Joseph Overton

I guess this topic comes down to how often do you like to change the oil... And how many ducks you want to drop everytime you do...

Just a reccomendation guys on running thin oil or even if you dont......instead of running the factory oil filter , replace it with a 2quart truck oil filter if you have the room..sorry dont have any part numbers off hand..But any parts supplier should have one in stock...

jim88iroc305

Starting using it at 70,000 miles. Pressure at idle was 20+. Now at 150,000 miles pressure at idle is down to 10-.

Checked out everything. No metal in pan, pickup OK, pump is OK. Replaced the sending unit.

Switched to Mobile 10 40 which got pressure at 16ish atidle.

Car gets good pressure 20+ as rpms go up driving. Just had low pressure at idling with the GC.

Next move is to put redo the pump arrangement, maybe going HV but I'm not the convinced this is the route to go.

I'm wishing I had stuck to the Mobile 1 trisynthetic 5W 30 I was using prior to switch.

Not trusting myself I had it checked out by three shops who have experienced racers as mechanics who confirmed the heavier oil was route to go since everything else checked out.

Car is not raced, just daily driven.

Engine internal are pristine when the heads are removed.

1racerdude

http://www.amref.com/

You can find the original Kendall GT1 racing oil on this site.There is none better. Used it in the '60's and still use it in my dirt track sprint engines. Never had a failure even when engines were run 15 more laps with the water temp pegged on a 300* gage.
Ya can try a 20/50 or use a straight 40W. I would try the 20/50 to see if the OP comes up at idle first, then the 40W.

n2ceptor

Wix 2 QT filter number.....

Part Number: 51794
UPC Number: 765809517943
Principal Application: Chevrolet and GMC Trucks (73-93)
All Applications
Style: Spin-On Lube Filter
Service: Lube
Type: Full Flow
Media: Paper
Height: 7.822
Outer Diameter Top: 3.674
Outer Diameter Bottom: Closed
Thread Size: 13/16-16
By-Pass Valve Setting-PSI: None
Burst Pressure-PSI: 270
Max Flow Rate: 9-11 GPM
Nominal Micro Rating: 24

1racerdude

Some people don't understand the difference in clearance and viscosity.
A 20/50 oil is not likely to pop the relief on cold start.It is still 20 weight. 20/50 synthetic is not as thick as dino oil and only has 50 weight lube "properties" when hot not the viscosity. The 20 weight side is the same way

Some people may not know it gets hot in NY city too.


Build ya an engine with 2.5-3.0 thou on the rods and 3-3.5 on the mains and put in some 0-10 weight(Royal Purple has it) and see where your OP is at any time. There won't be any relief problems either.

Still haven't found a reference to 0 weight oil in the GM manual. There cold weather oil is 10/30 down to 0*.

1racerdude

1-Do the search thing.If ya want to find out.Any pump has a bypass even the big Sustrand pumps that power the Manitowoc cranes that are as big as an LT1 engine. So bypass valves are no stranger to me and neither are hyd motors and their controls either electric or fluid.
2-The THIN oil and clearances are very relevant. Ya say OP can't be changed when ya have extra clearance.BS
3- Uh, look at any of them for an LT1.

I would still like to see the reference from GM about 0 weight oil. There is none and it's just your opinion.
Oil co's will say anything to sell oil.

EnerjetF67

First of all GM does not reccommend use of 0w-anything in their engines for a good reason...the stuff is just too thin !
They do recc. 5w30, which I find far too thin still. This gets the nod from GM partially due to mileage and emissions requirements.
I won't run ANYTHING thinner than 10w30 in ANYTHING including a LAWNMOWER, and in my LT1, which had over 265,000 original miles on an untouched LONG-BLOCK before it puked a head gasket, was ran exclusively on Red Line or Royal Purple 20w50 EVEN IN MICHIGAN WINTERS. Oil was changed roughly every 15,000 miles, of which generally 90% were long highway drives (over 50mi each way to work at the GM Tech Center where I am an engineer)
My 383 build will be using the same....I can't argue with 265,000 miles

1racerdude

Jazsun

Why does everyone thing thicker oil is better? Thinner oil can get into places thicker oil cant..

1racerdude

Could ya explain where those places might be at.

Injuneer

Moroso makes a 2Qt filter, but its 8" long.

http://www.moroso.com/catalog/catego...?catcode=20002

I'm a little puzzled as to why 0W-30 and 5W-30 are "thinner" than 10W-30. By definition, they all exhibit similar SAE viscosity at 212degF. Yes, "0W" is thinner at 0degF..... and that's a good idea if you live where it gets that cold.

