[64speed]

I am gonna switch to VR1 10-30 over 20-50 for the rest of the winter cause I am getting 92 pounds at cold startup and if I don’t get it get to at least 100 degrees before moving or giving it any RPM it puts the high pressure alert on the DD RTX gauges and says I have over 100 pounds. I’m afraid that’s gonna blow my filter off and is causing my pressure leaks.. after it’s warm if I’m cruising it’s between 55-65 and if I drive it hard and really get the oil temp up it’s goes to 40 at and 895 rpm idle. Will the juice be worth the squeeze to change viscosity or should I just live with it?

[Gach]

It may drop 15-20 lbs. but I would leave it.

[64speed]

Originally Posted by Gach

It may drop 15-20 lbs. but I would leave it.

You wouldn’t switch for the winter?

[Gach]

Oh ok, if your just doing it for the winter then yes I would.

[steve25]

Your misguided if you think the leaks your having are due to 100 psi of oil pressure.

[Half-Inch Stud]

Small filter can might provide peace of minding it. Sealing surface is the same though. I never had 1 blow off (100PSI cold starts, 80 running revs)

but Pontiac Dude had the filter can be the pop-off valve for a Maple Grove oil-down at 300' for some darn reason.

[78w72]

Why are you running a thick 20/50 oil in a street engine? Was this engine built with loose race type tolerances? If not theres really no benefit to using that thick of oil in a street engine in the summer or winter. If pressures are good with 10/30, that is the better weight to use.

Crazy high psi numbers are not important unless youre doing crazy high rpms, good oil flow at start up & while running is more important IMO.

[Gach]

More then likely his engine builder recommended 20-50 because of the clearances he build in. I would never use 10-30 in any but stock factory clearances. Especially for longevity.

[tom s]

Lou,you are showing your age.Tom

[steve25]

Basically with a street strip motor if even with a 3.250” main if you have more then .0025” in the mains and rods then you or your builder are at fault, but I would still not run a 20-50 oil unless my oil temps where getting above 300 degrees , and especially if I was running a non mineral based oil.

Synthetic 10-30 oils have far higher sheer properties then a mineral based 20-50 oil.

[Gach]

Originally Posted by tom s

Lou,you are showing your age.Tom

Why because you disagree, with me.

[Gach]

If you have and engine builder you trust, and he recommends 20-50 thats all that counts. Then why would you deviate from others opinions. If he goes with 10-30 only for winter and it accomplished his goal then go for it. The fact he’s willing to try it temporarily makes him feel comfortable, then there’s nothing wrong with it.
The end result will be up to him.

I mean we can get into this big discussion, with all these different opinions on who's right and wrong. The name of the game is going with who’s opinion you trust. I have no idea what he’s running for clearances but given his past experiences his builder opinion for me anyway is one I would trust. He just wants to feel confident in making his choice.

[Stan Weiss]

Originally Posted by 64speed

I am gonna switch to VR1 10-30 over 20-50 for the rest of the winter cause I am getting 92 pounds at cold startup and if I don’t get it get to at least 100 degrees before moving or giving it any RPM it puts the high pressure alert on the DD RTX gauges and says I have over 100 pounds. I’m afraid that’s gonna blow my filter off and is causing my pressure leaks.. after it’s warm if I’m cruising it’s between 55-65 and if I drive it hard and really get the oil temp up it’s goes to 40 at and 895 rpm idle. Will the juice be worth the squeeze to change viscosity or should I just live with it?

What is the pressure relief valve in your oil pump set at?

Stan

[78w72]

Originally Posted by Gach

More then likely his engine builder recommended 20-50 because of the clearances he build in. I would never use 10-30 in any but stock factory clearances. Especially for longevity.

Thats great if the builder suggested it based on bigger clearances, but thats just a guess at this point. If that is the case then the next question is why did the builder build a street engine with big clearances more intended for a race motor? Most builders wont build an engine intended for street use & cruising around town with big clearances like that.

So if the engine is built to tighter specs like most street type engines, chances are he just read somewhere that he needs to use 20/50 race oil for some reason.

My question to the OP about why hes using 20/50 needs an answer based on engine specs or some other reasoning. He can use whatever oil he wants & im sure the engine wont blow up, but there are benefits to using a thinner oil that provides adequate psi vs a thicker oil than is needed.

[Gach]

Really his question was how much will the 10-30 lower oil pressure. Its still VR-1. If I have known it would create a chit storm, then again I should know better and just answered his question.

[chiphead]

What clearances call for going from a 10w30 to a 15w40 or thicker oil? Is it larger than .001 per inch of journal? Or is based on desired psi vs rpm? I find that going from 10w30 to 10w40 changes the pressure like 5psi once the engine got up to temp, over 175F water temp. This in a high mile 400.

I use the lightest weight oil to get desired pressures which is 20psi hot idle and 40-50 At 2500. Excessive oil pressure helps nothing on a hot street motor.

[TB1]

"it get to at least 100 degrees before moving or giving it any RPM it puts the high pressure alert on the DD RTX gauges and says I have over 100 pounds." this is a built in safety of the Dakota digital gauge set up, It states in the instructions that the transducers are rated for 100 PSI and the oil filter should handle way more than 100 psi before it bursts. As for the 20W-50 oil run what you feel will work best for the season.

[steve25]

I look at it this way.

Top fuel cars running over .0035” clearance and making close to 10,000 Hp run a straight 50 weight oil and that’s mainly due to oil dilution from passing 6 gallons of fuel through the motor in less then 4 seconds!

If a guy is sleeping better by running a 20w50 oil and loading the oil pump drive gear and cam gear more heavily then that’s your choice.

I will not even go into how oil temperature goes up in relation to oil pressure.

[Dragncar]

This subject, and oil iteslf is the most over talked subject in the car nut world. Its strictly personal preference. None of it will amount to a hill of beans.
Engine is doing fine with 20-50 and nothing bad has happened. Run 10-30 and nothing bad will happen either.
IMO if that engine has 92 lbs with 20-50 cold I would run 10-30 years round as the engine has plenty of oil pressure.
I was a 20-50 guy for years, but that was with a 455 that had the mains .0035-.004 when new. .002 on rods.
The new engine had oil pressure like his cold with 30WT. I put 10-30 in and brought the pressure down 15-20 lbs, acceptable.
The Boss Bird fellows have made more Pontiac horsepower than anyone and are 10-30 guys. Good enough for them good enough for us.
"Builders" ? I bet you would get answers all over the range if you asked them what viscosity for this engine, that engine.
Oil is almost like your favorite color. It will all work.
I run straight 30WT in a old car getting near 300,000 miles. Does the engine know the difference ?

[64speed]

Only reason I am running 20/50 is builder said to. I am not married to any particular weight I just don’t want a failure because the damn filter exploded or something. I am using VR-1 or Lucas whatever I can find.