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Discussion Starter #1
Slowly putting the engine together after getting the valves done. I got the exhaust cam timing marks aligned perfectly, but the intake cam is just a tick off (pics below). How critical is it to be perfect on both camshafts? And if I need to adjust the intake, would anyone be willing to loan me the special tools for adjusting the intake camshaft for the Bosch L-Jet with electronic VVT? Thanks in advance.

Exhaust:




Intake:

 

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If I remember, I bought a short thin 55mm for one side, and used a giant but precise crescent wrench on the other. I'm doing a Bosch motor now and need them, but if nothing else pans out, I can mail them to you after I get my engine together.
Andrew
 

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I don't think you could improve on the alignment of the timing marks.

But if you wish to try, I have copies of the Alfa tool for the VVT cam. If you are willing to pay shipping, you can borrow them.
 

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Discussion Starter #4
I don't think you could improve on the alignment of the timing marks.

But if you wish to try, I have copies of the Alfa tool for the VVT cam. If you are willing to pay shipping, you can borrow them.
Thanks, Eric. Definitely I would pay the shipping, but if there is little to be gained, I may not mess with it. I'll send you a PM if I decide to try.
 

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Discussion Starter #6
Just out of curiosity...how did you determine you are at TDC?
I rebuilt the whole engine, so I could see the pistons with the head off when I installed the oil pump, front cover, distributor, and main crank pulley. After putting on the head and connecting the timing chain, the distributor and crank pulley are aligned properly to the correct marks after hand turning the engine in the proper direction (without reversing).
 

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If you put it back together with the same upper chain and same make head gasket, you can end up with the marks aligned. This was true for me on the Motronic I'm doing. Not always the case though.
Andrew
 

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Once you have #1 on the tdc with the cams as shown, loosen the chain tension bolt, relax the chain and retighten bolt, turn intake cam to correct mark, it isn't pc but you can turn/hold the cam between the lobes with vicegrips, while holding the intake cam to the marks release the chain tension bolt, the chain will retension, remove the vicegrips from the intake cam and tighten the chain tension bolt. now you can adjust the exhaust cam by loosening the front nut and adjusting the vernier.
 

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Richard Jemison
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Cam timing

Once you have #1 on the tdc with the cams as shown, loosen the chain tension bolt, relax the chain and retighten bolt, turn intake cam to correct mark, it isn't pc but you can turn/hold the cam between the lobes with vicegrips, while holding the intake cam to the marks release the chain tension bolt, the chain will retension, remove the vicegrips from the intake cam and tighten the chain tension bolt. now you can adjust the exhaust cam by loosening the front nut and adjusting the vernier.
Very un-clear and to be honest not correct.

Since the exhaust is right on the mark, all you need to do is loosen the big 55mm locking nut. Do not`t loosen the chain at all!
With the nut loose you can turn the cam to the very next notch and lock it down.
Now with the current location of your mark on the cam cap and the notch on the cam you are 2 degrees retarded. When you move the cam forward to the next notch you will have moved the cam 3 degrees advanced. So your cam will be 1 degree advanced of the mark.
Such minute differences are not going to make a noticable difference at all! If I were making the choice I would leave it where it is as TECHNICALLY a wider lobe separation angle will /should result in better lower RPM output.
With Alfa stock cams any movement resulting in less than 5 degrees change in LSA will be hard to notice with your butt dyno!
 

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Richard Jemison
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Cam timing

Once you have #1 on the tdc with the cams as shown, loosen the chain tension bolt, relax the chain and retighten bolt, turn intake cam to correct mark, it isn't pc but you can turn/hold the cam between the lobes with vicegrips, while holding the intake cam to the marks release the chain tension bolt, the chain will retension, remove the vicegrips from the intake cam and tighten the chain tension bolt. now you can adjust the exhaust cam by loosening the front nut and adjusting the vernier.
Very un-clear and to be honest not correct.

1- You never have to loosen the chain to adjust cam timing!

Since the exhaust is right on the mark, all you need to do is loosen the big 55mm locking nut. Do not`t loosen the chain at all!
With the nut loose you can turn the cam to the very next notch and lock it down.
Now with the current location of your mark on the cam cap and the notch on the cam you are 2 degrees retarded. When you move the cam forward to the next notch you will have moved the cam 3 degrees advanced. So your cam will be 1 degree advanced of the mark.

Such minute differences are not going to make a noticable difference at all! If I were making the choice I would leave it where it is as TECHNICALLY a wider lobe separation angle will /should result in better lower RPM output.

With Alfa stock cams any movement resulting in less than 3 degrees change in LSA will be hard to notice with your butt dyno!
(FYI LSA is the total LC of both intake LC and Exh LC divided by 2
In your case (as they sit in the picture) unadvanced LC is 108 + 118 (224) or 112 LSA
When advanced it is 108 + 104 or 106 LSA. A good LSA for street cars.
 

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Discussion Starter #11
Now with the current location of your mark on the cam cap and the notch on the cam you are 2 degrees retarded. When you move the cam forward to the next notch you will have moved the cam 3 degrees advanced. So your cam will be 1 degree advanced of the mark.
Such minute differences are not going to make a noticable difference at all! If I were making the choice I would leave it where it is as TECHNICALLY a wider lobe separation angle will /should result in better lower RPM output.
With Alfa stock cams any movement resulting in less than 5 degrees change in LSA will be hard to notice with your butt dyno!
Thanks, Richard. This is very helpful. I'll just leave it as-is.
 
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