[old66tiger]

Everything you ever wanted to know.

http://www.bobistheoilguy.com/motor-oil-101/

[Joel Koontz]

I have been using Synthetic in just about everything for decades.

I generally break engines in on regular oil. I think the engines may break in faster/better and since I will be draining it after just a few miles it seems like a waste to run synthetic for break in, even if both would yield identical results.

Many factory engines are broken in on synthetic, but I do not think that is because they think it will break in better on synthetic. My guess is that since they don't plan on it being changed after a few miles, they think it will break in adequately on synthetic and it will protect better in the long run.

IMO, the first oil change is the much more important than the subsequent ones. There will be much more wear during the first few minutes of operation and you want to get the debris flushed out with the oil as soon as possible. After the initial run in, there is much less wear per mile of operation.

One reason synthetic oil may leak more in an older vehicle that has been run with regular oil is that regular oils are much more likely to create sludge(which may seal/partially seal some areas that might otherwise leak) When you put in synthetic oil, it dissolves some of the sludge and this may result in more, or more severe leaks.

[David Jones]

Originally Posted by Sirrotica

Were wall things equal such as viscosity? Most times syn oils have thinner viscosity index than conventional oils and by your own admission there were already leaks. Thinner fluids will seep through where thicker fluids won't, basic physics here. Compare apple to apples not apples and oranges.

I use synthetic in every car I own and none have any leaks, according to your logic they should all leak profusely which is not the case. One car has 160K on it the other 94K.

Any manufacturer that makes syn oils has exactly the same information on their websites as far as synthetic oils leaking after switching. The information came from Pennzoils site, however all sites I checked have the same info as well.

I guess your engine is the exception to the rule because none of my cars leak any oil whatsoever, and have had nothing but synthetic oils.

I use synthetic in all my other cars. Always have. No problems. They started with synthetics.
Same weight syn went into the GTO as the conventional that came out of it.
Your ability to swap my "logic" over to your cars is inspirational. What I described happened to my car. And that is my reality. I'm not sure you have one since you get your info from a mfg'er..... One trying to sell a product.

[68 Firebird]

I am with silver bullet and have been running brad penn all the zinc you need.
catch it on sale from summit with free shipping.

Gerry

[Sirrotica]

I started using synthetics in 1977, Pennzoil PZL one of the first synthetics from a large oil manufacturer. The first engine I ran them in was a 70,000 mile 389 and even with it being a factory built engine 12 years old. There was no leakage after switching it over from regular oil to the synthetic. The rope seal is where most Pontiac leaks develop as the engines get older and the seal wears, this one was dry.

The one theory about synthetic removing sludge and varnish could be plausible, my 389 however didn't leak and it did have sludge in it because I put a new cam and lifters in it and I knew what the inside of the engine looked like.

All the engines I have switched over from conventional oil have not developed leaks just as the manufacturers said they wouldn't, your mileage may vary. If I hadn't spent all of my adult life wrenching on cars as a profession and switching many cars over to synthetic, I wouldn't have just one instance to draw my conclusion from.

David, you tell your story about your one case, and leaks developing and going away after switching back to conventional oil to whoever you like. In my experience which is many times more than one instance, synthetic oil does just as the manufacturers say, and causes no leaks after switching. Actually the majority of oil leaks I've repaired in my time as a mechanic, were engines using conventional oil and the leaks I've repaired were from every point that an engine can leak at, front to back and top to bottom. Engines do leak, attributing leaks to what kind of oil they have in it seems pretty far fetched.

Anyone reading this will have to make up their own mind from what's been posted here because I'm not going to dispute the point any further.

[Blued and Painted]

Originally Posted by Mr Twister

Synthetic in my diesel Silverado, changed every 15,000 miles.

Your not doing yourself any favors.
Those high oil change intervals lowers the yearly maintenance cost of the vehicle. It's a sales gimmick by the manufacture to keep up with the competitors.

There is a lot of ash build up in the oil with Diesels.
I've been in the business 30 years. IMHO the synthetic must be changed every 7500. max

[Sirrotica]

Anyone wanting to extend oil change intervals in any vehicle, gas or diesel, needs to have a bypass filter system to filter every bit of solids. No matter what oil your running, oil that is kept clean will last 10 times longer than oil going through the factory designed strainer system. I call it a a strainer system because no matter how many times the oil circulates through the strainer anything smaller than 20-30 microns will go right through the pores in the single ply filter material. These small particulate are the major solids that wear the internal engine parts. Even if the filter would fill up with solids and be blocked entirely then all the oil will open the bypass valve in the filter or the factory installed bypass valve in the block and run non filtered oil through the engine.

What type of oil you run in an engine is of little consequence if you don't keep it clean with something more efficient than the factory full flow strainer system. There is NO full flow filter made that can filter out the fine 5-10 micron material that causes the majority of engine wear. These facts are fairly well documented if you bother to do your research.

