does anyone know if its ok to gp back to conventional grade oil after a engine has been using synthetic ? i just cant justify the price of synthetic oils

 

Engines can use either conventional or synthetic oils as long as the recommended or same viscosity is used... 5w30 conventional to 5w30 synthetic or whatever. The main reason people are skeptical to switch to synthetic on older engines is that the tolerances are greater causing burning oil or leaking out, but you should have no issues going back to conventional.... FYI synthetic Mobile-1 is like $23 for 5 quarts @ Walmart...

 

oh ok ill look around , whats youre recommendation , this is all greek to me lol

 

Well I was confused when you said the cost was too great, I mean $30 for an oil change + a filter isn't too bad every year... I do mine once a year regardless of mileage because why not. Lol, If you have synthetic and it is staying in there, I would keep it. My 2cents

Walmart has the cheapest Mobile-1 synthetic oil I have found

 

okay thanks

 

Don't forget that they have taken nearly all the zinc out of motor oil. A flat tappet cam needs some of that stuff to keep the lifters from galling on the lobes. I'm using Valvoline VR1 conventional racing oil because it has zinc in it. And most of the local parts houses carry it. But the cost is close to synthetic.

 

I think the flat tappet approved oil is the Rotella T.

Found at any Tractor Supply store.

5 quart jug is $15

My 352 is very happy with the Rotella.

Aaron

 

okay so synthetic has the quality of zinc additive , that conventional doesnt anymore ? thanks im interested in this now

 

If you google zinc and motor oil you will get more info than you ever wanted. I do not believe that synthetic has any more zinc than regular oil now. They took most of it out because it is poison to catalytic converters and almost all new engines have roller lifters and don't need it anyway. I don't think having a lot of zinc is a big deal in an engine with a lot of miles on it already. But having wiped a cam lobe using Rotella in a new OH engine I ain't taken any chances. Too much work and money to fix.

 

In general, synthetic will have the same amount of zinc and phosphorous as conventional. Synthetic has no benefit over conventional in that regard.

You can look at the product information sheet for the particular oil you are interested in to see how much it contains. This is usually available on the manufacturer's website. If not, you can e-mail and ask.

 

That good info. Mine has synthetic and it wants to seep out and when hot and at idle I'm getting a low oil pressure light just flickering. Back to conventional for me. Thanks

 

 

Run a good diesel oil to get the zinc and other additives that help prevent flat tappet cam wear. I run 15w40 diesel oil in my Jeep 4.0 because it has a flat tappet cam.

 

That is not an Oil issue but an engine issue (bearing clearances).

 

Actually, diesel oils are starting to have a reduction in zinc and phosphorous so they may not be viable, in that regard, in the near future. Diesel oils also increase wear in gasoline engines and are not a good choice for the long term. There are plenty of gasoline engines oils available that are "safe" with flat tappets and you can use just about any oil that is not if you change the oil at 1/2 to 2/3 the usual interval, so there is no reason to use an oil that is not designed for the application. Given the number of miles typically put on a 50+ year old vehicle, that means realistically that you can use just about any gasoline engine oil of appropriate viscosity at the local parts store, and you will be changing oil exactly as frequently as you do now. Only those who drive daily or go on several long trips a year might have to change it more often.

Break in Oil