"72 318 question

[John Reddie]

A couple of years ago I picked up a 41,000 mile '72 318 engine that was in a Satellite that the owner switched to a 440. I installed it into my '67 Plymouth Fury because the original engine was really tired. I have been adding the Motor Medic Lead Substitute to the gasoline for valve protection but I recently read an article from the Exxon Company written back when unleaded gasoline first came into use and it stated the Mopar engines from '72 and beyond were made to run on unleaded fuel. Is this true? I know that Chrysler changed to the electronic distributors in '73 but this engine still uses contact points. Any info here will be great. Thanks.
John

 

[rapidtrans]

A quick look through my old sales brochures shows the 318 as capable of running on regular low leaded fuel. The electronic ignition was also new but just on the H.P. engines.
Agreed, brochures show all engines got electronic ignitions for ‘73.

 

[cbarge]

I would just run ethanol free gas at the pumps and not worry about it.
I am assuming you are not racing the car nor towing with it.
1968 to 1974 teens used the same 2843675 heads which did not have hardened valve seats.
They had small valves and in 1972 a low 8.6:1 compression so adding lead additive would not make any difference.
Avoid overheating and ensuring the 'teen is in proper tune (retarded timing can cause overheating,pinging can hurt valves if timing is too advanced) there will be no damage to the valves other than normal wear .
When the 973 heads came out in 75,they had hardened valve seats. FYI
Hope this helps
.

 

[cbarge]

The electronic ignition was also new but just on the H.P. engines.[/QUOTE|
First seen on 71 340 A bodies,
Standard equipment on 72 HP,optional on all others.
I had seen a few 318 72 cars with electronic ignition and two cars confirmed by fender tag.

 

[FURYGT]

FYI, Electronic Ignition was an option in 1972 & became standard in 1973.

 

[cbarge]

As most of you know,I have a 73 Satellite wagon with a 318.
During the rebuild,we did not install hardened valve seats in the original heads.
Not necessary with the low compression.
Just new valves with a back cut and 3 angle grind,opened up the bowls,some massaging in the ports,port match the intake and gaskets...
Basically worked with what we already have to improve torque and a cleaner burn..

 

[CBODY67]

After GM made their big deal of having everything built after April 15, 1971 being able to use unleaded fuel exclusively, Chrysler followed by stating that their 1972 model year cars COULD operate on 87 pump octane fuel (low lead or no-lead), BUT with no-lead fuel, they recommended that each third tank of fuel be low-lead or "normal" lead fuel. Then, in 1973, they went to the induction-hardened valve seats for full unleaded fuel compatibility.

Electronic ignition was originally for just the HP 4bbl motors, but was later optional in 1972 on all engines. Our '72 Newport 400 2bbl had it as an optional item, as it was a later in the year production date.

I also found a Chilton magazine in 1973, which had a proving ground report on a '72 Chrysler wagon, 440, HD trailer package, with a max-weight-rating trailer hooked to it. They ran it around the proving grounds until it would not run any more. After about 12K miles of that HD use (high speed, heavy load), the majority of the exhaust seats in the head had eroded such that the heads had to be replaced. The heads did not have induction-hardened exhaust valve seats and the fuel was no-lead fuel.

The basic depth of the induction hardening was basically on the surface metal, which would probably be ground away on the first valve job? Or at least the heat-discoloration of the metal.

In the case of the '72 318, as long as it's got good compression, it'll probably be fine for a good while longer. The valve seat erosion does not happen quickly, but over time. The first thing to happen might be oil consumption from worn valve guides, which can then lead to a burnt valve on that particular cylinder. THEN, you'll have the option of pulling both heads and getting hard seats installed, if and when that might happen.

For general principles, you might start a "valve job" savings fund to cover that when it might happen. Hopefully, it'll have grown a huge amount before it's needed.

Drive it and enjoy!
CBODY67

 

[70bigblockdodge]

If the heads have never been redone there is enough lead pounded into them and weak valve springs that you should never have to worry about it.
I would not worry about it.

