Oil For 348

[mercsrus51]

Everyone has a different opinion on which is the best type of oil, not brand, but is it stright 30, non detergetnt, or 10-30 . what is the recomended weight for the 348's.....I know not to use any synthetics, but I use to use the straight 30, in the older cars,, 56 's so please clue me in thankyou .....LOU

[348NUT]

Lamar Walden suggests using 20-50 oil although when questioned he said a straight 30 weight is good also. I'm running 10-30 in mine but will be switching to straight 30. He said the big pistons in these engines like a little thicker oil. NUT

[mercsrus51]

thankyou LOU

[bobs409]

I never knew that. I've always used 10w/30.

Should I switch to 20w50????

[29Coupe348]

i run castrol 15-40...works fine for me.

[bobs409]

Oh sure, confuse me more. :D

We need more input. Who's running what?

[348NUT]

I wouldn't worry about it too much Bob. Lamar was talking race engines so if you aren't running your engine very hard, I don't think it's going to make much differance. My 348 is a little loose to begin with (the oil pressure drops about 15 lbs when it warms up) so I figure the extra weight might be good for it. To confuse the issue a little more, I was once told that an engine that burns oil will burn even more with thicker oil because it can't wipe it away from the cylinder walls as easily. :dunno NUT

[29Coupe348]

ok....last year i called Curt Harvey, i was explaining to him that i had low oil pressure, and i would like to buy a high volume oil pump. he asked me how low the pressure was, i said its like 15lbs at idle when warmed up, he told me that wasnt uncommon, but if im uneasy with it, try castrol 15w-40...he said for some reason, he has no idea why but that oil will raise the oil pressure a little, and he was right, when warmed up at idle now its at 20lbs....so thats what i have been running for the past year or so.

[FYN409]

Well, it makes me feel a little better to hear that I am not the only one with low oil pressure at an idle. I was a little worried about it also, I run a Pro-lite with a 15lb sending unit, and when the engine is warm and idling in gear the light will flicker, and sometimes come on steady. Once it is a little over an idle it jumps right up. In fact if I take it out of gear, it will go up about 100 rpm and then the pressure is about 20lbs.

-Ryan(FYN409)

[bobs409]

I've got no problems with oil pressure! It's 60 when driving it cold, 45 when driving it hot and lets see, idling cold is about 45+ and idling hot is about 30 or so. (nuetral)

[oil4kids]

Come on guys are you still using petroleum oil? I have not used petroleum oil in anything since 1986 and the military has not used any petroleum oil in military jet engines since the early 60s- Although you know i have a financial interest in synthetic oil- ask yourself why synthetic oil was factory fill in the callaway corvette and zr1 corvette and the GMC Typhoon and Syclone etc etc and the current z06 corvette

If you must use petroleum, then use a straight weight ie sae 30 because a 10-30 oil is a 10w oil with plastic expanders called viscosity improvers that do not lubricate-most synthetic oils have very little additives unlike petroleum that may have 30-40% plastic expanders not to mention zinc and phos


Most of the big nascar boys have been on synthetic oil for years and they generally use a very light weight synthetic like 0-20 to qualify to get the most HP out of the engines for a few laps

If you 348 or 409 has the original seals and drips oil it will drip a lot more oil with synthetic since it finds its way out of you engine much easier then petroleum

I know Lamar may like a straight 30 oil but he is not a oil expert and he only needs to go a 1/4 mile with that oil

Not all synthetics are equal and do your homework

By the way the synthetic grease in the lunar rover that went to the moon in 1969 costs $20,000 an ounce!

Im glad prices are a little better now

[mercsrus51]

Sorry I opened such a big can of worms asking , what is the "correct" oil for a street 348...we do drive to far away car shows , and it seems when I used the 10-30 this year,, I lost (or used) a of quart of oil after 1000 miles....so thats why I asked.... I was told never to use syntho in the 348 ,,by a chevy guy........so I think the answer is gonna be straite 30 and lets see what happens... .Whats this about plastic particals in the 10-30????? hmmmm LOU

[bowtieollie]

To make a general statement of which oil is the best to use in these engines is too generic.