Yes, there is a range of viscosities that can be called "30" weight, so it is possible for brands to be different, and still meet the definition of "30" weight.

And, multi-viscosity "conventional" motor oils will often be "thinner" when the range of viscosities is widened (0W-40 vs. 10W-40), due to the reliance on long chain polymer viscosity enhancers. But true synthetics will show very little difference as the viscosity range covered by the specifications is widened.

HardcoreRM125

I hate to start this ... But in all honesty ... I really dont think you are going to see a significant difference between that or mobil. Just because a few guys have shown excellent analysis on 0W30 Syntec, doesnt mean everyone will. No two motors are the same. You cant say "This worked on his LT1 so it will be the best on mine" To find out for yourself, you need to do two oil anaysis's and before that you would need to "clean it out" with a few runs other oil to not skew the results ...

And just because one analysis is showing less bearing/ring/block metal in the oil doesnt necessarily mean it is a better oil over the other one. Perhaps Mobil is showing higher numbers because it does its job even better than Castol. It could be pulling the pieces away from the bearings, etc., and leaving a better non-friction surface in the motor while giving "worse" analysis results. That was long, and sort of wordy, it sounds "stupid" because I dont know how else to put it, but think about it. Would you rather have an oil that shows clean analysis, and doesnt really lubricate and wash away the worn material from the engine, or one that comes out filthy the first few times you analysis it but it really is cleaning all that **** out of your motor?

Just something to think about. I dont know that I believe in it, but I know that you guys are getting too picky, and need to just talk to a serious engine builder who knows thier **** such as LE, Bret Bauer, or 1RacerDude ... These 3 will never lead you wrong.

speed_demon24

If anyone here really thinks there is going to be ANY noticable difference in there motors from mobile 1, or gc 0w30, they are sadley mistaken. I personaly use mobile 1 5W40 since mobile 1 runs on the thin side, + i havent seen any german casteral at all around here.

Joseph Overton

There is nothing wrong with 0w oil ....only downfall is it breaksdown quicker so oil changes should be done more frequent....cold start-up is mainly where most wear occurs, so a lighter weight oil will actually be better on initial start-up... lighter weight oil will have a lower oil pressure when oil temps start to get around 200* which may scare the unknowing( coolant temp isnt even a issue,its oil temp that should be monitored),...But does anyone here know how much oil pressure you actually need at idle?? cruise or even WOT?? I'm betting few do..The other benefit of thinner oil is less drag,less drag equals better fuel economy,and more power..

Ideally you want to run a oil that circulates filtered oil as quickly as possible,while providing adequate protection.

Just to touch on the even thinner oils out there:
0w/10 royal purple offers and very expensive...but 0w/5 is even more to the order of around $350+ for 5 gallons..NEITHER of these oils are for street use... matter of fact you be pressed to get 5 1/4 mile passes out of 0w/5 because it breaksdown so fast ...

Which leads me back to the original post I made,, 0w/? oil just needs to be changed more frequently because it breaksdown faster.. why ? like I said it circulates quicker so ofcourse oil temps will rise much quicker than a conventional manufacturer reccomended oil. And why a 2 quart filter would be a good idea to have either way..Or even a oil cooler would be a good idea... This is a consumer minded world and as such the wallet of the consumers is took in consideration. because 5w /30 is stamped on your emmissions tag doesnt mean thats the only oil you suppose to or even have to run.... just means every 3500 miles you should change that 5w/30 they reccomend... These cars were meant so grandma could drive one off the lot and run through jiffy lube if she wanted to and it wouldnt be a inconvenience to have to do it twice as much if they had stamped a lighter reccomended oil on the emmisions label.. how big is your wallet???

As far as the bypass , lets just hope no trash gets through...

A/G

Joe makes a good point in regards to where most wear occurs. This I alluded to above when I referred to cold startup with thin oil and GM's preference to first and foremost provide oil, and provide filtered oil at startup, secondary. Remember, B4 the engine was previously shut down, the oil was continuously being filtered. To be concerned about initial startup with unfiltered oil is not necessary as the oil did not magically, all of a sudden become dirty. To put it another way, ititial startup with by-pass open means unfiltered oil, it does not automatically imply unclean oil. GM obviously knows this as well. For those purists out there that demand filtered oil on startup, I'll reply with; I'll take [adequate] unfiltered oil on startup over an inadequate supply of pristine oil anyday.

Also, some here apparantly are confusing 0W40 oil as being thinner at engine operating temps than a 10(or 20)W40 oil. This should not be the case.