1968 Mopar Engine - Do I need Lead substitute?

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Hello fellow BITOG members,

I keep hearing conflicting information on this one from various sources. I have a 1968 Dodge Polara with a 383 under the hood. I've been running the engine on Premium since I purchased it. I have the timing set to factory specs and no pinging whatsoever. Does anybody know if this engine would need some form of lead substitute added to the tank?
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I believe I read that Lucas UCL can function as a replacement to the missing lead but I'm looking for some guidance. I'm also thinking about running a seafoam treatment to clean out the intake manifold/combustion chambers.

Any input would be appreciated
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Ed B.
 
Can't go wrong with Lucas
I don't think you can go wrong with lead in those engines ither for that matter
 
I'd run some "instead-o-lead" from CD-2 - always helped with pinging in my old '68 Volvo along with premium octane fuel, so it does help.

Maybe even run a lead substitute and the UCL - it doesn't cost much if you want a better peace of mind, plus I doubt you're putting tons of miles on it.
 
A lot depends on how you run it.
Lead is used for valve seat 'lube'. But tests seem to
indicate that it's only really usful at 3000 rpm or more.
Easy driving, even some hyway use, not really needed.
The need for lead to stop ping or detonation is not a problem with premium gas.
My 2¢
 
The lead that you need is for the valves and seats, any proper octane fuel will correct any pinging.
There is residual lead [if the engine isn't rebuilt] on the valve guides, seats, and valves. For a very occasionally driven car, you won't have to worry about it.
I'd use UCL and a lead subsitute otherwise.
 
Is that the 383 with the 2bbl carb or 4bbl? If it's the 4bbl, I believe it was designed to run on 100 octane Ethyl. I would be surprised to learn that today's premium gas doesn't allow occasional pinging.
 
rriddle3,

My engine is the 2bbl version. Carter BBD I believe. 9.2:1 compression. Premium - 92/93 octane yields no ping.

MechTech - As far as I know, the engine has never been opened up. It has 126,000 on it.

Everybody else - Thanks for the input!! I already have Lucas UCL in the tank so it looks like I was already on the right track.
 
A few years back, when lead was being phased out, I recall the various muscle car magazines printing articles on how to handle the situation.

Can't recall the details but one recommendation was to yank the heads and have a qualified machine shop harden the spot where the valves hit the heads. Can't remember if they recommended that valves be replaced with harder-faced ones.

A good machine shop should be able to inform thee fully and there is likely a few Web sites with good info, though you can't believe everything you read.

As the chap above mentioned. Intermittent use of the older engine likely wouldn't require adaptation, especially if you kept your foot "out of it."

But, if you're gonna' show folks what a mighty Mopar can do.... might be a good idea to do a little upgrading.

Of course, a later-model or aftermarket set of heads may be the way to go but then you lose your "numbers matching" style originality.

Mopar rules!!!!!!!!

Coot dream machine: 1971 Plymouth GTX with either Hemi or 440 6-pack.

Coot practical machine: 1970- early 1972 Duster with 340 and a 4-speed.

Dear Santa...........
 
Old Coot wants a Mopar muscle car.
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I had a friend years ago that had a 1969 GTX with the 440 and 4-speed. He said that it was the best car he had. He sold it in 1977 because of the gas costs. He had another friend that asked him if he still had it. If he did, it would have been worth 16 grand. And that was 15 years ago.
 
My first new car was a 1970 RoadRunner. I sometimes still have dreams that I own it today. Guess it really made an impression on me. Seeing them on Barrett-Jackson really hurts.
 
I still sob at night.

In 1974 I had the opportunity to buy an immaculate 1971 'Cuda. Red, many options, 440 Six-Pac, 4-speed, CONVERTIBLE. Worth mega-bucks now. Price? $2,600 0r $2,800... one of those two, forget which one of the two prices was the asking price.

And....

A Plymouth SuperBird. Blown-up 440 replaced with a 383. Minor body damage, various dents and scrapes from circle track racing. Easy fixes and the engine could have been replaced with a 440 from the same year without decreasing value a whole lot. Selling price? $1,800

Just no place to store them. If I had had a relative with the room in a garage or barn or shed, I KNEW that those cars would never be built again and would go up in value. No idea they would go up as much as they have.

