Oil pressure drop during vtec
07-31-2024, 07:11 AM
#11
Was the rocker arm assembly removed? Maybe one of the locking pins fell out or sits incorrectly.
There is also a special VTEC system test that pressurize the bolt holes in the cam towers using air pressure.
Maybe try this with valve cover off and check for leaks.
There is also a special VTEC system test that pressurize the bolt holes in the cam towers using air pressure.
Maybe try this with valve cover off and check for leaks.
07-31-2024, 07:29 AM
#12
This thread is from 10 years ago but covers the same topic involving excessive oil pressure drop during VTEC activation. Seems one thought is that not all dry sump systems are capable of providing adequate oil volume to satisfy the needs of the F20C engine.
https://www.s2ki.com/forums/s2000-un...e-vtec-999235/
https://www.s2ki.com/forums/s2000-un...e-vtec-999235/
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windhund116 (07-31-2024)
07-31-2024, 07:45 AM
#14
If your dry sump is pulling vacuum in the crank case you would expect a few psi drop, proportional to the vacuum in the crank case. OP's readings are still a little low. 45-55psi is safe. Below 40 psi in VTEC, and you're pushing it. If you're pulling 14" of vacuum, expect to roughly drop around ~5-7psi of oil pressure. Air pressure contributes to the resistance to flow, which gives you your oil pressure. Less air less resistance, and as a consequence less pressure. Drop the crank case vacuum too low and you can cavitate your pump.
Last edited by Slowcrash_101; 07-31-2024 at 07:49 AM.
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windhund116 (07-31-2024)
07-31-2024, 07:49 AM
#15
I would question if there is proper flow to each part of the engine with that high of a viscosity oil. I would also question if the higher viscosity oil is not creating higher pressure yet poor flow. The pressure is not being measured at the exit of an oil journal, yet prior to that in the system. So it can be possible to read high pressure and still have terrible flow to portions of the engine. I am not sure I would trust any pressure readings in terms of them showing good oiling with a very high viscosity oil. Maybe there is something I am missing on this setup but I think this is by far the highest viscosity oil I have heard anyone running in a tracked S2000. I cannot say for certain if that is too far above spec to damage the motor since I am not sure if it has been tested. But it does seem unnecessarily high.
Have you tried running 10w-30 or 10w-40 and seen the same fluctuation in pressure?
Have you tried running 10w-30 or 10w-40 and seen the same fluctuation in pressure?
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windhund116 (07-31-2024)
07-31-2024, 08:59 AM
#16
07-31-2024, 09:51 AM
#17
We need more information.
Where's your VTEC engagement rpm? What's the oil pressure not-under load at that rpm vs when VTEC engages? In other words what does it drop from-to when it loses 40psi at that rpm and throttle position? Are you sucking air via the dry sump?
Normal oil pressure with normal oil is listed at 36psi at idle and 85psi at 3000 rpm, a drop of nearly 50psi. VTEC, though, is not engaged at this rpm.
10W-60 motor oil will indicate a artificially high oil pressure as the oil pump struggles to push very thick oil thru very thin passages.
-- Chuck
(For the very few who don't know VTEC requires both a minimum rpm and minimum load. A standard car can cruise as 8000rpm and never go into VTEC unless there's sufficient load on the engine. WOT? Yeah the cams will change as soon as the minimum rpm is reached. This is what's known as the "Power of Dreams" cuz it just takes forever.)
Where's your VTEC engagement rpm? What's the oil pressure not-under load at that rpm vs when VTEC engages? In other words what does it drop from-to when it loses 40psi at that rpm and throttle position? Are you sucking air via the dry sump?
Normal oil pressure with normal oil is listed at 36psi at idle and 85psi at 3000 rpm, a drop of nearly 50psi. VTEC, though, is not engaged at this rpm.
10W-60 motor oil will indicate a artificially high oil pressure as the oil pump struggles to push very thick oil thru very thin passages.
-- Chuck
(For the very few who don't know VTEC requires both a minimum rpm and minimum load. A standard car can cruise as 8000rpm and never go into VTEC unless there's sufficient load on the engine. WOT? Yeah the cams will change as soon as the minimum rpm is reached. This is what's known as the "Power of Dreams" cuz it just takes forever.)
Last edited by Chuck S; 07-31-2024 at 10:27 AM.
07-31-2024, 02:03 PM
#18
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windhund116 (07-31-2024)
07-31-2024, 02:15 PM
#19
We need more information.
Where's your VTEC engagement rpm? What's the oil pressure not-under load at that rpm vs when VTEC engages? In other words what does it drop from-to when it loses 40psi at that rpm and throttle position? Are you sucking air via the dry sump?
Normal oil pressure with normal oil is listed at 36psi at idle and 85psi at 3000 rpm, a drop of nearly 50psi. VTEC, though, is not engaged at this rpm.
10W-60 motor oil will indicate a artificially high oil pressure as the oil pump struggles to push very thick oil thru very thin passages.
-- Chuck
(For the very few who don't know VTEC requires both a minimum rpm and minimum load. A standard car can cruise as 8000rpm and never go into VTEC unless there's sufficient load on the engine. WOT? Yeah the cams will change as soon as the minimum rpm is reached. This is what's known as the "Power of Dreams" cuz it just takes forever.)
Where's your VTEC engagement rpm? What's the oil pressure not-under load at that rpm vs when VTEC engages? In other words what does it drop from-to when it loses 40psi at that rpm and throttle position? Are you sucking air via the dry sump?
Normal oil pressure with normal oil is listed at 36psi at idle and 85psi at 3000 rpm, a drop of nearly 50psi. VTEC, though, is not engaged at this rpm.
10W-60 motor oil will indicate a artificially high oil pressure as the oil pump struggles to push very thick oil thru very thin passages.
-- Chuck
(For the very few who don't know VTEC requires both a minimum rpm and minimum load. A standard car can cruise as 8000rpm and never go into VTEC unless there's sufficient load on the engine. WOT? Yeah the cams will change as soon as the minimum rpm is reached. This is what's known as the "Power of Dreams" cuz it just takes forever.)
07-31-2024, 04:06 PM
#20