1971 Cutlass 350 timing - ClassicOldsmobile.com


Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old August 12th, 2018, 03:53 PM   #1  
Registered User
Thread Starter
 
Join Date: May 2018
Posts: 90
1971 Cutlass 350 timing

Hi guys,

My new timing light has arrived and I am exited to get the timing adjusted and then the new carburetor installed.

This is the light:
https://innova.com/en-US/Product/Detail/3568

The light is at work so I haven't had a chance to read any instructions yet but I am sure they will set me off in the right direction. Is there anything specific to these cars or any better procedure that I should be aware of? Probably a dumb question but I haven't adjusted timing for about 15 years and even then was just a plain old light, nothing fancy.

Second part of the question is what the timing should actually be. The car is basically bone stock, including the carburetor that will be going on after. Should I just look up the original manufacturer recommendations or are there better settings to use?

Thanks for the help and knowledge, like I said it has been a long time and I have never used a light with any kind of advanced features.
71OldsCut is offline   Reply With Quote
Old August 12th, 2018, 07:27 PM   #2  
Registered User
 
Fun71's Avatar
 
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 5,366
Assuming it still has the points distributor, use the factory timing procedure and settings.
If it has a GM of similar HEI, you need to use different initial timing settings.
Fun71 is online now   Reply With Quote
Old August 13th, 2018, 06:51 AM   #3  
Old(s) Fart
 
joe_padavano's Avatar
 
Join Date: Mar 2007
Location: Northern VA
Posts: 29,666
Quote:
Originally Posted by Fun71 View Post
If it has a GM of similar HEI, you need to use different initial timing settings.
Why? The engine determines what the timing requirements are - cam, CR, etc. The engine neither knows nor cares whether the spark is triggered mechanically with points or electronically with an optical or Hall effect sensor. All the engine cares about is when the spark plug is fired. Yes, the mechanical and vacuum advance curves in the distributor have an effect on the optimum initial timing, but given how much variability there is among HEI distributors, that needs to be figured out no matter what.
joe_padavano is online now   Reply With Quote
Old August 13th, 2018, 01:40 PM   #4  
Registered User
 
Fun71's Avatar
 
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 5,366
I say that because points distributors have more mechanical advance than GM HEI distributors, which translates to a higher initial setting in order to achieve the same amount of total advance.
Fun71 is online now   Reply With Quote
Old August 13th, 2018, 05:11 PM   #5  
Registered User
 
Join Date: Nov 2008
Location: Central Fl
Posts: 4,951
Quote:
Originally Posted by Fun71 View Post
I say that because points distributors have more mechanical advance than GM HEI distributors, which translates to a higher initial setting in order to achieve the same amount of total advance.
Then you adjust accordingly, per Joe’s statement. The engine combination dictates the correct amount of advance etc., not the distributor.

Last edited by cutlassefi; August 13th, 2018 at 05:31 PM.
cutlassefi is offline   Reply With Quote
Old August 13th, 2018, 06:07 PM   #6  
Registered User
Thread Starter
 
Join Date: May 2018
Posts: 90
So the numbers I have dug up say 12° at 1100RPM. It also says the idle should be 600RPM in drive. Does that sound reasonable? Seems OK to me, but again I haven't adjusted this type of stuff in a lot of years, lol.

With that said, I guess the best way to do this is to use the idle adjusting screw to get the engine to 1100RPM, adjust the timing to 12°, then adjust the idle back down to 600RPM in drive? It just seems like it would be difficult to be accurate with either opening the carb manually from under the hood to get to 1100RPM and move the distributor or have someone in the car raising the rpm and holding it steady.

The website also gives me "point gap" and "dwell angle" but I am not even entirely sure what those mean or how to adjust them so I think I will just stick to the timing for now, lol.
71OldsCut is offline   Reply With Quote
Old August 13th, 2018, 06:45 PM   #7  
Registered User
 
droldsmorland's Avatar
 
Join Date: Jul 2010
Location: New Tax York
Posts: 2,705
Run as much base timing and vacuum advance as the engine can handle at curb idle without preignition. Don't worry about what the book says. Ive been doing this for many years and never have set my timing above curb idle. 11-1200rpms makes zero sense to me for performance tuning.

A starting point for you could be 12-14* base timing with the vac advance disconnected.
Add another 10-12* with the advance can hooked to unported vacuum. Get an adjustable limit (not rate) advance canister if yours is not right.
Then the centrifugal should bring in the rest at about 2700 rpm for a total of 36-40* at 2700-2800 rpm at sea level with good non-ethanol gas. If it spark knocks under load back off the base 2* and limit the vacuum to 8* vs 10 and road test.
Use a vacuum gage hooked to manifold vacuum to tune. Turn the air/fuel screws in/out to obtain the highest vacuum signal possible. Tweak the timing and A/F mixture adjustments in unison to obtain the highest vac signal possible. You don't really need a timing light tuning with a vac gauge. The light helps dial in each of the three events so you can see the actual numbers. I always go to the vac gauge.

Point gap is a static gap measured with a clean feeler gauge between the points on the highest spot of the crown of the cam (distributor cam). .016" to .018".
Dwell is the same adjustment but measured with a tach/dwell meter. 30* of dwell = .017" point gap but is measured running.
If you have a QuadraJet you will likely need to mess with the AVS valve. We'll save that for another discussion.
Follow this recipe you'll be rewarded with a great running engine and might smell some rubber.

Last edited by droldsmorland; August 13th, 2018 at 06:56 PM.
droldsmorland is offline   Reply With Quote
Old Yesterday, 05:29 PM   #8  
Registered User
Thread Starter
 
Join Date: May 2018
Posts: 90
Thanks droldsmorland, is this still a wise thing to do if you are just looking for fuel efficiency and proper running condition and not too concerned about performance? It isn't a performance car and we don't try to use it as one.