 

[Big_John]

A couple of years ago I picked up a 41,000 mile '72 318 engine that was in a Satellite that the owner switched to a 440. I installed it into my '67 Plymouth Fury because the original engine was really tired. I have been adding the Motor Medic Lead Substitute to the gasoline for valve protection but I recently read an article from the Exxon Company written back when unleaded gasoline first came into use and it stated the Mopar engines from '72 and beyond were made to run on unleaded fuel. Is this true? I know that Chrysler changed to the electronic distributors in '73 but this engine still uses contact points. Any info here will be great. Thanks.
John

Chrysler had decent valve seats right along so it's not a big deal, but maybe after driving another 100k miles, you might have a little more vale seat wear, but are you going to drive your car that much? You are in Massachusetts, so let's assume that you aren't even driving 12 months out of the year. So maybe 5k miles a year? Maybe less? It's gonna take a long time to wear the valve seats out at that rate.

I personally don't like using additives. It's a PITA to dump in and it's another chemical you are exposing yourself to. Spill it on you? A good thing to remember about chemicals like that is "If it's on you, it's in you". Read the fine print or better yet the MSDS on that stuff and I'll bet you are supposed to be wearing rubber gloves etc. Just food for thought. IMHO, it's just snake oil anyway, so why waste your money.

 

[rapidtrans]

If the heads have never been redone there is enough lead pounded into them and weak valve springs that you should never have to worry about it.
I would not worry about it.

You know. An old mechanic told me the same thing when a had my GTO. When I asked about reworking the heads for unleaded he said 30 years of running on leaded then unleaded gas probably hardened the seats plenty. Car never pinged or had an issue running on premium unleaded.
That motor like my Monaco has never been pulled apart and with the the few miles I put on it in a year I think I’m good.

 

[3175375]

After GM made their big deal of having everything built after April 15, 1971 being able to use unleaded fuel exclusively, Chrysler followed by stating that their 1972 model year cars COULD operate on 87 pump octane fuel (low lead or no-lead), BUT with no-lead fuel, they recommended that each third tank of fuel be low-lead or "normal" lead fuel. Then, in 1973, they went to the induction-hardened valve seats for full unleaded fuel compatibility.

Electronic ignition was originally for just the HP 4bbl motors, but was later optional in 1972 on all engines. Our '72 Newport 400 2bbl had it as an optional item, as it was a later in the year production date.

I also found a Chilton magazine in 1973, which had a proving ground report on a '72 Chrysler wagon, 440, HD trailer package, with a max-weight-rating trailer hooked to it. They ran it around the proving grounds until it would not run any more. After about 12K miles of that HD use (high speed, heavy load), the majority of the exhaust seats in the head had eroded such that the heads had to be replaced. The heads did not have induction-hardened exhaust valve seats and the fuel was no-lead fuel.

The basic depth of the induction hardening was basically on the surface metal, which would probably be ground away on the first valve job? Or at least the heat-discoloration of the metal.

In the case of the '72 318, as long as it's got good compression, it'll probably be fine for a good while longer. The valve seat erosion does not happen quickly, but over time. The first thing to happen might be oil consumption from worn valve guides, which can then lead to a burnt valve on that particular cylinder. THEN, you'll have the option of pulling both heads and getting hard seats installed, if and when that might happen.

For general principles, you might start a "valve job" savings fund to cover that when it might happen. Hopefully, it'll have grown a huge amount before it's needed.

Drive it and enjoy!
CBODY67

In 73 all Kalifornia cars ran on unleaded. My parents had bought a 73 Mercury Colony Park 10 passenger station wagon with a 460 in it and it ran on leaded regular. My dad found out that it was a 49 state car, which is why it didn’t have a catalytic converter.

 

[John Reddie]

Thanks to all for your great tips and info. I run both of my '67 Plymouth's year around except in poor weather. I don't think a car sitting idle for a while is a good idea but this is my feeling only for sure. My '67 convertible has a '76 318 so I never worried about the valve situation there.
I am 79 and still like to work on my cars and I want to keep them going which at the present time they are performing admirably. In foul weather with heavy rain and snow, I use my '98 Ford Contour. Stay safe and healthy.
John

 

[Snotty]

In 73 all Kalifornia cars ran on unleaded. My parents had bought a 73 Mercury Colony Park 10 passenger station wagon with a 460 in it and it ran on leaded regular. My dad found out that it was a 49 state car, which is why it didn’t have a catalytic converter.

