I'm about to pull my motor and rebuild it, and I just wanted to know what is nessasary to run synthetic oil. I was also thinking I should use moly rings. What do you guys think? Is it worth the extra expense? Will the synthetic oil ruin particular gasket materials? Thanks, Scott

Rebuild the motor with moly rings, they will seat quickly. Break the motor in thoroughly with dinosaur lube before switching to synthetic. Synthetic oil isn't a lot more expensive than regular oil. Synthetic is compatible with every gasket I know of.

Sybthetic in my 355 was worth 2mpg. Atfer break-in with straight 30, I switched to synthetic. I had to turn the idle down, because the synthetic idled 100 or so rpms higher(less friction?).

The only drawback I have ever found with synthetic is that some gaskets that aren't real "tight" will leak with synthetic oil were they might not with traditional oil. Its real watery at room temp.

When synthetics were first introduced there was some problem with the seals, but AFAIK, that problem has been solved.

Onabudget's right about the increased gas mileage. I got at least 1 mpg more with a synthetic.

Stay away from Super fancy 0w60 or 5w50 or other wide spread visco oils.

They have alot of Visco additeves that breaks down easy.

A race or streetrace car is often best with Straight oils. It is not so demanding lika a car that has to be started in -20c degrees. revved cold to 7000rpm, driven for 100000km or so.

Youll have more stable oil pressure with a straight oil.

A good mineral oil is cheaper than a bad synthethic oil.

You can measure all clearances in your engine and talk to a guy for ex http://www.autoinvent.se

Most new oils made for standard cars and longlife will not work very good in a long mile motor.

In our climate in sweden usually 20w50 mineral QS oils works best.

And many synthetic oil addetives are hard on gaskets.

Wow 1-2mpg thats amazing! I would have never thought you could actually increase your mileage with the choice of motor oil smile.gif I'm goin synthetic for sure, the motor I'm building I plan on putting about 40-50,000 miles on so synthetic sounds good.

Synthetic is great for reducing internal friction and can also handle much more heat than a conventional oil (I had to take a course on lubricants for training when I was an auto tech). I used Mobil 1 in a low mileage car (47K)that had sat for 5 years. The Mobil 1 blew right by the rings and smoked heavily. That is how slippery the stuff was. I switched back to conventional and it stopped smoking. If you have a strong, tight motor with a good ring seal, the stuff works great. Some racers use Redline or Royal Purple Synthetic and supposedly see a 1 to 2 tenth drop in ET due to the reduction in friction. I don't know from personal experience, though.

It is not better with heat. Its worse because of its additives.

My an new synthetic oil blows by, is that it cant hook that well, and has to little friction in it. That will get lower pressures, larger risk for empty tray, more bearing failures, and with larger clearance no pressure at all.

And its not a Mineral/Synthetic question. Its all about additives.

Find a straight 20 or 30 mineral/syntethic oil if you dragrace. never hit throttle until it fully warmed up.

A 20w50 mineral oil has the same visc like a syntethic oil with same numbers. even @ 220 deg.

When a synthetic oil is like water. Its ruined. Aditives for wide ratio visc has bean chrashed.

With 1-2 tenths it equal to 40-50 flywheel HP. Come on. Are you guys totally addicted to ADs or sponsor talks?

If it reduce friction. It cant withstand pressure. An oil should have friction to build that film up.

I ran 20-50 mobil 1 for about 900 miles in my motor, 1300 miles total since rebuild, a couple of weeks ago I pulled out the roller lifters and they all look like the rollers are flaking like a wheel bearing when it starts to go bad, one roller had pits on the face of the roller. Five lifters felt grainy after I cleaned them in mineral spirits. I haven't cut the filter apart yet. I started using the syn oil because of overheating problems I had. My spring pressure is about 530 lbs open.

Overheated oil or oil pumped by gears will soon be ruined.

Syn oils have greater film strength. Making rollers hit harder at the lobe. They have thinner oil film too.

You should never run Passenger type oils in a Race setup car even if you street driven it.

Godsend, you must be full of yourself with a name like that. tongue.gif Synthetics are MUCH better with heat. They can run at much higher temperatures and don't break down as quickly. I'm not really sure what caused ricks_67 motor to do what it did, but I wouldn't blame the oil. Pretty high spring pressure. I did state that I didn't have personal experience with any ET figures, but I did read this when it was tested on a 5.0 Mustang. They changed all lubricants to Redline Synthetic, and gained better than a tenth in the 1/4. I guess you have to take it for what it was worth as a magazine article. Nascar and NHRA use the stuff in their vehicles, so WHY do they if there is no advantage with heat or friction reduction? Maybe they just like to spend money foolishly, but I doubt it.

"oil pumped by gears will soon be ruined."

Huh?

So are you implying oils such as GC are substandard too or not for performance applications?

You might want to check out bobistheoilguy.com for a comparison of the various oils.

As an aside, we bought a 1969 Chevelle with an sbc a year ago. The engine had about 130,000 miles on it at that time. I switched to a synthetic immediately after we bought it. It doesn't burn or leak any oil.

I'm not going back to conventional oil.

It isnt a Mineral / Syn issue.

