12 replies to this topic

[Brigbeale]

As title suggests, my son's 1990 998cc Racing Green has an irritating noise.

Brief history:
I had to change the short engine due to old unit oiling up no 3 spark plug (turned out to be broken top piston ring). Found it was cheaper and easier to replace short engine rather than replacing damaged piston and the usual work entailed.

Short engine sourced from Mini parts dealer and replaced. I carried out the work myself. Replacement was pretty straight forward, had to replace crank pulley as Metro/Late Mini pulley was fitted and obstructed the radiator mount.

Torqued every nut and bolt up as I went according to Haynes Manual. Definately remember torquing up crank pulley bolt as the engine tipped and nearly fell off B&D workmate! Strapped engine down and torqued it up.

Engine sounded fine at first then developed a metallic knocking noise on tickover from the radiator end of the engine and only disappeared when a number of RPM were applied. At first, I thought it was the water pump bearings. Took it off and wasn't happy with the feel of the bearings when I turned it and replaced it. Noise still present. Checked Alternator for play/rumbly bearings - no play and bearings felt smooth. Noise still present. Put it down to slight wear in timing chain and lived with it for over a year now.

3 weeks ago, my son came in with his girl-freind one evening and asked what it meant when steam came out from under the bonnet!!!
I had a look and there was no water visible in the radiator. Topped it up with hot water and told my son to keep an eye on it.
Checked it next morning and noticed the front subframe under the radiator was damp where-as the front of it was dry. Looked at the bottom of the radiator and noticed it had signs of water over it so concluded it had given up the ghost and ordered a new replacement in the form of an aluminium radiator off ebay for about £50. It arrived well packaged and it fitted fine.
While the radiator was off I checked the water pump for play again and found movement. Not play in the shaft, but rotational movement.
Found the belt was moving with it and noticed the crank pulley moving on the shaft. (The pulley was moving back and forth and the bolt and locking tab remained still).

I am pretty sure I put the woodruff key in when I changed the pulleys over.

It appears the locking tab where it locates in one of the two grooves on the pulley is the only thing that is stopping it from turning completely. I also quickly checked the pulley bolt to see if it was loose with a big pair of adjustables but found it seemed tight.

Obviously it's got to be dismantled again, but would like any suggestions on securing the pulley securely.

[ANON]

the only way it can spin is if the key is missing.

[Brigbeale]

the only way it can spin is if the key is missing.

I'm hoping that's the case!
I don't want the crank to be damaged if the key is present an has beeb wobbling around. (seen this on a Toyota diesel engine although a 'mechanic' did bodge it with bearing fix )

[matty...]

Ive had a pulley crack on the keyway then the key accesively wear, fortunately no crank damage though.

Minispares sell a longer bolt (cap head instead of hex). With the longer engagement its got more threads to hold on, and if the existing bolt has come loose it could be likely that the thread on the end of the crank isn't in the greatest condition.

Since fitting the minispare bolt I ditched the locktab and used a good quality locktite and it has been fine, and my engine sees some abuse/vibrations. lol

Make sure you clean the threads in the crank with some kind of degreaser to get rid of any oil and do the same on the bolt, then you can be sure the locktite will take properly.

[bmcecosse]

The keyway in the damper can and does sometimes widen - allowing some slop. But not quarter turn. Hard to imagine how the key could come out.......

[ANON]

if the pulley will turn on the crank either the bolt has come loose or there is some wear or possibly both.
don't be surprised if the crank is scrap.

[tiger99]

The keyway is for location only and does not transmit dynamic torque if the bolt is correctly torqued up and gripping the pulley.

As it happens, I have seen this exact problem, also on a 998. The bolt was correctly torqued up, but was not gripping the pulley.Something was machined incorrectly, either the shoulder on the crankshaft was too long or the pulley centre, or maybe the timing gear, was too short, so the bolt was clamping against the end of the crankshaft, and the pulley was slightly loose. A very thick washer with a bore big enough to clear the crankshaft end was the fix.

I strongly suspect that you have the same problem. I too assembled everything by the book, but it was just plain wrong.

Oh, and the keyway was a bit worn, but when torqued up properly with the bolt actually gripping the pulley there were no more problems for many tens of thousands of miles.

[Brigbeale]

The keyway is for location only and does not transmit dynamic torque if the bolt is correctly torqued up and gripping the pulley.

As it happens, I have seen this exact problem, also on a 998. The bolt was correctly torqued up, but was not gripping the pulley.Something was machined incorrectly, either the shoulder on the crankshaft was too long or the pulley centre, or maybe the timing gear, was too short, so the bolt was clamping against the end of the crankshaft, and the pulley was slightly loose. A very thick washer with a bore big enough to clear the crankshaft end was the fix.

I strongly suspect that you have the same problem. I too assembled everything by the book, but it was just plain wrong.

Oh, and the keyway was a bit worn, but when torqued up properly with the bolt actually gripping the pulley there were no more problems for many tens of thousands of miles.

I like the sound of this answer!!!!
Usually i'm a stickler for jobs being done correctly and I remember putting the pulley on and pulling it back to see if the key was located correctly and it was.
Will try the thicker washer trick.
Thread lock was applied to the bolt when I fitted it and torqued it up.

[samsfern]

If the key was missing would this not affect the crankshaft timing sprocket? I can't remember if that's driven off the same key though.

[Brigbeale]

The timing sprocket is inside the timing casing.
I didn't disturb the timing gear other than changing the cover as the one on the replacement engine was different to my mini's one.

Edited by Brigbeale, 09 January 2012 - 05:15 PM.

[Brigbeale]

Also just looked at Somerford Mini's site.
http://www.somerford...age=page&id=112

It appears that the pulley bolt washer (item 41) has a keyway cut into it.
Is this the case?
If so, it may be that the washer could be in the wrong position and fouling the key on the shaft preventing the bolt from holding the pulley tight on the shaft.

Any thoughts???

[tiger99]

Yes, if the key protrudes,the washer could be fouling it, unless it too is keyed. I seem to remember just using a plain washer. But if you push the pulley into position without the bolt, you should be able to see whether the bolt is going to bottom on the crankshaft end face before it grips the washer. Unfortunately there is not much room in there to see what you are doing unless you already have the radiator out.

It is also possible that the bolt itself is slightly too long and is bottoming in the crankshaft. You should be able to screw it in till it contacts the end of the crankshaft, with the pulley off. If not, shorten it slightly.

The trouble Ihad was on a genuine, factory assembled Gold Seal engine! Not much excuse. The first one blew a core plug and siezed. They replaced it under warranty even though I fitted it myself. I then fitted a temperature gauge. The second Gold Seal engine was the one with the loose pulley,and a few weeks after fixing that, it too blew a core plug. No damage, easily fixed and in that case the engine stopped abruptly as it drowned the distributor.

But two incorrectly fitted core plugs and one loose pulley did make me wonder about QA in BL's factory!

[Brigbeale]

Finally found some time to sort this problem out.

Can somebody tell me the diameter of the crank-shaft where the pulley slides on to?

I need to get a washer from the local screws/fixings supplier.