info please

[lilrobo]

just joined here guys
i have a 1958 Chevy with a 235 6 cyl don't know the miles , now i have about 40 psi oil pressure when cold and when hot ( hot day ) i have seen 10 maybe 5 psi ,, i do have some rattling issues , like when it shifts from low to high i here something going on ,, i changed the oil when i first got it and use i think it was 15w40 fully sync oil and was told not to use that so i changed and started using straight 40 weight ,, that being said what should i use to keep better oil pressure, i am going tom overhaul the engine this winter but i want to drive it till then , i was told that 20w50 would be better ???

please help guys
thanks

 

[dave1251]

Not enough information provided by you. What is the pressure readings in correlation of RPM's.

 

[lilrobo]

everything is based on idel

 

[jsnyder49090]

how much at 1000rpm 2000rpm etc

 

[Rand]

Originally Posted By: lilrobo
just joined here guys
i have a 1958 Chevy with a 235 6 cyl don't know the miles , now i have about 40 psi oil pressure when cold and when hot ( hot day ) i have seen 10 maybe 5 psi ,, i do have some rattling issues , like when it shifts from low to high i here something going on ,, i changed the oil when i first got it and use i think it was 15w40 fully sync oil and was told not to use that so i changed and started using straight 40 weight ,, that being said what should i use to keep better oil pressure, i am going tom overhaul the engine this winter but i want to drive it till then , i was told that 20w50 would be better ???

please help guys
thanks


please use better typing if you want good answers and less ridicule aka chevyboy style.

also you need to provide oil pressure with rpm not just idle.

I'm curious what 15w40 full syn you found.. there isnt very many out there.

If you cant take 30sec to make your post legible readable most people wont take 30sec to give you a good answer.

 

[eagle23]

I am going to assume it won't be a daily driver, just a weekender? Do you know how much it burns or leaks?

If a weekender, I'd use either 20w50 conventional or 15w40 conventional whichever was cheaper and available. The 40 wt is the old recommendation from the 1950s (don't ask me how I know), but for summer use would be fine.

I might get flamed for these recommendations, but hey it's only a few months from overhaul, so why are we splitting OCD hairs? Oh, right! This is BITOG

With the overhaul in a few months, I can't imagine any of them making a difference you would notice.

 

[NHGUY]

Lucas anyone??
lol

 

[carwreck]

Originally Posted By: lilrobo

1958 Chevy with a 235 6 cyl...
now i have about 40 psi oil pressure when cold and when hot ( hot day ) i have seen 10 maybe 5..

please help guys
thanks

As noted by dave1251 and lilrobo, you must measure the oil pressure at a specific rpm.

Per Chevy manual, http://chevy.oldcarmanualproject.com/chevyresto/58041.htm Oil grade 10w30, filter RPO 237
The normal oil pressure is 35PSI@ 2000RPM. The manual only gives pressure at 2000 RPM. Since your car idles at only 475RPM, oil pressure will be lower at idle.
____________________________________________
1987 Toronado
1999 Olds GLS

 

[lilrobo]

WOW ok i will see if i can do better ,now as far as checking at a rpm i haven't, i only have done it at idle ,sorry .i removed the sending unit and installed a gauge just for checking, i have now put the sending unit back in.
yes it is a weekender ,and for the oil its a Shaffer oil that's all i was ever told ( real green )
all i was asking was if 20w-50 is better than 40w

thanks for the info

ridicule aka chevyboy style, must be a ford guy

 

[CATERHAM]

Originally Posted By: carwreck
Originally Posted By: lilrobo

1958 Chevy with a 235 6 cyl...
now i have about 40 psi oil pressure when cold and when hot ( hot day ) i have seen 10 maybe 5..

please help guys
thanks

As noted by dave1251 and lilrobo, you must measure the oil pressure at a specific rpm.

Per Chevy manual, http://chevy.oldcarmanualproject.com/chevyresto/58041.htm Oil grade 10w30, filter RPO 237
The normal oil pressure is 35PSI@ 2000RPM. The manual only gives pressure at 2000 RPM. Since your car idles at only 475RPM, oil pressure will be lower at idle.
____________________________________________
1987 Toronado
1999 Olds GLS

Good advice.
Since that is of course a hot OP spec', you likely don't need to run anything heavier than the 15w40 you're running now and even that may be heavier than necessary.

When you rebuild the engine a modern HDEO like Amsoil 5w30 HDD would be a good choice although even that maybe heavier than necessary.

 

[lilrobo]

Thanks guys

 

[mechtech2]

You don't want a straight weight.
That is, use a 15-40 . NOT a straight 40.
When hot, they are the same thickness.
When cold, the 15-40 is far superior, and flows better.

 

[lilrobo]

thank you for adding that , i will change it , that might get the oil up top faster also ???

 

[crazyoildude]

15w40 rotella summer
10w40 rotella in the winter
dont go super thick there is no need and the engine will run better..

 

[lilrobo]

i got me some rotella 15w40 and add a bottle of lucas oil treatment i will check the psi after i get it in.

thanks

 

[CATERHAM]

Before you change anything, you haven't mentioned what your hot OP is at 2,000 rpm yet on the 40wt oil you're currently running?
Is it actually below the spec' 35 psi and if so by how much?

BTW, a 15w40 by modern standards is anything but light on start-up, with a typical 130 VI it's not much better than a straight 40wt. If you actually need a 40wt oil (which has yet to be determined) Rotella T6 5W-40 would be the logical choice. Your engine would have to be very worn indeed to need anything heavier than that.

 

[lilrobo]

has anyone use sea foam in the classic ride???, i was told that it might help my oil pressure
thanks

 

[lilrobo]

update
i installed oil pressure gauge inside the car and got a lot of info ,every time i turned to the left i lost pressure went to 0 and when i got straight it came up ,, so i came home i added 1 qt of oil and it never went below 25psi at that time even in turns,, i am running 15w 40 ( 6 qt ) maybe someone change the oil pan ,stand to reason why i cant remove the pan.i need to drve the car more to get more info ,it was running at 170 temp at that time , never the less better than 0 psi

i'll give more info later

thanks

 

[donnyj08]

Originally Posted By: CATERHAM
Before you change anything, you haven't mentioned what your hot OP is at 2,000 rpm yet on the 40wt oil you're currently running?
Is it actually below the spec' 35 psi and if so by how much?

BTW, a 15w40 by modern standards is anything but light on start-up, with a typical 130 VI it's not much better than a straight 40wt. If you actually need a 40wt oil (which has yet to be determined) Rotella T6 5W-40 would be the logical choice. Your engine would have to be very worn indeed to need anything heavier than that.


^ excellent advice here.

 

[Hendo]

If your rebuilding it I'd just go thick and bide your time. It's a good opportunity to experiment with cleaning and valve deposits etc...

I've heard of people running some diesel in the oil before they tear it down, just to clean it out before rebuild. Also ghetto style water injection to clean the valves and combustion chamber might be worth a shot, with before and after pics for us to see of course!

In short, run anything in the thick side- 40, 50 weight. Also look into baffling your sump when you tear it off. It sounds like you have a starvation problem.