25w50 or straight 50 wt oil

Posted By: rebel

25w50 or straight 50 wt oil - 09/13/14 08:35 AM

any members running this weight oil in their rollercamed engines? my stock block street/strip car was having low oil problems from the fresh build. i figured it was due to the roller lifters bleeding past too easy so i fitted a restricter to the second gallery. this bumped up the pressure to more acceptable pressures but when it starts getting hot after a few rounds the pressure isn't making the mark. currently i'm running 15w40 semi synthetic oil & it was suggested i use 25w50 or straight 50 wt oil. i'm curious to who using it & what pressures do you experiance?

Posted By: radar

Re: 25w50 or straight 50 wt oil - 09/13/14 04:01 PM

I always ran 20/50 in the winter and straight 50 in my shovelhead harley. The straight weight seemed to keep the pressure up in the heat. Apples to oranges but fwiw the shovel is an air cooled roller tappet motor. I've run hydro and solid rollers in 'em. The newer harleys I always ran thinner oil.

Posted By: Quicktree

Re: 25w50 or straight 50 wt oil - 09/13/14 04:09 PM

I think it's been stated many times, any attempt to control oil pressure by messing with different oil is a band aid to the problem.

Posted By: Clanton

Re: 25w50 or straight 50 wt oil - 09/13/14 04:24 PM

Did you restrict rocker oiling?A welding tip in the rocker stand will work.

Posted By: andy3965

Re: 25w50 or straight 50 wt oil - 09/13/14 08:57 PM

Quote:

Did you restrict rocker oiling?A welding tip in the rocker stand will work.

can you give more info on this? we have used the screw on terminal from a champion spark plug for this in the past.

Posted By: Clanton

Re: 25w50 or straight 50 wt oil - 09/13/14 10:04 PM

Quote:

Quote:

Did you restrict rocker oiling?A welding tip in the rocker stand will work.

can you give more info on this? we have used the screw on terminal from a champion spark plug for this in the past.

My pics are gone but I can let you know what to do.I have a better topic on it but can't find it from last summer.you cut off a mig tip to 1/2" after drilling it to what jet you want and install it in the rocker stand befor you put the bolt/stud in.
https://board.moparts.org/ubbthreads/show...rue#Post7739265

Posted By: rebel

Re: 25w50 or straight 50 wt oil - 09/14/14 12:37 AM

Quote:

I think it's been stated many times, any attempt to control oil pressure by messing with different oil is a band aid to the problem.

if it's a band aid repair, why do they make so many different grade oils? i was advised by a dirt track racer to use the 50wt oil as most cars that race in his class use this weight oil due to the fact they're old school V8's & they all seem to have this problem when running solid roller cams. when i was using a solid flat tappet cam the oil pressure wasn't a problem but with just a cam change now it is.

Posted By: 440Jim

Re: 25w50 or straight 50 wt oil - 09/14/14 02:40 AM

It would be best to use roller lifters that don't have that problem. But before that, what is the oil pressure going down the track when "hot"? i.e. at 4000-7000 rpm.
A Mopar big block high volume oil pump should put out tons of oil and the relief valve spring can be changed to regulate at a higher pressure.

IMO, 70 psi is nice. But even 50 should be fine. I think 90 psi is too much. Idle pressure is not so important, and I feel 20 psi at 800 rpm is fine as long as the pressure goes up with rpm (maybe 35 psi at 2500 rpm).

Also, what heads are you running? The Indy heads with external oil lines should be restricted to avoid excess oil to the heads, which also reduces oil pressure to the rest of the motor. Did the roller cam have the #4 journal grooved for more (too much) oil?

Posted By: rebel

Re: 25w50 or straight 50 wt oil - 09/14/14 03:17 AM

Quote:

It would be best to use roller lifters that don't have that problem. But before that, what is the oil pressure going down the track when "hot"? i.e. at 4000-7000 rpm.
A Mopar big block high volume oil pump should put out tons of oil and the relief valve spring can be changed to regulate at a higher pressure.

IMO, 70 psi is nice. But even 50 should be fine. I think 90 psi is too much. Idle pressure is not so important, and I feel 20 psi at 800 rpm is fine as long as the pressure goes up with rpm (maybe 35 psi at 2500 rpm).

Also, what heads are you running? The Indy heads with external oil lines should be restricted to avoid excess oil to the heads, which also reduces oil pressure to the rest of the motor. Did the roller cam have the #4 journal grooved for more (too much) oil?

i'm using Compcams offset roller lifters, i don't know of any other offset roller lifter that doesn't have an recessed oil band around the body. when the engine is really hot i found the oil press was only 50 psi @ 7k, not really what i was wanting, i'm a believer in 10 psi per 1k rpm on the safe side. when its cooler like on its first run it tops out at 75 psi which is acceptable in my books.
the heads are stage VI & are fed from the cam. there is no groove in the bearing that feeds the rockers so it's not like Indys that need the restricter. the oil pump has a fat washer inder the spring to boost the pressure before the relief lets go.

Posted By: ahy

Re: 25w50 or straight 50 wt oil - 09/14/14 03:56 AM

Since you said "street/strip" I'd pick 20W50 between the two. Its a decent 3 season oil and won't act like molasses on a cool'ish morning. As others have mentioned, if it's 50 PSI at speed with shimmed spring when hot something does not sound right. Does it have a HV pump? What are bearing clearances?

Posted By: rebel

Re: 25w50 or straight 50 wt oil - 09/14/14 10:26 AM

yes HV pump, 0.002 crank n rod bearing clearences, new cam bearings. it's definately the lifter bores bleeding as it surprised me during the priming with the cordless drill. blocking 1 side bumped up the pressure a lot. when it was a solid FT cam the pressure was higher & the lifter bore bleeding was less, way less.

Posted By: Clanton

Re: 25w50 or straight 50 wt oil - 09/14/14 03:21 PM

Can you Mic both type of lifters you have?

Posted By: GTX MATT

Re: 25w50 or straight 50 wt oil - 09/14/14 05:03 PM

Quote:

Quote:

I think it's been stated many times, any attempt to control oil pressure by messing with different oil is a band aid to the problem.

if it's a band aid repair, why do they make so many different grade oils? i was advised by a dirt track racer to use the 50wt oil as most cars that race in his class use this weight oil due to the fact they're old school V8's & they all seem to have this problem when running solid roller cams. when i was using a solid flat tappet cam the oil pressure wasn't a problem but with just a cam change now it is.

Posted By: rebel

Re: 25w50 or straight 50 wt oil - 09/14/14 08:51 PM

Quote:

Can you Mic both type of lifters you have?

yes already checked that. the solid was 0.9032 & the roller is 0.9030

Posted By: MR_P_BODY

Re: 25w50 or straight 50 wt oil - 09/14/14 09:40 PM

Quote:

Quote:

Can you Mic both type of lifters you have?

yes already checked that. the solid was 0.9032 & the roller is 0.9030

And what are the lifter bores... .001 is pretty good
for clearance... I'm at .0015

Posted By: rebel

Re: 25w50 or straight 50 wt oil - 09/15/14 08:18 AM

thats where things aren't so great with it being 0.0028 . they're all perfectly round but a tad big which is why i'm seeing the heavy bleed off with the priming pump.