Cambelt every 4yrs no matter what....True??

robin · Post by **robin** » Sat Feb 03, 2007 7:55 am

dr al wrote:the only problem is that there was NO way a torque wrench was going to fit in there, so i had to guess the tightening torque. - i bit worried about that but i'm absolutely sure i havn't UNDER torqued it! - i guess i'll find out next time i try to get it off!!

Hmm. The torque is 205Nm from memory. With a 30cm torque wrench that still requires a pull equivalent to lifting 60Kg. If you had a 2 or even 3 foot bar then fair enough, but anything shorter and you might be surprised. And you obviously need to use thread lock.

I have seen the consequences of this bolt coming undone - it varies from disasterous to totally disasterous and is always expensive. It's easy enough to crack it open and retorque it without any complex dismantling of the engine, so it might be worth doing that?

definately worth getting the wee jobber that holds your two cam gears in place, though. i improvised with a bit of wood, but it slipped, causing some concern!!! - elise parts sell them for a few quid.

LOL.

Cheers,
Robin

robin · Post by **robin** » Sat Feb 03, 2007 7:59 am

Shug wrote: Yeah, just remember when tightening the crankshaft pulley back up:

clicking from tensioner = bad

What? When you are doing the pulley bolt up, the tensioner shouldn't be doing anything - why would it click? Unless of course you left the cam lock in whilst trying to tighten up the bolt in which case you are naughty and asking for the timing to slip (the torque on the bolt is probably 10x the torque required to turn the cams, so the pulleys and belt are no good to lock the engine whilst tightening the bolt, right?

Cheers,
Robin

Rich H · Post by **Rich H** » Sat Feb 03, 2007 9:03 am

I don't think the lock was in (can't remember but I really doubt it!) it was because we were struggling to find a way to lock the crank as the cover plates flywheel end wouldn't come off. So I levered one back to get a screwdriver in to jam it. Problem was we couldn't get enough movement on the (Crappy) torque wrench to get the required torque and every time we tried and released the tensioner clicked as the tension came off. We just ignored it (Plastic type tensioner) unfortunately each click was the belt jumping a tooth so when everything went tight we assumed it was the screwdriver finally in place where actually it was the valves on no.4 (IIRC) meeting the piston...

Now I think about it I have no idea why it was slipping, as you say the cams should have been turning, but they were v.stiff as they had been sitting for quite a while. Even then...

I remember when we tried to turn it over by hand for the first time and it wouldn't, I imagine my face was quite a picture....

We were left with either strip it all down and have a look or fcuk it and carry on, reset the timing and see. We went for option b obviously.... and it all works fine, over 6k miles later and no probs, doesn't even use any oil. (Touch wood!)

Victor Meldrew · Post by **Victor Meldrew** » Sat Feb 03, 2007 9:39 am

RICHARDHUMBLE wrote:I don't think the lock was in (can't remember but I really doubt it!) it was because we were struggling to find a way to lock the crank as the cover plates flywheel end wouldn't come off. So I levered one back to get a screwdriver in to jam it. Problem was we couldn't get enough movement on the (Crappy) torque wrench to get the required torque and every time we tried and released the tensioner clicked as the tension came off. We just ignored it (Plastic type tensioner) unfortunately each click was the belt jumping a tooth so when everything went tight we assumed it was the screwdriver finally in place where actually it was the valves on no.4 (IIRC) meeting the piston...

Now I think about it I have no idea why it was slipping, as you say the cams should have been turning, but they were v.stiff as they had been sitting for quite a while. Even then...

I remember when we tried to turn it over by hand for the first time and it wouldn't, I imagine my face was quite a picture....

We were left with either strip it all down and have a look or fcuk it and carry on, reset the timing and see. We went for option b obviously.... and it all works fine, over 6k miles later and no probs, doesn't even use any oil. (Touch wood!)

I think your face looked a bit like this...

not exactly what I would call a picture..

Rich H · Post by **Rich H** » Sat Feb 03, 2007 9:45 am

Good one John!

BTW I think I should have changed to oil a bit sooner than I did (5k miles later!) as all the assembly grease and cam lube stuff was a bit sticky and thick apparently! The tappets have gone all quiet now!

Victor Meldrew · Post by **Victor Meldrew** » Sun Feb 04, 2007 3:21 am

Well chuffed its still running well. You not had a chance to put it on the dyno yet?

robin · Post by **robin** » Sun Feb 04, 2007 8:30 am

It really would be worth getting to the bottom of what you were doing wrong - I cannot imagine how you would make the belt slip unless you put the cam locking tool in - the cams would always just turn rather than the belt slip?

I always use the handbrake and 5th gear when doing up or releasing the crank shaft pulley bolt. If it gets really bad you can put the road wheel back on and chock the front wheels too, but I haven't ever reached that stage.

It will take quite a few clicks on the ratchet to wind out all the gearbox backlash, but even with a rubbish ratchet like mine (1 click is all I get in the full travel from wishbone to wishbone, as it were) you should be able to do it up.

Cheers,
Robin

roadboy · Post by **roadboy** » Sun Feb 04, 2007 3:04 pm

I use a specially made flywheel locking tool.

Dan@JPS

Rich H · Post by **Rich H** » Sun Feb 04, 2007 5:18 pm

I dunno what was going on, but with the new gearbox fitted I have noticed a distinct lack of a pause when going from power to engine braking (And the associated jolt!) so the backlash must have been significant!

Also we could not get the bolt to torque up at all against the clutch, it was just springing back every time, we assumed that it was the clutch springs fighting us but that said we didn't have much room for the torque wrench and couldn't get even one click. The plugs were out so no compression and it was in gear and handbrake on, but I don't know which gear.

pretty sure it was the lack of space for the torque wrench so we weren't taking up the slack from the gearbox.

IIRC what was happening was we were torquing up the crank bolt, the tensioner was compressing and as the pressure was released the belt jumped a tooth around the crank. This implies the cam lock was in, but I'm pretty sure it wasn't. The cams were v.stiff to turn, not possible by hand and there was little lubrication at this point as the head had been dry for quite some time. Doesn't really matter as the results speak for themselves, but it did cause quite alot of concern at the time!

There is a dyno day round here sometime, it will be interesting for a ball park figure (I know that they are highly subjective!) and to see the curves.

Rich