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OP
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You should, if your engine will idle with that much advance. That's the same port I have on my HS4 that mine is hooked on and it's ported vacuum. I also have dual carbs, so less vac/flow in one of mine than in yours. Cause yours is feeding all cylinders, and you might have to set idle open enough that you are already comming into the port area at idle.)
What he's saying is mainfold vacuum is o.k if your engine will idle with that much advance. Mine wont. It'll putt puut puofff put the exhaust with that much initial advance.
The advantage is, vacuum advance senses engine load and retard timing when you need it retarded. If you set the base at 26*, it would knock/ping itself to pieces once you put a heavy load/throttle on it.
What he's saying is mainfold vacuum is o.k if your engine will idle with that much advance. Mine wont. It'll putt puut puofff put the exhaust with that much initial advance.
The advantage is, vacuum advance senses engine load and retard timing when you need it retarded. If you set the base at 26*, it would knock/ping itself to pieces once you put a heavy load/throttle on it.
Morris
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<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Sorry for being such a numbskull[/QUOTE]
You are not a numbskull... if something is difficult to understand, it's always the explainer's fault :wink:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]if I set the timing to 10 or 12 BTDC(vacuum disconnected and plugged at the carb) and then re-connect the vacuum, then I should be good to go? And have the benefits that Kellysguy obtained?[/QUOTE]
I would plug your vacuum advance, then set your timing to 28-30° BTDC at about 3500 rpm. The place that timing advance is most critical is when the car is under load. The 1500 makes max torque at about 3500rpm, so this where you want your timing advance to set accurately. If your timing advance is off here, it can cause damage to your engine or seriously affect your performance. You have a lot more leeway at cruise and idle (these are the areas where your vacuum advance come into play). Get it close for cruise and idle, and you will be fine.
You are not a numbskull... if something is difficult to understand, it's always the explainer's fault :wink:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]if I set the timing to 10 or 12 BTDC(vacuum disconnected and plugged at the carb) and then re-connect the vacuum, then I should be good to go? And have the benefits that Kellysguy obtained?[/QUOTE]
I would plug your vacuum advance, then set your timing to 28-30° BTDC at about 3500 rpm. The place that timing advance is most critical is when the car is under load. The 1500 makes max torque at about 3500rpm, so this where you want your timing advance to set accurately. If your timing advance is off here, it can cause damage to your engine or seriously affect your performance. You have a lot more leeway at cruise and idle (these are the areas where your vacuum advance come into play). Get it close for cruise and idle, and you will be fine.
bigjones
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Kellysguy,
I took the carb off the car and had a good look at the advance pickup hole. Even with the throttle disc fully closed there was still about 25% of the hole exposed to the manifold. (It is a small hole by the way). As you say, there are 4 cylinders sucking on it so I think that is why there is vacuum at idle. Anyways, it is immaterial now.
Morris,
You are a true gent. Thanks for the explanations. I need to get a new timing light anyway - I'll get the model that will allow me to dial in the timing and then look at the O deg mark. When it arrives I'll check the timing at 3500 as you suggest. I'll put the old timing light in the trunk - it is a good trouble-shooting tool!
Cheers!
I took the carb off the car and had a good look at the advance pickup hole. Even with the throttle disc fully closed there was still about 25% of the hole exposed to the manifold. (It is a small hole by the way). As you say, there are 4 cylinders sucking on it so I think that is why there is vacuum at idle. Anyways, it is immaterial now.
Morris,
You are a true gent. Thanks for the explanations. I need to get a new timing light anyway - I'll get the model that will allow me to dial in the timing and then look at the O deg mark. When it arrives I'll check the timing at 3500 as you suggest. I'll put the old timing light in the trunk - it is a good trouble-shooting tool!
Cheers!
OP
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As long as you don't have solid core plug wires (like me) you'll love your new light. Mine can't get a clean signal and is picking up EMP's from all five wires. My light will flash from about 3 feet away from the car.