I urge anyone that is doubting what I say to do research on bypass style filter systems and the huge advantages they give you on engine longevity and the ability to extend oil change intervals with no danger whatsoever to causing premature wear with extended oil changes. You can do extended oil changes and cause almost zero wear on internal engine parts, like having your cake and eating it too.

Over the road trucks go a million miles without any engine wear or damage, they DO have very efficient filter systems in them to do this feat though. The filtration system is the main difference with a car or light truck engine running 100-200K with a full flow strainer system. Many trucking corporations go 15K oil change intervals or more, with a excellent bypass filtration system in them going a million miles with no engine overhaul.

[David Jones]

Weird. My one case of leaking synthetic is supported by a quick Google search where there are endless examples. Maybe a small percentage and only in certain circumstances but it's there. Maybe it's just taking it to the right mechanic......

[HWYSTR455]

Originally Posted by arcitech

There is a lot of chemistry going on in todays oils. But the major factor is that the modern manufacturing techniques and the EPA emissions requirements have forced the car makers to build much better engines. Along with the improved engineering and better lubrication products, we see cars that consistently go over 100K, this was rare in the 70's and early 80's. Fast forward to today, if you build an older motor using modern equipment for machining, using proper procedures for assembly and using the best lubrication products, these motors will last longer, maybe as long as a new car would. There will always be exceptions, but technology has our hobby going strong and keeping us running long after GM ever expected their cars to last.

There's considerable truth in this, but not only in machining, parts quality too.

One area to keep in mind is ring technology, and cyl finishing. OEs are using harder ring material and finer cyl finishes, rings just plain last longer. (but do have a longer sealing/break in time). Looks at performance tests of like 'vettes and mustangs, they tend to actually pick up some after the 20k mile mark.

Break ins, ring break in as soon as possible is critical, just as critical as HFT cam break ins.

Another good point is contaminates from assembly, those should be flushed right after startup in my opinion. For this reason, and the one above, I chose conventional oils for break ins.

Leaks and viscosities, well, I believe the biggest factor here is clearances. Maybe seal materials, but think clearances are the biggest factor. Thinner oils require closer tolerances, right? To flow faster? Look at clearances on newer engines, and what viscosities are recommended. And what about oil wedge? It's common for machinists on performance engines like Pontiac engines to use wider clearances. So thinner oils are not particularly an option, right? And selection of syn oil viscosities that are more than say 30wt are limited, right?

One thing I don't understand is in this day and age, why isn't there a replacement for ZDDP/zinc? Why such a heavy focus on ZDDP? There I'm sure is something better out there than ZDDP, why isn't that being used? Is it because people are just hell-bent on ZDDP? Is it because the specs for engine oils need to be revised? (Which may not be that easy).

Like who is going to fund going back to 60s & 70s engine oil specs and do testing to approve a different spec for those engines? Ain't gonna happen. Like, you would have to build like 1000 engines the way they were built in the 60s, same materials, same process, etc, THEN run tests on those, and then do that from multiple manufacturers? Would be millions and millions of dollars to do that. Is this the factor?

So it's no mystery or debut that syns are more slippery than conventionals, so why the heck IS there a problem with HFT cams with syns? Just makes no sense to me.

.

[goatwgn]

I have a 1974 Oldsmobile Cutlass Supreme that I have used as a "daily driver" for 26 years that I bought from a relative in 1988 that was the original owner. It had 135,000 miles on it when I got it. At the time it didnt knock, smoke or leak any between oil, changes. She had used Valvoline in the car since it was new. I used Valvoline 10w30 conventional oil with 1qt marvel Mystery Oil in it until it had about 275,000 miles on it. I then starting using Amsoil 10w30 in it. When it got about 400,000 miles on it it started using about a qt and a half between oil changes. The rear mail seal, valve covers and intake end gasket were leaking at this point, but they never leaked when I started using the Amsoil, and it came on gradually as the engine got tired. At this point I started using 20w50 Amsoil and it slowed the leaking and usage down to almost nothing again. Last year, when the engine had 493,000 miles on it it developed an intermittent "miss" due to low compression on number 7 cylinder. I went ahead and yanked it for a rebuild. To my surprise, the engine was very clean on the inside, and the only thing wrong in the engine was very weak valve springs causing the intermittent miss. only went .010 on crank just to "clean it up". I beleive changing the oil often, not ever overheating it (if there ever was a hose or something leaking, it was addressed right away), and even the 3.08 gear (plus the fact that older Olds engines seem to run on forever), contributed to the longevity and the engine being clean inside. I used the synthetic oil because I always wanted to put the best thing I could in the crankcase. I do beleive, however, that you can get very good service with conventional oil of the proper weight and change the oil on a regular basis. I changed it at 3000 miles when I was using valvoline, and at 5000 when I used the Amsoil. I broke it in again with 30 wt Brad Penn, then went back to "High Zinc" Amsoil 10w30.

[Blue'69]

I switched about 5-6 years ago. Longevity is amazing. Oil still comes out relatively clean after 14K miles. Got 175K-223K on several different makes and still purring along.

