affliction1

hi guys so i switched from 5w30 to 20w50 because 5w was letting the oil preasure fall dangerously low when hot,so my buddy whose been a grease monkey for 30+ years said switch to 20w50 thats what he uses on his fieros,gnx and sierra now it has some upper engine noise,and id like to know what is going on exactly.ive hade some valve chatter for sometime but only at 2k rpms and up(not sure what this is either).now the uper engine noise is happening at idle to,oil preasure is around 60PSI post change,pre change it was around 5-10 psi at idle,oil level is good,help me please,jsut need car to last till i drop 350 in in january any ideas would help greatly thank you.

TwinTurboROC

Fuel psi, i assume u mean oil psi

20-50 is way to thick, put in 5-30 or 10-30, and 1/4-1/2 bottle of lucas heavy duty oil stablizer.

reason = thicker oil 20-50 will provide alot more "cushion" between metal parts than 5-30, but will flow alot less. as bearings wear out oil pressure will drop off little by little, along with a wearing oil pump.

also climate and temperature plays a role, colder oil flows, less thicker oil flows less. so if you have 20-50 in cold temps, your car will struggle to start, ive seen some not even spin 300rpms cuz of thick oil.

Theres more to it than that, but useless info unless you work for valvoline.

affliction1

so in fl where it rarely gets below 40 can i run 10w30 year round,and this was also an shot at trying to quiet my valves over 2k rpm,still cant get them to shut up lol and do you think that i can run this for around 200miles or so to run some mmo thru?

jwande

Multi-viscosity rating oil were developed originally to improve fuel mileage, reduce startup wear, and improve cold weather performance. There are different temperature grades where the change takes place, and normally this can be found in your owner's manual. Viscosity is actually a measure of flow, and so your "pressure" gauge isn't really pressure. The numbers on the viscosity are actually referencing a film thickness. Acts like a 10 weight oil below a certain temperature, then acts like a 30 weight oil. So your 20W-50 will provide a greater film thickness, but will it get to all of the moving parts quickly enough (especially on older engines with oil ports plugged and restricted)?

If you are looking for a band-aid, you might try Rislone. I have never used the Lucas oil stabilizer, but I am sure it is good as well. You should be able to make it a few more months, but if it is going to go, there isn't a single thing you can put in to prevent it.

RED86Z28

20w50 is not too think for a worn sbc. You may now be experiencing some restriction of flow of the thicker oil to the top end because of a buildup of gunk. I would go buy a bottle of Marvel Mystery Oil and dump in a half quart and see if things get quieter.

iroczracer07

iTrader: (2)

It sounds like your bearings are worn, but instead of using 20w50, why don't you try straight 30 weight with the lucas or risoline. Either product should work, provided your oil ports aren't clogged. If the noisey valvetrain continues, just pull your valve covers and use a phillips head screwdriver to clear the oil ports and see if that fixes your problem.

GICATA

I wouldn't recommend 20/50 for anything but engines that see extended use at higher temps. It's really just too thick.

A good oil for worn street engine could be a 15/40 or 10/40. There are many weights thinner than 20/50 but heavier than 5/30, which is very light for newer cars with low friction components and EPA milage efforts.

affliction1

i appreciate all the help,like i said just need it to last till jan when i rip out computer and all the sensors and crap and go mechanical any sujestions on good donors for 350s and trans?like what makes and years to look for(i know its off subject lol)

GICATA

What do you plan to do with it? If you use a V-8 you'll need a trans also.

A 350 is cheap and easy to find. A LS is popular, and everyone knows there's no replacement for displacement...find a 400SBC or buy a stroker crate engine.

You'll need a good exhaust system....a 3 inch single should be easiest and are popular. Shorty headers will be the easiest to deal with.

A built 700R4 will be less $$ than a T-56 (probably) and are plentiful. A TKO 500 (or 600) will stand the abuse of the big inch motors. A T-5 will hold up to a plain old 350 for a good while if you're only street driving it.

Then you'll need a good rear end.....9 bolt, 9 inch, or built up stocker...or a Dana....lots of options there.






I love spending someone elses money.





....oh and don't forget upgraded suspension components and SFCs.

3rdgenmaro

iTrader: (9)

I love the vortec headed 5.7s. Probably be the cheapest and easiest swap. Great heads and roller cam. Swap out the cam, throw on some headers and a decent intake and you will be very happy.

AlkyIROC

I run a thick oil in my race car but that's only because the thinner oils are not very compatible with alcohol fuel.

Having your pressure drop like that means you have clearance issues inside the engine. Thicker oil won't help. As a rule of thumb, an engine only needs 10 psi per 1000 rpm. I was working on a SBC engine that once the oil got hot, the oil pressure dropped so low that the warning light came on at an idle and reving it up barely got 25 psi. No engine noises and good pressure when the engine was cold. Ended up being bad cam bearings. Good thing I had a special tool to allow me to change the bearings without pulling the engine. I had a hoist at the time which made it much easier. Changed all the bearings except the back one.

Depending how long you want to run the engine before tearing it down and fixing, selling or replacing it, drain the oil and fill the engine up with straight Lucas oil stabilizer. A simple oil change won't change the fact that something is wrong internally and needs to be fixed properly.