Cambelt failure

[Martyn Cracknell]

Following a cambelt failure on my 1986 micra, is it likely that the valves will have been damaged by the pistons and vice versa.?

The garage to which it was taken by the AA, says that they've replaced the belt but it runs roughly. They are telling me that they need to strip it down as they think that 3 valves are damaged.

 

[Ed]

Valves will be bent - without question usually 3-5 of them depending on how unlucky you are.

 

[stonesie]

I heard that they can damage the pistons too by crimping the rings?

dunno if this is right or not but i am getting nervous as i think mine is still on its origional belt:suspect:

 

[Ed]

Change the belt NOW you can do it in a few hours first go or even less than an hour once you get good!!

 

[stonesie]

hmmm you know what i have had it with cambelts LMAO managed to cut my arm open doing a belt and waterpump on a rover k series today (damn siezed engine mount bolts)..... if i am quiet at work tomorrow i will try and sweet talk my boss, we only fit goodyear or gates so should do the job

 

[james betley]

dont 4 get 2 get everything in line when u put the cam belt on

 

[K10]

well if I can do it anyone can! :grinning:

take these bits off

then whack on the new belt

turn by hand to make sure you aint got it really far out, put everything back together and drive off :grinning:

theres a bit of info on this thread http://www.ppcmag.co.uk/forum/topic.asp?TOPIC_ID=1400&whichpage=1 (well, explanantions of how i ballsed it up at first) but I just followed the haynes and had no problems

Hope this helps,

Dan

 

[Phil_the_Chill]

One of the nuts on the upper engine mount is a bit inaccessible. And I found the tensioner an utter swine.. it kept popping off and flinging the spring all over the shop. Personally I found the tensioning process quite difficult. One one cycle the belt was slack as hell and on a second turn it was tight as hell.
I wondering if I was a tooth out on fitting the sucker.

Is it worth doing the water pump at the same time?

 

[Ed]

Always worth changing the water pump at the same time..

 

[SammoHung]

lol mine sounded like a double decker bus when i got a new one fitted..

...too tight?

well now its worn in a bit now (+30k from new one fitted at 63K) didnt get the water pump done though....may be i should have? I' just under 100K at the mo

on the other hand i do a bi-yearly drain, backflush, thermostat & new coolant job. Always looks fairly clean fluid.

That reminds me ...I'm due a change right now...

and winter is comming too

 

[stonesie]

Sammohung

If it was too tight when it was fitted it will shorten the life of the belt, if i were you i would be aiming to do the belt and pump at about the 100K mark.

I did mine today and what a mare it was.... 2 reasons
1) the old waterpump gasket was welded to the engine and took ages to get off
2) that damn tensioner spring (little more, little more and its there.... PING... bloody f****** thing lmao

the bit that the spring sit's on, on the tensioner got ''tweaked'' by a large screwdriver:wasntme:

 

[mrmaz]

Tensioner Spring

I had the same trouble with the tensioner spring flying off.

If you follow the Haynes manual for putting the timing belt back on, it say something like turn the cam (Upper one) 2 turns anticlockwise with the tensioner loose to allow it to correctly tension the belt. (Use a length of wood with two screws correctly spaced to turn the CAM Shaft).

Unfortunately it seems to fail so mention that YOU SHOULD DO THIS WITH THE SPARK PLUGS REMOVED, otherwise the compression in the cylinders causes the Crank Shaft (Lower one) to jump round and the tensioner spring flies off!! If your not careful the belt may slip too!!!

If the Belt does slip, then slide it off. Rotate the crankshaft whichever direction takes it the shortest distance so the TDC Marker is at either 3 o’clock or 9 o’clock. Now the pistons are all in a line in the centre of the cylinders (no chance of valves hitting pistons). Line up the CAM Timing Marks, then the Crank Timing mark (Shortest distance i.e quarter turn!) Belt on and try again.

I'm sure ED can confirm this, as he is the master to be able to do this in an hour, takes me just over two!!

 

[stonesie]

it took me about 2 and a bit, i wasnt going to do the waterpump but once i got the timing covers off i noticed it had just started weaping so had to wait for 1 to be delivered, best to make sure i get the right 1 before taking the old off.

if i did another without waterpump it would be close to 1 hour now i know how to sort that damn spring :upside:

 

[SammoHung]

Sammohung

If it was too tight when it was fitted it will shorten the life of the belt, if i were you i would be aiming to do the belt and pump at about the 100K mark.

Cheers stonesie, I think I might go with that advice...good call!

 

[Ed]

lol at the comments on the spring. it is a bit of a pain. you can do them quite quicly however after a few goes. Its usually just a case of the right tools and methods

 

[bombz4]

hehe my tensioner is in my boot! i didnt put it back on tbh mine was so old and decrepid it didnt really work!