Premium Gas for Prewar Cars?

[Dave@Moon]

I speak for myself and I don't think that what you write reflects on me, and I don't think that you should feel that what I write or what others write, reflects on you. We are each responsible for ourself.

....I wish we could just politely talk about antique cars.

Matt, try to imagine how discussions like this make it hard for our advocate organizations like SEMA. They go into a meeting with legislators or regulators making perfectly logical points about our hobby and it's trivial impact on the environment, with the gravitas of representing a substantial number of organizations that themselves represent thousands upon thousands of American citizens. Those points are listened to politely, and then they leave.

Then some other advocacy group comes in with their points, usually one trying to obfuscate their own transgressions by putting the blame on whatever's in arm's reach (including us). They cite whatever they can about our groups to discredit SEMA (us) as biased and uninformed. Where do you think they might get such ammunition?:mad: This ain't a private chat room, and leaving unchallenged disturbed and disturbing muck-raking on this forum will be as good as blessing it with official sanction. Nobody here has the guts to delete posts like the one that started this "discussion", they'll only delete the responses. It's kind of like a badly officiated hockey game, only the second offense is ever noted.

I wish nothing more than to talk politely about antique cars. In the last 30 minutes I've made 6 or 7 posts on 4 threads about Jaguars, Cords, and Duesenbergs. That fun is frequently ruined here by this kind of hogwash, which (if you'll notice) I never initiate.

It's going to continue. Next week somebody is going to hear something on AM radio or Fox News that they'll take at face value, believe it, and that's going to set them off. Then some thread here that's vaguely related to the topic will be hijacked just like this one was, with people chiming in who heard and believed the same baloney and weren't ambitious enough to look at the real data the last 500 times I and others linked it here, or to look at it anywhere else either.

This silliness has driven dozens if not hundreds from the forum, making it an even richer source for the people who would damage this hobby to save the expense of cleaning up their own messes. Until people learn restraint, or truly educate themselves in a manner in proportion to the issue they're purporting to be interested in, it won't stop.

[Dave@Moon]

I believe you confuse well deserved skepticism for ignorance.

No.

There is a lot of money involved in the climate movement...

Laughable.

[F&J]

Y am in France ,your advices are so interrestings.

Here we have not possibility to buy Kerosene for the cars.It is reserved to Aeroplanes!!

If not y would like try it in my Stutz 1929.

Someone know what is the compression for this 6 Cylinder Blackhawk 4 L. ??....

For the olds cars we have the practice to change the seats exhaust valves and valves for resisting at unleaded fuel.

What? an on topic post? thank you

I am sure the early engine guys can answer your compression ratio question if you do a new thread and title it like: Compression ratio for 29 Stutz?"

When you say "for the old cars we change seats and valves", what years of old cars? In my experience with working on engines for many decades, the engines that don't have to "lug" almost all of the time, will not show valve recession.

But I saw ONE case of extreme recession. It was a very small Ford E100 van -nosed mini motorhome. It was so small it only had single rear tires. However it had the tall bunk above the cab which caused a lot of wind restistance. The motor was a 289 V8 Auto trans, but had highway gears. The gear ratio was too much and the engine labored all the time. The prior owner only used it for short trips.

My friend purchased it and rebuilt the motor. He went on a cross country trip from east coast to west and back. He had noticed it was losing power through the trip. He pulled the motor apart, and the valves had sunk 3/16" on some. The valves would still open, but the valve then was barely level with the top of the seat. So, the fuel/air mix could not get past.

So most engines do not lug like that all the time, so very few engines have this problem.

[Rusty_OToole]

Condescension…check.

Strawman….check.

Does not address topic….check.

Holier than thou attitude….check.

OK Dave you can go. Your work here is done.

[Dave@Moon]

But I saw ONE case of extreme recession. It was a very small Ford E100 van -nosed mini motorhome.

That's interesting. The only vehicle I have personal knowledge of where this happened to the same degree (actually a little worse) was also a Ford Van, a 6 cylinder 1968 Econoline. The owner thought he was doing a good thing by not buying leaded gas (which was then still available), but burnt the valves down to the point the van wouldn't run at all any more. This in a van that was mainly used on rural highways in Iowa. His son told me the van lasted only about 10,000 miles on unleaded alone (over the course of about a year).