Engine age, condition, and operating conditions must be reviewed to make an intelligent decision.

First off the bat - API classification SL is highly desirable.

10-30 is highly recommended for normal driving use on an engine that is within factory tolerances. If a high mileage engine, or more than normal wear, the weight of the oil can be increased to 20-40.

Straight weight oils are passe. Unless your operating conditions warrant its use (namely hot weather consistently) - it causes engine wear during start up, since it takes longer to circulate. Straight weight oils also take more HP away from the engine due their viscosity.

I have run 10-30 Pennzoil for over 30 years in my W engines without a failure - the oldest being 150,000 miles before she was sold.

[Fran Preve]

Both Bowtieollie and Oil4kids are correct in my opinion. Lamars piston comment was very funny, big block Mopars, Caddys, and other engines have a HUGE 4.310 bore!. And don't require any special oils. As I've posted before, I put a stock forged 409 piston an a digital scale, then a stock forged 454 piston. within an ounce. If the engine is freshly rebuilt AND TO MODERN STANDARDS, synthetic should work fine. If it's used and moderate miles then a QUALITY 10-40 should work just fine. Anything else is just bloviating. There are tens of millions of engines on the road today that run just fine on good 'ol 10-30, and a W block is just another engine, albeit with a 74 degree head bank.

Here's a tip: ever see that magnetic sheet that is about a 1/16th of an inch thick and flexible, bendable?. Well cut yourself a piece and wrap it around your oil filter, then use duct tape to hold it on, collects iron particles. A magnetic drain plug helps to (after market or GM). And GM makes a truck oil canister (or oild filter) that holds around an extra 1/2 quart and the filter is 50% larger to boot.

[bowtieollie]

In regards to the use of syn oil in these engines - the owner seriously needs to review the operating conditions present - otherwise you are pouring money down the drain.

A quality brand name oil, such as Pennzoil, with an API classification of SL offers "almost" the same protection as their own syn oil. Presently, the best syn oil available is Mobil One.

What are the benefits to this more expensive product?

It offers a small margin of heat protection and a longer drain interval.

I would like to think that most of us on this site "are in love with our W engines" and therefore maintain them to a higher standard than some soccer mom driving her minivan and changing her oil at 7,500 to 9,000 miles (which is an average for lease cars in the USA today!)

I bet that most of us here - are changing our oil based on time (since the cars are not driven frequently), or are changin the oil at 2,000-3,000 mile intervals (if you are lucky enough to enjoy your car weekly).

The use of syn oil in this application is overkill as the hydrocracked regular oil offers the same protection as the syn oil.

A comment was made about factory fill syn oil in the new Corvettes etc. This was PURELY an accounting decision. The choice was to install an oil cooler as standard equipment and use regular oil - or use syn oil and make the oil cooler optional. Since the production numbers on these vehicles is relatively small - the financial decision to use syn oil was made - since it was CHEAPER than installing an oil cooler.

If you are going to use a multigrade oil - keep the viscosity range within 20 - as in 10-30, or 20-40. As long as this number is under 20 - the oil performance is more desirable. 20-50 would be "30" - not recommended (if you decide to extend your oil changes only)

Bob, with oil pressure as you posted - 10-30 is perfect for the application.

[bobs409]

10w/30 it is then. I was thinking the same thing, I don't drive mine enough to warrant using synthetic. (I don't use it in any of my other cars/trucks either) If I used synthetic in the 409 and changed based on mileage, I'd be changing my oil every 15 years! :eek: :D I put about 1,000-1,500 miles a year on the 409 but like to change it once per year.

I used to use Pennzoil religiously but was talked out of it by many here on this board. I switched to Valvoline for the '09 but have been using Havoline in my small blocks. Better? Worse? I have no idea. I'm starting to think any brand would do just fine. I've had worn out, oil consuming engines that I used cheap no name oil in and they still ran and ran and ran. I never had an engine get slugged up while in my care either.

