Crankshaft pulley fell off today

[Griff]

Just slowing down for a 30 limit today and the oil pressure light came on - fortunately managed to stop in record time so am hopeful but not certain there's no inteneral damage. On checking I found both the alternator and dry sump pump belts had come off. Seemed strange until I saw the crank pulley at an odd angle and the bolt not even finger tight.

 

Not had time to strip things down yet, but I assume the crank pulley is keyed onto the crank? If it is, then I can't feel any resistance as I turn the (loose) pulley on the crank.

 

Also what torque should the pulley bolt be tightened to? Seems there wasn't locktite on the joint before, but is this advisable?

 

Next concern is starting the engine again - any suggested precautions? I'm thinking to remove plugs and turn the engine over by hand first, if OK then use the starter to get oil pressure. Only if all seems well then fire it up.

 

Thanks & fingers crossed.

 

Mike

 

 

[rj]

From the top of my head:

 

163Nm/120lbf (checked with Haynes)

 

It is keyed

 

And I'd crank it with the spard plugs removed, the LT wire(s) removed from the coil(s) and the injectors disconnected (or inertia switch) not to overfuel...

[Tom White]

Assuming this is a K, I would take off the cam belt cover and take a quick look to see if the cam timing is still ok before you attempt a hand crank

 

Good luck

 

Tom

[Griff]

I was thinking about the valve timing too. Last April (700 miles ago and before I bought the car) it had new verniers, cam belt etc fitted. I wonder if this would mean removing the crank pulley and it wasn't refitted properly?

 

Is there a key on both the timing pulley and the crank pulley? They're separate parts I believe?

 

Not happy..

 

 

[Peter T]

Yes they are seperate. It is hardly a key, more of a dimple really so putting the two together and spinning them does not engage it that well.

Slowly rotating them you will feel that the align.

You might want to hold the flwheel when doing up the front pulley, it is easier than winding the engine up.

Inspect bolt for damage before you re-use it, it could be damaged which is why it came loose.

 

R500 Mango Madness

[Mark Durrant]

IIRC the bottom pulley on which the cambelt runs is keyed so hopefully your cam timing will not have moved. However, I would remove the cam cover and check the belt before carefully turning over by hand with the plugs removed. Then you will need to check the cam timing. If all OK then refit the front pulley ensuring it lines up correctly and engages on the bottom cambelt pulley using locktite. As Peter has said you will need to stop the engine turning over to ensure it is torqued correctly.

 

Mark D

Comp Sec

 

[micksmetafors]

Griff,

 

I had a similar experience. Oily said that the bolt hadn't been doen up tight enough. The "key" on the lower cam belt pulley is pretty small and may be damaged. In my case a used pulley, bolt and damper sorted the problem. There was no cam timing movement on my engine and no damage to it either.

 

What oil ysstem are you running, mine was Caterham scavenge and Rover intenal pump with a Brise tank. All was well afterwards.

[Sheds Moderator]

The nut should be done up to 120 lbft with Loctite.

[Beelzebub]

I don't wish to confuse or stir things up here but I'm not convinced that loctite is required. There was none on mine when removed & I put it back after installing the DS pulley without any. ISTR talking to DVA about exactly this & from my slightly foggy memory, he said if if it's done up to the correct torque it wont come undone.

[oilyhands]

Quite right Dave.

 

Loctite in the threads can easily give rise to a false torque reading.

 

Oily

[Peter T]

And tends to go off before the bolt has reached it's loading.

 

R500 Mango Madness

[Paul Deslandes]

Are you sure the loss of oil pressure wasn't sufficient to have done any damage? Gambo had the oil pump belt come off his Vx engined car earlier this year, thought it was only for a second or two, and a couple of weeks later had a rod out through the side . Might be worth having a chat with Oily before you start it up to see if there are any checks you can do before you start her up again. The problem is if one of the bearings has picked-up on the crank. If so it will start tearing lumps out of the bearing which will quickly fail. It has been suggested to me that you should never carry a spare oil pump belt so that you're not tempted to replace it without removing the bearing caps to check that all is well first.

 

 

[Griff]

Excellent responses - thanks all.

 

I've checked with 7-Indulgence who fitted the verniers a few months back. They said there would have been no need to remove the crank pulley on this job so clearly not their fault. Anyhow, they advised I should use loctite for the bolt but balance of opinion from replies here seem to be against this.

 

I've now checked with CC who tell me definitely NOT to re-use the old pulley bolt as it's a stretch bolt - they ought to be replaced every time they're removed which I guess prompt some more feedback. Also CC said NOT to use loctite for the same reasons others have mentioned. They tell me the correct torque is 114 lb-ft (where's my scaffolding pole?).

 

As a precaution I'll also change the pump and alternator belts. They look OK from the outside but can't tell if there's any internal damage to the reinforcement from being thrown off the pulley.

 

Of course this is all on the presumption the engine survived the momentary loss of oil pressure.... ☹️

 

 

[oilyhands]

CC are confused.. the pulley bolt at that torque will not deform or stretch significantly.

 

The Rover K series engine manual ex-factory does not mention renewal of the pulley bolt.

 

Oily

[martinwhitcher]

Griff, of all the people who have responed, I would take anything Oily says WRT K-series as gospel

 

Martin

 

MW 51 CAT

Superlight No.171

now known as:Superlight DVA 207

[Peter T]

Does anyone have the correct length of this bolt to see if it has stretched beyond use??

 

R500 Mango Madness

[SouthernBanana]

CC are confused...

 

They seem to get confused on several engineering principles these days. I recently received some duff info on a DS pump, so sought the information and bought the pump from the manufacturer instead. I think the parts dept should stick to answering the phone and posting things, rather than giving out factually incorrect advice....

[oilyhands]

Overall length of new bolt 89.78mm

length from underside of head flange to end of bolt 69.80mm

depth of head to underside of flange 19.98mm

 

There is no guarantee that all pulley bolts will be from the same manufacturer.

 

This one is from SPS and is 10.9

 

Oily

[Peter T]

Thanks Dave, i have an old one and just wanted to see if it could stretch with this small amount of torque.

 

R500 Mango Madness

[John Howe]

You may well find the location "key" has got worn away as the pulley became loose. If so, simply drill it out and drive in a rolled steel pin to recreate a locating lug.

 

JH

Deliveries by Saffron, the yellow 230bhp Sausage delivery machine

[Griff]

It's a bit concerning we can't rely on technical advice from CC.

 

I'm going to check out this bolt torque versus tension question. I've a utility at work which calcs the tension based on size, thread, torque and lubrication.

 

Anyone know the size/thread of the pulley bolt? I assume it's a fine pitch - will check myself as soon as I can get to the car which is now surrounded by builder's stuff...

 

 

[Peter T]

It is an M14 with a 1.5 Pitch.

 

R500 Mango Madness

[SLR No.77]

And the correct torque figure for the bolt is 205Nm (taken from the Rover build manual).

 

Stu.

[oilyhands]

For the old and gnarly, that's 150lb/ft..

 

Oily

[SLR No.77]

😬