I wonder if Ford had softer valve seats than other cars at the time?

[TexRiv_63]

This has certainly been a wide ranging discussion. I know that I don't need premium gas in my prewar car. How we got to this point in the discussion is absolutely amazing. I wish we could just politely talk about antique cars.

I started this thread and was happy to see that many people were interested in it and added their thoughts on this TECHNICAL issue. Unfortunately it has now been hijacked and turned into a nasty political argument and for that I am sorry.

I have been a member of many car-related online forums and groups over the years. Every one of them have a few members, usually with very high post counts, who feel the need to insert their own political and social biases into the discussion. Some of these groups have been destroyed by this behavior, to the detriment of the other members who were just there to talk about cars.

If certain people want to talk politics let them post their own thread, maybe we should add a "Politics" forum. Personally I get far too much politics from watching the news, I definitely do not want to hear it in a technical car forum. I am not a moderator but I am "locking" this thread for myself and will not be back.

[F&J]

That's interesting. The only vehicle I have personal knowledge of where this happened to the same degree (actually a little worse) was also a Ford Van, a 6 cylinder 1968 Econoline. The owner thought he was doing a good thing by not buying leaded gas (which was then still available), but burnt the valves down to the point the van wouldn't run at all any more. This in a van that was mainly used on rural highways in Iowa. His son told me the van lasted only about 10,000 miles on unleaded alone (over the course of about a year).

I wonder if Ford had softer valve seats than other cars at the time?

The valves on this late 60s Ford van were not burned at all. I had never seen this before; The valves had receded down into the seats, just like someone had bored the seats 3/16" to1/4".

Somewhere I read a long time ago that with many thousands of miles driven with leaded gas, that there are molecules of lead "pounded" into the surface of the seats, and then when the engine was forced to survive on no-lead, that there would be lead protection "unless you ground those seats during a rebuild"

I have no idea if that is what happened.

[ted sweet]

boy did this get way off topic.

[Rusty_OToole]

Today I bought the April 2010 Hemming's Classic Car. The one featuring Chevy sixes with a 56 4 door hardtop on the cover.

The reason for reviving this old thread is inside the back cover. They reproduce an Ethyl Corporation ad from 1939.

It has some things to say about gas that tie right in with this thread.

First they describe how much better the new 1939 models are.

They go on to say that the farther you advance the spark of a modern high compression engine, up to the point of maximum efficiency, the more power you get from gasoline.

But the motor "knocks" or "pings" if the spark is set farther ahead than the anti knock quality of the gasoline permits.

There are 3 grades of gasoline: Low Grade, Regular, and Ethyl.

1939 cars have a device, called a "distributor adjuster" "Octane Selector" etc for setting the spark for each of these grades.

Poor performance with "low grade" gas. There is no anti knock fluid in low grade gas.

Good performance with "regular" gas. Most regular gas has anti knock fluid. Spark can be advanced considerably for more power without "knock" or "ping".

Best performance with gas containing "Ethyl". Spark can be fully advanced for maximum power and economy.

This ties right in with what I said earlier. Keep in mind that in the late 30s "Ethyl" gas octane was in the mid 70s, "Regular" in the 60s, and "Low Grade" or "straight run" gas in the low 50s.

Today's regular is in the high 80s. So you can easily run your prewar car on today's gas with the timing fully advanced.

And in the case of cars with very low compression, below 7:1 it could pay to reduce the octane farther by adding kerosene or other heavy fuel.

[Guest zantafio]

F and J ,hello!

here y have already change four exhaust seats from a 544 sport Volvo.Like that no problem with our unleaded fuel. Y hope make the same chose with my 1929 Stutz.

This engine is realy remarkable.Double ignition,overhead camshaft !.

In this time y have begining the cylinder head removing.

This is a pleasure !....

[Guest pssmls]

I have a 1923 Buick model 44-6 (6 cyl). My question - what about the valve seats, do I need to use lead additive to protect them? My son has a 28 Dodge & he says he needs to use it in his veh. & tells me I should use it too, or I will be in trouble. My veh was partially disassembled by the previous owner, who found that he only needed to hone the cylinders and replace the rings. He did nothing to the valves, as they appeared to be fine. Would adding diesel or coal oil (I am in my 70's & that is the name I remember) have the same effect as the lead additive? Or do I not even need to worry about it? I will be doing only limited driving - at car shows and maybe a Sunday afternoon or holiday local drive. If someone could answer with specifics this question, I would very much appreciate it. THERE, I HAVE GOT US BACK ON TRACK!

