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Discussion Starter #1
hi, does anyone know what is the diference of a crankshaft pulley of a gtjunior 1600 from 1967 and a Alfetta GTV 2000 from 1980.

thanks in advance.
 

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I'm using a 1600-1750 degreed front pulley from Classic Alfa on my 2 liter engine. If you have a European engine with carbs or use a European front cover, the pulley fits perfectly.

The pulley appears to be a bit smaller than the two liter pulley, however. I'm not finding that to be a problem.

The Classic Alfa pulley is fully degreed although, oddly, the one I got had its TDC and advance marked wrong. That shouldn't be a problem since the pulley is marked in 360 degree segments.
 

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the only diferences in Alfa front pulleys are that the small one are for dinamo fitted cars and bigger ones are for alternator fitted cars, at least here in Europe
 

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I repeat, different pulley circumferences and different timing markings. As noted above, they both will fit your motor. Changing the size of the crank pulley will either slow down or speed up your generator or alternator, depending on the size of that pulley. Either way, it probably won't matter. Regardless of which pulley you end up using, it is best to check the timing marks with a degree wheel, which is most easily done with the engine out of the car.

My 2L is built to rev, so I chose pulley sizes to slow down the rotation of the alternator, meaning smaller pulley on the crank than on the alternator. You also want to be sure the fan belt lines up across the two pulleys.
 

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I fitted a small crank pulley from Gordon Raymond because I have a high revving engine and I want to avoid cavitation in the water pump and Premature alternator failure.
 

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Discussion Starter #7
thanks to all for your help, today i received the pulley from classicalfa, it is a bit smaller and the marks of tdc and advance isn't on the same place because the pulley is smaler like someone said, i need to mark the tdc and then i think that will be ok, this pulley is 2cm smaller so the pointer on the water pump that i use to see the tdc is now 2 cm up from the new pulley, should i bend it or should i change the pointer?

one more time Thanks to all.
 

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No, don't bend the pointer. That will ensure that you never tune the engine properly again. Take off the cam cover and bump the engine to the point where both cam lobes on the #1 cylinder are pointing away from each other when the #1 cylinder is at the top of its travel. That is TDC. The pointer should be aimed at the new pulley's TDC mark when the cams are as described.

The next step is to make sure you know the correct timing for your motor. Timing is set at different points for various Alfa engines, so look up your motor's spec at Centerline.com, International.com, Papajam.com (just kidding. Papajam is on AlfaBB and has specs for everything) or, better yet, buy a manual that explains all of this for your on-going reference.

Once you know where your motor is supposed to be timed, check your new pulley and see if the F and M marks are where you need them to be. If new marks are required on your pulley, a degree wheel will tell you where to put them. I only time my engines to maximum advance (M), but it doesn't hurt to mark both static and maximum advance lines on the pulley.

(It also helps us to provide better answers if you tell us where you live and give particulars about the engine you're working on; i.e., does it have carbs or fuel injection.)
 

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Discussion Starter #9
i live in Portugal, i use 45 dellorto carbs, i have 123 ignition distributor, pistons 10.4:1, kent cams AFJK303, kent double spring valves, kent cam folowers, and a very good head work, also have a big bore exaust and gta like exaust manifold, i think thta will help you to help me.

kind regards
 

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Sounds like you've got all the good pieces. Carbureted cars with 2-liter engines are normally timed in the 34- to 36-degree range. Mine is happy at 34, others whose posts I've just read can handle 36 degrees. If your new pulley has a mark for maximum advance in that range, just put it on, make sure the TDC mark lines up with the pointer when the #1 piston is at TDC, and you'll be in good shape to start the engine and put a timing light on it. If you have a smaller motor, you'll need to look up the timing spec.
 

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Mine is happy at 34
Mine is too. It made equal power at 34 and 36 on the dyno but less power at 32 and 30.
 
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