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Discussion Starter #1
Hi there, This is my first (well second after the one in the intorduction section) Posting on AlfaBB.
First of all I hope you are all well in these strange times.

I have a question. (not native english speaking so forgive any faults) Today I decided to adjust the valves of my ´73 EURO - spider 2000 veloce. First time since I have the car, hear a valve ticking, so I tought I better have a look. To my pleasent surprise the cams were spot on the markings on the camcaps, checked with a dial in the cilinder no.1 sparkplughole. So I pulled the cams and changed the shims to a 0.16/0.19 setting as adviced by Richard Jemison on this forum. He also adviced to change the timing of my (10548) cams to 104/104 in stead of the 99,5/99,5 as par factory. So I went to the centreline site and downloaded the templates to mark the new settings on the capping.
For the inlet cam this was not a problem: the marking on the capping was in line where the template showed where the 99,5 should be:
1618588


Well maybe the camera angle was not ideal, but it is between the 96 and 102. (and that is pencil right from the marking)
But now the exhaust showed something quite different:
1618590


That shows the marking about between 102 and 108! Now fysicly the marks aren´t mirrored, that is what I would expect with a 99,5/99,5 setting. I am a bit baffled here.
I have a few questions.
1. my car runs pretty good, even if a few valves were out of spec, but it lacks a bit of torque. By looking at the position of the cammarkings relative to the centreline templates, I have been driving with a 104 (106?)/99,5 cam timing. Would this make my car run good, but with lesser torque?
2 I am not the first owner and don´t know it´s history, so it might be possible that the camcap was chanegd over the years. But is there an exhasut cam cap with a 104 or 106 marking? If so could it theorectly be possible that a bloke in Arese in the early 70ties just put his hand in the wrong container with camcaps?
3 Will it still be adviseble to change the inlet cam to 104?

Any thoughts on this would be greatly appriciated.

Thanks very much - stay safe!

Willem
The Netherlands.
 

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Richard Jemison
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Your template is cut poorly and doesn`t fit in the cap "centered". Likely that mark is 108. Center your template or better yet make a new set cut wider than the lines. Set the cams at 104.
 

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Discussion Starter #3
Thanks Richard, will do. As an excuse: I work in an enviroment (architecture) where PDF´s are allways on scale. So I didn´t doubt that the centreline template was correct. After your message I knew I was wrong as the drawing is made in imperial measurement and printed in PDF base on US-paper size, so my printout in a metric enviroment couldn´t be right.
 

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Well I´ve managed to get the prints in the correct scale and this is the result.
The exhaust looks like to be marked on 108 as the inlet could be 99,5.

I am still puzzeled on the fact that there seems to be a wrong exhaust cam capping in my engine.

I will now get the timing on 104° conform the templates.

1619318
1619317
 

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Different cams I know, but my 2L motor made the best power and torque with the settings that you currently have,
 

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Different cams I know, but my 2L motor made the best power and torque with the settings that you currently have,
Ed,
You run 99,5°/108° IN/OUT ? It seems to me that by retarding the exhaust that much with the intake not changed, you increase the overlap and loose power through the exhaust. Could be wrong though...
 

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The cam caps were not always marked correctly at the factory. I just worked on a 92 spider that the exhaust cap was marked wrong. Also the cam timing change year to year. Especially here in the states. Also if your head was ever replaced with a different year head.
 

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The cam caps were not always marked correctly at the factory. I just worked on a 92 spider that the exhaust cap was marked wrong. Also the cam timing change year to year. Especially here in the states. Also if your head was ever replaced with a different year head.
Thanks Jim, for that info. Makes me a little more confident in knowing it better than the factory markings. Will soon be working on the timing an will let you know if the car runs better or not.
 

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Richard Jemison
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Ed, the off the seat duration is totally different from my cams you are running. They are opened about 45 degrees longer and to get correct valve events timing has to be different.
 

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Jim reckons that duration at .050" lift is more significant than off the seat duration. The comparative dyno curves for the 785 and 457 cams support that idea. The torque and power curves were almost identical despite having different duration below .050" and at high lift. The 457 with shorter off the seat duration was a little better below 3500 rpm.
 
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