Let's look at NADA for a GENERAL guide.

'71 Cuda:

TOTAL PRICE Low: $123,300 Medium: $197,550 High: $357,750

Superbird

TOTAL PRICE Low: $65,543 Medium: $112,219 High: $211,883

You can buy a lot of shanties with those bucks.

Sniff.
 
SuperEd73 , that sounds like a fun car to have
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- any more details ? Always thought highly of that year and that engine . Well, I'm digressing . As to the other yes , you are on the right track as is dwendt44's first post - thats definitely part of it - although on this one I think those rules are a little severe .

Quote:


I keep hearing conflicting information on this one from various sources.




Yep , esp. from the Chevy , Ford and now the Import guys who now are collecting Mopar .

What pray tell , have you been hearing ?

Is this by any chance about potental valve/valve seat recession with unleaded fuel ?

If so , this is not as simple a subject with 60s Mopar as it is with '60s everything else .

Thats not a bad thing , but rather , a good thing although with the internet and I guess the passage of time its now all 'confused up', if you follow .

Quote:


I have a 1968 Dodge Polara with a 383 under the hood. I've been running the engine on Premium since I purchased it.



How long have you had it ? Do you happen to know what the PO was running ? Is this a two door ?

Quote:


I have the timing set to factory specs and no pinging whatsoever.


No surprise on this one . Does this include the UCL ?

Quote:


Does anybody know if this engine would need some form of lead substitute added to the tank?
dunno.gif





Well , the short answer on this specific 383 'B' block build from this specific year is it depends - its a little more variable than most .
Again not a bad thing - you have more possible outcomes and choices in a sense from superior metallurgy and some other things so its a little more complicated than some others .
From the sounds of it you definitely don't need it for preignition and detonation avoidance - assuming your mechanical and vacuum advance are stock (or better ) and working properly .
In only general terms if you've got what your manual specs for an advance curve up thru about 32 - 38 degrees dialed in by anywhere between 1400 - 2400 rpm you are definitely ok and are not stuck with a reverse set of cheater springs on the mechanical portion or something similiar in effect on the vaccum side ie unecc. additional spark advance 'retard' .


Quote:


I believe I read that Lucas UCL can function as a replacement to the missing lead but I'm looking for some guidance. I'm also thinking about running a seafoam treatment to clean out the intake manifold/combustion chambers.


In the meantime Lucas UCL is yes , a real good idea - in more ways than one , and it definitely won't hurt anything . Right now for no particular reason the oldy and junior we have here ( all Mopar ) are for summer being doped with basically a 1/2 dose of UCL combined with a 5/8 dose of STABIL on one and MMO/100 LL AvGas with a little pump premium on the other which is working well enough in both cases .

Same thing with the Seafoam ( done correctly ) , although I usually prefer steam .

So , SuperEd73 , have you done the more manly '68 Mopar things here such as adjusting your torsion bars for your own fancy , favorite 'road course' and local area road crown ?
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Checked the driver's side lugnut torque ?
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patriot.gif
 
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g20ooh, Hmmmm I'm now interested in this "steam" method you mentioned.

Yes all of that internet chatter is exactly why I'm here. Just hoping to find somebody with first hand info instead of "well a friend of mine has 19xx whatever and did blah blah".

As for my Dodge, it's pretty much bone stock outside of a mellow sounding dual exaust with a couple of old style turbo mufflers. Has 383 2-bbl which is untouched. Still has original single-point distributor. I tuned it up a couple of weeks ago and I realized the vacuum advance was dead. Doesn't hold vacuum. I have one on order and I'll install that when I get a chance. The car doesn't seem to ping with or without Lucas UCL in the tank. I think the high octane is taking care of that on it's own.