Oh well, this thread was about weight, not brand so that's a whole other can of worms. ;)

[oil4kids]

A comment was made about factory fill syn oil in the new Corvettes etc. This was PURELY an accounting decision. The choice was to install an oil cooler as standard equipment and use regular oil - or use syn oil and make the oil cooler optional. Since the production numbers on these vehicles is relatively small - the financial decision to use syn oil was made - since it was CHEAPER than installing an oil cooler.
.

this is not true. GM experienced Cam failures in colder climates with the LT5 dual overhead cam ZR1 engines and the decision to go with synthetics was at that time since Callaway was having good experience with the twin turbo 5.7 with Mobil 1, which then became a factory fill. This carried over to some other speciality vehicles.

Mobil 1 is a baseline oil and other synthetics such as amsoil, royal purple and redline are much better. There have been others such as HPS and EON which Smokey Yunick wrote about in his engine performance books but there not sold anymore.

If you dont ue synthetics for the engine, consider using the other products ie gear oil and atf, grease for the drivetrain. Do not use synthetic GL5 in the Muncie 4 speed trans that use GL4, synthetics are too slippery and it will wreck the syncros.

Ollie is right that we now use SL rated oils , and the original spec oil for the 409 was SD or SE.

By history, there were over 1000 different synthetics made and invented by german scientists in 1940s during WWII, but we use only 10 or 20 types of molecules today.

[Tman]

So what would you break in a 348 with good mid range tolerences that has just been machined and built with?

And what Oil would you run, annual mileage would be 2500-5K. Tri-power, 3.89 gears, cheater slicks and lots of hard driving and smokey burnouts.

[Fran Preve]

My 85 Corvette has the OPTIONAL oil cooler, my 2002 Extreme has a iol cooler, and surprisingly my 1994 Transport with a 3800 does too. GM specified synthetic is SOME cars but more for emissions and fuel economy, also the "edge" it gives if the engine is overheated. GM can do it because of their engine machining processes (today). I agree that synthetics are an overkill, and a QUALITY 10-30 or 20-40 oil changed every 3000 miles is all ANY engine needs, and of course change the filter too.

PS: Synthetic in a well used engine will leak more and burn more than a regular petroleum motor oil.

[bowtieollie]

Hi Tman,

I would recommend a 10-30 engine oil, mfg'd by a well known quality brand (such as Pennzoil) - with the API classification of SL.

Change it between 2,000-3,000 miles - as the additive package begins to deplete after this usage.

If the engine is new - then run it for 1/2 hour at 2,000 rpm - then shut it down, change the oil/filter.

[oil4kids]

I dont want to get into any arguments or bad feelings on the benefit of using synthetic oil over all the other crap 3rd world petroleum oils but if you look at the last issue of super chevy magazine one of the engine builders switched to Amsoil and noticed a 10 Hp dyno gain just by using amsoil synthetic oil-

My feelings and what ive heard from other off shore boat racers is that Amsoil gives you about 6 more hp so I think the 10hp is a little high. But you do get 4% increase in gas mileage.

[29Coupe348]

Mark, are there any ill affects from switching to synthetic after running regular oil for many years?

[Loafer409]

" and the original spec oil for the 409 was SD or SE"
==
I don't belive those classification existed back then...I believe it would have been a SB or SC...

[oil4kids]

29Coupe348

Well you can switch to a synthetic any time but here are my experiences with Amsoil since 1986

Although I used other synthetics prior to Amsoil like Eon and HPS, when I switched to amsoil racing 20w50 in my 70 nova 396/375 motor the solid lifters were much quieter on startup then the castrol gtx i was previously using. This was very impressive since the noise in my solid lifters with the GTX was very scary after letting it sit for a month or so. Also the oil pressure guage did respond quicker as if i had faster oil pressure. This nova had about 55,000 miles on the clock. It ran cooler in hot days also.

But this is the downside of synthetic oil, it tends to leak more. Ive noticed this time and time again when switching a high mileage motor to synthetics.
For some reason, maybe due to creaping action like a penetrating lubricant, synthetic oil will tend to find its way out of an engine with old seals. Although it tends to give you better ring sealing, which promotes spark plug life, it will drip thru seals if they are not in good shape which means you could burn more oil if your valve seals are bad.

