the parts that worked for me please PM me. the difference between the 2 kits was vast in my experience, and neither was a premium product.