Which Oil?

[smg1404]

I am not really sure... I used to build hot SAAB engines , and the guy I bought my parts from was a long term race builder... I asked him once about running the thinner synthetics. He did not recomend it for his race engines. His claim was that the thicker oils protected the engine better... His quote was something like the thicker oil keeps the parts from beating themselves to death... I don't know if I conpletely buy this idea, but who knows. I have read the info on the synthecic oils, and they sure sound superior. But I think that if you keep clean reasonably good quality oil in your car, you may have a hard time proving any difference. If your car will last 200,000 to 300,000 miles either way. And a Z will,, what's the difference... I will want to rebuild before then anyway..

[bonniec75209]

Someone told me that synthetic oil could clog up your oil pump. Has anybody ever heard/experienced that? Bonnie

[2ManyZs]

Not unless it is contaminated, the synthetic should actually flow better than regular oil in that the viscosity should stay more consistant over a wider temperature range than petroleum based oils.

The only thing that might make it clog up an oil pump is that it might have more detergents in it, and then releases more built up crud from the use of "bargain-basement" petroleum based oils and allows them to circulate through the engine, although it would probably end up clogging the filter first, if you are lucky that is....

That's why we usually advise not changing over to synthetics on older engines. It is usually best to stick with one type of oil, unless you do a complete rebuild and start with a clean engine when you change.

[peterc]

Can't contribute much to this with regards to Z's, but I once saw a video done in the winter up here (Ottawa, Canada....Motto: 9 months of winter, 3 months of bad sledding).

I can't remember what kind of car it was but they were running 10W30 oil in it. The oil was new, the engine cold. They took the valve cover off and started the engine (-20F). It took over 2 minutes at high idle before two 6" long spaghetti-like plugs of white waxy sh*t came oozing into the head.

This was followed by very viscous oil, more pudding-like than liquid. It was closer to 5 minutes before the engine started pumping anything that we would normally recognize as oil.

I've owned 2 Dodge Caravans (Z's make terrible family cars...but are a good way to promote birth control ), both with over 300,000 Kms, (that's about 200,000 miles) with zero work done to either engine. They both used 5W20 oil.

You really notice the viscosity difference in the winter. I've never plugged either car in during the winter and they start on the coldest day as if it were summer.

As for m Z's, I use 10W30 in both as thats what is called for in the manual, and I DON"T run them in the winter.

Peter

[norcal z]

This is always an interesting topic for discussion, and one that elicits a wide range of opinions.

On a the jeep forums I particpate on, the general impression is that if you switch to synthetic fluids from dino fluids on an older vehicle, the syn fluids find every place to leak out that they can. And in fact, on my now 6 year old jeep v8, they did just that. I once swtiched to a synthetic motor oil and had so many leaks by the next oil change (engine), I went back to dino oil and have kept it that way (that was with only around 35K miles, too). Also had to have the engine cleaned, and it's still ok now at 54K.

As for racing, I agree with Rick Hanson's comments, as I was a former stock car racer (dirt modifieds) and both our machine shop and lube products sponsor (a local Quaker State distributor) recommended 20-50. We were running a methanol fueled 383 ci. chevy with a 6800 RPM limiter, and we were constantly bumping the limiter in dirt track racing. We had no lubrication-related failures with that setup.

[CoastGuardZ]

Dear GOD I LOVE OIL!!!!!

Lets start with my preferences... C.A.S.T.R.O.L. God's gift to the motorheads.:cheeky: Just my preference...I like kendal too.

5w20 and 10w30

for a little insight...non-detergent(ND) oils only last a top of 500 miles in an OLD model T ford. also good in Briggs and Stratton...THATS IT!

multi viscosity (ie: 10w30)

---These oils have polymers added to the base stock (10) to give it the "protection" of a heavier oil (30). When the oil is cold (ie: startup) the polymers are coiled up and the oil flows like a thin oil that the base stock is. As the oil warms up the polymers uncoil and become intertwined which "thickens" up the oil, thus allowing more protection.

---theory goes...The farther these two numbers are apart the protection factor goes down. (ie: 10w40) The base stock is a 10 weight...as the oil warms the polymers are trying to absorb 30 points of difference there causing premature breakdown of the base stock.

Changing your oil

---Never can happen too often.

---The reason you change your oil...During the run cycle of the engine the polymers are sheered apart an become weaker.

...The combustion cycle creates acids in the engine case...and condensation builds up significant amounts of water in the case and short drives will not always allow the engine to vaporize all this water.

---I've heard people say that they run synthetic and at 4000miles the oil still looks new. Bulls#!t. The oil will turn dark after just a few hundred miles. It happens. This is not bad. There is oil in there you will not get out which mixes with the new, also the heat cycle will turn the color of the oil.

Synthetic

---Synthetics (ie: Mobil1 and Syntec) are not made by man but rather altered by him. You see these really smart lads in white lab coats know what in the oil isn't good. So they go in and remove it. Then they put in a couple of additives and call it synthetic.

---I like the stuff. If I hadn't seen many many engines go to 200,000miles plus on regular Castrol 5w30 I'd say everyone shoul use it.

---Switching to... Unless the motor is young and less than 60000 or so I wouldn't do it. After time when your oil has built up inside and you switch to a synthetic you could break up deposits which may block your oil pump...possibly. Some gaskets have been prone to leakage after the switch on older engines. Plus your bearings have been brought up on the thickness of conventional, switching to a thinner synthetic oil can cause bearing wear.

This could go on for days...

I'll end with my useages

...88 Chevrolet 1/2 ton 305ci 190,000 miles on Castrol 10w30 year round in South Carolina, traded in on Toyota MR2 which I totalled a month later.

...Mom's 89 S-10 Blazer 4.3V6 215,000 miles on Castrol 10w30 year round in S.C., traded on Hoda Civic.

Both of those trucks were WELL used and were traded in. Neither used oil and neither had any mechanical failures. Both owned and maintained from New.

...72 Datsun 620 300,000 mile on God only knows how many types and weights before it was parked and abandoned..I was too late to save her!

-----Currently-----

...95 Acura integra 1.8 135,000 I currently use Cas. 5w30. She has that typical Honda valvetrain clickclickclick sound. Poor engineering? Chances are she'll run forever.

...03 Frontier castrol 5w20 700miles Will switch to Syntec 5w30 once broke in...~5000-10000 miles.

...97 Kawasaki Ninja 600 12000 miles. Motorcycle require special oil. They have "oil-bath" clutches and Rev to ungodly RPMS (12000-14000!!!) Mobil 1 4-stroke 10w40 (as recommened by Kawasaki) hiperformance motorcycle oil 3 liters at $8 a quart!!!

Heres a link too!http://www.geocities.com/chrislonghurst/engineoil_bible.html

My dimes worth!

Nate:cross-eye