regarding full synthetic oil

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Bob Barry said:
I am new to owning Chrysler products and recently purchased a 1967 440 cu in Imperial, is synthetic motor oil preferred ?
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I wouldn’t.
That motor wasn’t designed to run synthetic.
Not to mention synthetic may very well increase or cause leaks on that 440.
Castrol GTX 20/50 is a great oil for that motor.
You will get lots of opinions on oil brands and types, but Castrol and Valvoline are both really good.
 
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Bob Barry said:
I am new to owning Chrysler products and recently purchased a 1967 440 cu in Imperial, is synthetic motor oil preferred ?
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No. What's preferred according to the factory that made it is in the 1967 Chrysler Imperial service manual. It's broken down according to climate.
 
than
TrailBeast said:
I wouldn’t.
That motor wasn’t designed to run synthetic.
Not to mention synthetic may very well increase or cause leaks on that 440.
Castrol GTX 20/50 is a great oil for that motor.
You will get lots of opinions on oil brands and types, but Castrol and Valvoline are both really good.
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k you trail beast, the sticker on the widshield states 'synthetic' but I was having my doubts as to possible leakage, and the car does have small leakage. I appreciate your advice and will have the oil changed to Valvoline which I was told is the best for my Imperial. It is a survivor with only 63,040 origional miles and an 8 1/2 to 9 out of 10, I want to keep it that way. Thanks again, Bob
 
Welcome to FABO. The Welcome Wagon forum is to introduce yourself and show off your car.
 
TrailBeast said:
I wouldn’t.
That motor wasn’t designed to run synthetic.
Not to mention synthetic may very well increase or cause leaks on that 440.
Castrol GTX 20/50 is a great oil for that motor.
You will get lots of opinions on oil brands and types, but Castrol and Valvoline are both really good.
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agree with this ^^^^^^^^^^^^^^^^^
but, synthetic hasnt caused any problems with my 440/505......jfyi
 
Not enough information to give you meaningful advice.

The most important part is the style of camshaft, if it has a flat tappet cam the oil needs to have a fairly high zinc content so the lifters and cam lobes stay happy. But if it’s got a roller cam upgrade you don’t need the zinc.

Next up is if the engine is original or rebuilt. If it’s all original with 60’s tolerances you don’t want to run thinner oil, you could lose oil pressure and pick up leaks. But if the engine has been rebuilt with more modern clearances then you can run more typical modern engine oil weights.

Just saying it’s a 440 and it needs 20-50w is nowhere near the whole story.
 
I run Valvoline syn blend "high mileage" 10/30 in everything except my 2015 Renegade that calls for "euro spec".

...for the last 20 plus years.
 
72bluNblu said:
Not enough information to give you meaningful advice.

The most important part is the style of camshaft, if it has a flat tappet cam the oil needs to have a fairly high zinc content so the lifters and cam lobes stay happy. But if it’s got a roller cam upgrade you don’t need the zinc.

Next up is if the engine is original or rebuilt. If it’s all original with 60’s tolerances you don’t want to run thinner oil, you could lose oil pressure and pick up leaks. But if the engine has been rebuilt with more modern clearances then you can run more typical modern engine oil weights.

Just saying it’s a 440 and it needs 20-50w is nowhere near the whole story.
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I gave better information than we got. :D
The Castrol GTX 20/50 in Florida was a safe answer.
Having run it in every new and classic for over five decades without failure is proof enough for me.
 
I initially ran Castrol 20/50 in my 70 Super Bee and found that it broke down relatively quickly.
The lifters started chattering before I thought a change was due.

In my quest to resolve that somewhat chronic issue, I tried Valvolne and it lasted MUCH longer.
That's what sold me on that brand, and I've been happy with it ever since.

I did run Motorcraft syn blend a few times when it was on sale and was pretty happy with it, too.
 
