72 Plymouth Duster with a 318. Need oil advice!

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Hello everyone, my first time posting here after being a lurker for awhile.

I just bought a 1972 Plymouth duster, it's got the original 318 5.2L V8 in it. The odometer only shows about 80,000 miles on it. As far as I know it runs like a champ, starts up easily, purrs like a kitten, and doesn't show any oil leakage at all.

It will be driven in city stop and go traffic roughly 15 miles 2 to 3 times a day, 3-4 days a week year around in Tucson, AZ. Temperatures can fluctuate from the very rare 30s in the winter to the more normal 100-110 in the summer.

I can't find any information on what type of oil this engine even calls for! I'll pick up a manual this weekend but I still wanted to tap into all yalls experience on here and ask what would you prefer? And why?

Should it be synthetic or conventional?

Thanks!
 
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I put over 400,000 miles on my 73 318, and I can tell you that its not going to be picky about oil at all. If you give it a good quality oil, it will serve you well.

For your climate, a high quality 5w30, 10w30 will be fine for many years of service. Synthetic or conventional, either one. I'd probably use Pennzoil yellow bottle conventional, and either Mobil 1 or maybe Pennz Platinum if I wanted synthetic.

If you want to go the extra mile to be sure the flat tappets have MORE than enough ZDDP, you could run a heavy duty oil like 5w40 Rotella T6, or a performance-oriented synthetic like M1 0w40. I run M1 0w40 in my old Mopar big-blocks because it keeps the oil pressure from going off the scale on cold startup (high-volume oil pumps).

One thing I would ABSOLUTELY advise you to do is have the timing chain and gears replaced. The weakest link (pun intended...) of a 318 from that era is the cam gear in the timing set. Its made of nylon to run quietly, but a common failure mode is for teeth to start breaking off. This at first doesn't do anything except let plastic teeth get stuck in the oil pickup screen, but eventually enough will break off so that the timing chain can jump, and when that happens you'll probably put an exhaust valve through a piston. Don't ask how I know, but I know.... Put on a high quality steel timing set- I prefer dual roller sets like this:

http://www.summitracing.com/parts/MIL-15011/

Its a fair amount of work but it really is necessary if you want the engine to last. If you do it yourself it also lets you look down into the oil pan in addition to the timing chain case to assess how clean things are. (and by the way, just use RTV to re-seal the oil pan to the timing case- the little gasket segments they give you to do that are useless).
 
I have never owned a 318, but I do know they are bomb proof.
Just use whatever 10w30 looks good to you and the engine will live an (even longer) happy life.
 
We ran our fleet on Dodges for many, many years. Great, simple engines.

As 440 said above^^^ expect timing chain failure. It's common. And don't fall for the high volume oil pump hype if you rebuild, as it is a bowl of rocks.

Odds are by 80k miles you should not have any issues, but the plastic gears degrade by TIME as well as mileage. So a new chain and gear set is highly recommended.

Cool old car, too!
 
Their the Mopar boy`s!
grin2.gif
 
Flat tappet in Arizona: 15w-40 or Rotella 10w-30 if it gets chilly.

Todays SM/SN grade passenger car oils are way low on ZDDP.

Yeah, the cam might survive on regular PCMO, but why take the chance when HDEO can be had for about the same price.
 
Originally Posted By: 440Magnum
I put over 400,000 miles on my 73 318, and I can tell you that its not going to be picky about oil at all. If you give it a good quality oil, it will serve you well.

For your climate, a high quality 5w30, 10w30 will be fine for many years of service. Synthetic or conventional, either one. I'd probably use Pennzoil yellow bottle conventional, and either Mobil 1 or maybe Pennz Platinum if I wanted synthetic.

If you want to go the extra mile to be sure the flat tappets have MORE than enough ZDDP, you could run a heavy duty oil like 5w40 Rotella T6, or a performance-oriented synthetic like M1 0w40. I run M1 0w40 in my old Mopar big-blocks because it keeps the oil pressure from going off the scale on cold startup (high-volume oil pumps).

One thing I would ABSOLUTELY advise you to do is have the timing chain and gears replaced. The weakest link (pun intended...) of a 318 from that era is the cam gear in the timing set. Its made of nylon to run quietly, but a common failure mode is for teeth to start breaking off. This at first doesn't do anything except let plastic teeth get stuck in the oil pickup screen, but eventually enough will break off so that the timing chain can jump, and when that happens you'll probably put an exhaust valve through a piston. Don't ask how I know, but I know.... Put on a high quality steel timing set- I prefer dual roller sets like this:

http://www.summitracing.com/parts/MIL-15011/

Its a fair amount of work but it really is necessary if you want the engine to last. If you do it yourself it also lets you look down into the oil pan in addition to the timing chain case to assess how clean things are. (and by the way, just use RTV to re-seal the oil pan to the timing case- the little gasket segments they give you to do that are useless).
x2 on the timing chain and gears. A 318 will bend every exhaust valve if the chain jumps. BTDT!
 