[71 Goatman]

Started using synthetics about 20 years ago and have never looked back. Usually Mobil 1, tried different weights throughout the years. 5W20 in all my cars, Honda minivan, Nissan Maxima and the 462 in my GTO following break-in back in 2009.

Bracket raced a Nova that ran low 11's for about 10 years, 358 small block, 4:56 gears, shifted at 6800 rpm, big solid lifter cam, 1.50 60ft. Used 0w20. Took it apart after 400+ passes and the thing looked like brand new, no carbon anywhere, no wear on the bearings. That was the deciding factor for me.

Have never had an issue with flat tappet cams, I do use a bottle of zinc additive in all the older engines. I watched a single 4-bbl 320 cu. in. comp eliminator engine at the local dyno make 750hp @ 9500 rpm on royal purple 0w20, the guys at the dyno refereed to it as "grape juice", got a kick out of that. Never any of the reported issue of synthetic leaking any more than conventional oil.

I do however break in all my engines at the dyno with conventional mineral oil / additive. No flat tappet cam failures to date.

[HWYSTR455]

Originally Posted by 71 Goatman

Started using synthetics about 20 years ago and have never looked back. Usually Mobil 1, tried different weights throughout the years. 5W20 in all my cars, Honda minivan, Nissan Maxima and the 462 in my GTO following break-in back in 2009.

Bracket raced a Nova that ran low 11's for about 10 years, 358 small block, 4:56 gears, shifted at 6800 rpm, big solid lifter cam, 1.50 60ft. Used 0w20. Took it apart after 400+ passes and the thing looked like brand new, no carbon anywhere, no wear on the bearings. That was the deciding factor for me.

Have never had an issue with flat tappet cams, I do use a bottle of zinc additive in all the older engines. I watched a single 4-bbl 320 cu. in. comp eliminator engine at the local dyno make 750hp @ 9500 rpm on royal purple 0w20, the guys at the dyno refereed to it as "grape juice", got a kick out of that. Never any of the reported issue of synthetic leaking any more than conventional oil.

I do however break in all my engines at the dyno with conventional mineral oil / additive. No flat tappet cam failures to date.

What are/were the main & rod clearances on the 358 and 462 engines, and what are the oil psi readings with the 5-20w/0-20w?

.

[geeteeohguy]

I've been running full synthetic in my 4X4 Toyota for years. It has over 200k and is still going strong. Main reason is that synthetic will still flow at extreme temps that would cook conventional oil into tar. I venture out into remote desert regions on vacation, and like the insurance that if I get severely overheated and have to drive out to save my life, the engine will run a bit further in that situation with oil pressure. Also, on cars that sit a long time (like collector cars) synthetic has much better cling to bearings and journals etc., allowing for better lube at initial start up. That said, I run dino oil in the GTO's.

[old66tiger]

You mean that you run synthetic in the GTO'S right?

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[geeteeohguy]

No, I run Rotella in the GTO's at present. Used to run Kendall and Valvoline, until the zinc was removed. Been running Rotella with a ZDDP additive for the past 8-9 years or so. Thinking about trying out Brad Penn. Synthetic is superior to dino oil, IMO, but I just haven't gotten around to using it in the goats.

[72LuxuryLeMansLa.]

Originally Posted by geeteeohguy

. Also, on cars that sit a long time (like collector cars) synthetic has much better cling to bearings and journals etc., allowing for better lube at initial start up. That said, I run dino oil in the GTO's.

Driven Oils has some good additives for storage: http://www.drivenracingoil.com/news/...ge-protection/
There is a Mil-spec for oils that uses additives for storage. They allow the oil to cling for long storage, like over the winter, and help fight corrosion during storage. Check out their tech articles they may be of interest to you.

[goatman65]

One thing I was surprised to learn is that oil actually has a 'shelf life'.

[Joel Koontz]

Originally Posted by goatman65

One thing I was surprised to learn is that oil actually has a 'shelf life'.

I know that some manufactures(perhaps all) indicate that oil has a shelf life, but I have not seen much info(other than speculation) about how it supposedly deteriorates after 4 or 5 years.

Some say the additives may fall out of suspension, but if so, where did they fall to? If they fell to the bottom of the bottle, shaking it well should put it back in suspension.

I have a lot of synthetic oil that is >10 years old(that I continue to use) and when I look at the bottom of the bottles I don't see that anything has settled out.

I don't recall where, but I have seen posts that said 20 year old tested to identical specs for the oil grade.

IMO, the shelf life is more about having people throw out their old oil, so they will buy new oil, than about the oil actually going bad.

[71 Goatman]

HWYSTR455,

Sorry for the delay been traveling.............Typically all my rods and mains are .002 to .0025. When warmed up idle oil pressure is 25 - 30 psi, 60psi at 5500. Haven't found much difference in pressure between 5w20 and 0w20. Has served all my newer and older traditional V-8 engines well. Three Power Tours on the Goat, getting ready for #4 in June.