MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Cam belt tensioner bolt replacement

I'm about to replace the cam belt on the other half's TF. Doesn't look to much of a challenge but in the manual it states that the bolt that holds the tensioner should be discarded and replaced with a new Patchlok bolt.

What's the general consensus on this. I don't mind changing the bolt, I'm a bit disappointed it's not included with the tensioner and they didn't mention it when I picked it up from MGOC spares.

Bob
R.A Davis

I replaced mine last October, at 56K , now my MGF has 71K on it ( i do 440 miles a week..) and i used the complete kit from CarParts.. (@£60.00 it had all the bolts,tensioner, belt, & new water pump etc... Given that a new bolt should be fitted, and the cost of one compared with a lost tensioner and wrecked valves et al.. is really minimal, my advice would be replace it..

The work isnt difficult, but access is not easy if you dont have a four post lift... the most likely thing to cause you grief is not the tensioner or fitting the belt or setting it up.. but getting the crank shaft pulley bolt out, might.. you need a strong long bar to break the locking torque and free it..and the means to stop the engine trying to turn....

this makes it look very easy.. :)

http://www.youtube.com/watch?v=CM5oA2X03z8

N.J. Simon

I'd already watched the youtube video and he reuses the old bolt (or at least he doesn't mention a new one), that's why I hadn't picked up on this earlier.

I believe also that the MGF had what's known as a manual belt tensioner, this didn't require the bolts to be changed.

I do plan to change the bolt, I was just looking for other people's opinions on the subject as it's the first time I've come across bolts used in this type of situation requiring replacement.

Regarding the crankshaft pulley I plan to use an impact wrench so hopefully that won't be an issue.

Bob
R.A Davis

i put the brakes full on.. and the gear stick, in fifth.. and gave the arm connected to the pulley, a short sharp shock, and the torque lock cracked with an audible sound.. the tensioner is specicif to the model.. and i can .... for ezample , see no reason why a automatic tensioner should not be used on a 2001 mgf trophy.. the same year as the Freestyle, but it does.. ignore that at your peril.. the freestyle is specified as an aurto tensioner, the trophy is specified as a manual one... ?
N.J. Simon

i dont have a TF... maybe the m - tf spec is diferent.. unless someone here gives you better logic.. based on experience that you can see, i would go with any mgf recognised input... the choice, is not mine.. its yours....
.
N.J. Simon

Update

Cam belt now replaced. This job is a complete pain, not because it's technically difficult but because access is a pain and you need to use a mirror to get things lined up.

Getting the alternator belt off was the first challenge. To slacken the bolt that holds the adjustment bracket to the alternator body you need an offset ring spanner.

The crankshaft pulley bolt didn't put up to much of a fight and all the covers came off easily. I undid the 2 large bolts on the engine mounting and lowered the engine on a jack to give clearance for the belt. The old belt and tensioner looked almost new and the pump had no play or signs of a leak so I left well alone.

The new belt was a bit of a challenge to get back on but only because of poor access. A couple of pegs helped hold it in place while I got it around all the pulleys. Getting the tensioner set correctly was fiddly having to use a mirror to check it.

I think I got to the bottom of why you need a new patchlock bolt. The new bolt has locking compound applied to it, the old and presumably original bolt didn't. I can only assume it was realised the locking compound was required and therefore the bolt needed to be replaced when the belt was changed. See photo

Would I do it again? Not if I could find someone else to do it for a reasonable price.

Bob


R.A Davis

i understand BOB, its not as straightforward to do as the video suggests.. folks get one tooth out of alignment, cant see the marks, move the crank pulley all kinds of things..
it took me a weekend to do mine.. a leisururly weekend, since the weather was good, and i could just stop and take some time to think about it.. i actually put the belt on, and took it off again while fitting it.. several times... and setting up the tensioner to get the marks lined up perfectly not just close, is fiddly.. but important, certainly the cam locking tool is vital, and the first and last thing to do...
i know you have probably shut up the engine bay now... but another thing to check while you are there is the alternator, since the adjusting screw located in the alternator bottom bolt fixing, siezes in the alternator body, as does the bolt that locates the bottome bracket to the engine...

the engine locating bolt had sheared off, a centimetre inside the block... and i had to drill it out and retap it.. i replaced that bolt with a stud, and changed the spacer that sits between the bracket and the ebgine with a tapped one, therefore now i have a locked in stud for the bracket to sit bon with a locknut instead of a bolt head.. and only needing a few turns to free it off...

also the mgf has a rear pivot point grease nipple.. behind the shock abdorber

and its a good time to give the pivot point some grease too.. and check the shock bottom bolts and rubber bushes too..
N.J. Simon

I am convinced that in the video the guy doesn't put a proper bolt in. It all goes back together too easily. I couldn't get the bolt in its hole if I put the belt on first. I'm convinced he popped a bolt in with no thread at the lead end.

It mus t be a big advantage to have an air wrench. Locking the flywheel is another challenge. The engine bay was designed by a sadist.

Andy
ANDREW WRIGHT

I found changing the timing belt, tensioner and water pump was about a two hour job. The problem was remoing one of the RH mount bolts. It was completely seized on the mount. It took an extreme effort to get the bolt out.
Mark Jones

This thread was discussed between 27/07/2012 and 13/09/2012

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now