[Guest pssmls]

Also, appears maybe my veh would run better by adding the diesel or coal oil. If that is the case and it will help to lubricate the upper part of the engine, then it appears it is a win-win situation. Please advise your thinking regarding this and the above posts. Thank you.

[Restorer32]

To my knowledge leaded gas was not available in 1923.

[Dave@Moon]

Ethyl (leaded) gasoline was first commercially introduced in 1923. It was not widely available for about a year, took several years to be the standard-bearer in the gasoline market, and was never completely ubiquitous. American Oil Co. (Amoco) never did have lead in it's Premium (high-test) gasoline, and by 1970 (years before EPA's requirement to do so) Amoco began marketing lead-free regular (initially in Indiana).

I don't know the susceptibility of the 1923 Buick 6 to valve seat wear, but even in engines where this problem occurs it's mainly happens during "extreme use), like hauling heavy loads, sustained highway driving, etc.

[Guest]

Interesting to note that by 1975 and the muscle era gone and compression ratios and high lift cams with high performance valve springs gone as well, that the manufacturers in that year of unleaded fuel decided to equip their engines with hardened valve seats and they have done so ever since.

Don

[Guest cben09]

Some of this new gas burns hotter,,and as a result the ex valves grow from the heat,while running only,,,so increase the valve clearence so the valves will seat,,If they are held open there will be power decrease,,and may stall when you idle it,,AND on using the starter,there may be no hint of compression,,,,I increased my valve clearence from .004 to .016 on the old Packard,,the one with the loooong stems,,,Ben

[Guest 31DH]

We drive our 1931 Dodge carsix-cylinder with overdrive at cruising speeds 50 to 55 mph with RPM about 2000. We also pull small tent trailer. The exhaust valves running hot is a continuing problem. Replacing them at least every 10,000 miles. We have had many suggestions, what we can do to solve this problem. One of them is to add two cycle engine oil to the gas, which we did on our trip to Alaska, and it did not help. The machine shop keeps telling me that my internal temperatures are running too high and he feels the only solution is to add lead to the gas. My question is, is a lead additive available?

[Guest cben09]

what valve clearence are you using,,Ben

[unimogjohn]

Lead additive available? Well, sort of, I do not know if it really contains lead. I have seen this at many auto parts and shops. I have no clue if it really works or not. But you asked.

AutoParts2020 :: CD-2 Super Concentrated Lead Substitute

Edited May 28, 2010 by unimogjohn (see edit history)

[Guest]

You can mix aviation fuel ( 100 low lead ) with premium 91-92, a ratio of one part to three but it is illegal to do so. Seems it's ok to fly above us letting lead come down on us. What it really means is the government dosen't care about old cars that require leaded fuel, but it does care about planes falling out of the sky because of a burnt exhaust valve/seat.

Don

FYI , if there is a race track near your house you can buy racing fuel, and it comes in assorted octanes.

[Rusty_OToole]

The problem is the gas is too high in octane. You need to lower it. Do not add lead additive, av gas or any high octane substance. For a 1923 Buick you should be able to add 25% kerosene or more. Diesel may work but it is oilier and may cause smoke.

This has all been discussed pretty thoroughly in this thread already.

[Guest]

The problem is the gas is too high in octane. You need to lower it. Do not add lead additive, av gas or any high octane substance. For a 1923 Buick you should be able to add 25% kerosene or more. Diesel may work but it is oilier and may cause smoke.

This has all been discussed pretty thoroughly in this thread already.

The addition of lead from aviation fuel is not used to bump octane as much as it is used to lubricate the valves and their stems and the valve seats.

Don

[bhclark]

I had a 68 Buick Electra 225 with the optional 425 cu in 10:1 compression 375HP engine. It ran OK on pump hi test as long as I did not floor the gas pedal.

If you baby your DeSoto it should be OK, otherwise you may need octane booster or a water injection unit.

I've got a '69 Electra and when I floor it, I get a hesitation. If I feather the accelerator, she'll squeal the tires nicely. I thought I needed to rebuild the carb, now I'm thinking maybe I need more octane for that 430 engine?

