Cambelt change - anyone completed one before?

[chrisB1983]

Hi All,

So i started a cambelt change on my 1.7 yesterday but unfortunately ran out of daylight so i've still got to fit the aux belts and a few other parts before i fire it up. I have some questions though that hopefully someone who has completed one before can help. I have looked at every guide i can find on the net and none of them really explain this detail.

Firstly when re-fitting the crankshaft (aux) pulley i had to use the old bolt to pull it home. I did this up physically as tight as i could get it but i'm concerned that it hasn't pressed the pulley on enough. It seems to line up with the other aux pulleys so maybe i'm being a but over cautious. Does anyone know if the cambelt pulley behind relies on this - is there a possibility of the cambelt pulley slipping if it's not sandwiched by the aux pulley? How the hell would i press this on any further anyway.

Secondly, i quickly found that the Laser locking bar i bought in preparation to lock the camshafts in TDC was too thick for the job. There was no way it would fit. The slots on the camshafts are not central so there are effectively two possible 'TDC' positions...and neither way round would the timing bar fit. I ended up making my own. After everything was set, i checked the timing by spinning the engine over a few revolutions but the inlet cam was out by a degree or two every time. I noticed in the end that i could rotate the cam back to the VCT stop (pushing spanner towards bulkhead) and the timing bar would then fit. Is it possible for the VCT mechanism to adjust slightly while turning the engine over manually?

Any help would be appreciated. Chris

 

[tuonokid]

Hi Chris
First of all both the crankshaft pulley bolt and the camshaft VCT pulley bolt (the one behind the cover) are stretch bolts and should only be used once. If you've not used new correct ones and tightened to the correct procedure the belt change will fail. You could use the old crankshaft bolt to pull the pulley into place and then swap it for the new one to tighten it up but that would probably move the crankshaft pulley and move the timing (there is a special puller that stops the crank pulley rotating whilst tightening the crank bolt up). The lazer tools camshaft bar will fit in only one position but you need to rub the paint off at least one side of it and it is a very tight fit. This is not a locking bar as the pin is not a locking pin if you use them as locking tools you will probably break the camshafts and break the crank timing pin.
You really need to read gates technical bulletin #036 for tensioning the cam belt as this is a two stage affair and if you get that wrong the cambelt change will fail.
Whereabouts are you?
Barry

 

[chrisB1983]

Hi Barry. Thanks for your reply.

Firstly i should have used a different term of phrase and referred to the 'locking' tools as setting tools. I have not and would not use these to hold anything in position for tightening of fasteners. I have used a genuine Ford kit that supplied the replacement bolts. I used the old bolt to install the crank pulley (using a tool to hold the crank pulley in position) then fitted the new bolt for final assembly. As per the Ford guide, this is done before releasing the tensioner and setting the timing. I set the crank to TDC using the timing pin in the block, then making sure the cams are aligned using the setting bar i then tightened the cam pulleys (new bolt in inlet) while holding the camshafts with a spanner. I am also aware that the tensioner pin has to be partially released before tightening the lower bolt so i'm sure that is correct.

The problem i have is when turning the engine over to check the timing the inlet camshaft is slightly out but can be rotated back into the correct position (back to the VCT stop). It seems that the VCT mechanism is adjusting slightly.

I am in Chatham, Kent.

 

[tuonokid]

Hi Chris
Sorry about the delay I had some errands to do. Well at least you've cleared up some things there. In answer to your original posting there are no woodruff keys on the cams or crankshaft so the tightening of these is critical as it stops the pulleys from moving on the shafts once tightened. Don't worry about the VCT pulley when you're timing everything up as long as you have tensioned the cam belt prior to tightening the camshaft bolts with the timing plate and crankshaft pin located the engine will be timed correctly. TBH when I did mine (it's on my thread) my inlet cam was marginally off but it was so marginal I wasn't going to buy a new camshaft pulley bolt so I reassembled it and it runs ok with no EMLs.
To re-iterate the critical things on this cam belt change are;
To tension the cambelt tensioner with the cam pulleys free to move on the cams using the method described in Gates technical bulletin #036
To make sure everything is timed correctly using the crank pin and the cam plate.
Use new bolts on the crank pulley and the VCT pulley and ensure they are tightened to the correct torque/degrees.
I hope that helps and good luck.
Barry

 

[chrisB1983]

Hi Barry. Thanks for the info. That's set my mind at ease with respect to timing. I released the tensioner, checked the crank is against the TDC pin then lastly torqued the camshaft sprockets. I'm fairly sure that is all correct.

My only issue is the crankshaft pulley? How do you know if it's all the way home. I didn't remove the bolt before removing it so i have no idea if the pulley is supposed to be flush with the end of the crankshaft or still has a small step (end of crank recessed).

Do you have any pictures of the pulley in it's final position with the bolt removed?

Chris

 

[tuonokid]

Hi Chris
There may be a picture on my build thread but you know when the pulley's fully home as whatever you use to tighten it up will come to a dead stop. I used the proper tool and could easily feel it.
Barry

 

[chrisB1983]

I've checked your build thread and it looks like i've pressed it on far enough. I certainly couldn't have applied any more torque to the bolt.
I finished putting everything back together and started it up tonight and all in all it's not running correctly. I wouldn't call it lumpy but it's definitely not as smooth as it was.

I did fit some new spark plugs while i was at it so there could be something wrong there. I'm going to re-fit the old ones and see how it goes. Failing that i will re-check the timing.

 

[chrisB1983]

SUCCESS!! :grin: :grin: :grin:

The new spark plugs were the wrong ones. I should have checked them against the old ones but was rushing. Put the old ones back in for now and it runs as sweet as a nut! Well pleased...although i am still concerned about that bottom pulley.

Barry, where did you get your tool from (303-510)? I would like to order one up and check it's home properly.

 

[tuonokid]

Hi Chris
I can't remember where I got it from now but there's quite a few makes but it comes in a complete kit costing circa £200. I shouldn't worry about the pulley being fully home as the Torque used and the degrees, if you've done it as per directions (15NM +90deg? from memory) will ensure it's home properly. From memory pulling the pulley back on it's on a straight shaft rather than a taper so you can feel whatever you are using to draw the pulley on coming to an immediate stop rather than just getting tighter.
Barry

 

[chrisB1983]

Thanks for your help Barry. It all worked out ok in the end.

 

[tuonokid]

Cheers Chris, well done
Barry

 

[YOG]

Hi Chris
.............. (15NM +90deg? from memory) will ensure it's home properly.................
Barry

Crankshaft Sprocket Bolt is 40Nm + 90˚, according to the Gates installation Guide.

Gates do Crankshaft Tools - GAT4629 Crankshaft Pulley Remover and Installer Set and GAT4736 Crankshaft Pulley Holding Tool:
http://ww2.gates.com/common/downloads/files/australia/brochure/4404c.pdf" onclick="window.open(this.href);return false;