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Discussion Starter · #1 ·
What's the deal with adjusting the cam timing on the V6? From what I'm always reading, folks that seem in the know say you need to slot the hub or get adjustable cam sprocket setup, but the factory manual just says to pull the "tongue", twist the cam to the position, assemble and be done.

Is this "tongue" the keyway or the peg that sticks out of the hub?

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Thanks for any insight on this.
 

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I'm not sure about the 24v engine. I do know the 12v engine cams and sprockets are aligned with a woodruff key, so there is very little if no adjustment as such. 12v camshafts can be removed to set the valve clearance without removing the cams.
I think the above procedure is for minor adjustment to align the cam and sprocket key.
 

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No cam timing adjustment on 12v v6 from the factory. If your cam timing marks are off half a belt tooth then maybe the crank pulley is off a whole tooth as it turns double time compared to the cams.
 

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Discussion Starter · #4 ·
The no adjustment thing is what I have always heard, but the 12V factory manual above says you can pull the "tongue" (which I assume is the woodruff key) and just turn the cam to align the marks. The taper locks the cam to the sprocket. This is to make up for maybe milling the head or some other discrepancy that can't be addressed with advancing / retarding a tooth.

I read this in the manual like 35 years ago, but never asked anyone. I'm curious why it seems nobody talks about this adjustment procedure? Is it because it is buried in the manual and not common knowledge ? Or maybe it is not trusted? :unsure:
 

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Not to be trusted. I don't think any manufacturer will allow for adjustment without a positive drive system in place, like splines, woodruff keys and the like.
The hold of a taper fit can be pretty strong. Even the cam nut getting undone is rare, I can't remember if this part is left hand threaded or not.

I can't remember if there are wrench flats on the camshaft, so you can hold and tighten. I can't imagine holding with vise grips while tightening cam nut. It can be done, but not to be trusted.
 

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Discussion Starter · #7 ·
I'm pretty sure the Audi 2.8 V6 I did the timing belt on 20 years ago didn't use a woodruff key and there are some other VAG products that don't, the Morse Taper being sufficient.

It is weird nobody seems to know about this official factory procedure. I can see holding the cam from turning could be an issue. It has been probably 30 years since I've had the cam sprocket off on an Alfa and can't remember how all the pieces fit together.
 

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I guess you can consider the manual as endorsement of this method. IIRC, the taper diameter wasn't that large, and a keyway was cut thru the taper. Taper keyway might be a good thing.
That page is from the 1986 Workshop Manual. I guess nobody remembers this because, maybe nobody has done it this way. Basically, if I disassembled, and it came with the woodruff key, it can be (and should be) reassembled with it.
I imagine that if you're were building an engine where both heads were milled 0.020" (or more, actually I can't imagine wanting more), this can be a problem. But, probably not, I think the resulting error is about 1 degree on the passenger side head, so not huge, and I'm guessing not a valve contact issue yet. If you have more lift, and especially if earlier opening than stock, than it needs to be carefully checked.

The Alfa cam sprocket to camshaft is pretty nice, in that you can remove the camshaft without having to undo the timing belt.
They can only be assembled one way, when using the key.
Pieces:
Camshaft sprocket and separate bearing shaft: This assembly stays in head with belt attached.
Hub (pulled using A.3.0521, I used a harbor freight puller, I thought the force required was exorbitant, so it might be good for "no key"). This hub connects camshaft and sprocket assembly. I removed mine because it was leaking alot of oil. And that keyway is a leak path, and they do require an o-ring to seal the camshaft nut.

And on the Audi V6....whaaa.....
Anyway, I did do the timing chains on a BMW M62TU, and I was forced to buy the camshaft locking tools. This was because a camnut came loose and the timing sensor wheel was not keyed, so it can be assembled in any position. I haven't taken the cam sprockets off yet, but may need to, in the near future...so might be just a taper and no keyway. I have the cam locking tools now, so no problem, if it is.
 

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Discussion Starter · #9 ·
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I bought the factory camshaft hub puller and holder decades ago, but lent them out and never got them back. Figures, now I need them. What did your Harbor Freight puller look like? I also remember the cam hub pops off with a big bang, so maybe the 'ol Busso knew what he was doing. :p

To keep the camshaft from turning when tighten the nut, I read someone on this forum suggested locking the camshaft by placing a thin feeler gauge between the cam and the bearing cap and tightening the cap down. Maybe the taper will keep the cam from spinning so I won't have to worry about the cam turning?

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I may just be able to not bother with all this and turn the crank a tooth to take care of this anyway.

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It was weird not having a key when I did the Audi, but it is actually a very easy install with the tools. You can see in the video below the sprockets are popped off and free to spin while you lock the cams are in place. Put the belt on, tension it and then tighten the cam sprockets. The free spinning cam sprockets are not keyed so you don't have to worry about the cams turning when tensioning the belt.

See at 9'36"
 

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First things first, what kind of timing belt tensioner is on the engine being worked on, original
oil- fed detensioner, later model mechanical spring tensioner, Tom Zat tensioner or newest John Baucom Fiat Specialty one sold by Centerline?


