Tuning Suggestions

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Old Aug 7, 2018 | 08:59 AM
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76 Regency's Avatar
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Tuning Suggestions

Hi gang,

I'm looking for a few suggestions regarding a few tools for tuning my cars. I have 2 '76 Ninety Eight's, both of which are essentially bone stock, except for the exhausts. They both have dual exhaust. I really want to get both cars dialed in as they run well but not as well as I know they should. I've replaced the timing chains and gears on both cars so the timing holds well.

I have a timing light but it's a more basic one that does not provide RPM. Any suggestions?
I believe I should have a vacuum gauge. Any suggestions?
Does a vacuum gauge also help find any potential vacuum leaks?
I'd like to do a compression test as well. Any suggestions on a tester?

Any other tool suggestions and/or sources for info on tuning would be greatly appreciated.

Thanks!
John

Last edited by 76 Regency; Aug 7, 2018 at 09:13 AM.
Old Aug 7, 2018 | 09:03 AM
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A tach would be required to set idle speed and timing.
Old Aug 7, 2018 | 09:06 AM
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Originally Posted by oldcutlass
A tach would be required to set idle speed and timing.
thanks for the quick reply. Do you suggest a standalone tach that I believe could plug into the distributor or is a timing light that displays the RPM sufficient?
Old Aug 7, 2018 | 09:31 AM
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Like a cheap tach and dwell, your only going to use the tach portion. I've used my old Sears one for over 40 years. You can get them at a pawn shop, ebay, yard/garage sales, etc...
Old Aug 7, 2018 | 10:41 AM
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Originally Posted by oldcutlass
Like a cheap tach and dwell, your only going to use the tach portion. I've used my old Sears one for over 40 years. You can get them at a pawn shop, ebay, yard/garage sales, etc...
is this something like you use?

https://www.ebay.com/itm/Vintage-Sea...sid=m570.l1313
Old Aug 7, 2018 | 11:36 AM
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Wideband O2.
Old Aug 7, 2018 | 11:44 AM
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Originally Posted by cutlassefi
Wideband O2.
what do you mean? Forgive me for being a little inexperienced in this area.
Old Aug 7, 2018 | 12:01 PM
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hey Mark, what kinda numbers would he be after, idle, part cruise, wot.
Old Aug 7, 2018 | 12:06 PM
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Originally Posted by woodie582
hey Mark, what kinda numbers would he be after, idle, part cruise, wot.
I want to correctly set the idle, choke high-idle, A/C high-idle and then tune all that can be tuned

John
Old Aug 7, 2018 | 12:08 PM
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Wide band would measure air to fuel ratio
Old Aug 7, 2018 | 02:23 PM
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Originally Posted by 76 Regency
I have a timing light but it's a more basic one that does not provide RPM. Any suggestions?
I've never used one that has an RPM gauge. Just get a cheap tachometer from the auto parts store. Your basic timing light should be fine.
Originally Posted by 76 Regency
I believe I should have a vacuum gauge. Does a vacuum gauge also help find any potential vacuum leaks?
Get one, yesterday. A vacuum gauge is probably the single most useful diagnostic tool you could have in your automotive medical kit. The behavior of the vacuum reading can indicate many kinds of problems. As far as finding a vacuum leak, no, it won't show you where it is, but it will indicate that there IS a vacuum leak if the reading is low.

Here's a chart that shows what various vacuum readings can indicate. You can find charts like this online with a google search.





Originally Posted by 76 Regency
I'd like to do a compression test as well. Any suggestions on a tester?
Whatever is cheap at the local auto parts store. A compression tester is a very simple device.


Old Aug 7, 2018 | 02:56 PM
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Originally Posted by 76 Regency
Yes something like that or any other functioning one.
Old Aug 7, 2018 | 02:58 PM
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Originally Posted by cutlassefi
Wideband O2.
That's funny Mark... While it would be a great tool for a performance engine, I doubt its really necessary for this.
Old Aug 7, 2018 | 03:20 PM
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Originally Posted by oldcutlass
That's funny Mark... While it would be a great tool for a performance engine, I doubt its really necessary for this.
I couldn’t disagree more. Whether it be on a performance build or grannies grocery getter an incorrect air/fuel mixture can be the cause of a lot of problems, from stumbling to pinging to poor throttle response. An O2 takes all the guess work out.
i do lots of basic stuff on the dyno as well as performance builds. They ALL benefit from being able to dial in the correct air/fuel.
Idle is normally around 14-14.5:1, depending on camshaft. Cruise is about the same, maybe a little leaner, but again dependent on camshaft.
Full throttle I shoot for 12.5-12.8:1. Seems to work best in or around that area.
Old Aug 7, 2018 | 06:49 PM
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Originally Posted by cutlassefi

I couldn’t disagree more. Whether it be on a performance build or grannies grocery getter an incorrect air/fuel mixture can be the cause of a lot of problems, from stumbling to pinging to poor throttle response. An O2 takes all the guess work out.
i do lots of basic stuff on the dyno as well as performance builds. They ALL benefit from being able to dial in the correct air/fuel.
Idle is normally around 14-14.5:1, depending on camshaft. Cruise is about the same, maybe a little leaner, but again dependent on camshaft.
Full throttle I shoot for 12.5-12.8:1. Seems to work best in or around that area.
I agree, what we used to pay 15K for back in the early 90's you can buy a wide-band A/F for about $200-$250 and know your in the ball park carb etc wise
Old Aug 8, 2018 | 07:21 AM
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Thanks for the information guys. I'll definitely be much happier when my cars are better tuned.
Old Aug 11, 2018 | 07:24 PM
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What was the condition of your timing chains and how many miles were on them. I have to do my 70 Cutlass with 82,000 miles before it skips.
Old Aug 12, 2018 | 04:26 AM
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One car's set was in much better shape than the other. Both had approximately 150K. The Car with the worse set had loads of bits of the can hear in the oil pump screen. That car made a dramtic performance improvement.
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