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Discussion Starter #1
Hello,

Looks like I may have a jumped tooth as the engine is running rough especially when cold and get a bit better when hot, but still nowhere near as good as how it was before.

Thinking of doing timing belt service as it is well overdue on that. I can get a set of cam dies on eBay from Europe, but wondering who is holding on to the Steve's 24V tool set. Would like to borrow them for couple of weeks, especially the tensioner setting tool.

Meanwhile, if someone can suggest me some tips on working on a jumped tooth timing, would really appreciate. Read a lot on doing the timing belt service posted by Steve and others, but I didnt come accross anyone discussing about doing this on one with jumped tooth/off-timning

thanks
 

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Big jump to to come up with cam timing has altered causing engine to run rough. There are so many other possible reasons, like a coil has failed, etc.

Pete
 

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A 24V V6 that has jumped a tooth on one of the cams (usually the rear) has a specific sound and characteristic with regard to the way it idles and runs. In other words a mechanic that knows these engines will be able to listen and see if the engine's cam timing is out with 90% certainty.
 

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Discussion Starter #4 (Edited)
Thanks Pete and alfettaparts2 for your replies, both are valid points, here is how I came to this conclusion. While I was doing my oil separator top hose replacement, at the same time I went ahead and removed intake plenum and cleaned the runner boots. During this process, I guess I slipped a bolt into the timing belt covers which I forgot to track it down (thinking that it may have fallen down into the steering rack and subframe area) before I turned over the engine. As soon as I turned it over, the bolt shot out creating a small crack on the timing cover as well. Since then it is sounding like this and I am very glad that it didnt end up seizing the engine.

I had someone from Santa Cruz stop by to pick up my old 164L engine block for his GTV6 project and he took as look at this and suggested to check for any vacuum leaks (he did a quick check of leaks and couldnt confirm any), but from the sound of it, he is suspecting a belt jump as well.

Probably the videos can give you some idea.
 
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My belt jumped when a bolt met the belt. It had dropped into the V the day before and assumed it would stay in there - it didn't. Belt had a hole punched through it - was really glad it hadn't snapped. Given the damage of belt failure, I'm with you in wanting to properly check it out and do a belt change in the process.
Good luck with it and take your time (no pun intended) - setting the tensioner is an art in itself, ideally let it all settle for hour or more and then recheck everything before restarting.
 

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Discussion Starter #6
Thanks Richard, from what I read over the forums here and also on the digest, it looks like having the 24V belt tensioner setting tool makes it much easier. I also read that after setting all up to leave it overnight and check in the morning for any slack on the tensioner. This is not my daily driver, so I want to make it right even it takes couple more days. I got the cam dies and TDC gauge, I only need to get my hands on the tensioner tool. I can fabricate something homemade for drift pin etc.
 

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Gee you will be a lucky boy if you get away with that. Hopefully your not driving the car because the belt will be damaged. When you get in there make sure you inspect all the pully's for damage as well. Good luck with it.
 

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Discussion Starter #8
This is more like a weekend car for me and I havent been driving it since it happened, turned it over couple of times, once to record and another time to have another guy inspect it.
 

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I'll have a couple of sets of cam locks available in a month or so.
 

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Discussion Starter #10
Thanks Jim, nice to know of another source just in case if the set I bought turned out to be not accurate.

Still waiting to hear on the tensioner tool and cam pulley wrench
 

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Might also have a cam wrench.

My cam locks will be original Alfa ones.
 

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Discussion Starter #13
S
Might also have a cam wrench.

My cam locks will be original Alfa ones.
Great, probably I can buy the cam wrench, but I read that there are two versions depending on 3 hole or 4 hole cams and I am not yet sure what I have
 

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Hope you guys had a good xmas day.

Not sure what you mean by cam wrench? The cams can be turned using the bolt that holds the sprocket on.
You will need a good 41 mm socket for the bottom pully that's for sure.
 

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Discussion Starter #15
Hope you guys had a good xmas day.

Not sure what you mean by cam wrench? The cams can be turned using the bolt that holds the sprocket on.
You will need a good 41 mm socket for the bottom pully that's for sure.
I am referring to the cam pulley tool used to hold the pulley while removing the pulley nut (useful when replacing cam shaft seals)
 

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Ah yes that's what I thought however the 24V V6 is different. You can hold the camshaft with a open end spanner once the cam covers are off then undo the bolt holding the sprocket. You then have to break the sprocket of the tapper. Unless you really have to break this tapper your best advised to leave it alone.

Edit: sorry pavanbabut I just re read my post and it doesn't even make sense to me.

What I mean is you don't need the cam pulley tool because you can hold the camshaft with a spanner. So if you can not get hold of the tool it is not a problem.
In general you don't loosen the pulleys on the camshafts of 24V when resetting jumped timing or changing the belt . That's what people do when they don't know what they are doing.
In fact to just change the belt you don't need the cam dies all at.

24v 01.jpg
 

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Discussion Starter #17
Thanks alfettaparts2 for the tips. For changing a belt that is on perfect timing, I guess you can loosen the tensioner and remove the old belt and slide in the new belt and re-tension it properly, correct? How to you retime a jumped tooth timing? I mean how will you know which cam was off and also whether it is lagging or leading?
 

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For changing a belt that is on perfect timing, I guess you can loosen the tensioner and remove the old belt and slide in the new belt and re-tension it properly, correct?

Yeah you just have to figure out how to hold the cams in place because they move when you loosen the belt. Its a little bit of a dancing act.

How to you retime a jumped tooth timing? I mean how will you know which cam was off and also whether it is lagging or leading?

You absolutely need the dies if you have no other reference marks (from a previous belt change for example).
 

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You don't really need the tensioner tool with the weight to adjust the tension. It would be nice to have it, but not necessary.

I just retimed the cams in my Milano (3.2 24V) and I only had the cam dies. Your 164 should have the 6-hole cam gears, so don't get the cam gear wrench for a 156.

All you need to do is to remove all the plenum, cam cover and rotate the engine, check TDC and position of all cam marks. I would mark the position of all the cam pulley wrt to the cam belt teeth for the cams which are correctly timed. Then clamp them and undo the tensioner. For the cam which is mistimed, you need to unbolt the cam gear bolt and pull it off from the cam. Then use the cam locks to adjust the cam back into proper timing and then reinstall the cam gear .

Sounds easy, but it's a nightmare on the 164 due to space restrictions. I would also you double check with Steve on this. I'm not a 24V expert. For the Milano there's a lot of space because the engine is installed longitudinally.
 

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For the cam which is mistimed, you need to unbolt the cam gear bolt and pull it off from the cam.
This is not wrong but you don't have to do it this way. You don't need to break the tapper on the cam pulley. Its just more work and you run the risk of making a mess of the job. Just reposition the camshaft. My view is from a workshop perspective where I did one or two of these a week for ten years so make of that as you wish.
Not necessary to break the tapper. Think about it. Imagine that the pulley has a keyway. Just rotate the whole assembly (camshaft and pulley). Anyway I'll leave it there.
 
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