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MG MGF Technical - Cambelt change

Hi guys.

Am doing a cambelt change on my f.
My aircon belt seemed like a ancient vase, all cracked up and since I had 70k (km) on the clock thought I might as well change the cambelt.

Got all the bits and pieces (flywheel and cams locking etc)

I found it very hard to get the starter motor out. Bolts are very hard to reach.

Next problem I encountered were the engine to subframe bolts. Two problems actually. 1. I couldnīt use my ratchet extention piece, as the line straight up from the bolts doesnīt exit the engine bay, but ends under the sides of engine bay cover (better where the cover sits on) leaving barely room to manoeuvre with the ratchet. I donīt see any way to get my big -what do you call it - [Nm] moment ratchet in there upon tightening later on. How did you manage?

2. Next the crank bolt. I Used a 35-40cm boom (big moment ratchet) to no avail. I was pulling/pushing that hard I thought that or itīd break or the car would fall of itīs stands.
Has anyone ever used a torch to heat up the bolt? I did this on the cat nuts in the early days.

cheers,
david - with the knackerd knuckles - peters
;-)
David Peters

For the engine frame bolt you need an extension with a cardan (sp?) so the extension just gets clear out of the body.Do NOT use a ratchet but a solid piece and an extension. Beware that when fitting the bolt again it can be difficult to engage correct windings. Rock the engine slightly to engage the first windings of the bolt.
A bit late now,but best way to undo the pulley bolt is to leave the starter in place and use an air-tool with settable or at least known torque + hardend socket. This will both undo and fasten the bolt easily. If no airtool the bolt can at least be spun off by using same hardend socket+ extension to the floor. A quick run of the starter undoes the pulley bolt...If using flywheel locking + "armstrong" the extension to the hardend socket need to be long !
Let us know how you get on. / Carl.
Carl

Hi Carl,

thanks for the cardan extension tip! didnīt think of it. I did undo thos bolts though.

Why doesnīt it matter that the starter is in place when undoing the bolt with an air tool? It should rotate, not?


second crank unboltbolting solution is ingenious! Love that trick. quick run of a starter! But then youīd need to realing flywheel and cams.

since I went through all this trouble, itīll have to be "armstrong". *LOL* I am a prety persistant guy...until all resources fail.

Iīll keep you posted.

Might not be tomorrow that I continue though. I have to prepare some exam questions for the students. And with the e.a. the crank bolt misery going on, I reckon theyīll have a hard time solving for the answers.*LOL*

cheers
david
David Peters

Itīs getting late ;-)

thos: those
unboltbolting: unbolting
realing: realigning/timing
prety: pretty
David Peters

Good luck David, I'll be doing the same in the next couple of weeks. I was planning to have the crank bolt loosened with an air impact wrench and re-tightened by hand for the short drive back to my garage, I guess that's the wimpish way but I don't have students to take it out on... ;o)
Mike Hankin

Hi David, what I ment about the starter is that it isnīt needed to take it away if the first thing done when starting to work on the engine is to undo the pulley bolt.
When using an air-tool it is interesting to see that despite the brute force due to the action of the tool there is absolutely no need for any locking of the flywheel etc. The crank simply doesnīt move a bit, but the bolt comes out easily ! But be sure to get a hardend (dark or black) socket to avoid injury. Normal cromed sockets can split.This is of course also valid for the "armstrong" method ;O) And donīt forget to use a mild locking fluid on the bolt when re-fitting. Lock-Tite blue or any other liquid will do fine.
Comes as a stick to smear on or in small bottles.
If you re-new the cambolts (for the VVC) and use Mike S kit there is a small bottle that can be used also for the pulley bolt and any other bolt/nut that needs to be secured. / Carl.
Carl

Oh, Oh, David, that's still not all ...

I think this will get a long thread more Q&A after you did off the pulley bolt ;)

See you again soon.

Rgds
Dieter
PS. ... didn't do that job alone, and I found it most useful to have a second person available, ...with an air impact tool ..
Dieter

I brought a real beefy airtool from halfords (does twice the tightening torque). and it was useless - even when (naughty I know) I used higher pressure than rated.

I did undo it with a bar over the end of my breaker bar making the length about 2'6" - of course to do this you need the locking tool in place.

Also if found the blet to be a right ar*e to get on, and removing the locking tool alows you to move the crank _ever so_ slightly (about 1/2 tooth) so you can fit it easily over the pullys in one direction and then back so you can pull it over the cam tensioner.

removing the adjustment bolt (the 8mm headed one, not the cental one) makes it so the tensioner can be adjusted to give extra slack, but getting that blot back in is an ar*e (perhaps an art) because you can't see sh*te. Get your girlfriends makeup mirrors in there!
Will Munns

Have you been able to source a better aircon/alternator belt ?? My original was cracking up at 4 years and 21K miles. I did not have time to find anything other than an OEM to refit.
Geoff F.
G. Farthing

@ Dieter: please let me find out those questions step by step *LOL*. Guess Iīll be annoying you for the forthcoming week *ROFLOL*

@ Will: quite surprised you werenīt able to undo it with the air tool. 2'6'' :-O what a piece.
You took out the flywheel and cam locking tools to get the belt on? kinda like fitting the chain over the cam of a bike, moving it back and forth.
The cams will move independantly from the flywheel. How do you retime these then. Wait, donīt answer, just wait untill I get there.

Re the 8mm allen key bolt for the belt spanner. There are two in my case. The one for the aircon/alternator and the one for the cambelt. The first one is a real pain to get out. As you cannot fit a socket to it. The engine subframe is in the way (2,5 cm clearance), so not enough room. I hope that once the engine is lowered I will be able to reach it more confortably.
Also,I have the auto tensioner type and I will have a hard time to remove the clip (L-shaped metal bracket to the spanner) Because even with mirrors, you can hardly see it.
Donīt even ask me how I will- after I removed it- reinstall it.

Cheers,
david.
David Peters

>The cams will move independantly from the flywheel. How do you retime these then.

Kept these locked with the tool, only shuffled the crank to get the belt over, then it was just a case of making sure the two dots were aligned with the rib (you can't use the pully as it is on the floor next to the plastic bit with the line on it)
Will Munns

Hi all,

back from my garage. delighted to say the belt is on, timing is still spot on.

1) Yesterday I soaked the crank bolt with WD40. Today, I fitted the socket and torque wrench (which is bigger than my regular wrench) directly to the blot, without extention to clear the wheel arch, as you loose a lot of power in the connections of the extention piece. Then I layed myself down on the floor, head facing the front of the car (and of course face up-->for the jokers around here). I then grabbed the wrench and just pulled with two hands. The bolt came of just like that. It went so easy I thought I was chipping of the hexagon, but no, the bolt came of.

2) Getting the belt of was easy. Did it from to down (cams, waterpump/tentioner), crank pully). A bit of a twist and turn to get it between the lowered engine and engine mount.

3) to get the new belt on, I did several trials with the old belt. I found it easiest from top down. Twist and turn gently to get it through the space engine/engine mount opened by lowering the engine. Gave it 5 trials until I got the hang of it. Then did it with the genuine belt.

4)refitting the tensioner proved to be easier than anticipated. Make sure you have a mirror and good light.

5) After about one hour fiddling, I thought itīd never fit. But, There is a trick to it, as I found out. I tried to stretch the belt over the crank pully, but guys that will never work. If it would work, that would mean the belt is faulty. So what I found to be the trick is to fit the edge of the belt to the crank pully teeth, so the belt is at an angle upwards with the pully, then push and twist it downwards and it will slide over the pully. Done. And happy. Called the Mss straight away for the good news *LOL*

6) Jacking up the engine and fitting the engine frame bolts. As Carl mentioned, you have to swivel the engine a bit untill threads and holes line up. Give the bolts 3-5 manual turns to make sure you have the correct thread and donīt mess up the OEM thread! Upon tighting, I didnt get to the prescibed torque (155Nm) I used a (4 way) flexible torque wrench joint to clear the engine bay. These joints leads to loss of power applied. So the wrench didnīt "tick over". Iīll get me U shaped extention piece next week and try again.

7) at this point, I torqued up the tensioner bolt (25Nm) and took out the cam locking tool. Blimmy, upon a "mirror" check, the IN-Exhaust lines didnīt meet up anymore. About 1/2 turn. At his point I doubted, redo the whole thing or continue. The dots on the crank pully (itīs not actually the pully, but the thing behind it, donīt know how to call it) were also a little out of line with the mark on the engine. So I continued.
How is this possible, the flywheel locking tool was still in place?

8) torqued up the Crank bolt pully(after fitting the lower belt cover and pully) in the same way as I unbolted it. Easy.

9) removed the flywheel locking tool and gave the crank a couple of turns. Looked and listened for any strange noises... None. OK

10)re-aligned the cams (IN-exhaust) and checked for the marks on the lower belt cover and pully. They alligned perfectly. so the problem in (7) must be of a manufactoring intollerance?

Well thatīs where I got today. Left is to put in the starter engine (promising a lot of swearing with the difficult to reach bolts), install the alternator/aircon belt, upper cambelt cover and presto. One extra happy man.

I learned a few lessons:

1. Get ALL your tools sorted

-torque wrenches (0-20Nm and 20-220Nm)
-U shaped/flexible extention piece for torque wrench to clear the engine bay
-all your sockets (n°22,...)
-allen keys (n°6)
-regular tool set
-cissors to cut the wrap tie around the starter motor
-flywheel locking tool (I honnestly donīt recommend other options like screwdrivers etc)
-cam locking tool.
-mirror (like the ones you stick on the windshield as an additional rear view mirror)
-a long thin walking light (?) to stick into the engine bay and see everything. 10' or so.
-cloth to cover carīs bodyparts

2. tidyness

-good overall lighting.
-table to put all the things you took out
-pen and paper to note what bolt came from where or tape to stick the bolts to i.e. to the upper cam belt cover.