I also have a fully restored quadrajet rebuilt by Ken at Everyday Performance. It should be all setup and ready to go other than the fuel mixture screws from what I understand so hopefully that part will be fairly straight forward.
71OldsCut is offline   Reply With Quote
Old Yesterday, 06:55 PM   #9  
Registered User
 
droldsmorland's Avatar
 
Join Date: Jul 2010
Location: New Tax York
Posts: 2,705
With the tweaks I mentioned above you will get performance and economy...if that's even possible with a 71. 13-14mpg downhill with a tailwind is about it. Possibly more with a 2bbl but I've never owned a 2bbl Olds.
Its simple to tune with a vacuum gauge. Plug the gauge into intake manifold vac source either the carb base or a nipple on the intake(preferred). Adjust the A/F screws until you obtain the highest reading. Have the distributor somewhat lose enough to turn while it's running and again observe the vac gauge and shoot for the highest vac reading. Go back to the A/F screws then back at the timing at least twice both times achieving the highest vac reading. Done. Test drive. If it pings back off the timing a degree or 3.
Verify the point gap/dwell is spot on too.
Verify zero vacuum leaks too.
91 or better non-ethanol gas as well.
droldsmorland is offline   Reply With Quote
Old Yesterday, 07:11 PM   #10  
Registered User
Thread Starter
 
Join Date: May 2018
Posts: 90
Ok, and when making these adjustments shooting for the highest vacuum, is there a tipping point where it will actually start going down or is it just the pre-ignition sound I am listening for? I am just concerned about going too far and damaging something.

I am guessing I would want to check the point and dwell before doing all this, or it doesn't matter?

Thanks!
71OldsCut is offline   Reply With Quote
Old Yesterday, 07:19 PM   #11  
Chevy budget Olds powered
 
coppercutlass's Avatar
 
Join Date: Jul 2011
Location: Elgin, Illinois
Posts: 7,338
On my street/strip SBO 355 I ran 14 intial 22 mechanical for a total of 36. car ran 12.2's more than that didn't help . as far as people who say you need as much initial as possible it can become a balancing act because of hot starts. They can be slow sluggish and you wont be happy. I run a really aggressive curve so as soon as its off idle the timing is climbing fast coming . Just Fwiw. Even on my much milder sbo powered B body Pontiac it likes a fast cruve with only 12 degrees initial all in by 2800. This is just my experience on my setups.
coppercutlass is offline   Reply With Quote
Old Yesterday, 08:18 PM   #12  
Registered User
 
droldsmorland's Avatar
 
Join Date: Jul 2010
Location: New Tax York
Posts: 2,705
Quote:
Originally Posted by 71OldsCut View Post
Ok, and when making these adjustments shooting for the highest vacuum, is there a tipping point where it will actually start going down or is it just the pre-ignition sound I am listening for? I am just concerned about going too far and damaging something.

I am guessing I would want to check the point and dwell before doing all this, or it doesn't matter?

Thanks!
Yes, the vac signal will drop so will RPM when too lean or too rich. "Just right" on the A/F mix will produce the highest vac signal. Additively so will timing. That is why you need to do small tweaks to both....one at a time.

Beware of any vacuum leaks, poor ignition components or fuel delivery problems as it will make these adjustments canted lean or rich. Always verify everything is in good service before making any adjustments or you will go off into the weeds.

Post your results so we know we all helped you and your Olds.
droldsmorland is offline   Reply With Quote
Old Yesterday, 08:25 PM   #13  
Registered User
 
droldsmorland's Avatar
 
Join Date: Jul 2010
Location: New Tax York
Posts: 2,705
Quote:
Originally Posted by coppercutlass View Post
On my street/strip SBO 355 I ran 14 intial 22 mechanical for a total of 36. car ran 12.2's more than that didn't help . as far as people who say you need as much initial as possible it can become a balancing act because of hot starts. They can be slow sluggish and you wont be happy. I run a really aggressive curve so as soon as its off idle the timing is climbing fast coming . Just Fwiw. Even on my much milder sbo powered B body Pontiac it likes a fast cruve with only 12 degrees initial all in by 2800. This is just my experience on my setups.
Good point. Each engine is slightly different. So are ambient conditions such as elevation (air density), temp etc...Same for fuel and driving style. Your specs are what I always recommend as a starting point. 12-14, another 10ish on the can and all of it in at 2700 2800, 36-38-40* total.... Its an Olds thing. My Chevys like a bit more(small block 327). Cadillac a bit less (8.2L!).
Bottom line is super tunning is a technique of using all of your senses to super tune to dial in just what it likes...arent modern self-adjusting cars boring?

Last edited by droldsmorland; Yesterday at 08:27 PM.
droldsmorland is offline   Reply With Quote
Old Today, 06:28 AM   #14  
Registered User
Thread Starter
 
Join Date: May 2018
Posts: 90
Alright guys, I will see what I can do.... hopefully this Friday, if not sometime Saturday and Sunday. Should have some results by the end of the weekend.
71OldsCut is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Timing cover sealing after timing chain replacement Destructor Small Blocks 7 July 23rd, 2018 03:43 AM
Timing Experts, I need more timing! jpc647 Small Blocks 7 June 10th, 2013 11:48 AM
timing 1971 cutlass 350 danthedirtguy Big Blocks 10 March 30th, 2013 08:55 AM
Timing Chain & Gears 1971 Cutlass 350 dallasite21 General Discussion 1 April 1st, 2010 07:24 PM
TIMING, TIMING, TIMING.....AGAIN 442scotty General Discussion 8 May 13th, 2009 05:42 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -7. The time now is 01:46 PM.


© 2018 MH Sub I, LLC dba Internet Brands
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.