Hondoctors

I've been reluctant to post this because I thought that eventually I would find the problem on my own, but I'm at a dead end and tired...

I'll try and keep this as short as possible, while giving the important details. I have a boosted GSR motor (sleeved, CP pistons, eagle rods) and the problem is that the engine drops oil pressure as soon as VTEC engages at 5500 rpms, and continues to decline as RPM increases. Oil pressure gauge reads about 60 psi, then VTEC opens and it suddenly drops to 45 psi, and if I stay in the throttle, the oil pressure will continue to drop to 40 psi, and that's when I let off. Other weird things I've noticed. Oil pressure seems to fluctuate 3-5 psi at constant 3500 rpm. If the car has been sitting for more than a day, it seems to take longer than normal to build oil pressure from a cold start, about 3 to 4 solid seconds. Here's a list of things that I have changed:
-oil pump and O-ring
-tighter rod bearings
-tighter main bearings
-oil pump pick-up
-removed factory oil cooler
-eliminated piston oil squirters
-switched out rocker shafts and rockers
-switched out VTEC solenoid
-replaced O-rings for oil orofice in block (oil feed to head)
-replaced 3 O-rings in head (2 orofice, 1 under cam caps)
-removed oil line to oil pressure gauge and cleaned out
-tried a different autometer oil pressure gauge
-installed Golden Eagle oil filter sandwich and took turbo oil feed from there
-went from 4 AN to 3 AN turbo oil feed line (no oil restrictor, yet)
-switched out entire head, virgin
-installed a virgin crank

I've been hunting this problem for a while, and there's more things that I've inspected. Once problem I found was that the oil pump pickup was a little tweaked, but there's a new one in there now. The oil pressure gauge is coming out of stock oil pressure sending unit hole on back of block. Suspicions I have at this point: turbo oil feed line needs a restrictor, oil pump cavitation, bad voltage going to VTEC solenoid, is there anything inside the block that would cause an oil bypass?

D@nnY

was there metal or copper dust in the oil pan? is there any metal in the screen on the vtec solenoid?

is the oil jet /restrictor in the top of the block? what kind of oil pan are you using?

Hondoctors

No metal in the VTEC screen, the restrictor is in the block with a new O-ring. The old crank main and rod journals looked fine, but number 1 and 5 main bearings were scratched, and I replaced them when I put in the virgin crank yesterday. The engine has a new set of ACL rod and main bearings, standard size. The oil pan is a stock P72 with a fitting welded on for turbo drain. The pan is not dented, but I have a new one on hand just incase...

Kelly.

also might help to add that we saw small gains in oil pressure by switching from the ACL race bearings to ACL std bearings

i think there was something else that helped oil pressure, but only by ~ 5psi,

littlebluecrx

oil pressure should not drop at all,are you sure you dont have a oil pump issue? sounds like you replaced it, as far as tighter clearances, that should only increase pressure. if the sump is not restricted, and you have no leaks.... like plugs in the head" the one under the cam cap by the distributor is left out by machine shops all the time", then why dont you hard wire vtec to the battery and monitor your oil pressure, youll have to raise idle to around 2500 so it does not stall.... see if it steadys.... does the car feel like it has vtec? I am also wondering if something is wrong with your main cap aligment, you said you replaced 1 and 5 main bearings... makes me wonder is something is not quite right in the bottome end.... there are only some many things in a head that could cause your issues, and they are very consitent, besides it does it with a swaped known good head.... good luck, but I would either look at vtec cutting in and out, out worse something not right in the bottom end clearances.....

gsrt nick

what kind of bearing clearnce do you have and how are you checking it
the difference between the acl race and regular bearings is the race bearing is a little harder material they have bigger chanfers on the sides. they also run a little wider specs to me it sounds like a clearence issue. the oil is escaping out the sides of the journals to quickly resulting in lower oil pressure

also it sounds stupid but did you check your oil that would be the most basic answer to the problem

ghostskinner

might be your oil pump going check it out

IndySporty

tried running higher viscosity?