TrailBeast said:
I gave better information than we got. :D
The Castrol GTX 20/50 in Florida was a safe answer.
Having run it in every new and classic for over five decades without failure is proof enough for me.
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If the chemical makeup of Castrol GTX had stayed the same for the last 50 years you’d have a point. It hasn’t.

Pretty much all the major oil brands have dropped the zinc content of their non-specialty oils in the last decade (or two) as most cars run roller cams. The Castrol you buy off the shelf today is not the same oil it was 50 years ago, that’s a fact.

For the most part, only specialty oils still have appropriate zinc levels for a flat tappet cam.

Now whether the OP has a flat tappet cam or not, well who knows.
 
I have always considered 20/50 a VERY heavy oil for our engines. That said, I've seen a LOT of people run it through the years and every time without fail they had great service from it. I tried it in my slant 6 and it literally made it feel like it was bogging down trying to start cold. It would start and cut off several times. I could also tell a difference in how the engine ran. It would not idle well until it got warm. I ended up switching it to the same I run in everything now. Motorcraft 5/w20 synthetic blend and zinc additive added to it. As soon as I made that change, I felt an instant difference in how the engine ran. I couldn't believe it, but that's what happened.
 
72bluNblu said:
If the chemical makeup of Castrol GTX had stayed the same for the last 50 years you’d have a point. It hasn’t.

Pretty much all the major oil brands have dropped the zinc content of their non-specialty oils in the last decade (or two) as most cars run roller cams. The Castrol you buy off the shelf today is not the same oil it was 50 years ago, that’s a fact.

For the most part, only specialty oils still have appropriate zinc levels for a flat tappet cam.

Now whether the OP has a flat tappet cam or not, well who knows.
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Understood, and I realize this is a fact.
Just saying I have personally never had cam/lifter or any other lubrication failure using either of the two mentioned oils with flat tappet valve trains.
I do think it’s possible zinc additives may be more important with todays lack of metal and machining quality.


RustyRatRod said:
I have always considered 20/50 a VERY heavy oil for our engines. That said, I've seen a LOT of people run it through the years and every time without fail they had great service from it. I tried it in my slant 6 and it literally made it feel like it was bogging down trying to start cold. It would start and cut off several times. I could also tell a difference in how the engine ran. It would not idle well until it got warm. I ended up switching it to the same I run in everything now. Motorcraft 5/w20 synthetic blend and zinc additive added to it. As soon as I made that change, I felt an instant difference in how the engine ran. I couldn't believe it, but that's what happened.
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Not sure how to address this.
Maybe your motor doesn’t produce enough power to overpower the oil pump?

Gotcha :D

Seriously though, I have never experienced anything like that.
Of course every single time oil comes up there is always other opinions.
The OP is in Florida where it can get pretty warm, and 440’s are not generally regarded as high winding motors with tight tolerances.
Those two facts are what guided my suggestion.

Sure, if it was a motor originally designed to run synthetic my recommendation would have been different.
 
TrailBeast said:
Understood, and I realize this is a fact.
Just saying I have personally never had cam/lifter or any other lubrication failure using either of the two mentioned oils with flat tappet valve trains.
I do think it’s possible zinc additives may be more important with todays lack of metal and machining quality.




Not sure how to address this.
Maybe your motor doesn’t produce enough power to overpower the oil pump?

Gotcha :D

Seriously though, I have never experienced anything like that.
Of course every single time oil comes up there is always other opinions.
The OP is in Florida where it can get pretty warm, and 440’s are not generally regarded as high winding motors with tight tolerances.
Those two facts are what guided my suggestion.

Sure, if it was a motor originally designed to run synthetic my recommendation would have been different.
Click to expand...
It's a slant 6. They're pretty sensitive to a lot of things since they are "two holes down" so to speak. The HP output at idle is at its lowest, after all.
 
RustyRatRod said:
It's a slant 6. They're pretty sensitive to a lot of things since they are "two holes down" so to speak. The HP output at idle is at its lowest, after all.
Click to expand...

You know I was just messing with you.
 
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