My adjustable cam gears

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bran100
Posts: 155
Joined: Thu Feb 08, 2007 12:34 am
Your car is a: 1982 Spider
Location: Draper, Utah

My adjustable cam gears

Post by bran100 »

Now that I'm replacing my head gasket, I'm questioning wether I had the adjustable cam gears set up correctly. With my Millers Mule gears set so the holes in the gears aligned with the markers, the valve and cam lobe positions just didn't look right. The cam lobes were at odd positions on the bucket with none really fully closed or open.

When I tried swapping the intake and exhaust gears, things just look better. 1 and 4 intake lobes are at 90 degrees to the bucket. 2 intake is fully open and 3 intake is fully closed

On the exhaust side, 1 and 4 are at 90 degrees and 2 is fully closed while 3 is fully open.

I can't find any markings on the pulley telling me which goes on which side.

I'm thinking of leaving them swapped from what I had. Thoughts?
vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: My adjustable cam gears

Post by vandor »

To properly set adjustable cam gears one needs a degree when and a dial indicator to degree the cams.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
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bran100
Posts: 155
Joined: Thu Feb 08, 2007 12:34 am
Your car is a: 1982 Spider
Location: Draper, Utah

Re: My adjustable cam gears

Post by bran100 »

Agreed on degreeing the cams, however, I assume there's general guidelines on what the valve and lobe positions should generally look like when the gears are aligned with the pulleys.

At TDC, and with cam gears lined up, I assume that #1 and/or #4 should be closed.
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bran100
Posts: 155
Joined: Thu Feb 08, 2007 12:34 am
Your car is a: 1982 Spider
Location: Draper, Utah

Re: My adjustable cam gears

Post by bran100 »

Oh and I really appreciate Ramzi's service at Autoricambi for overnighting the new head gasket to me.
131
Posts: 672
Joined: Sun Nov 14, 2010 1:13 am
Your car is a: 1982 131 Superbrava warmed 2.0 litre.
Location: Tasmania, Australia

Re: My adjustable cam gears

Post by 131 »

bran100 wrote:At TDC, and with cam gears lined up, I assume that #1 and/or #4 should be closed.
#4 should be closed, #1 should be on overlap. If you hunt down a photo, there are several on the forum, you can see that the timing mark either leads or lags the dowel pin hole on the cam gears. That's the only way to tell which gear is inlet or exhaust if there are no other markings.
Mick.

'82 2litre 131, rally cams, IDFs & headers.
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bran100
Posts: 155
Joined: Thu Feb 08, 2007 12:34 am
Your car is a: 1982 Spider
Location: Draper, Utah

Re: My adjustable cam gears

Post by bran100 »

Thanks Mick, that's exactly what I needed. Apparently I had it right the first time.
vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: My adjustable cam gears

Post by vandor »

At TDC the #4 cylinder lobes are supposed to point up and slightly toward the center of the engine.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
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