It's a 2-door hardtop in original Dodge WW1 White with black interior. No vinyl roof. Was repainted about 6 years ago. I only purchased about 3 months ago. Very solid car. Any rust issues were taken care of at the time of the repaint with real metal. Floors are solid. Previous owner is a mechanic so he took care of anything under the hood/under the car that needed attention. He installed new water pump, 26" radiator, high-output alternator, new drums/shoes/brake lines, leaf springs (torsion bars are still good), shocks, etc. Everything works. PO also installed a Hella H4 conversion for the headlamps. They look stock but have halogen cartridge style bulbs. So, I can actually see at night! Condition wise I believe it's a solid "3". I really don't want it to be anything more than that. It's a car that runs nice, looks good and if I get a paint chip on the hood, I won't cry over. Of course if anybody is dumb enough to bump into those big solid chrome plated bumpers, I won't be the one crying! Haven't had to check the driver's side lugnuts but I know they torque to the left.

It's pretty neat when I get somebody next to me in a Mercedes S65 bi-turbo and they say "nice car".
 
I'll join in here on a few points.

The method of reporting octane has changed since that car was built. Today's 93 octane is about the same as 100 octane was back then.

Lead helps prevent valve seat recession. It doesn't take much lead to provide protection. In the 60's lead was used as a cheap way to increase octane and much more was used than needed to protect the valve seats. A better way to think of it is that since there was plenty of lead in the fuel the engine designers didn't need to make the seats robust enough to run without lead. The high levels of lead (or weak seats) actually contributed to burned valves, a problem that has all but disappeared.

Lead tends to stay around in the combustion chambers for a while even after you stop using it in the fuel.

Valve seat recession is much less likely to be a problem on an engine that isn't worked hard. If it isn't a daily driver and subjected to hard driving there is less chance of there being a problem. Pulling a trailer over long grades would be a time I would want some lead substitute added. An occasional full throttle blast is not likely to be an issue.

Hotter cams and higher spring pressures would also contribute to valve recession.

This issue also came up with vehicles converted to Propane that were built in that time frame. In some areas, a lot of cab drivers converted to Propane to same money (Calgary, where Propane was about 1/4 of the cost of gas). The prevalent feeling among those who were involved with such conversions was to not worry about the expense of hardened valve seats until there was a problem. Most never had to make the upgrade.

In your case, for peace of mind, I would add some lead substitute occasionally, especially when I knew that I would be working the engine hard.
 
Quote:


I tuned it up a couple of weeks ago and I realized the vacuum advance was dead. Doesn't hold vacuum. I have one on order and I'll install that when I get a chance. The car doesn't seem to ping with or without Lucas UCL in the tank. I think the high octane is taking care of that on it's own.




Once you get that vacuum advance working you may start to see a pinging problem. No vacuum advance may be why you don't have a pinging problem now.
 
I don't remember how it works on a Chrysler product, but many of those vacuum advances were adjustable. With Ford for many years it was by adding spacers (washers) to increase spring tension. Later Fords were adjustable with an allen wrench through the vacuum nipple. I think I remember Chrysler being the same way. You should start by matching the old one to the new one. Turn the screw all the way in and count the turns. Do the same with the new one.

Ping from too much vacuum advance usually is only during part throttle when engine vacuum is highest. If it does ping at part throttle under light to moderate load, try tightening the screw before resetting the timing from twisting the distributor.

Your fuel economy should go up from having the vacuum advance working. That's the main reason for it being there.
 
You're going to need a lead substitute, but the better option is to just pull the heads and machine them for hardened valve seats. I rebuild old Mopars as a hobby, and any pre-1972 head won't have hard valve seats, and you will see exhaust valve recession into the head over time. I just rebuilt a '70 440 that had 60K original miles that had exhaust valves that were sitting 1/4" farther into the head than the intake valves were, as well as having their seats burned. If your head casting numbers are either 906,518, or 342 (last 3 digits of casting number), you don't have hardened seats. The only big block heads that came ready for unleaded gas were on '76-'78 400s or 440s (452 heads).

Exhaust seat recession will (1) lower compression (good for you with today's gas), but (2) will slowly increase your chances of burning an exhaust valve over time, or (3) end up eroding into the cooling jacket.

Honestly-as long as the Polara's not a daily driver, I wouldn't worry about it. But if you starting hearing a popping noise from your exhaust, or notice coolant in your oil, you'll know why. At some point you'll probably want to rebuild the engine anyway, and you can have the inserts inserted then. I had my machinist insert hardened seats on the 440 I was talking about above, and the total cost including parts came to $50-so it's not too terribly expensive.

HTH-
Fitz
 
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