Honda D Series Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
1,342 Posts
Discussion Starter #1
recently rebuilt z6 is making low oil pressure
stock crank
tuner toys rods
je pistons
bearings were all plastigauged and within spec
new Honda oil pump

could a bad seal between the pump and block or pump and pick up cause low pressure? I assume I could

what about a blocked oil passage? where would I look?

been going back and forth trying to decide if I want to pull it out or if I should leave it in and try a few things

if I left it in I would probably first try a new strainer and gasket, see what that does
if that didn't do it I would try resealing the oil pump to the block
if that didn't do it I'd have to pull it out and look for the cause

any flaws in my logic?
 

·
Registered
Joined
·
1,348 Posts
If I remember correct a member on here had a bad cyilinder head that caused low oil pressure. How low are we talking? Do you have a gauge or are you just going off the oil light?

What were your cam to journal clearances?
What were your bearing clearances?
What oil are you running?
 

·
Defender of the D
Joined
·
2,495 Posts
How many miles is on this rebuild?
 

·
Registered
Joined
·
1,348 Posts
If your light is on at idle then it means your at about ~5 psi. Does the light go off if you rev it a bit? If the light is solid and there's nothing in the pickup screen your going to have to pull it. Be very careful shimming the relief spring, I used a .025" washer and had over 95 psi of oil pressure at cold start. As the oil warms the psi goes down; I have 40 psi at 3000 rpm+ normal driving.
 

·
Classic Man
Joined
·
16,355 Posts
shimming the relief will do NOTHING but raise the maximum pressure your pump can create. so, if you are under 80psi it will not make any difference at all

think of it like a waste gate.



i think your problem is associated with bearing wear. just a hunch, how ever.

it might be worth trying a heavier weight of oil
 

·
Registered
Joined
·
6,966 Posts
agreed with dan... shimming the spring will do nothing until the oil pressure reaches 80psi. did you make sure you used good assembly lube?? did you turn the motor over with the injectors unplugged to prime the oil pump on the first start up?? is this a new oil pump?? if not did you spec it to make sure it was within spec? is this low oil pressure with a cold start? should be over 60 psi with a cold start until the oil thins out. what type of oil..??? seems to me that it has to do with the bearings.
 

·
Registered
Joined
·
13,322 Posts
Here's my question...why do people spend $100's/$1000s on building/re-building a motor and not have the most key/important component on that motor during startup? Can anyone guess what item this might be?










































An oil pressure guage! Ding ding ding!
 

·
Registered
Joined
·
1,342 Posts
Discussion Starter #12
1. Pull the pan, check pick up gasket.

2. Shim the relief spring.
im going to order a new pick up and gasket and try that first, probably wont shim the spring unless i get as far as pulling the motor

If your light is on at idle then it means your at about ~5 psi. Does the light go off if you rev it a bit? If the light is solid and there's nothing in the pickup screen your going to have to pull it. Be very careful shimming the relief spring, I used a .025" washer and had over 95 psi of oil pressure at cold start. As the oil warms the psi goes down; I have 40 psi at 3000 rpm+ normal driving.
i didnt rev it.

shimming the relief will do NOTHING but raise the maximum pressure your pump can create. so, if you are under 80psi it will not make any difference at all

think of it like a waste gate.



i think your problem is associated with bearing wear. just a hunch, how ever.

it might be worth trying a heavier weight of oil
the bearings are brand new and plastigauged toward the tighter end of the specs

agreed with dan... shimming the spring will do nothing until the oil pressure reaches 80psi. did you make sure you used good assembly lube?? did you turn the motor over with the injectors unplugged to prime the oil pump on the first start up?? is this a new oil pump?? if not did you spec it to make sure it was within spec? is this low oil pressure with a cold start? should be over 60 psi with a cold start until the oil thins out. what type of oil..??? seems to me that it has to do with the bearings.
i used good assembly lube, clevite. turned it over for a bit without the fuel pump fuse in. newer honda oil pump, was on the motor for maybe 500 miles before this rebuild. it was the first startup when i saw the low pressure. i am running castrol 5w30

Here's my question...why do people spend $100's/$1000s on building/re-building a motor and not have the most key/important component on that motor during startup? Can anyone guess what item this might be?

An oil pressure guage! Ding ding ding!
i dont like oil pressure gauges, i will notice a red light coming on every time, i will rarely notice a gauge fluctuating as easily
 

·
Registered
Joined
·
6,676 Posts
Ummm

You can leave the light there when you install the gauge.

If you don't like the look, you can leave the gauge under the bonnet directly on the engine and only check it when when troubleshooting.

Danz is correct. It is nothing to do with your pressure relief valve unless the spring is missing or the piston seized in the bore in full open position.

A blocked gallery tends to increase pressure.

Poor cleaning allowing crap into the pump can score the pump so it does not work well.

A fuel or water leak into the sump can thin the oil and drop pressure.

You don't even know if the oil pressure light switch reads correct, so it might have good pressure.

Plastigauge is a guide only, it is no substitute for propper measurement for size and roundness of journal.

Is the top end oil restrictor in place and correct size.

Are the cam bores and journals good and straight.

Does the head gasket properly seal the oil passage to the head.

Is the oil pickup working correctly, clear of the bottom of the sump, well submerged in oil and not sucking any air anywhere.

Is it a good brand oil.

Is it a new correct model quality filter.

For crying out loud, GET A PRESSURE GAUGE even if you only borrow it to test what pressure you actually have.
 
1 - 17 of 17 Posts
Top