I think I am running the wrong weight oil

[john.thompson068]

I think the guy who built my engine the first time said to run 20-50. But he didn't build my motor right and I had bearing damage from not enough oil pressure. Last time I changed oil I decided to put in 10W-30. When the motor is at idle in park it has 30 psi oil pressure and when in drive it has 20 psi. When the motor revs up some it has over 60 psi. I think I need to have more oil pressure at idle. Should I run a thicker oil like 20-50?

 

[lewtot184]

i use either a straight 30wt or 15-40, just depends. too thick doesn't flow. too thin doesn't protect. there are various factors for "low" oil pressure at idle; such as main bearing grooves, bearing clearances, and rod side play can be a factor. your pressure numbers aren't that bad. just take a step up in viscosity.

 

[ArtH]

I think the guy who built my engine the first time said to run 20-50. But he didn't build my motor right and I had bearing damage from not enough oil pressure. Last time I changed oil I decided to put in 10W-30. When the motor is at idle in park it has 30 psi oil pressure and when in drive it has 20 psi. When the motor revs up some it has over 60 psi. I think I need to have more oil pressure at idle. Should I run a thicker oil like 20-50?

At idle in park or neutral, your engine is operating at a higher RPM probably around 750 to 800 (+/-). Then you put it in drive it drops down to about 550 rpm so naturally your oil pressure drops somewhat. That's normal just as it's normal to be higher when the engine is cold and then it drops some when it warms up and the oil starts to thin out. If you're getting 60 psi at higher rpms, that's good. I have a 1977 400cid engine and according the service manual, minimum idle oil pressure should be 8 psi. It should run between 30 to 80 psi at 2000 rpm. That's quite a range.

I've never been a fan of 20W50 oil for normal driving I think it puts a strain on the oil pump. Most owner's manuals recommend 10W40 or even straight 30 weight. The viscosity requirements vary depending on the climate temperatures that you are driving in. 10W40 was always the most commonly used. My manual does recommend the heaviest weight oil for high performance engines that being 20W40 or 20W50. These days, most cars are using 5W30 because of the improved lube qualities motor oils have now.

The bearing failure you mention on the first rebuild may or may not have been oil pressure related. It's more likely the bearing didn't have the proper clearance. Did it spin or did it seize?

 

[tpodwdog]

LMAO.... dude....you always got something goin on.....funny stuff...youre a good writer by the way! what gauges are you using?...are you going by the factory gauges...if ya are,,,,THEY SUCK...get a good mechanical oil gauge. i got 30 at idle and 75 cruisin...AND THATS ON A stock 383....i dunno whats goin on in there!

my factory gauges( 70 RR) the oil says 20 all the time!..DONT GO BY THEM !

 

[Ron 73]

I run 10 W 40 in my car (73 SB). Always did with my cars back in the day.. I agree with tpod on using a mech gauge, more of a precise reading then factory..

 

[bigmanjbmopar]

oh oh, get to show off my new gauges ;) Use the 10-40 I use the Brad Penn 10- 40 and love it. It's green weird to pull you dip stick and see green oil on it lol. Anyway in this pic it's cold just started up but like said 700-800 rpm in park cold gets me 70 psi. In drive hot she drops to 20 no worries, it if went to below 10 or 0 I would panic and pull over to save the motor.

 

[Ron 73]

Thumbs up bigman, i can see why, there purdy!

 

[bigmanjbmopar]

Night shot, was surprises to see the back light is close to the cluster color

Sorry for the thread high jack JT

 

[65 Plymouth Satellite 426]

Nice Guages!

 

[70rr-brian]

I have heard on several occassions if you are running a solid roller on the street that a minimum of 30 PSI is recommended at idle to keep the lifters lubricated. I run 20w50 in mine and in drive at idle I get 30psi with a high pressure oil pump. When it is starting up I get about 80psi until the engine reaches operating temp. If I run 10w40 or less the idle in drive will drop oil pressure to around 20 or less. But on really hot ambient temperature days even the 20w50 will get down to around 22psi. I just avoid long idles while in drive by putting it in neutral and giving it enough gas to keep the pressure up to about 30...which is about 1k-1.2k rpms.

I see you live in Florida. I imagine you get quite a few hotter days then I do. I really don't have any issues running 20w50 but I never start the car below 60 degrees ambient.

 

[Moparsmitty]

I have heard on several occassions if you are running a solid roller on the street that a minimum of 30 PSI is recommended at idle to keep the lifters lubricated. I run 20w50 in mine and in drive at idle I get 30psi with a high pressure oil pump. When it is starting up I get about 80psi until the engine reaches operating temp. If I run 10w40 or less the idle in drive will drop oil pressure to around 20 or less. But on really hot ambient temperature days even the 20w50 will get down to around 22psi. I just avoid long idles while in drive by putting it in neutral and giving it enough gas to keep the pressure up to about 30...which is about 1k-1.2k rpms.

I see you live in Florida. I imagine you get quite a few hotter days then I do. I really don't have any issues running 20w50 but I never start the car below 60 degrees ambient.

I agree Brian. I've been using Valvoline VR-1 racing 20-50 in my 440 for over 5 years with no problems. But I'm not driving in the winter months. I think your oil pressure numbers are ok John.

 

[BIGSHCLUNK]

I agree Brian. I've been using Valvoline VR-1 racing 20-50 in my 440 for over 5 years with no problems. But I'm not driving in the winter months. I think your oil pressure numbers are ok John.

Been running the same thing in my HEMI.... no OP issues.....

 

[383man]

I also run Valvoline 20W-50 racing oil in my 63. Ron

 

[robinsonwr]

Well I just want to throw my two cents in if you do not mind. Really, the correct answer for what weight oil to run is in the bearing clearances. Most highend engine builders will tell you to run a certain weight oil and may even specify brand because of viscosity, ingredients, or longevity of the oil.

 

[Dennis H]

10-40 Amsoil. Oil pressure stays pegged on factory gauge. 440 rebuilt about 35k ago. Per the builder. I hammer it, no problems.

 

[luther]

FYI, a guy on my street (has a thing for late 70's police Mopars) said I should use a zinc additive because today's oils don't have it. The only thing I was able to find with zinc was STP. So it's in my 73 Runner 2-BBL 318 (tho not quite as hi perf as you hot rodders--ha!)
Luther

 

[Moparsmitty]

FYI, a guy on my street (has a thing for late 70's police Mopars) said I should use a zinc additive because today's oils don't have it. The only thing I was able to find with zinc was STP. So it's in my 73 Runner 2-BBL 318 (tho not quite as hi perf as you hot rodders--ha!)
Luther

There are several zinc additives on the market that you can use with regular oil. Comp, ZDDP Plus, etc. Any decent size parts store should have a few of these if that's the way you want to go. Like I said before, I just use Valvoline VR-1 Racing oil and it already has zinc and phosphorus additives in it. You can go either way and the cost is about a push.

 

[luther]

Thanks Smitty, didn't know Valvoline VR1 had that good stuff in it.
--Luther

 

[67 B-body]

I tried the STP (with zddp) additive in my first go around with my current 440. I lost two cam lobes out of that venture!
After a tear down and repairs made, I broke it in with Bradd Penn oil 20-50! No further issues again!!!!

 

[Secret Chimp]

Doesn't diesel oil stil have ZDDP in it? You can get really good Shell stuff at Wally World for less than $20 a jug.