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Omega Help Area => Omega General Help => Topic started by: sev on 06 May 2009, 22:48:03

Title: refitting 5K old cambelt
Post by: sev on 06 May 2009, 22:48:03
I'm going to do a change of cams and lifters soon (as i've got one or two sticking), and I was thinking of refitting the existing belts as both were replaced 5000 miles ago.

What belt tension should I use?, do I set the tensioner as I would a new belt?

Also the best i've had fuel economy wise is 23 - 24.5 mpg, and that's on a motorway run!  I've tried all the cleaning additives for fuel, put shell UL and optimax in,  - any other suggestions?
Title: Re: refitting 5K old cambelt
Post by: HGV mechanic on 06 May 2009, 22:51:05
NO!! replace belt and tensioner once removed!!
Title: Re: refitting 5K old cambelt
Post by: KillerWatt on 06 May 2009, 22:52:28
As above, do NOT refit the old kit.....replace with new.
Title: Re: refitting 5K old cambelt
Post by: sev on 06 May 2009, 22:52:35
that's made it one hell of an expensive cambelt!
Title: Re: refitting 5K old cambelt
Post by: Lazydocker on 06 May 2009, 22:56:10
I'd say that the tensioner could be re-used but fit a new belt. It's the bearings that give up on the tensioner.

Or leave the cam change to the next time the belt is due
Title: Re: refitting 5K old cambelt
Post by: HerefordElite on 06 May 2009, 22:56:25
if the belt looks ok with no cracking or crazing then no need to replace as long as you know that the belt and tensioners were only replaced 5000miles ago.

Belt tension should be set on the mark rather than above it as you do when new :y  (hope i've got that the right way round - need to check the cambelt dvd but can't find it sorry :-/)
Title: Re: refitting 5K old cambelt
Post by: KillerWatt on 06 May 2009, 22:58:20
Quote
Also the best i've had fuel economy wise is 23 - 24.5 mpg, and that's on a motorway run!
I don't think our's (2.5 CDX Estate Auto) does much better to be honest, although I am quite heavy footed.

The computer will report 40mpg (instantaneous consumption) at 60mph on a run, but I don't believe that for a minute.
I'm off down to Pompey again tomorrow, so I'll report back then what I can screw out of it if I drive it like a tart (tart driving = 60mph in the middle lane with my nose 2 inches from the steering wheel  ;D)
Title: Re: refitting 5K old cambelt
Post by: Darth Loo-knee on 06 May 2009, 23:02:36
I personally can't see why you cant refit the belt and tensioners if you know they have only done 5000 miles...
As already said put to the other mark  :y
Title: Re: refitting 5K old cambelt
Post by: Darth Loo-knee on 06 May 2009, 23:05:47
Quote
Quote
Also the best i've had fuel economy wise is 23 - 24.5 mpg, and that's on a motorway run!
I don't think our's (2.5 CDX Estate Auto) does much better to be honest, although I am quite heavy footed.

The computer will report 40mpg (instantaneous consumption) at 60mph on a run, but I don't believe that for a minute.
I'm off down to Pompey again tomorrow, so I'll report back then what I can screw out of it if I drive it like a tart (tart driving = 60mph in the middle lane with my nose 2 inches from the steering wheel  ;D)

23-24 mpg on a run out of a 2.5? you are either foot down then, towing something or you have a problem..
I have a 3.0 auto fully loaded with camping gear, roofbox with four people in and got 32 going on holiday sitting at 70mph.... I got 29 mpg going to Dumfries sitting at 85-90......
Title: Re: refitting 5K old cambelt
Post by: sev on 06 May 2009, 23:06:21
Quote
if the belt looks ok with no cracking or crazing then no need to replace as long as you know that the belt and tensioners were only replaced 5000miles ago.

Belt tension should be set on the mark rather than above it as you do when new :y  (hope i've got that the right way round - need to check the cambelt dvd but can't find it sorry :-/)


I pretty certain as it was me that done the replacing  ;D !

All part of my big mig diary thread!
Title: Re: refitting 5K old cambelt
Post by: Darth Loo-knee on 06 May 2009, 23:07:55
In which case I personally would have said you will be ok then :y
Title: Re: refitting 5K old cambelt
Post by: sev on 06 May 2009, 23:08:16
Quote

23-24 mpg on a run out of a 2.5? you are either foot down then, towing something or you have a problem..
I have a 3.0 auto fully loaded with camping gear, roofbox on and foutr people in and got 32 going on holiday sitting at 70mph.... I got 29 mpg going to Dumfries sitting at 85-90......