Originally Posted By: 84zmyfavorite
Chevy and Mopar V8s of that era both used nylon covered timing gears. Stupid idea if you ask me. Yes, quieter for awhile, until it comes apart.



Ford`s did too didnt they?
 
Originally Posted By: Arnoldr45
Hello everyone, my first time posting here after being a lurker for awhile.

I just bought a 1972 Plymouth duster, it's got the original 318 5.2L V8 in it. The odometer only shows about 80,000 miles on it. As far as I know it runs like a champ, starts up easily, purrs like a kitten, and doesn't show any oil leakage at all.

It will be driven in city stop and go traffic roughly 15 miles 2 to 3 times a day, 3-4 days a week year around in Tucson, AZ. Temperatures can fluctuate from the very rare 30s in the winter to the more normal 100-110 in the summer.

I can't find any information on what type of oil this engine even calls for! I'll pick up a manual this weekend but I still wanted to tap into all yalls experience on here and ask what would you prefer? And why?

Should it be synthetic or conventional?

Thanks!


The odomater showing 80K might be 180K, 280K, etc...? Hopefully for you it is truly 80K. If it were me I would run a 10W40 due to where you are at. More than likely the OE spec was 10W30 for most temp ranges and in high temp ranges such as you will see 10W40. 10W30 is ok but not my personal choice. I have had a lot of A & F Body MOPARs with everything from the 225 S-6 to the 318/340/360 engines and I have always run 10W40 or 20W50. 20W50 would not be crazy especially in AZ during the summer in your vehicle. IMO a 30 weight is not the best option.

I would also run a High Mileage oil in it or some type of muscle car oil along the lines of Brad Penn specifically made for older vehicles that need ZDDP. Valvoline MaxLife synthetic blend is probably the easiet to find and most affordable. It is also, IMO, the best HM oil out there. I would definitely get some ZDDP additive for it unless the oil yuo get has a lot of it already. I would not run a modern SN/SM oil in it, straight, without an additive. Your top end and cam will suffer long term if you do. JMHO.

Also, here is a HUGE tip for you backed up by many years of MOPAR experience. Get yourself an extra ballast resistor( or 2 or 3 or 4, etc... )and keep it in your glove box. These are a common thing that fails. You will know it has failed when your engine turns over but won't start. I ALWAYS kept at least one in the vehicle when I had a MOPAR with one( your 72 Duster has one ). I kept a couple back ups at home for it too.

Enjoy the vehicle.

PS - I will also echo the timing chain problem comments others have made. Had that happen on a couple older vehicles of this type with the 318.
 
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Originally Posted By: 84zmyfavorite
Chevy and Mopar V8s of that era both used nylon covered timing gears. Stupid idea if you ask me. Yes, quieter for awhile, until it comes apart.


Add Ford- my '68 302 had a nylon cam gear. And Pontiac... at least one of my friends went through that with a Poncho in HS.

Not all engines got them. In Mopar-land, the 340, 383HP, 440 HP, and 426 Hemi all got steel timing sets (in some cases dual-roller) from the factory. So did the industrial engines, including the industrial 318.

It was a dumb fad trying to make engines ultra-quiet so ignorant owners wouldn't complain, and automaker "B" had to do it because automaker "A" did. Add offset wrist pins to that stupid list too- they increase friction and wear but eliminate piston slap which is harmless.
 
Well [censored], I guess I'll be replacing a lot more than my oil this weekend!

I've heard from various people that adding an additive to oil messes up the levels of the oil and in effect degrading it since it's no longer a fine balance done by the manufacturer, any truth to that?



I appreciate the help fellas, thank you!
 
FWIW... as a long-time Mopar guy, I really don't think there's a sound reason for using 15wXX or 20wXX oils for a 318. (sorry, NHHEMI, we usually agree on stuff like that)
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NO, it absolutely WON'T hurt. But all its going to do is slow oil flow on startup, jack the oil pressure up silly-high, put some (probably not measurable) extra wear on the oil pump drive, and make the lifters tick longer on startup (if they tick, not all do). Go ahead if you want to, but it just isn't needed. It sure isn't worse in that regard than the old straight 30 weights back in the day and these engines did fine on them. But in today's world of very high VI oils (even budget oils)... for anything in the continental US, a good 10w40 or 5w40 is absolutely the thickest thing that engine needs. And if cost isn't an option, 0w40 is just about ideal.
 
I put a 15-40 at the top of the list for that car in that locale.
For a bunch or reasons.

And the guys are not kidding about the timing chain thing.
All cars ate timing chains once or twice in their life. But plastic toothed gears were time bombs.
 
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