Spark knock in a 32 Packard ??

[Alfa]

Brilliant !!

[Morgan Wright]

To answer the original question of whether 10% ethanol gas causes knocking because of lower octane, the answer is

 

NO

 

Ethanol has a MUCH higher octane than gasoline. Something like 140 or 180. It has a crazy high octane. Adding ethanol to gas raises the octane not lower it.

[trimacar]

Ethanol has an octane of about 113.  It raises 84 octane regular gas to 87 octane when mixed at 10%.  The oil companies adjust for this during the process, so if you see 87 octane at the pump, even with ethanol, that's what it is, not higher than 87.

 

Octane has nothing to do with power, however, and any time you add ethanol to regular gas, you lose available energy, and your mileage suffers.  Most studies show that 10% ethanol cuts your gas mileage 3 to 4%.

 

Octane is the measure of how much compression gasoline can stand before self-igniting.  As discussed above, most early engines had low compression ratios, so it's not usually an issue.

[Guest]

Something to consider,  If your timing seems okay now you could put a dot of white paint on your harmonic balancer and one appropriately on the timing cover so that you have a reference point in the future.  It would be simple enough to remove the distributor cap and make sure the points are just opening for number  one cylinder.  Perhaps not as accurate as if you could do it when you had the starter off so it would be exact but a reference point is at least a place to start.

By the way I'm glad to see your ignition problem solved.  Good luck with the carb.

Edited January 6, 2018 by Guest (see edit history)

[carbking]

Came late to this thread, may be able to contribute.

 

Octane is, at best, confusing, because there are three different systems, and the USA has used two different of the systems in different eras. The three systems are: Motor, Research, and AKI (anti-knock index). Here is an article I did some time ago to attempt to explain: http://www.thecarburetorshop.com/Octane.htm

 

As to the carburetor: Zenith carbs from about 1934 to about 1980 have a round tag approximately the size of a dime riveted to the body of the carburetor. There should be at least one, and probably two sets of numbers. If two, then there will be an inner and outer set. The outer set would be the "customer's" part number (eg. Ford, Chevrolet, Gray Marine, etc.) while the inner number would be the Zenith number, and the number that is most useful. Acquiring the Zenith number will allow you to determine the original application, and therefore the applicability of that carburetor to your engine.

 

Packard in 1932 would have used the Detroit Lubricator type 51 carburetor. While an excellent carburetor when in proper working condition, the design is totally different than most other makes of carburetor, and rarely understood by the owner of the vehicle or his/her mechanic. Also, the DL is QUITE EXPENSIVE to correctly restore. Many of them have been replaced over the years.

 

Jon.

[gward1211]

I'm a bit puzzled by the comments on dwell angle.  A modern coil and single points can run a V8 up to 6,000+ rpm and still fire well.  In a 30's engine (perhaps with a modern coil) with maximum rpm around 3,000, surely there is ample coil charging time at a much reduced dwell angle, ie, a wider points gap.  Why is dwell important (within reason) in an old, slow-revving engine?

Kind regards

 

Geoff Ward