Having just jumped back into the hobby after a 17 year hiatus, I will be posting a few questions...hope you all will abide my inquiries.1. What is the best gasoline, in todays market, to run in a '67 w/L79 engine.2. Can we use synthetic oils in these older cars and if so what rating (I live in Texas)? This car will see about 1500-2000 miles per year.Thanks.
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Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star Regional -
Re: gas and oil
Hi Leif,
Welcome back. I would say non Ethanol gas would be best if you can get it. Are you a member of the Texas chapter? Maybe the locals can advise you. I don't know if you need premium or not. Duke's San Diego presentation would probably help you. It's here:
For oil, I would recommend API CJ-4 oil. Shell Rotella T is one brand. It's available at Wal-Mart. CJ-4 has the right amount of Zinc and Phosphorous for our old cars with sliding surface valve trains. Here's another Duke Williams article for you (scroll down to page 3 for his oil article):
Joe -
Re: gas and oil
thanks, Joe, for the guidance. Not a member of the Texas Chapter as of yet...used to be.Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: gas and oil
Check your area for pure gas, without ethanol, here:
I always try to run ethanol free premium, about 90 octane in my altitude. Not as high octane as the ethanol blend, but to get rid of the ethanol is the key issue for older cars.Big Tanks In the High Mountains of New MexicoComment
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Re: gas and oil
Not the Satan Ethanol argument again......................
Try to get 91 or 93 octane either E10 or pure gas. This should allow you to use factory timing settings without encountering detonation.
As for oils, zinc (ZDDP) levels and viscosity are far more important than any synthetic vs. dino concerns. Read Duke's paper
you'll be all set.Comment
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Re: gas and oil
thanks, Michael...i'll do some local checking of the gasoline grades.Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: gas and oil
Leif,
FWIW, after you make sure your L-79 is in good tune check and make sure the distributor centrifugal and vacuum advance are working. I would suggest 10-12* initial timing with the original #236 vacuum control which provides 15* additional timing.
This along with the 3810 Holley in good tune and a properly functioning heat riser valve and gasoline should not be a problem. Keep in mind the gasoline is different than the old leaded gasoline from 60's-70's and you can get better performance with some additional tuning but the stock settings still work fine.Comment
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Re: gas and oil
You're welcome. My local jobber feels there will be many more popping up now that EPA has backed down on the E15 mandate, and more importantly, the new farm bill drastically cut subsidies for ethanol production.Big Tanks In the High Mountains of New MexicoComment
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Re: gas and oil
Leif,
I went back to 91 pump gas here in CA in the 425 BB that's in my Chevelle. It ran so good with factory timing that it continued to shake rattle & run after I turned the ignition off. I had to retard my timing and take a power hit.
DOMComment
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Re: gas and oil
Ara,
I hope Mike is right that there will be more alcohol free stations added to that list. The nearest to my home is 57 miles.
Last year as i wandered the highways & byways with the Z06 I tested it on alcohol free gas -- or I tried to. My first effort revealed a station erroneously listed on that list, and since the low fuel light was on, I gave up that time. Subsequently I found a station in Bowling Green Kentucky (guess why I was there
) and another in Marsailes Illinois. Both were fuel depots with no attendants and the posted octane was 88 or 89. If you intend to use locations on that list I highly recommend checking the gasoline availability before you are committed in your travels.
TerryComment
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Re: gas and oil
Dom,
Many times when a engine runs on after shut down it's because of high cylinder temperature. This can be caused by retarded timing which causes high engine temperature and a improperly adjusted primary throttle blade.
FWIW, set the idle using the secondary throttle stop after setting the primary throttle blades to where the transfer slot is exposed .010-.020 max. You can turn the secondary stop screw around so the carburetor does not need to be removed again to set.
If necessary the initial timing can be advanced to a limit which will allow the throttle blades to be closed further.Comment
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Re: gas and oil
If an engine with ported vacuum advance exhibits run-on after shutdown it can usually be eliminated by converting to full time vacuum advance assuming the VAC meets the Two-Inch Rule.
DukeComment
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Re: gas and oil
Timothy and Duke...you think I could get you guys to tune my L79? y'all appear to have more knowledge than anyone I've run into in a long, long time. thanks, again, for all the terrific information.Leif
By the way, I'm being reminded every time I read a post why I missed my Corvette all these years. Beside the obvious (the car) it is all the genuine camaraderie off all that participate...can't thank you enough!!Leif
'67 Coupe L79, M21, C60, N14, N40, J50, A31, U69, A01, QB1
Top Flight 2017 Lone Star RegionalComment
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Re: gas and oil
Being as how I live in California, logistics would be a big issue, but my San Diego presentation linked to in post #2 gives you everything you need to know about how to optimize the performance of your L-79 assuming you can do basic automotive work and have the "tools of the trade".
Otherwise, someone in your local chapter might be able to help, or you might be able to find a competent Corvette mechanic in your neck of the woods, but it's not a slam dunk in any part of the country. In any event, make sure anyone you find to help reads the pdf too.
Search for threads started by me. There aren't that many, and look for the thread about the blueprint/overhaul of a L-79 distributor from December 2012.
DukeComment
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