Happy Easter and welcome to Packard Motor Car Information! If you're new here, please register for a free account.  
Login
Username:

Password:

Remember me



Lost Password?

Register now!
FAQ's
Main Menu
Recent Forum Topics
Who is Online
119 user(s) are online (71 user(s) are browsing Forums)

Members: 1
Guests: 118

Packard5687, more...
Helping out...
PackardInfo is a free resource for Packard Owners that is completely supported by user donations. If you can help out, that would be great!

Donate via PayPal
Video Content
Visit PackardInfo.com YouTube Playlist

Donate via PayPal



(1) 2 »

Type of gas and whether to use lead substitute?
#1
Home away from home
Home away from home

humanpotatohybrid
See User information
Wondering what the community consensus is on octane of gas and whether to add lead substitute for the 56 V8 engines with 9.5:1 compression?

Posted on: 2022/11/16 20:02
'55 400. Needs aesthetic parts put back on, and electrical system sorted.
'55 Clipper Deluxe. Engine is stuck-ish.
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#2
Home away from home
Home away from home

ScottG
See User information
My '55 352 runs just fine on 87 Unleaded. Previous owner of 10-plus years used the same.

Posted on: 2022/11/17 2:37
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#3
Home away from home
Home away from home

Jack Vines
See User information
Quote:

humanpotatohybrid wrote:
Wondering what the community consensus is on octane of gas and whether to add lead substitute for the 56 V8 engines with 9.5:1 compression?


Quote:
My '55 352 runs just fine on 87 Unleaded. Previous owner of 10-plus years used the same.
World's of difference between a 7.8 compression '55 352" and a 10:1 '56 374". The '56 with 9.5 is in-between. I've seen some with piston tops showing severe detonation effects from running cheap gas. No more miles than hobby cars get, go with the good stuff and keep a close watch on ignition initial timing settings.

jack vines

Posted on: 2022/11/17 10:53
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#4
Forum Ambassador
Forum Ambassador

Owen_Dyneto
See User information
Agree 100% with Jack. Even with 91 octane gas my 1956 Caribbean required the timing to be kicked back a few degrees to keep spark knock down to a tolerable level.

Posted on: 2022/11/17 11:53
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#5
Home away from home
Home away from home

humanpotatohybrid
See User information
Thanks for the responses so far, I have a couple questions:

Is there any sense to use octane booster with normal gas instead of buying premium gas? Or a booster/lead substitute combo?

Why does a 10:1 ratio need 90-something octane when new cars with 11:1 ratios run fine on 87?

Posted on: 2022/11/17 12:52
'55 400. Needs aesthetic parts put back on, and electrical system sorted.
'55 Clipper Deluxe. Engine is stuck-ish.
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#6
Home away from home
Home away from home

ScottG
See User information
Wow, I didn't know that there was that much of a compression jump between '55 and '56. Too bad really, because I've been in the situation of having to figure out what 'mix' is right for a car and it can be a real pain. It's nice just pulling up to the pump and reaching for regular.

Posted on: 2022/11/17 21:28
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#7
Home away from home
Home away from home

JeromeSolberg
See User information
"Why do new cars get away with 87 octane with 11:1 compression"

There are really 3 reasons:

1) Direct injection

2) Variable valve timing

3) Infinitely-variable ignition timing

All of them, in combination with computer control and knock sensors, allows the engine to run on the edge of knock all the time. In fact, many cars will detect and compensate for better or poorer gasoline - so you can get better performance with higher-grade gasoline (because of more advantageous timing), but the car will still run with lower-grade gasoline.

Posted on: 2022/11/18 2:37
 Top  Print 
Like (1)
 


Re: Type of gas and whether to use lead substitute?
#8
Home away from home
Home away from home

humanpotatohybrid
See User information
ScottG

Yeah, what's odd (and annoying) is that regarding fuel, the 55 and 56 owners manuals have the exact same phrasing to use "high octane fuels" without suggesting an actual number... unhelpful when there is easily a 5 point difference or more between the fuel needed for a 8.5:1 55 engine and a 10:1 56 Caribbean engine.

Posted on: 2022/11/18 9:28
'55 400. Needs aesthetic parts put back on, and electrical system sorted.
'55 Clipper Deluxe. Engine is stuck-ish.
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#9
Home away from home
Home away from home

Wat_Tyler
See User information
IIRCF< octane rating numbers changed sometime in the 70s, so any number suggested in factory literature would have gone the way of the dodo.


My bikes are 10:1 and 10.7:1 respectively. They both get 93 octane from Shell. They both have EFI and computers, so they likely could make do with other fuel.


My truck book recommends 89 octane but it runs fine on 87. I tried 89 once and noticed not a bit of difference. And I ain't spending the money if it doesn't care. It has EFI and a computer, too.


The '46 Deluxe gets 87.

Posted on: 2022/11/19 0:27
If you're not having fun, maybe it's your own damned fault.
 Top  Print 
 


Re: Type of gas and whether to use lead substitute?
#10
Home away from home
Home away from home

Packard Don
See User information
I don’t recall octane even being mentioned in the ‘50s or ‘60s. The cars used either Regular or Ethel.

Posted on: 2022/11/19 1:31
 Top  Print 
 




(1) 2 »




Search
Recent Photos
Photo of the Day
Recent Registry
Website Comments or Questions?? Click Here Copyright 2006-2024, PackardInfo.com All Rights Reserved