Not true at all. I still purchased regular leaded gas in 1981-2. Sometime after that Leaded gas was discontinued. Cats were not put on cars until 1975.

To the main question, Lead Sub is not necessary.

 

[3175375]

Not true at all. I still purchased regular leaded gas in 1981-2. Sometime after that Leaded gas was discontinued. Cats were not put on cars until 1975.
To the main question, Lead Sub is not necessary.

I didn’t say that leaded fuel disappeared in 73, I said that new cars were sold in 73 ran on unleaded.

I did a search and unleaded and low lead fuel was available as early as 70:

When was unleaded gasoline introduced in California?

“It seems Chevron introduced unleaded gasoline in California in late 1970 or early 1971 per this advertisement in the Santa Cruz Sentinel, dated 11/17/1970. Quote: "Chevron Unleaded Is for those 71 cars designed for lower octane unleaded gasolines"

 

[Snotty]

I didn’t say that leaded fuel disappeared in 73, I said that new cars were sold in 73 ran on unleaded.

I did a search and unleaded and low lead fuel was available as early as 70:

When was unleaded gasoline introduced in California?

“It seems Chevron introduced unleaded gasoline in California in late 1970 or early 1971 per this advertisement in the Santa Cruz Sentinel, dated 11/17/1970. Quote: "Chevron Unleaded Is for those 71 cars designed for lower octane unleaded gasolines"

Low-Lead and Unleaded were introduced, but that doesn't mean the cars ran on it. The '73 Maverick my parents bought new ran on regular Leaded gas. Cars were not required to run on Unleaded until 1975. That was when the gas tanks fillers went to the smaller holes. '74 tanks are normal.

 

[CBODY67]

In '74, in TX we had Exxon unleaded (87 pump octane), Exxon low-lead (91 pump octane), and Exxon Extra (94+ pump octane) leaded, as I recall. Full-leaded fuel used to have about "5 gms/gal of TEL in it, no matter the octane, but that amount had been decreased a good bit by the '73 time frame. Seems the low-lead was something like 2gms/gal TEL? The available octanes would vary with the altitude of the region they were sold in. DFW had 92 pump octane super unleaded, but Abilene, TX (a higher base altitude in near-west TX) had 91 pump octane super unleaded in the same brand, for example.

As mentioned, the first year for cat converters on light-duty pickups (6001 lbs GVW and below) and passenger cars was 1975. Unleaded fuel was necessary for the cats to live, so the fuel tank inlet restrictors were in place on those vehicles. Before the unleaded fuel became widely available, there was "white gas" that was available at higher altitudes. Tidewater Petroleum's "Flying A" brand of gasolines was fully unleaded (even their premium fuel) in the earlier 1960s, using another anti-wear additive that was not tetraethyl lead.

Enjoy!
CBODY67

 

[cbarge]

That was when the gas tanks fillers went to the smaller holes. '74 tanks are normal.

Up here in Canuckville, regular leaded gas was available until being banned by December 1990!!!
I remember that most gas stations did carry it but by mid-80's did not push it and sold more of the unleaded.
My 83 K car 2.2 with a carburetor and no cat convertor was designed to run on regular leaded gas if it had too!
It had the large tank filler hole.

 

[Snotty]

It had the large tank filler hole.
View attachment 437456

I was thinking yesterday, so does the '73 Gremlin in my garage.

 

[70bigblockdodge]

Not true at all. I still purchased regular leaded gas in 1981-2. Sometime after that Leaded gas was discontinued. Cats were not put on cars until 1975.

To the main question, Lead Sub is not necessary.

I agree I was able to buy leaded gas in California all the way up till I left in 1989.
It was long gone back along the east coast in August 1988 when I drove my Challenger home.

 

[Snotty]

I agree I was able to buy leaded gas in California all the way up till I left in 1989.
It was long gone back along the east coast in August 1988 when I drove my Challenger home.

I was attending Fuller Seminary in Pasadena from January '82 though March of '85. Until November '83 I drove my '70 Challenger, filling it up with Regular Leaded at the Chevron in South Pas where I/we lived. In that month we bought our first new car... and used Unleaded. I kept the Challenger until 1987 when I sold it to buy a Ramcharger.