3. personnal mood

-enjoy getting the crank bolt finally out.
that little b*gger *LOL*
-put some music on
-stop in time
-grab a beer and relax in the evening.
-tomorrow is another day.

I might take some pictures tomorrow of i.e. the flywheel locking tool in place etc. If that might be of interest

cheers

david.
David Peters

2) Did it from TOP to down

7) ... About 1/2 TEETH

8) torqued up the Crank PULLY BOLT

Donīt you just love this BBS, no "Edit" mode, etc etc. KEEP IT LIKE THAT PLEASE.
David Peters

2) Did it TOP DOWN

7) .... About 1/2 TEETH/TOOTH

8) torqued up the Crank PULLY BOLT

No Editing mode ;-) I just love this BBS.
Please leave it unique !!
David Peters

Nice write-up and hopefully a happy ending !
As you probably have been rocking the cams back and forth it might be that one or several followers are a bit low on oil. This will (as in my case) give an alarming loud ticking noise upon startup. It will go away as soon as the oil has reached temperature.
As for the alternator belt ,it must have been the lowest bidder that got the contract ;O). The number of cracks even on a low milage car is frightening... But fortunatly there are also quality parts that fits on the market.
At least for me (2 belt changes during the years)it has been impossible to avoid slipping noise upon startup from the alternator belt. That is another sound that could be scary... / Carl.
Carl

Hi carl,
Thanks for the compliments on the writeup.
I should add, people will also need a good jack and two axle stands. Some use a woodlog or the spare tire *LOL* but I like to be on the safe side. Changing cambelts is not my daytime job.

I canīt tell you yet about the ending. Cooked a 3 course meal today. My other favorite thing, cooking, hmmmm.

Iīll keep in mind those scary noises and catalogue them as not harmfull ;-)

Another question is the auto tensioner. I donīt know what tensioner you have.
But the autotensioner has a pointer and an index wire. With a allen key (N°6) you have to turn the pointer counterclockwise to reach the index wire from below. The manual also says that when the pointer reaches the index wire from above you need to redo the whole thing.
I was turing to eagerly and passed by the index wire about 5mm. I returned this 5mm clockwise. As I couldnīt figure out how the auto tensioner works, I donīt know whether this small "approach from above" could pose a problem.



David Peters

Have only been working on the old manual tensioner,someone with experience of the auto-tensioner has to fill in...
But I assume that you did several turns on the pulley bolt to ensure that the belt was suitably tensioned. In the old dayīs of the first cambelt engines there was the rule that it should be possible to twist the belt 90 deg. in the middle of the long run side with only force from 2 fingers.
With the manual tensioner it is at least possible to overstretch the belt slightly. This is immediatly recognised by a whirring noise from the belt when the engine is running at idle.
Carl

The alternator tensioner is of the manual type and by turning the pulley bolt you can see the belt getting tensioned.

However, by turning the pulleybolt on the cambelt, I didnīt really notice this. A pitty I donīt understand the workings of the autotentioner. I hate it, because I canīt control it! Maybe it tensions when the engine starts running? I donīt actually know. Hope someone comes along who has a autotentioner,
cheers,
david
David Peters

David,

the secret is the excentric bearing and a hidden coil sprin, like used in a roller blind.
http://www.mgfcar.de/cam_belt/rw_autotens.DSC05168.JPG
(old tensioner from my car)

I think it's better if someone native english speaking explains how it works.
Dieter

Thatīs the thing Dieter.

How I think it works:

The index wire is part of the spring. The spring is tensioned by the metal pointer, by turning it counterclock wise. I believe it is excentric to tension the belt. When the pinter faces the index wire, the tensioner is in its his most excentric point, tensioning the belt the most.

So there is no additional tensioning as the belt turns?

hmm Iīll just wait until someone comes along to confirm this.
David Peters

Funny, everyone is doing cam belt changes at the moment. As I understand it, and I have my new auto tensioner in my hand!, it only automatically tensions the belt to a preset figure if you follow the set routine. It is not really automatic. It is only a manual tensioner with an "automatic" method of setting the belt tension. Then it is permanently locked up.
Jerry Herbert

permanently locked up....by torqueing up the bolt! got it.
cheers,
david

good luck!
David Peters

That's exactly right.
Will we be seeing you at Kempenrit in August? If so, we can compare cam belt change techniques!!
Jerry Herbert

If all goes well Iīll be there Jerry. Interested in doing a workshop are you?
David Peters

I've not got round to changing the cam belt yet, job for the next few days. Already got the crank bolt off with an air impact hammer - easy!
Busy working on fitting a PRT up front near the radiator. That bit was easy, getting the old thermostat is the hardest part. Still struggling with non bendy arms. Can compare set ups if/when we meet?
Jerry Herbert

should have the MGR PRT fitted by then ;-)
David Peters

This thread was discussed between 26/05/2006 and 29/05/2006

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