Timing question
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Intermediate
Joined: Sep 2006
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From: Stanley Virginia
Timing question
I'd like to set the timing on my 327/365. The manual calls for 10 degrees BUDC. I believe that's Before Upper Dead Center. My timing mark on the engine has an "0" then above it an "A". I assume the "0" is DC and the "A" is advance?? Is that right? How many degrees are the tick marks in between? Do I set it 10 degrees from the "0" towards the "A" ??
(I just picked it up and I really want to get my hands a little dirty)
Tks
(I just picked it up and I really want to get my hands a little dirty)
Tks
Le Mans Master
Joined: Apr 2004
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From: Newark DE
Mike
is it a '64 or a '65.
I can't answer for '64's but if it's a '65 the actual Chevrolet spects for a 327/365 call for an initial timing of 12º BTC @ 700 rpm, not 10º.
This is straight out of the "Chevrolet 1965 Corvette Specifications" book that I got directly from GM as part of their information package you can order from them.
Each line should be 2º.
BTW, if you use a dialback timing light it makes it REALLY easy as all you need to do is set the dial on the light to 12º than adjust the distributor until the index line of the balancer is on the "0" mark.
Also, if your distributor is set up correctly it should have 24º of mechanical advance in it so when the timing is all in you will have 36º total timing with the initial set at 12º.
This is all with the vacuum can line disconnected from the can and plugged.
After setting the above, reconnect the vac. can and you should see an additional 16º of advance if you have the correct can installed and it's working properly.
is it a '64 or a '65.
I can't answer for '64's but if it's a '65 the actual Chevrolet spects for a 327/365 call for an initial timing of 12º BTC @ 700 rpm, not 10º.
This is straight out of the "Chevrolet 1965 Corvette Specifications" book that I got directly from GM as part of their information package you can order from them.
Each line should be 2º.
BTW, if you use a dialback timing light it makes it REALLY easy as all you need to do is set the dial on the light to 12º than adjust the distributor until the index line of the balancer is on the "0" mark.
Also, if your distributor is set up correctly it should have 24º of mechanical advance in it so when the timing is all in you will have 36º total timing with the initial set at 12º.
This is all with the vacuum can line disconnected from the can and plugged.
After setting the above, reconnect the vac. can and you should see an additional 16º of advance if you have the correct can installed and it's working properly.
Thread Starter
Intermediate
Joined: Sep 2006
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From: Stanley Virginia
Thank you.
I need to check into this more. I got that info from the owners manual. I've ordered a the shop manual for 63 and the suppliment for 64 (mine's a 64). I should wait ,but I love to tinker with cars and I'm very excited about owning a vette.
Thanks for the info.
mike
I need to check into this more. I got that info from the owners manual. I've ordered a the shop manual for 63 and the suppliment for 64 (mine's a 64). I should wait ,but I love to tinker with cars and I'm very excited about owning a vette.
Thanks for the info.
mike
Le Mans Master
Joined: Nov 2000
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From: Going too fast over the hill. Iowa
on the old engines, A is usually AFTER TDC. Go the other way.
At any rate, when I time my 350 and look at the timing scale, 2-4-6-8-10 degrees Before Top Dead Center is above zero - after top dead center is below zero.
At any rate, when I time my 350 and look at the timing scale, 2-4-6-8-10 degrees Before Top Dead Center is above zero - after top dead center is below zero.
Last edited by magicv8; Oct 1, 2006 at 09:43 PM.
Race Director
Joined: May 2000
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One set of specs I have says 12 nominal, 10-14 range, and setting timing on a 365 is tricky because the centrifugal starts at 700 and the engine will barely run at that speed with the vacuum advance disconnected, which must be done to set intial timing. Plug the line with a golf tee while it's disconnected.
Since the advance is all in at 2350 it's easier to set the total WOT timing, which is the sum of initial and full centrifugal. Use a dial back light and set it at 36 (or in the range of 34-38) at about 2500+ and verify that it doesn't advance any higher by quickly revving it to at least 5000.
Initial timing is a tuning parameter - like tire pressure. There's no magic "best" number, but the above range is good and if you can get to 14/38 without detonation, go for it. We typically can't run these engines with as much initial timing as we could with the higher fuel octanes back in the sixties, so we have to run in the lower end of the range if not retarded a couple of degrees below that.
With a little avgas blended in you can go to about 16/40, but probably not with pump gas.
Duke
Since the advance is all in at 2350 it's easier to set the total WOT timing, which is the sum of initial and full centrifugal. Use a dial back light and set it at 36 (or in the range of 34-38) at about 2500+ and verify that it doesn't advance any higher by quickly revving it to at least 5000.
Initial timing is a tuning parameter - like tire pressure. There's no magic "best" number, but the above range is good and if you can get to 14/38 without detonation, go for it. We typically can't run these engines with as much initial timing as we could with the higher fuel octanes back in the sixties, so we have to run in the lower end of the range if not retarded a couple of degrees below that.
With a little avgas blended in you can go to about 16/40, but probably not with pump gas.
Duke
Safety Car
Joined: Feb 1999
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From: Fountain Hills AZ
Also, unless you've already made certain that your distributor still has the same specs as original, check the curve. A 40 year old distributor has likely been rebuilt, replaced, or modified, and original specs may no longer apply. Be sure to do as Duke suggested and check your readings to at least 5k.
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From: Stanley Virginia
Yikes.........
I think I'm getting in a little over my head.What happen to the days of shinning my ol' Sears strobe timing light down on the 2 chalk marks and turning the dist until they meet??
Guess I need to do a little more research. Thanks for the info and heads up......
ps. what's a dial back light??:
Don't laugh. it's been a "few" years since I did any of this.....
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Joined: Apr 2004
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From: Newark DE
Mike
it's not that hard, believe me. I'm new at working on cars so I'm still basically an idiot at it but even I can set and adjust timing on these things so if you have done it before you can do it now.
a dial back light simply is a bit more advanced design of a timing light than the "older style" types.
this is the one I use and believe me, it makes checking and setting timing REALLY EASY.
http://www.sears.com/sr/javasr/produ...seBVCookie=Yes
it's not that hard, believe me. I'm new at working on cars so I'm still basically an idiot at it but even I can set and adjust timing on these things so if you have done it before you can do it now.
a dial back light simply is a bit more advanced design of a timing light than the "older style" types.
this is the one I use and believe me, it makes checking and setting timing REALLY EASY.
http://www.sears.com/sr/javasr/produ...seBVCookie=Yes
Team Owner
Joined: Oct 2000
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From: Washington Michigan
Originally Posted by magicv8
on the old engines, A is usually AFTER TDC. Go the other way.