Mineral oil break down too. Over 180 deg will start breakdown for every 1 deg the time you can use it is 1/2. But from start you can use an oil for many millions of years, if it dont get full of other stuff like water, toxic stuff, ash etc.

Youll get a good/better mineral oil with less money than a cheap not so good syntehic oil.

In many classes they run Mineral oils, in many they run single grade.

Many cam companies still recomend break in with mineral oils.

Many engine builders recomends it too. I know, there is alot old mammoths out there claiming old stuffs the best stuff.

There isnt a a big thing between Syn/Mineral oils. Same stuff they made off. Its the additives that makes diffs.

Wide ratio Synthetic oils isnt made for racing. They cant withstand it.

Theyre made for daily driven cars that Grandma rides, or some person in deep frozen russia. Or hot Sahara. They are a good compromise for lots of users. But not for racing. Low ratio oils, made specific for racing is the ones.


Nascar Runs special made oils. F1 too. It just ADs that make people think some cars run stock mobil 1.

QS 20w50 Mineral is a good oil for a stock clearanced bigblock with stock tolerances on rods and crank surfaces.

Any special clearance or oil pumps, or bleded with Alcohol, or Sahara driven etc will need an analys for about 50$ to get the right spec on oil.

Ever think that maybe your oil in Sweden has different additives than ours?

I don't think GM would deliver brand new CORVETTES, including the road-race read Z06 with Mobil 1 if they didn't trust the oil. In any other car, you could say GM might want it to actually break down earlier for servicing and all that jazz, but the vette is the flagship. Also, why does the LS1 pass such rigorous testing (that one marine test) on Mobil 1?

I have used both Castrol Syntec 5W50, and Mobil 1 of various weights in my '92 Lumina 3.4.

I change oil at about 6000 miles, and generally send in a sample (Detroit Diesel does the lab work-it costs about $12) The report comes back "fit for further service", except for the time I changed oil after the thermostat stuck open, and the car wouldn't warm up-moisture contamination.

I know its har to get understood in english.

But im writing again and again. For Standard cars, running in alot of different conditions. They must have an oil that fit all.

And thats a great compromise.

They even use longlife oils too extend services.

But for a performance engine. Running at given temps. Always warmed up before giving it throttle. With High spring rates. Tight Pumps/ Gears drives, Compressor Gears in blowers etc. will tear down and mesh the wide ratio additives.

You cant make an oil with more than 30 spread without additives. And most new syn oils are proud of their 0w60 oils or 5w50 oils. But there isnt many users that need them. And if you race them, change very often. Once they begin to feels like water. Change.

There is often people thats says GM usis it, it fine for me.

Use that Specs GM used when they built your engines for 30 years ago then. They were built for these specs.

Roller lifter engined with high spring pressures need a thicker oil film, with an higher friction oil, because they are not pressuzied on camshaft lobes.

Anyone thought why everybode recomends break in with mineral high friction oils? Or additives like EOS?

It is my understanding that everyone recomends breakin on elcheapo mineral oil so the rings will seat in. If the lubricant is really good the rings won't seat/wear in properly. I learned this the hard way on the first engine I built 21 years ago. I coated the cylinder bores, rings and pistons with STP oil treatment when I assembled the engine, it took a very long time for the rings to break in. Granted this was a budget job and wasn't honed with a deck plate, etc. but I was told at the time the STP oil treatment was to blame. Ever since than it's been straight weight motor oil for ring and piston install, and I've also done them dry. Did the STP attach itself to the open pores within the fresh cylinder bores creating a no contact problem for the rings? I have seen the synthetic breakdown mentioned, pressure drops and oil feels like water. But I've also seen the rpm increases and better gas mileage as well.

My 2-cents please.

I put Castrol's 20w50 in my 3-banger corn-popper one hot summer years ago when I had to drive to Pittsburgh from Columbia on I-70 fast and did notice the lowering of power the heavy oil made! (You notice things like this when you only have 48hp to begin with!!!)...

Switched back to 5w30 like factory recommended and gained the power feel back!!

I later added a half a small bottle of good old MMO to her, both in the oil at change on top of a full change and then put the rest in the gastank at fillup! I could feel the motor run smoother with less work having to be done b/c of the MMO!! (AND I gained a schosh better mpg thing too)...

I figure MMO is made using esters that are noted for their extremely good lubricity properties but I don't really know what the stuff is made of but it works!

Bttt, I also figure that since guys are posting about roller lifter wheels and cam lobes pitting/flaking/wearing or whatever, that synthetic oils are almost too slippery such that the wheel doesn't roll 100 percent of the time and so there is extreme point loading taking place which is causing this wear pattern to take place!!

Maybe, just maybe the wheels and lobes are too smooth to use 100 percent synthetics??

Anyway, if I was anal about oil which I am not b/c I use Walmarts Tech2000 stuff and have for years and years, I would run Mobil-1/Amsoil and add a can of EOS to it so that it has the old-fashioned extreme pressure "metallic soaps", if you will, in it like in the old days!! Then I would add two shot-glasses of 100 percent Soy bio-diesel on top of everything b/c of it's known/proven great lubricity properties b/c it is a mixture of 6 or 7 natural esters!!

Like I said, just my 2-cents worth is all..

pdq67