Cambelt replacement: Is it really that simple

[Simonavis]

Hi
I am rebuilding a 1.7 engine that I bought from eBay and am in the process of fitting a pair of updated camshafts but as the title says is it really as straight forward as setting piston 1&4 to TDC, inserting the crankshaft locking tool, refitting the camshafts and setting with the cam locking tool, refitting the camshaft pulleys ensure that the pulley isn't in the cam advanced position and then finally fitting new cambelt and tensioner.
It is just that I have read that changing cambelt is a real pig of a job on these, but everything so far has gone swimmingly, are the issues just when the engine is on the car with regards to limited access etc.
I just don't want to refit engine etc only to find on turning the key I have not fitted belt correctly

 

[tuonokid]

Hi Simon
No it's a pig of a job as you need special tools to lock the engine. The pin for the crank and the plate for the cams are TIMING tools and not locking tools, if you use them as locking tools you will probably break off the end of the camshafts.
The main problem is that the bolt for the crank pulley is tightened to an enormous torque which you just can't achieve without either locking the flywheel (engine out) or holding the crank pulley with the special tool as in Ford TIS. If you don't achieve the required torque you run the risk of the crank pulley not gripping the cambelt sprocket behind it(no woodruff key) and losing the timing with disastrous results. You also need to be aware of setting the tensioner as in Gates technical bulletin #036 as that's a two stage thing. You also need to fit a new crank pulley and VCT pulley bolt if they've been loosened off as they are both stretch bolts and should only be used once. If you have a look on my build thread you can see the special tools in use and get an idea of the force needed to tighten the crank pulley.
Barry

 

[Simonavis]

Hi Barry
Firstly thanks for reply.

As the engine is out I do have it locked off at TDC with a fly wheel locking tool, I also have a Gates cambelt kit which includes a leaflet explaining the tensioning process (the tensioner has a pin installed to help with the process) and includes replacement bolts for the cam pulleys. Furthermore I have also purchased the camshaft setting/installer, so it appears I have got everything covered.
It is also apparent from what you have described that it must be virtually impossible for the home DIY'r to carry out with the engine in the car due to accessibility issues, I certainly wouldn't fancy it laying on a cold concrete floor.
I will certainly take a look at your thread prior to carrying out the replacement, I was just dreading getting the engine rebuilt and back in the car only to find I had done something stupid when doing the cambelt

 

[tuonokid]

Hi Simon
From memory I think the instructions with the gates kit tell you what to do but don't explain why you should do it which is why I would recommend you have a read or even print off the technical bulletin. It is a two stage process and the bulletin shows you how the tensioner looks if you do it wrong as well as how it looks when done correctly so you know for sure.
I don't know what you mean by camshaft setting/installer but as long as you realise that the only way to keep the cams stationary whilst you are tightening the sprocket bolts is to use the spanner flats near the pulleys rather than the timing plate tool.
Doing the cambelt change is possibly easier to do with the engine in situ as you can use the weight of the car to your advantage in loosening and tightening the crankshaft pulley bolt but you definitely need the special tools to hold the crankshaft pulley. If you're locking the flywheel to tighten the bolt you will need something substantial to hold the engine otherwise the force of getting to the correct torque will just result in rolling the engine over (but I guess El Dude (Chris on here) can answer that one)
Just as a last comment the two bolts in the Gates kit are for the VCT pulley and the crankshaft pulley not for both camshaft pulleys.
Barry

 

[g-whizz]

Hi Simon,

Having just recently very nearly lost my engine to a problem camshaft change, which it's thought didn't follow the Gates bulletin, I'd strongly back-up Barry's words of advice... I've fished it out for you, hope it helps k:

http://www.partinfo.co.uk/files/Gates%20TB%20036%20K035433XS.pdf

The timing tool, not the locking tool, was also used it seems and yeah, it does shear off the ends of the camshafts. :evil:

 

[Simonavis]

g-whizz thanks for the shortcut, pictures are always helpful.
Barry thanks for the advice on the pulley bolts otherwise I would have been scratching around trying to find another stretch bolt halfway through putting it back together. Odd it doesn't come with the extra camshaft pulley stretch bolt as it comes with all the other bolts that need replacing

 

[tuonokid]

Hi Simon
The exhaust cam pulley bolt is not a stretch one, just re-use the one you have and note the different torque settings for each cam and tighten up the pulley bolts AFTER you've tensioned the belt (The pulleys need to be able to move as the tensioner tensions)
Barry

 

[Simonavis]

Sorry Barry I need to learn to read your posts properly in the first place as you clearly stated that it was just the vct pulley and crank pulley bolts that were stretch bolts but thanks for all the other snippets of advice that will help me hopefully avoid some of the more common pitfalls of changing the cambelt

 

[tuonokid]

Hi Simon
I didn't tell you all the pitfalls but if you read this which is a clearer version of Ford TIS you'll have a better idea and you still have no idea how tight the crank pulley will be and needs to be on re-tightening!

http://www.projectpuma.com/viewtopic.php?f=51&t=25102

Barry

 

[Simonavis]

Barry that is an awesome guide, thank you.
I am now off to the gym to prepare for having to torque up the crank pulley!!!

 

[tuonokid]

Don't forget the spinach Simon

 

[ElDude at Allison Automotive]

[post]358344[/post]
If you're locking the flywheel to tighten the bolt you will need something substantial to hold the engine otherwise the force of getting to the correct torque will just result in rolling the engine over (but I guess El Dude (Chris on here) can answer that one)

Barry

yeah I keep the pin in, lock the flywheel up nice and tight... and crank it over the 90 Deg.. keeping the engine still on the floor is tricky... I use a carefully selected and placed steel blocks/bars around the sump sections to steady it...

then I get my 3/4" breaker bar with steel box section over the end of that for extra leverage... none have loosened on me yet.. :lol: I also de-grease the stretch bolt and clean the mating face on the vibration damper pulley with a fine grit paper so it really grips into it...

:thumbs:

Chris

 

[tuonokid]

Hi Chris
Thanks for answering, I always wondered how you managed to hold the engine as with the flywheel in place you can't really use an engine stand. Yeah I also cleaned the face of the vib damper to ensure a tight fit. As you can see I tried to tell Simon how tight the bolt needed to be torqued so I hope he manages it.
Barry

 

[Simonavis]

Hi Barry and Chris
Thanks for those extra tips, fortunately I have some angle iron that I can bolt to the garage floor to create a frame around the sump and hopefully hold it still. I would never have thought about roughing up the surfaces to create extra friction.
Am I being stupid but tightening to 40nm doesn't strike fear into me, Is it the extra 90 degrees that hurts? I am still eating the spinach so it might have to wait until after Christmas now, building up the muscles lugging all my wife's shopping around.

 

[tuonokid]

Hi Simon
Yes it's the 90deg that really hurts. I had a mate sat at the end of the crank watching the degree disc whilst I put my weight (not inconsiderable) on a breaker bar with a 4" scaffold pole on the end. It's really tight but you should experience this when you take the original one off.
Barry

 

[Simonavis]

Looks like I need to be going to the gym twice a week!!!! I will look forward to taking it off, it will be a warm up.

 

[stuart1275]

Resurrecting an old post but just wonder how you got on with the belt change in the end Simon?

 

[Simonavis]

Hi
It’s all done and fitted back in the car and running spot on. Everything went well no hiccups but I did triple check each stage before moving on to the next. As Barry warned me the crankshaft pulley bolt was fun.......not!!! Got there after and lot of blood, sweat and tears of course a few choice words were also thrown in :grin: