Re: 25w50 or straight 50 wt oil
[Re: Quicktree]
#1670506
09/13/14 08:37 PM
09/13/14 08:37 PM
|
Joined: Dec 2006
Posts: 4,647 aotearoa
rebel
OP
master
|
OP
master
Joined: Dec 2006
Posts: 4,647
aotearoa
|
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.
|
|
|
Re: 25w50 or straight 50 wt oil
[Re: 440Jim]
#1670508
09/13/14 11:17 PM
09/13/14 11:17 PM
|
Joined: Dec 2006
Posts: 4,647 aotearoa
rebel
OP
master
|
OP
master
Joined: Dec 2006
Posts: 4,647
aotearoa
|
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.
|
|
|
Re: 25w50 or straight 50 wt oil
[Re: Clanton]
#1670513
09/14/14 04:51 PM
09/14/14 04:51 PM
|
Joined: Dec 2006
Posts: 4,647 aotearoa
rebel
OP
master
|
OP
master
Joined: Dec 2006
Posts: 4,647
aotearoa
|
Quote:
Can you Mic both type of lifters you have?
yes already checked that. the solid was 0.9032 & the roller is 0.9030
|
|
|
Re: 25w50 or straight 50 wt oil
[Re: rebel]
#1670514
09/14/14 05:40 PM
09/14/14 05:40 PM
|
Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
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
|
|
|
|
|