Originally Posted by dodge15004x45.9

Put my pass town mirror into a mail box.

Originally Posted by 95RAM360

did an oil change last night....used conventional for the first time, castrol gtx 5w30...tried it because of all the threads ive read on this forum...
getting 55-60 oil psi.

Originally Posted by redneckrocket38

I was always under the impression that you should never run conventional after running synthetic. Has any body else heard of that?

Originally Posted by redneckrocket38

I was always under the impression that you should never run conventional after running synthetic. Has any body else heard of that?

Originally Posted by bigslick050

YES indeed. I have heard that rumor before. I have no plans to ever go back to conventional now that I have been running synthetic for about 10 oil changes. Syn Oil comes out sooo much cleaner than conventional anyways

Originally Posted by cmckenna

The graphs are accurate however, there's one thing that must be taken into consideration and that is, the fact that most older engines have hydraulic lifters along with the fact the motor was designed to be run with dino oil- not synthetics and, since synthetics (most anyway) do not contain detergents (unless you purchase them separately and add them in to your oil), this represents a new problem that was not to be seen when using conventional motor oil and that is, lifter ticking and, the other issue is, over time, the engine parts build up a hard crust in the valve train area.

This I know for a fact after witnessing this on my own Dodge after using nothing but synthetics for 200K miles. After removing and replacing the heads and intake, the lifter valley was totally crusted up as were the old heads.

Now, at the time I discovered this, I called Rob Stark ( an Indy car builder and classic car restoration specialist and, in my opinion, THE best mechanic I've yet to encounter -bar none) www.robstark.com and, I asked him what the deal was with this. He told me it's from running synthetics.

That was also backed up by three engines that were tore down that also had the same issue at California Horsepower. The owner swore up and down never to use synthetics and, while at his shop, he presented a rather strong argument along with physical evidence that the synthetics are not designed to clean the engine for one and, secondly, they fail to hold hydraulic pressure at the lifter thus leading to premature lifter collapse or, intermittent lifter ticking and rough idle conditions. He had a new, Chevy vette and, it had been failing to hold pressure due to they now come from the factory running 100% synthetic motor oil. He changed the oil- problem solved.

Now, I must admit, I didn't know how to respond because, this was knew to me. I let him present his case along with the evidence along with conducting some real world tests on my own Dodge. I listened, I observed and I asked some questions. I found it rather eye opening to say the least so, I went home and experimented.

I ran 0-W -30 Amsoil full synthetic for test 1. I had noted noise and clatter at startup (Sharps). It did not work well. It was way too watery at hot and, I had noted rough idle and lifter ticking that was sporadic. Keep in mind - I do have over 200K. With new lifters, this probably would not have been an issue so much as it was. Due to serious time constraints, I did not have time to change the lifters.

I noted premature lifter collapse under heavy loading and valve popping due to that as well. Not something that I like to hear. This was partially due to larger compression forces / larger springs at the valves.

I removed the oil and filter and displaced all motor oil with conventional 10-40. Now, yes, it's a heavier weight and, I am aware of viscosity index but, hang on just a moment until we get to the next test which was 20-50 Amsoil full synthetic.

When running Valvoline 10-40-dino oil, it was smooth, quiet and idled perfectly. I ran this across country for 7000 miles (changing it of course on both ends of the trip) I didn't use all but a half quart on the way out and another half quart on the way back. This includes mileage to and from Boston to NY as well on the weekends. When using synthetics, I had to keep refilling it as it would thin out and make it's way past the seals, rings and valve guides.

Next test was to run Amsoil 20-50 100% synthetic. NOTE: While better than their 30W, I still noted startup noise and occasional lifter tick and valve clatter.

I purged out the regular motor oil and changed the filter as I did in the previous test.

I filled it to MAX using 20-50 as noted above. I ran it, noted startup noise, erratic oil pressure and worst yet, rough idle due to sporadic loss of hydraulic pressure at the lifters.

I immediately removed it after only a few days and repackaged it.

I replaced it with Valvoline 20-50 and noted it's smooth as silk, no lifter noise, no valve train noise either.

Now, in no way during any of this testimonial am I inferring that synthetic does not protect the engine as it surely does however, it's not just a matter of protection as far as lubrication is concerned, there's some other considerations to think about when using synthetic motor oil in an older vehicle that does not run solid lifters but, old, hydraulic lifters that were designed around dino oil.

One of the issues is, full synthetics have tendency to drain out of the lifters thus not holding hydraulic pressure at time of startup thus the clacking, or, worse yet, while operational hence, lifter collapse. Couple that with roller rockers and you've got more noise.

Now, again, I am not advocating one over the other just yet and, I am still going to run another run of their 20-50 with a modifier and possible detergent. Work in progress on that one and, in time, I hope to have some results.


CM

Originally Posted by Sheriff420

Well that makes me re-think using the valvoline synpower full synthetic 5w30 that I've used for the last couple oil changes.
I had that crusty baked on oil all in my lifter valley and the valve train.
actually, I have pictures of it to back up what you're saying. I've run full synthetic for 54,000 miles.



The picture I have of the lifter valley has shop rags stuffed in it, but it looked like the timing chain.