I currently run 93 octane with occasional lead additive and some MMO.

What's a water injection unit?

[Guest]

I've got a '69 Electra and when I floor it, I get a hesitation. If I feather the accelerator, she'll squeal the tires nicely. I thought I needed to rebuild the carb, now I'm thinking maybe I need more octane for that 430 engine?

I currently run 93 octane with occasional lead additive and some MMO.

What's a water injection unit?

Your lucky you can get 93 octane, here in California the highest we can get at the pump is 91 and to make it worse a couple of months ago the state mandated 10% ethanol so now we are getting even worse MPG.

What I would do on your Buick would be to take the air cleaner off and look down on the primary sides and open the throttle all the way and you should see a good steady squirt from your accelerator pump and I'll bet it's not doing it's job giving you a good hesitation / flat spot on hard acceleration.

Don

[Rusty_OToole]

I've got a '69 Electra and when I floor it, I get a hesitation. If I feather the accelerator, she'll squeal the tires nicely. I thought I needed to rebuild the carb, now I'm thinking maybe I need more octane for that 430 engine?

I currently run 93 octane with occasional lead additive and some MMO.

What's a water injection unit?

I had a similar problem with mine until I rebuilt the carb. There is a little metal gadget that sticks up at the top of the carb, from memory it has to be set with a clearance of .040". It gets bent easily if you are not careful removing and replacing the air filter. I had to readjust (bend) it once in a while to eliminate hesitation.

The acceleration pump is another thing to check.

93 octane should be OK, barely. Try retarding the spark a few degrees if you get ping.

Water injection is a small tank of water under the hood, and a device to squirt a small amount of water into the intake manifold. It has the effect of quenching ping and also keeps your combustion chambers clean. It allows the use of lower octane fuel safely.

In your case a lead additive or substitute may be the best idea.

[Guest 31DH]

what valve clearence are you using,,Ben

I'm using the clearance of 10 for the intake and 12 for the exhaust .

As far as using aviation fuel in our 1931 Dodge maybe would work for around home. But when we're traveling it would probably be next to impossible to get fuel quickly and would probably be very inconvenient.

Glen

[Guest cben09]

Hi Glen,, Seems to me before the war,,octane was far less than any numbers I hear now,,so I don't think octane is the problem Does it seem to loose some power after running at speed for a while,,If the valves grow til the clearance is nil,,power will fall off ,,If you have time to experiment,,try .016 on the exhaust,,,the intakes will be cooled by the cool mixture cumming in,and be OK,, Good luck,,Ben

[Guest]

I had a similar problem with mine until I rebuilt the carb. There is a little metal gadget that sticks up at the top of the carb, from memory it has to be set with a clearance of .040". It gets bent easily if you are not careful removing and replacing the air filter. I had to readjust (bend) it once in a while to eliminate hesitation.

The acceleration pump is another thing to check.

93 octane should be OK, barely. Try retarding the spark a few degrees if you get ping.

Water injection is a small tank of water under the hood, and a device to squirt a small amount of water into the intake manifold. It has the effect of quenching ping and also keeps your combustion chambers clean. It allows the use of lower octane fuel safely.

In your case a lead additive or substitute may be the best idea.

Water injection was used on some cars (Olds Jetfire Turbo) and aeroplanes in high performance applications especially where turbos were used. I was a Piston/Jet engine mechanic in the navy and we called it ADI (anti detonation injection). It was used on piston engines on take off or when using emergency power ( in persuit or being persued situations ). ADI or water injection in autos or aeroplanes uses a mixture combination of alcohol and water and never water alone. The mixture had a green dye in it whether you bought it from Oldsmobile or you were on the flight line getting it from the fuel truck or the airport or on the flight deck of a carrier. Each of the engines ( double row 18 cylinder 3,350 cu. in. radials with 3 PRT's that I worked on carried a 25gallon tank just behind the engine compartment. The Olds had a small glass (about a quart or so +- ) bottle on the rt fender well.

Getting back to the Buick, As said before I would look at the accelerator pump first, but there is another major area to look at on cars equipped with a Quadrajet carb. and that would be the tension on the spring for the secondary air flap. If it opens too fast there will be a huge flatspot on sudden acceleration.

Don

[Guest 31DH]

Thanks for the info on the octane ratings and valve clearance.

Glen