sc4dr

What kind of oil pressure gauge, maybe its a bad sending unit. shrug

Kelly.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ghostskinner &raquo;</TD></TR><TR><TD CLASS="quote">might be your oil pump going check it out</TD></TR></TABLE>

oil pump has been replaced already

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IndySporty &raquo;</TD></TR><TR><TD CLASS="quote">tried running higher viscosity?</TD></TR></TABLE>

what wieght oil?
do you think a lighter wieght oil will make you lose ~20psi in pressure?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sc4dr &raquo;</TD></TR><TR><TD CLASS="quote">What kind of oil pressure gauge, maybe its a bad sending unit. shrug</TD></TR></TABLE>

we have tried to different mechanical guages, and ill be lending him my electrical guae today.
problem is when we switched guages / lines nothing changed.

Turbogixxer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kelly. &raquo;</TD></TR><TR><TD CLASS="quote">

oil pump has been replaced already</TD></TR></TABLE>

Does not mean it is good

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kelly. &raquo;</TD></TR><TR><TD CLASS="quote">what wieght oil?
do you think a lighter wieght oil will make you lose ~20psi in pressure?</TD></TR></TABLE>

Changing the weight of th oil is a band-aid.


Dumb question, you have been using the same oil filter the whole time?

earl

Are you sure that the cylinder heads you have tried were not used as an ls vtrc head at one time? You would need to convert them back for straight vtec.
The fact that you say that you switched to a virgin head, with the same results, kind of throws me off.
My best guess is that the problem has to be with the cylinder head. There is a plug that gets left out of the vtec head that I THINK is hidden by another plug. Most V-8 style shops remove both plugs when cleaning the head. They reinstall the outer plug and can't figure out where the other plug went, so leave it out. I THINK once the vtec opens, the missing internal plug allows all the vtec oil pressure bleed back to the block. I thought I had come across this problem several years ago and I think that was the fix. My memory is not that good so I could be wrong.

Hondoctors

Jason- One thing I did leave out, which is important regarding the bottom end is that the thrust washers had excessive wear, especially the one facing the clutch. The thrust washers had only 45 miles or so, and it was scratched pretty good. I do have a very strong pressure plate on the clutch. Does this have to do with excessive crank run-out? Would that cause this oil condition? VTEC does work, and the car runs great on a street tune from Servion on 8lbs boost. Everything about the running condition of the car is perfect.

Earl- The only orofices I'm aware of are the intake and exhaust rocker shaft orofices, and the orofice in the block just under the head. I've inspected them numerous times, and the new head seems to have all the same parts, and I have the Helms right next to me. The old head was working fine on my old setup, but when I put the motor back together with new pistons, I dissassembled everything for cleaning. I'm familiar with all of the parts because this wasn't my first time...

When I removed the factory oil cooler, the engine did receive a new Honda oil filter, I only use those. The reason why I questioned the original crank that was in the motor was because it had been polished 3 times I beleive, throughout it's time in this block, when I would take it apart there always seemed to be some imperfections that would go away with a polish. I've never seen the main bearings and thrust washers scratched this bad before though.


Modified by Hondoctors at 2:28 PM 9/17/2006

Kelly.

bump

i hope we can get this figured out, servion will be here friday to tune, and i know jarrod would love to put down some good numbers.

any ideas are better then no ideas
and thanks for the help so far

Hondoctors

Today I hooked up a voltmeter to the A4 terminal connector at ECU and test drove the car. VTEC does open and does get battery voltage. VTEC works, does not feel like it cuts in and out. I'm wondering about the bottom end, that Jason was referring to. This week I want to pull off the oil pump, switch it out again, and while I'm there measure crankshaft run-out. The thrust bearing is really in bad shape, there may be a major problem in the bottom end that I haven't measured.

Would excessive crank run-out cause oil pressure problems like this? I'll build a new motor if I have to. Also, would my turbo allow too much oil through? It's a Precision GT30R (ball bearing)

I need to track down one of these oil restrictors I heard people using and put one in for the hell of it. I've changed everything else out.

littlebluecrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hondoctors &raquo;</TD></TR><TR><TD CLASS="quote">Today I hooked up a voltmeter to the A4 terminal connector at ECU and test drove the car. VTEC does open and does get battery voltage. VTEC works, does not feel like it cuts in and out. I'm wondering about the bottom end, that Jason was referring to. This week I want to pull off the oil pump, switch it out again, and while I'm there measure crankshaft run-out. The thrust bearing is really in bad shape, there may be a major problem in the bottom end that I haven't measured.

