Simple timing question
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From: morgantwn wv
Simple timing question
Hi Guys
I'm timing my 66 327/300. To set the initial advance, you have the idle adjusted to 500 rpms and disconnect the vacuum and plug. My question ...do you set the idle speed before or after you disconnect the vacuum? I checked Service Manual and many post....no answer. Thanks.
I'm timing my 66 327/300. To set the initial advance, you have the idle adjusted to 500 rpms and disconnect the vacuum and plug. My question ...do you set the idle speed before or after you disconnect the vacuum? I checked Service Manual and many post....no answer. Thanks.
Team Owner
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Army
An unmodified SBC 250/300 HP should idle fine a lot lower than 800 RPM. My SWC idle is intentionally high at 750 RPM so when I cut the A/C on it goes down to a nice, smooth 600 RPM (4 speed car). Of course age, vacuum leaks, timing variations, centrifugal advance coming on too soon, are all factors.
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From: At my Bar drinking and wrenching in Lafayette Colorado
Hi Guys
I'm timing my 66 327/300. To set the initial advance, you have the idle adjusted to 500 rpms and disconnect the vacuum and plug. My question ...do you set the idle speed before or after you disconnect the vacuum? I checked Service Manual and many post....no answer. Thanks.
I'm timing my 66 327/300. To set the initial advance, you have the idle adjusted to 500 rpms and disconnect the vacuum and plug. My question ...do you set the idle speed before or after you disconnect the vacuum? I checked Service Manual and many post....no answer. Thanks.
Lars
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From: morgantwn wv
When setting/checking initial timing, you have to do so with the rpm at a point lower than the start point of the centrifugal advance curve. Most centrifugal curves start adding advance at about 800 rpm, so you check the initial at an rpm a bit lower than that. If you can get it to idle at 500, that's fine, but may be a bit over-kill on the low rpm... It doesn't matter if you set the low idle before or after you yank the vacuum hose off, as long as the rpm you're checking the timing at is low enough to assure that the advance weights are fully retracted.
Lars
Lars
Thanks Lars and all replies.
Now at 3000 rpm all in is 30 deg recommended 36 deg. Should I adjust to 36 Deg? Would like it correct so how to fix? Car has hesitation above 4000 and accelerating. Wanted to adjust timing set up so I could feel I address any electrical gremlins. Bottom line the car runs rich and Holley has a high pitch whistle. Want rebuild but wanted to address any timing problem first. Thanks BTW initial set at 10deg.
Last edited by chuckaroo; Sep 3, 2014 at 02:27 PM.
Thread Starter
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From: morgantwn wv
Dwell dead on 30 degrees. I have an advance timing light and it will check volts, dwell, timing, rpm, maybe even barometric pressure and wind direction. How do I go about obtaining 36 deg? Up initial, change centrifugal advance springs? Is there a kit to handle this adjustment? Thanks for all your help I appreciate.
BTW I don't remember disconnecting the vacuum. Will that effect the final degree?? Apparently or you wouldn't mentioned lt. I'll try again. Thanks.
Last edited by chuckaroo; Sep 3, 2014 at 03:22 PM.
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From: morgantwn wv
Will do and check for 36. Will try later when I get a chance and let you know. Is this the usual way to get 36 deg just by adjusting the initial timing?? I will do this in the future. Sure appreciate your help. Thanks.
Team Owner
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From: Washington Michigan
You need to check for detonation in either case, but definitely if you crank the initial up from 10* to 16*.
If the Holley has a high-pitched whistle, you have a vacuum leak - usually that's a wrong baseplate-to-main body gasket and/or loose baseplate-to-main body screws.
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From: morgantwn wv
Timing Question
When setting/checking initial timing, you have to do so with the rpm at a point lower than the start point of the centrifugal advance curve. Most centrifugal curves start adding advance at about 800 rpm, so you check the initial at an rpm a bit lower than that. If you can get it to idle at 500, that's fine, but may be a bit over-kill on the low rpm... It doesn't matter if you set the low idle before or after you yank the vacuum hose off, as long as the rpm you're checking the timing at is low enough to assure that the advance weights are fully retracted.
Lars
Lars
Hi Guys
I'm back again. I haven't done much with my timing since advanced light isn't working so I started to checking out my distributor. Now, I remember being able to turn the rotor a few degrees against some spring tension and then return. When I tried mine it didn't budge. When I checked the centrifugal weights they moved in and out with no resistance...totally free to move. The small springs were in place. I would guess the weights would move out when cranking to start....no centrifugal advance. What's up with that?? What parts would be needed to fix the advance mechanism?? Thanks.