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That's correct. Oil pressure is highest when ice cold. Maybe these banjo valves relieve some of this high pressure, to allow bypass.
From what I've read on BITOG, engine damage is done (even with adequate oil levels) --- during cold starts. So, engineers design systems to get oil to operating temps and pressures to stabilize, ASAP.
Cold starts have highest wear levels as it takes longer to get oil to all of the parts after sitting for a while, and colder thicker oil flows slower. An engine driving down the highway fully warmed has almost zero wear, cold start up creates the most wear for an engine.
At cold start and idle the oil jet bolts would be fully opened as oil pressures are higher than the opening pressure of the bolts, at hot idle the bolts are supposed to be closed as oil pressures subside below the opening pressures of the bolts.
Thanks a lot for sharing this, I had no idea such a bolt existed! My S is fine at startup but I have an oil pressure delay in my Civic w/ a B16B engine thats been bothering me.
Having read that most B16s have oil jets too, I'm suspecting a similar issue with it.
Which is one of the big two reasons for using a synthetic oil that is 0W-30. Non-dino oil leaves more of a film and the "0W" is thinner at start for better lubrication.
I've added a note to my DIY oil bolt thread, with a summary discussion of this issue and a link to this thread. As stated there, my current conclusion is this:
Originally Posted by twohoos
As of now, I continue to recommend replacing the old 2-hole bolts with the newer 4-hole bolts. This is because, again, the failure mechanism in the new bolts does NOT compromise the high-rpm protection they provide. So, even failed 4-hole bolts can prevent a catastrophic engine failure, which far outweighs the (theoretical risk of) minor added wear during start-up. Nevertheless, I'll be following the community's findings, and if it ever becomes clear that this recommendation should change, I'll update this post immediately.
Depends on which issue you mean. The 2 hole banjo bolts were used on the early AP1's (pre 02, but there is a range of VIN's). Those are not really an issue besides the use cases discussed already. But in those more extreme use cases then it is recommended to change them out.
If you mean the springs breaking, I suspect it could happen with either of the bolt versions based upon the way they failed.
Thanks a lot for sharing this, I had no idea such a bolt existed! My S is fine at startup but I have an oil pressure delay in my Civic w/ a B16B engine thats been bothering me.
Having read that most B16s have oil jets too, I'm suspecting a similar issue with it.
The oil jets on the b-series could be similar, they are set to unseat the ball valve with 28 psi, I've got a b-series engine and shop manual, they appear to have the same design.
Depends on which issue you mean. The 2 hole banjo bolts were used on the early AP1's (pre 02, but there is a range of VIN's). Those are not really an issue besides the use cases discussed already. But in those more extreme use cases then it is recommended to change them out.
If you mean the springs breaking, I suspect it could happen with either of the bolt versions based upon the way they failed.
@engifineer Thanks...I meant the spring failure. Reading up on replacement...looks like no fun with the #1 bolt (the one with the oil pump in the way). I guess with 2005 (which should have the updated bolts), one should just wait until have the delayed oil pressure light on to start replacing?
Regarding the replacement of the Nr. 1 Bolt, behind the oil pump, it was not soooo bad while the car was on a lift. With the car on the lift, we had a lot of light and room to position the tool. I think its more diffcult to do with the car on Jack stands...
My theorie regarding the oil pressure light was wrong, i drove the car yesterday. The oil light still has the 1 second delay when starting the engine. Damned.
However,i am convinced that changing the bolts was worth the work and time, because it is good for the engine in the long term.
I found the time and cut open the remaining three bolts. No Surpise, 2 had broken springs, only 1 was O.K.
Last edited by Mr.Matchbox; Sep 18, 2020 at 04:56 AM.
