Cambelt slipped?

[shn7]

I rolled the 7 off my trailer this evening to wash it post Dunsfold.  Having washed/dried I started it up and all appeared normal.  I drove it back and forwards a couple of times on the drive then onto the trailer.  

Here's when things became worrying.  I got a squeal like a loose alternator belt.  I figured water from being washed might be aiding it slipping so planned to check the tension.  Just before switching off I then got a metallic tinkling kind of noise.

The alternator belt appeared well tensioned as did the dry sump belt.  However, to be on the safe side I loosened the alternator fittings and actually ended up removing it completely to lubricate the adjuster screw and replace a rusty bolt.  

Whilst doing the above I was pondering the tinkling noise and so removed the cambelt cover to find what I think is an excess of slack in the belt on the longest (non-tensioner) side.In fact this run isn't taught at all.

I can't see that anything has moved (adjustable cam pulleys, tensioner etc) and the belt looks in good condition.

Now I'm not sure what to do next!  I fear starting the engine in case the belt has slipped and more damage is done.  Can anyone advise?  Anyone local to Selsey experienced in cam belts?

 

[Wrightpayne]

What engine?

All engines will have timing marks for cam and crank position.

plugs out, turn over gently by hand using socket and t bar on crank pulley nut to align the marks.

If you feel any resistance stop. If the marks are out of alignment, estimate by how many teeth, which cam and which direction then seek advice from an expert on your engine to understand if there will have been valve/piston contact.

I have the rover manual and can send pics. Revillia posted an excellent article on k series belt tension recently with pics.

Ian

[elie boone]

if the belt would have slipped i guess the valves and piston would have touch. is it possible your tensioner bearing has given up ?  

[Mark Durrant]

Steve

IIRC the engine is a 1.8K and is likely to have verniers fitted. How loose is the cambelt and 'normally' you can turn the belt through 90 degrees on the side opposite to the tensioner, anymore suggests a problem. Is the tensioner loose? I agree with Ian remove the plugs and carefully turn the engine over but stop if you feel any increase in resistance. If you have verniers have these had marks added that align when no 1 cylinder is at TDC? If the engine needs attention then Tom New can probably assist. 

[oilyhands]

The marks align at 90BTDC, if they have been transferred correctly from the original pulleys.

Turn the engine carefully to 90BTDC on number one cylinder and check the alignment of the timing marks.

Oily

[shn7]

Thanks all.  I went to bed last night after posting this and came round thi morning thinking check the timing.  Last night I was too tired/dejected to think it through properly.

It is indeed a 1.8k tuned to 230bhp and Tom New has done work on it previously.  More convenient would be Andy/PGM are engines Andy's strength or is Tom preferred for such things?

Just got to find time (hopefully on Saturday) to check the timing.

[Mark Durrant]

Steve

I suggest you give Andy a call and I expect it will depend on what is found.

[shn7]

OK, so investigations so far  Plugs out and turn the engine over by hand finds no points of significant resistance.  The force needed to turn it does vary but I'm assuming that's cam lobe related.

Using a rod to check approximate piston height (I don't have dial guages) I believe I've found the 90BTDC position with all pistons at the same height and a red mark on the crank pulley lining up nicely with the engine centre line mark on the bottom belt cover.

However, I've not spotted any markings on the Piper vernier pulleys to indicate their correct positioning.  There are the Advance and Retard graduations but should I be expecting to find marks that align inlet and exhaust pulleys?  If not what should the next step be in checking the cam timing?

On the slack I found in the belt having read other threads and also found minimal slack once the engine's been turned over I'm more hopeful nothing untoward has happened. The slack does come back if the pull on or twist the belt but I don't think it's to a degree that would allow it to slip.

[Wrightpayne]

Do you have a standard pulley to hand? Possibly remove the cam pulley nuts, one at a time, to expose the locating notch then overlay the original pulley to mark the verniers with the timing marks. Might be advisable to slacken off the tensioner but leave everything else in situ. Refit bolts, then check the positions of your scribed marks as per the normal timing instructions.

DVA describes how to mark the pulleys on his website.

Ian

[revilla]

If you are going to do that, best to do it with the crank pulley timing marks aligned so with the engine safe, pistons all half way down the bores. At least then if a pulley comes off and the cams decide to flick round (which they tend to want to do, and quite violently too, as the lobes flick over the lifters and springs) nothing will make contact.

[Wrightpayne]

Just thinking about marking verniers again, I did mine on the bench with the verniers at zero i.e. no advance or retard.

If your cams have been timed and are not at zero then the applied marks could end up in the wrong place. Perhaps use tippex to mark the pulleys and allow for any cam timing adjustments.

Not a perfect solution - struggling to think of a DIY check to be certain. I guess timing the cams using 3 dial gauges would be conclusive. I entrusted DVA to do mine!

Ian

[shn7]

Sadly not got any standard pulleys.  Sounds like it's a trip to Andy Jupp @ PGM to check the timing as the next step.

[JNC]

Steve can't you ask the previous owner  ?

 

[shn7]

John,

Good point.  I will email Grubbster and see if can shed any light on the timing. I doubt he'll have the original pulleys as he gave me everything 7 related with the car I think.

[shn7]

Grubbster has nothing of help other than reminding me the engine was built by Rob Walker and that Tom New has looked after it in the past.

I'll give Andy J a call during the week as he's more convenient to get to for me.

Steve.

[Duckpit]

I had the dreaded squeal last week, it turned out that the alternator tensioner bolt had sheared  making the alternator & water pump belt loose- maybe you will be as lucky as i am.

I did have a cam belt slip couple of years ago and the drop off in performance was appalling and the valves may have even touched the pistons, I used an endescopic camera from ebay to check the damage but thankfully it was minimal/nil and a new cambelt sorted it.

Good luck

[shn7]

Booked to see Andy Friday next week for a timing check. <fingers crossed>

[shn7]

Huge thanks to Andy Jupp at PGM for checking my car over yesterday and finding nothing wrong - what a relief.

Great friendly informative service form Andy and a couple of good cups of tea from Colin.  Cam timing checked and found to match Piper's recommended settings. 

Time to get back out and enjoy the car.

[Wrightpayne]

Good news - you've not missed out too much with all the rain lately!

Ian

[JNC]

What about the slack in the belt Steve ?

[shn7]

Turned out it was nothing excessive.

 

The noise I heard must have been something hitting the trailer as I drove on to it.

 

[Mark Durrant]

[Grubbster]

Good to hear Steve, you might have heard the sump scrape the end of the trailer if the ramps were a bit steep. 

[shn7]

Yep very pleased. Don't think it was the sump. I know that noise.