cambelt tension ?

[wishbone]

Hi Guys,

Have just put my new head on, and put the timing belt on. I didn't need to have the crank pulley '1 tooth out' as has been mentioned on here a lot, and am now wondering if my tensioner is not tensioning enough ?

How much play should there be on the belt between the fuel pump pulley and the camshaft pulley ?

Also should I just rely on the spring to tension, or do I have to lever the tensioner slightly to get it tight enough ?

Cheers,
Rob.

Edit - I turned the engine over 4 times after fitting it and all the marks aligned correctly btw.

[TonyN]

You shouldn't need to put it on one tooth out, thats just for people who can't get the belt over the pulleys with everything timed right, and is always slightly worrys me when others say do it, espcially to newbie belts changers!

But as long as the marks all line up after one complete revolution, it'll be OK.

The spring is the tensioner, thats the whole point. As long as it dosn't look stretched out when off the hooks, thats what sets the tension, turn the crankpully clockwise a little to get all the slack out of the pulleys, then do up the idler bolt.

Check it by turning it one full rev of the cam gear, and if you've done it right, all the timing marks will line up again.

[wishbone]

Thanks Tony.

Rob.

[cataclysm]

If I remember correctly, the belt tensioner is connected to the throttle, so as your revs go up, so does the belt tension. Quite clever, as it saves the belt from stretching so much as it would with a permanent spring.

[TonyN]

If I remember correctly, the belt tensioner is connected to the throttle, so as your revs go up, so does the belt tension. Quite clever, as it saves the belt from stretching so much as it would with a permanent spring.

Huh? Don't think so! The spring sets the tension, then you lock the idler with its bolt through the middle, its not going anywhere

[NiftyNev]

If I remember correctly, the belt tensioner is connected to the throttle, so as your revs go up, so does the belt tension. Quite clever, as it saves the belt from stretching so much as it would with a permanent spring.

Nope. Belt tension on the 2.4 is set and forget. Initial tension is set by the spring whos coils close and then the tensioner bolt is tightened. Belt tension is mechanical and not hydraulic. The three litre has a hydraulic tensioner but I don't believe this is connected to engine oil pressure either.

Nev

[TonyN]

The three litre has a hydraulic tensioner but I don't believe this is connected to engine oil pressure either.

Nev

Nah its not, it'll open to allow for belt stretch, but won't go back again easily. They need resetting with a press or vise when changing belts on 3.0

[NiftyNev]

Nah its not, it'll open to allow for belt stretch, but won't go back again easily. They need resetting with a press or vise when changing belts on 3.0

Yeah, I thought that was the way it worked. I wonder why the 3 litre requires a tensioner to compensate for belt stretch and the 2.4 does not, or does the 3 litre tensioner fully extend to it's limit and in so doing set the correct tension. It seems like it can move though going by the diagrams in the EPC. No lock bolt like the 2.4 that I can see.

Nev

[TonyN]

Its not at its limit, if you undo one of the bolts it'll pop right out.

I think you'll find the pressure in the cylinder sets the belt tension, thats all.

This is why its important when you take it off to bin it if it shows any signs of leaking round the rod seal, if you can push it in by hand or if the push rod protrusion is wrong.

[wishbone]

Just ordered a new spring to be on the safe side. Couple of quid for the peace of mind.

Rob.

[daedalusminos]

New spring is what I did - if you've taken the water pump off/replaced, make sure you get the spring retainer (held under one of the water pump bolts) re-installed correctly.
With the belt installed (and marks aligned) and tensioner spring installed (but tensioner centre bolt loose so tensioner can take up slack), rotate the crank in the normal direction several revolutions and then tighten the tensioner centre bolt with the belt slack taken up on the drive side (i.e. don't let the crank rotate in the opposite direction)

I found locking the crankshaft quite easy for tightening up the crank pulley bolt:-
Locate and remove the plastic cover in the bellhousing plate (underneath the vehicle, drivers side (RHD) bellhousing plate) - the cover is approx 3" x 2", thin plastic and clips in - use screwdriver to remove and expose flywheel (do not drop cover in bell housing!).
Next take an old double open-ended combi spanner (i used a 7/16" - 1/2" AF) of the correct size and wedge the 7/16" end into one of the large holes in the flywheel front plate and the 1/2" end in the bell housing front plate (the crank on the spanner makes this possible). You'll need an assistant to slowly rotate the crank whilst you hold the spanner in position to take up the slack. The spanner should end up in compression when you're tightening the crank pulley bolt. Oh and it might be a good idea to tie something round the soanner before doing this so as not to lose it in the bell housing should it slip!
Whn done, remove spanner and replace cover (time approx 10mins - no need to jack car)

Should point out this is on a '93 LN130

Jonathan

[wishbone]

Great tip on locking the flywheel!

Thanks,
Rob.