Would excessive crank run-out cause oil pressure problems like this? I'll build a new motor if I have to. Also, would my turbo allow too much oil through? It's a Precision GT30R (ball bearing).

I need to track down one of these oil restrictors I heard people using and put one in for the hell of it. I've changed everything else out. </TD></TR></TABLE>
I doubt the turbo could cause that much of a pressure drop, besides I think it would be a consistent pressure drop, a resrictor is not a bad idea, it will save the turbo seals in the long run anyways, but if you checked all the plugs in the head and the block, i would look closer at your bottom end especially if you see bearing material in the oil after all this diagnostic work. the head only had one internal oil passage that will give you no vtec, it's right on the distributor side under neath the cam cap, but thats not your problem. No oil resrictor in the block would cause oiling issues from the start with or woth out vtec engage. Good luck still thinking ...

Kelly.

up

earl

When the rear thrust is bad, it is usually caused by a clutch out of adjustment or by a driver that rests his foot on the clutch pedal when driving. These actions push the crank forward in the engine and will wear out the rear thrust while the front thrust looks untouched.
How is the cold and hot oil pressure while driving out of vtec? If it is normal, the problem would not be caused by anything in the short block. It would have to be in the head.

earl

I THINK if this plug were missing, you would push oil in the head/valvecover when Vtec is activated. I COULD BE WRONG...

0xenocron

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hondoctors &raquo;</TD></TR><TR><TD CLASS="quote">VTEC does open and does get battery voltage. VTEC works, does not feel like it cuts in and out. </TD></TR></TABLE>

I believe that if you are running and have enabled the stock VTEC Pressure Switch, it will turn off VTEC and throw a code (21 or 22) if oil pressure falls below 40psi...so if you have all of this still and it isnt disabled on you, your VTEC oil pressure sensor isnt sensing oil pressures below 40 psi...

Try disabling VTEC and revving up to 7000 or so and see if the oil pressure still drops off...

EARLdaSQUIRREL

my best guess would be a dolly or a pin missing in the rockers for the vtec lobes......

Kelly.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">I THINK if this plug were missing, you would push oil in the head/valvecover when Vtec is activated. I COULD BE WRONG...

</TD></TR></TABLE>

we will look at this tomorrow,

but we have already swapped the entire head,
what are the chances that both heads were missing them.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by coptzer &raquo;</TD></TR><TR><TD CLASS="quote">my best guess would be a dolly or a pin missing in the rockers for the vtec lobes......</TD></TR></TABLE>
we will look around the rockers, too, but again, the head has been swapped.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xenocron &raquo;</TD></TR><TR><TD CLASS="quote">I believe that if you are running and have enabled the stock VTEC Pressure Switch, it will turn off VTEC and throw a code (21 or 22) if oil pressure falls below 40psi...so if you have all of this still and it isnt disabled on you, your VTEC oil pressure sensor isnt sensing oil pressures below 40 psi...

Try disabling VTEC and revving up to 7000 or so and see if the oil pressure still drops off...</TD></TR></TABLE>

jarrod will be able to answer this better, but i know he WAS getting a vtec pressure code, but that has since gone away. i think a combonation of tightening up the bearings, a new oil pump, and a undented pickup did it. just notsure which once exactly.

thanks a ton for everyone help.
ill call jarrod in the morning and see what he can find

littlebluecrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">I THINK if this plug were missing, you would push oil in the head/valvecover when Vtec is activated. I COULD BE WRONG...

</TD></TR></TABLE>
I had that plug out before engine oil pressure at the sender is normal, the car just does not have vtec. It caused no issues with premature bearing wear, just no vtec....good luck

Kelly.

Modified by Kelly. at 9:24 AM 9/20/2006

earl

Great news, information like this helps everyone with future projects.