Mixing SuperTech Synthetic and Pennzoil

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Sep 12, 2002
I'm using a 1981 Ford 302 V8 w/ 96000 original miles as the test bed. It uses the standard Motorcraft 2150 2-bbl carb (no electronic stuff).

It was originally fed 10W-40 dino every 3 months w/ a new filter for the past 20-21 years. I tried using 10W-30 and 5W-30 at one point, but for some reason it affect start up. The oil seemed to soak the spark plugs and all the cranking would flood the engine.

Fast forward a few months (using 10W-40), I changed the old decrepid valve stem seals with new FelPro Polyacrylate(sp?) valve stem seals. Now it starts up with 10W-30 and 5W-30 without any problems.

After a few months on 10W-30 and 5W-30, I switch to Synthetic 10W-30 but I accidentally flooded the engine once w/ a disconnected evap hose. I found that switching synthetic oils would become too costly with this carb'd motor - so I got an idea.

I would use 1 quart Super-Tech synth with 4 quarts of Pennzoil dino (only dino I have).

I figure the moly in the dino would help, and the synthetic (group 3 albeit) would do its part.

Now fast forward to sub zero (F) temperatures in NJ. It starts, runs, and drives like it used 5 qt of Synthetic 10W-30. I don't hear or feel any difference with this setup.

I was wondering - if I continued to do this even on modern engines like a brand new Ford 5.4L SOHC V8 or a slightly used 4.6L SOHC V8 for the next 5-10 years - what would happen? Would it sludge up faster than if I used straight dino or straight synthetic?

With the failing economy, I don't have a lot of $$ to spend on Mobil 1 engine oil. If I can get by with my "ghetto" synth blend routine, I think it'd be worth it.
With 5 qt of supertech dino (has moly) w/ 1 qt synth, it comes to roughly $1.20 a qt for synth "blend"

Any thoughts on this? If I overlooked something simple - please shoot this down gently
That's all I ask! Thanks in advance!
I am not really sure of the quality of the aditive package of either the Supertech dino or syn oil. So I really don't see any advantage for using a quart of the SuperTech syn with the other oil. Personally I think you would be much better off using a quality dino oil like Chevron 10W-30 or Castrol GTX which have been known to give good analysis results. Really the only advantage of even a good synthetic is the ability to run longer drain periods and extra protection in case of an overheat situation. You will get neither of these benefits with the one quart of the Supertech syn-so why bother. I vote for the Chevron Supreme 10W-30.
What are you planning on as drain intervals? If your not going too far over 3k then stick with conventional oil as AL stated. Chevron Supreme has impressive specs and has shown great UOAs for a $1.08 quart oil. If your stuck on using synthetic though get the Mobil 1 and then run say 6-7k drain intervals which M1 can handle and then the cost will be the same as running your blend idea. If your engine is well maintained and you don't overextend your drain intervals then your motor should never sludge up. Your blend idea will work fine however I would not try for extended drain intervals.

If you're priority is the moly, use the S/T. If you can live w/o the moly, use Chevron Supreme or Chevron Texaco Havoline. If you want an oil with some Group II basestock and more moly than S/T for a buck a qt., use Citgo Superguard. I'll have a UOA of this oil in the not so distant future.
The blending isn't going where you want to go.
I do maybe 3000 miles a year.

six quarts of M1 will cost me $28.62
and if I have to service my engine or something, I would have to replace that mid-year.

I wanted synthetics for its low temp flow capabilities and its resistance to breaking down at high temperatures. Extended drain intervals mean nothing to me because changing oils at 6k-8k miles would mean changing my oil every 2-3 years!!!

So I should stick with the SuperTech dino for the moly? I would use Pennzoil but its almost $1.66+ a quart now. It used to be $1.08

My T-bird's 302 V8 sludged up, even with 3 month oil + filter changes using 10W-40.

I'm afraid that the 4.6 and 5.4 will both do the same even with constant oil changes using 5W-30.
Pennzoil has moly in it too (probably just as much as Supertech) and I bet Pennzoil's cold weather performance is pretty close to that of Supertech synthetic anyways.

Go with 100% Pennzoil and save even more money.

I'm seriously considering switching my mom's 94 Probe GT over from Mobil 1 to Pennzoil now, since she does such a low amount of driving and I'd like to change her oil twice a year (mainly to get the winter stuff out of there, plus I'd like to try different viscosities in her car now) I just don't like dumping out expensive Mobil 1 after such a low amount of mileage, which is why I'd rather start using conventional in her car. (another reason for choosing Pennzoil is because I may try out their 5w20 in her car next winter, as I mentioned in the other topic in here, and Pennzoil is the only 5w20 sold commonly up here-so I'd run their 5w30 in her car in the warm months, and 5w20 in the cold months)
does your mom know what you are doing (trying these oils on here car?) What are you using in now? Try the Pennzoil 5w-30 in it.

Originally posted by JonS:
does your mom know what you are doing (trying these oils on here car?) What are you using in now? Try the Pennzoil 5w-30 in it.

My mom's car has always run Mobil 1, I started with 5w30 but early on went to 10w30.

Next up in the spring will most likely be Pennzoil 5w30, with an Auto-rx treatment, then another Pennzoil 5w30 interval.

She doesn't have a clue about different oils, neither does my sister, they just enjoy getting free oil changes.

Pennzoil is at $1.66/qt right now.

Anyone else get it at a lower price?

I normally buy it for .69 cents a quart from Checker when it's on sale.

Right now it's .99 cents all weights.

I've had excellent luck with their oil and the Tests I've gotten back have been very good (as far as wear levels.. The coolent in the oil is another story (see Ford Taurus in the Analysis section for more info)

Take care, Bill


I'm moving to Utah.


It's not a bad place, But the real reason I live here is that I've been to Iowa and Ohio and have run out of four letter states to live....

I always check the ads in the sunday paper and find it very interesting that the Checker ads are always wrapped around the comics...

Guess they know what section the Males will read!

Checkers has Castrol GTX in 4 qt jugs and after the rebates it's .69 cents a quart! All Weights avail and you can buy four jugs for a total of 16 quarts.

Whats a guy to do?

Take care, bill

PS: Of course, no water here anymore so they will get you one way or another...
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