I drive mine like an old maid since the lifter started making a racket, so I think that I do have a problem  :(
Title: Re: refitting 5K old cambelt
Post by: Andy B on 06 May 2009, 23:14:32
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In which case I personally would have said you will be ok then :y

I agree! Perfectly acceptable to put it back on after only 5000 miles.
Title: Re: refitting 5K old cambelt
Post by: tmx on 06 May 2009, 23:29:14
i find it very hard to keep the 3litre at 70 it seems much happier at 100+  ;D ;D ;D ;D

maybe thats why £50 lasted me 130 odd miles  :'(
Title: Re: refitting 5K old cambelt
Post by: Darth Loo-knee on 06 May 2009, 23:43:19
Quote
i find it very hard to keep the 3litre at 70 it seems much happier at 100+  ;D ;D ;D ;D

maybe thats why £50 lasted me 130 odd miles  :'(


Just as happy at 95, and you will be too when the Plod pull you :y
Title: Re: refitting 5K old cambelt
Post by: Andy B on 06 May 2009, 23:45:21
Quote
Quote
i find it very hard to keep the 3litre at 70 it seems much happier at 100+  ;D ;D ;D ;D

maybe thats why £50 lasted me 130 odd miles  :'(


Just as happy at 95, and you will be too when the Plod pull you :y

Avoid the M180 then!  :-?  :-?  :y  :y
Title: Re: refitting 5K old cambelt
Post by: Kevin Wood on 07 May 2009, 00:23:44
The old belt will be fine but remember that when refitting a belt they must be replaced so that they rotate in the same direction (not all of them have markings!) and that the final tension should be adjusted so that the marks on the tensioner align as opposed to a new belt where tension is set a little higher to allow the belt to bed in.

Kevin
Title: Re: refitting 5K old cambelt
Post by: Welung666 on 07 May 2009, 05:41:02
As Loo-Knee and Kevin have said you should be fine refitting it if you 110% it's only 5k old but make sure you mark the belt and refit so it's turning in the same direction as it is now :y
Title: Re: refitting 5K old cambelt
Post by: feeutfo on 07 May 2009, 07:13:43
cant see any problem at all. Your not removing the tensioner, as other posts suggest, and even if your where what would be the problem re fitting it?

Re belt direction, i had forgotten this, my understanding is you should re fit as same, as said. But not clear as to why exactly? Presumably the leading/drive faces of the belt will wear more than trailing edge? negligable though?
 Also seem to remember something about the way the Kevlar bends...? Anyone?
Title: Re: refitting 5K old cambelt
Post by: Welung666 on 07 May 2009, 07:32:01
Quote
cant see any problem at all. Your not removing the tensioner, as other posts suggest, and even if your where what would be the problem re fitting it?

Re belt direction, i had forgotten this, my understanding is you should re fit as same, as said. But not clear as to why exactly? Presumably the leading/drive faces of the belt will wear more than trailing edge? negligable though?
 Also seem to remember something about the way the Kevlar bends...? Anyone?

Correct :y It becomes brittle with a combination of lots of heat and change in flexing.
Title: Re: refitting 5K old cambelt
Post by: ians on 07 May 2009, 10:57:39
I would resuse it, assuming its fairly recent and of course looks ok (not covered in oil) when you strip down.

I get 35 out of our 3.0 saloon (auto) on a run, so I think you either hammering it or have a problem.  First stop would be a thorough service, filters, plugs, oil etc,  breather clean (not sure if that would affect fuel consumption, but worth doing anyway).   Also worth a look at your exhaust - my 3.2 has improved significantly since replacing the old (original) system with partly blocked back box.
Title: Re: refitting 5K old cambelt
Post by: Marks DTM Calib on 07 May 2009, 11:05:17
Lol, refit the original belt and tensioners/idlers and set the tension to the used mark.
Title: Re: refitting 5K old cambelt
Post by: KillerWatt on 07 May 2009, 13:20:59
Quote
I have a 3.0 auto fully loaded with camping gear, roofbox with four people in and got 32 going on holiday sitting at 70mph
That's quite impressive, especially as the Vauxhall figures claim 32 mpg at 56mph with just the driver.