So thats the trade off, better protection for the motor but if the motor has a lot of miles on it expect leaks. Switching back and forth does not seem to make a difference.

On the other hand, after knocking off a deer in missouri one year, and driving without water with the temp guage pegged for 20 minutes and only amsoil in the engine, a certain 400 small block chevy was saved and was later transplanted into a buick wagon and driven for years after that. I doubt that petroleum oil could have done that.

The bottom line is its expensive, harder to find then regular oil, may leak out of your engine, but is a much better lubricant in cold and hot weather, has a higher film strength then conventional oil gives you a little better gas mileage and hp. You decide.

[dq409]

Oil is a deap subject and I would suspect there are as many different answers and opinions as cars on the road.

My opinion is as long as you change your oil regularly use what ever you are comfortably useing.

ME? I use a 15-40 wt in my daily driver same as they use for over the road trucks.
In my 409 I am now useing a 30 wt but will change to a 15-40 or even a 20-50wt Racing oil on the next change.

Comparing oils used in Nascar or other racing engines is a mute point as far as I`m concerned.
Those engines run and last only a few minutes (drags) or miles(Nascar) and most are paid to use the oil brand in them.

I`ve used 20-50wt racing in high mile worn engines and have seen the oil consumption decrease with its use.

I was supprised to here Lamar say he uses 20-50 wt racing oil in his engines because I have used it and get flack from some when they hear I do.

It would seem that the 20-50 racing would give added protection to the pistons and bore of the "W" blocks due to the design and the fact that the pistons are pushed to the outside of the bore.

Lamar did say to use oil that do not contain ash.

Any information on this and what to look for to get an oil that doesn`t contain ash would be appreciated.

There is a difference between regular 20-50 wt and the racing 20-50 so thats why I added the racing after the wt.

JMO,,,,dq

[Fran Preve]

According to what I've read in Circle Track the recommendation of their tech writers based on what engine builders say (and this is for regular circle jerks who are asking) a 10-30 QUALITY oil is all that's needed. As far as the brand, the guy building the engine uses what he has found to be best for his engines, name on the car be damned (when hundreds of thousdands of dollars are at stake would YOU use Quaker id Pennzoil was better?). Heck the all might be using Amasoil!.

I like what bowtie ollie said, except maybe 10-40 if the engine has some miles on it. It's a fact however that synthetic has a higher temperature tolerance, you can get it hotter without it breaking down, but we're talking HOT here!.

[Tman]

After sseing oil testing some biker pals did for comparison, here is what I am going to do.

I am going to pick an oil, whether it is synthetic or dinosaur. break in the mill. test the oil. then test a fresh baseline and then test after the first oil change. Back about 154 years ago, the military had us start testing as opposed to reg scheduled maintenance. Some vehicles needed it changes at 1000 miles and some would go 5ooo!

Why I havent picked a type of oil is based on the fact that most of us drive these cars less than our dailys and tend to watch things like fluids more closely. I think most oils do a good job under these criteria. I might just run Pennzoil to screw with the antiPenz crowd!!! hehehehehhee :brow

[raymar58454]

My dad had 82 cutlass diesel that was using oil and GM done the change the head deal, no better. He wanted a rebuilt engine from the factory, but the GM district reps said that as long as it wasn't "blown"up it would have to be rebuilt by the local dealer. the local dealer was not known to do very good work. After the reps repeated the blown up phrase I told my dad to quit arguing I knew what they wanted. I DRAINED the oil out in my shop and proceeded to drive it wide open in low gear between my shop and another guys shop a mile away.After about 3 trips it started to knock. Put the oil back in,started it and the darn thing stopped knocking. It only collapsed a lifter. Drain the oil again. Held the throttle wide open and proceeded to empty 2 cans of starting fluid through it. It finally locked up. Put the oil in it and pushed it outside. Did I mention the tailpipes on the Cutlass point to the ground where they made the concrete pop. When they came with the wrecker the next day the thing started right up although it did knock quite a bit. This was my oil test.
The oil. Pennzoil straight 30. Guess what I use in everything.

Was this Bloviating.
Ray