On the Alfa Romeo GTV6/Milano(75)/164 12v V6 Busso engines there is not any factory adjustment to the mating of the two cam pulleys and two cam pulley hubs. The hubs are keyed to cam tapered ends and the pulleys are bolted to the hubs with M7 fine threaded bolts. These are fixed positions and non-adjustable.

To set up cam-timing with sparkplugs removed and distributor cap off on GTV6/Milano models, if timing belt still on engine and pulleys haven't slipped in timing belt rotate crankshaft CLOCKWISE until P(unto) top dead center (TDC) scribed mark on crank pulley aligned with pointer on front of engine.

Now either remove valve covers or use the timing template downloadable PDF link from the 164 forum to verify cam timing marks on either cam shafts and cam bearing caps OR if using timing template downloadable printable PDF link from the 164 forum. The paper timing template hub centers are cut out in centers to fit over cam hubs so you don't have to remove cam covers as the cam hubs have scribed timing marks on them.
Cam timing template http://www.alfabb.com/bb/forums/att...95/66906d1179330802-cam-timing-cam-timing.pdf

You have to remove distributor cap on GTV6/Milanos to check ignition rotor to be sure it is pointed to #1-cylinder sparkplug wire terminal in dizzy cap.

If cam timing not on timing marks with pulley at TDC you may have to rotate crankshaft pulley another 360 degrees CLOCKWISE AND RECHECK TIMING MARKS AND DIZZY ROTOR POSITION.
 

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It might be this one.

If that's where your camshaft is currently, and you are at TDC, I think you are one full teeth off. (You can only be a full teeth off, or multiples of teeth, on an unmodified engine) I usually turn the cam slightly clockwise (with the cam sprocket turning tool, and key in place) to get the belt on. And follow the order as given in the manual, left sprocket, then right sprocket, then distributor sprocket, then set tensioner, spin 2 times to make sure things stayed lined up.

For reference.
I counted teeth once. Camshaft has 42 teeth (crankshaft better be 21). That means one tooth error is 360/42 = 8.57. That's what you're picture looks like, about 8.57 degrees off. I would actually eyeball that as 10 degrees, but you get the idea.

It would have been super cool if Alfa made the connection of sprocket to cam as 41 tooth spline. If you do the math this becomes 0.21 degree increments in adjustability (Of dubious value on SOHC engines), this then becomes similar to the torsion bar adjusting nightmare. The torsion bar has this logic as one side has one less tooth than the other.
 

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Discussion Starter · #13 ·
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Thanks guys. I have the mechanical tensioner. Those images are at TDC via a dial indicator. It may very well be a tooth out on the crank. It's been that way for 30K.:p

So it seems nobody uses the procedure printed in the manual on ditching the woodruff key. I just find that really curious.:unsure:
 

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View attachment 1745235
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Thanks guys. I have the mechanical tensioner. Those images are at TDC via a dial indicator. It may very well be a tooth out on the crank. It's been that way for 30K.:p

So it seems nobody uses the procedure printed in the manual on ditching the woodruff key. I just find that really curious.:unsure:
If your engine is truly at TDC with dial indicator in #1 cylinder and crank scribed mark P is at pointer on front of engine, cams are both slightly retarded which is Okay. That setting should give engine a little more low-end power.
 

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If your engine is truly at TDC with dial indicator in #1 cylinder and crank scribed mark P is at pointer on front of engine, cams are both slightly retarded which is Okay. That setting should give engine a little more low-end power.
chrisv
If you reset the timing maybe you could give us a report on how the engine behaves compared with the retarded cam timing.
 

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Discussion Starter · #17 ·
Maybe you could give the woodruff key delete a try and report back any damage ;)
I guess that's the problem. Nobody wants to be the first. :p

Still, it has always been right there in the manual and machine tapers are a legitimate way of securing pulleys. From what I understand, Alfa later dropped the key from that location altogether in their 24V engines.
 

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Discussion Starter · #18 ·


From this..



...to this.

A follow up on this for those in a similar position. Turns out the crank was one tooth out! I never realized it as the car ran good and I put 30K on it. I went from Shankle cams to "S" cams so there was no reference on how it should run. Idled pretty smooth, especially compared to the Shankle cams, and pulled well, or so I thought. I can't wait to put it back on the road.

I definitely recommend locking the pulleys together. Makes fitting the belt so much easier.



I set the belt on the way it originally was (TDC referenced with dial indicator) and then turned the crank back carefully one tooth. Slipped the belt on and turned the crank clockwise to take up the slack. That gave me a lot of slack on the tensioner side and the belt slipped relatively easily over the tensioner. Buttoned it all up and spun it a bunch of times to double check.

If I didn't lock the cams, it could have been a pain to hold everything in line.

Thanks everyone for the suggestions and help. (y)
 

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When the cam timing is off as much as the above pictures show, it`s apparent that the belt has jumped one tooth on the LOWER sprocket (Crank )
When you move the belt 1 tooth the result at the camshafts is 1/2 of the distance that a movement of 1 tooth on the cam pulleys would result in due to size difference of the two sprockets..
 
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