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MG Midget and Sprite Technical - stuck camshaft

Just before I get a bigger hammer, has anybody got any ideas, my cam is stuck in the bare block.


when I started to dismantle I noticed the cam sprocket was a tough to turn, but it did turn.

everything is off, plates, oil pump etc, dizzy, its drive and crank.

its lost a lot of piston & rings are debris, strange that before I stripped it I did a quick compression test and it did not show anything much wrong.

so I am thinking the shells have gone and are giving too much interference to tap out the cam, a hammer and copper drift are moving it 5 or 6 mm

any tips?

thanks.
mog

Ive not heard of that before... any chance a lifter is jambing the works

Id probably (guessing) use a 3 jaw pulley remover on the front and pull it out by way of the camshaft nut, id also use some plywood over the front of the engine to help disperse the load and forces and keepbthe front of the engine block from flexing

Intresting

Prop
Prop and the Blackhole Midget

.
Prop and the Blackhole Midget

Just a thought....

Have you removed the oil pump yet... im not sure that would make a differsnce... but being that im throwing spaghetti agianst the wall....

Prop
Prop and the Blackhole Midget

What engine is it? Late ones have 3 cam bearings but I think some early ones had fewer. If it's 3 bearings they may all come out with the camshaft.

It could be there is some debris locking the cam. It just needs a bit of metal between a lobe and the engine insides.

I assume you have got all the followers out? I know, I know. A silly question, but in the heat of the moment stranger things have been forgotten.

Rob

Rob aka MG Moneypit

Are the pistons out? I think they are, but when the timing's gone, the big ends hit the cam lobes.
Nick and Cherry Scoop

Thanks

yes everything is out, apart from the cam and its three bearings.

mog

Have you removed the cam followers (small-bore) or turned the engine upside down (1275)?
Dave O'Neill 2

Distributor drive. Have you removed it?
Lawrence Slater

Sorry, I should have mentioned, its a Sprite Mk1 948 - yes everything is out,

Followers out and I noticed the exhaust ones had suffered more than inlets, which is strange?

I put the block on its nose supported by blocks and it still did not budge much with a drift in the tail end of the cam. I might put the crank back in If I hit it some more, the extra support from the crank and caps etc might lessen any possible distortion from hammering.

mog

sounds like you might have some debris from the piston/rings in the oil way trapped in the oil ring of the front Cam journal (unlucky).

If that's the case you have limited options! Try a flush with petrol/paraffin/degreaser in the hope that you get lucky or hit it with a bigger hammer and accept the high risk of damage to the CAM, bearing and/or block.

best of luck with this one...
MGmike

M McAndrew

Try screwing the nut back on the front of the camshaft and then gently tap the cam back in as far as it will go, then lube what you can get at of the journals with oil or a penetrant lube and then get a socket or spanner on the nut and turn the camshaft till it spins free in place, and then maybee it will come out' If it doesen't you could put a little pressure on the back end of it with something and turn the cam back and forth with the spanner while holding pressure on the back
If it has gotten itself a piece of something in the oil hole as MGMike suggests, which would be real bad luck-you won't be able to get it to spin free----If you lay the block on it's side with the camshaft side upwards and wriggle the cam about, whatever is in there "might" just drop back into the oil gallery and give you a free camshaft If that doesn't work try the same thing with the motor in the upside-down position as the debris could be down the rocker feed hole
good luck
willy
William Revit

There was an article in a recent edition of MASC about how to remove bits from engines that didn’t want to play ball, starting with soaking the parts with good penetrating oil and leaving for a couple of days to heating. It also included some “Non Standard” options if none of the above worked, although they seamed a bit extreme.
R Barker

At the moment I am contemplating throwing the block out of a 3rd storey window, with a rope attached to the cam sprocket that is 2.89 storeys in length, is that drastic enough or should I go with 2.95 length.....






mog

Well, it was the middle shell that caused the problem.

thanks for the advice all.


mog

The original 948 engines only had one shell at the timing chain end. The camshaft just ran in the block. 3 camshaft bearings were introduced in the MK2 Sprite/ MK1 midget 9CG engine range.
Bob Beaumont

Cheers Bob

I must admit I just walked away from it after getting a quick pic to show you all, its toast the cam so yet another thing on the shopping list.


yes it has only the one shell at the front. I had noticed on the AH spares site that it has a set of 3 cam shells listed, but didnt see it was for the later 948 car. Learning curve.


Is there a resource for these engines, Is it possible to fit a newer cam in an older engine and is the block bored for the shells for example?

any pointers appreciated.
mog

Yep, cams from a later engine will fit providing the cam uses a pin drive for the oil pump. The block will need to be line bored if you wish to put in the three shells. If the casting is OK then you may get away with just replacing the front shell. The standard cam is very gentle being the same as the morris minor and early mini. The later 948 9CG engine had a slightly livelier cam but still very mild. Its the same as fitted to the later mini's and 1100's so should be easy to source. If you want a new one then I would talk to Kent Cams who are very helpful.
Bob Beaumont

How can the middle shell have been the problem if it hasn't got one? Any damage to the middle bore in the block?
David Billington

With the A35 race engines, I used to get them line-bored and 3x shells fitted by Coventry Boring...

http://www.coventryboring.co.uk/#/at-the-heart/4537729699
Dave O'Neill 2

Hi David, yes damage to the block, I saw the debris on the cam, thought well thats a toasted bearing and then Bob pointed out it does not have a bearing.

I must admit its a shock this engine, I know Coventry thanks Dave, as I plan on getting another block bored & white metaling by them - I did not expect to line bore a cam housing on a sprite: after all its a more modern engine - wrong. Well I know they do good work and the cylinders etc need work.

So I need to figure out what is what, dont want to go overboard on performance, thanks for the suggestion on the cam. Any other suggestions once again most welcome.

mog

I bought a new cam (266) last year, and found that they were all spade drive. As a result the pin drive oil pump was no good, and nearly all the pumps from the specialists would not fit the new cam because they had a projecting tapered boss that used to fit into the big scoop at the end of the cam.

Peter Burgess managed to get hold of a flat-face pump - A+ I think - and it fitted. Hooray.

Then the pump wouldn't fit through the hole in the backplate, so I had to grind the backplate in a couple of places, and reposition the tin cup.

Good luck, mog.
Nick and Cherry Scoop

Just came across this, wot I must have posted some time ago. . . . . . . .


Nick and Cherry Scoop

The 'long-nose' pump is 1275. The short one is 998 A+
Dave O'Neill 2

http://www.leacyclassics.com/catalogsearch/result/index/?p=3&q=oil+pump

shows me what to watch out for, thanks
mog

This thread was discussed between 25/02/2015 and 27/02/2015

MG Midget and Sprite Technical index

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