rod oil clearance
Moderator: Team
-
- Member
- Posts: 86
- Joined: Thu Nov 07, 2013 8:23 am
- Location:
rod oil clearance
has anyone run .005" oil clearance on a 2.375" rod journal successfully?
° alt+0176 °
-
- Member
- Posts: 86
- Joined: Thu Nov 07, 2013 8:23 am
- Location:
Re: rod oil clearance
You need to fix the clearance. You're not going to have a happy engine with that much clearance. Even Top Fuelers don't run that much clearance with a 70 grade oil. It gets sketchy past ~.0035" as the ability of the oil film, regardless of viscosity, to keep the journal from going too eccentric is greatly diminished. Peak load carrying capacity for a journal bearing is ~.001" per 1" of journal diameter which is why that's the industry standard. I wouldn't even think of trying to make .005" clearance work. I'd be getting the clearance tighter.
-
- Pro
- Posts: 297
- Joined: Tue Aug 22, 2017 5:58 pm
- Location: Louisville,KY
-
- Member
- Posts: 86
- Joined: Thu Nov 07, 2013 8:23 am
- Location:
Re: rod oil clearance
ordered a new set of rod bearings. not sure how i ended up with the clearance i did with all new parts, but i suppose that is how things are these days.
fingers crossed that the next set are better.
fingers crossed that the next set are better.
° alt+0176 °
-
- Guru
- Posts: 1745
- Joined: Tue Jan 15, 2013 8:10 pm
- Location:
Re: rod oil clearance
how did you determine clearance ?
What were the Journal diameters and housing bores.
What were the Journal diameters and housing bores.
-
- Member
- Posts: 86
- Joined: Thu Nov 07, 2013 8:23 am
- Location:
Re: rod oil clearance
2.375 journal
2.380 id of bearing snapped into rod and torqued
measured a couple different spots with telescoping gage and mics. double checked with decent calipers. (we are looking for thousandths after all...)
there was a couple tenths here and there, but it was a solid .005 on all.
2.380 id of bearing snapped into rod and torqued
measured a couple different spots with telescoping gage and mics. double checked with decent calipers. (we are looking for thousandths after all...)
there was a couple tenths here and there, but it was a solid .005 on all.
° alt+0176 °
Re: rod oil clearance
Not a fan of snap guages. I suggest you buy a piece of plastigauge as a pretty accurate check of what you are seeing.
- af2
- Guru
- Posts: 7014
- Joined: Sun Jan 28, 2007 4:42 pm
- Location: Grass Valley, CA :Northern Foothills
Re: rod oil clearance
I know of few dozen blown Alky that run .009"..............................RDY4WAR wrote: ↑Thu May 19, 2022 9:39 am You need to fix the clearance. You're not going to have a happy engine with that much clearance. Even Top Fuelers don't run that much clearance with a 70 grade oil. It gets sketchy past ~.0035" as the ability of the oil film, regardless of viscosity, to keep the journal from going too eccentric is greatly diminished. Peak load carrying capacity for a journal bearing is ~.001" per 1" of journal diameter which is why that's the industry standard. I wouldn't even think of trying to make .005" clearance work. I'd be getting the clearance tighter.
GURU is only a name.
Adam
Adam
- af2
- Guru
- Posts: 7014
- Joined: Sun Jan 28, 2007 4:42 pm
- Location: Grass Valley, CA :Northern Foothills
Re: rod oil clearance
And I wouldn't on a steel rod deal,af2 wrote: ↑Fri May 20, 2022 3:36 pmI know of few dozen blown Alky that run .009"..............................RDY4WAR wrote: ↑Thu May 19, 2022 9:39 am You need to fix the clearance. You're not going to have a happy engine with that much clearance. Even Top Fuelers don't run that much clearance with a 70 grade oil. It gets sketchy past ~.0035" as the ability of the oil film, regardless of viscosity, to keep the journal from going too eccentric is greatly diminished. Peak load carrying capacity for a journal bearing is ~.001" per 1" of journal diameter which is why that's the industry standard. I wouldn't even think of trying to make .005" clearance work. I'd be getting the clearance tighter.
GURU is only a name.
Adam
Adam