Subject: Re: [Healeys] Oil pressure

From: [email-masked]
Date: Wed, 15 May 2013 17:43:35 -0400 (EDT)

Magnus
Very interesting. The difference in pressure reading between hot and cold also
doesn't make sense to me. I would ask DW about the oil pump specs. Would also
double check the gauge pressure with another gauge. I had issues with high oil
pressure on a small block Chevy when the pump supplied was not high volume but
high pressure. DW offers two different pumps for under 6K RPM and another for
over. I have no idea what the pump specs are.
Aloha
Perry

-----Original Message-----
From: Magnus Karlsson <[email-masked]>
To: Healey Lista <[email-masked]>
Sent: Wed, May 15, 2013 5:14 pm
Subject: [Healeys] Oil pressure

I have a problem with an engine that I just restored completely. The oil
ressure gets too high when revved over 2500. The pressure reaches all the way
p too 80 psi, which of course is way too much. The strange thing is when the
ngine is cold and you rev it, the pressure will not rise above 60 psi. Quite
ontrary to the normal behavior. The oil pump is a new Denis Welch unit, the
il pressure release valve and spring are new, all bearings in the engine are
ew, all parts have been machined to the right tolerances. I4ve tried with a
sed release valve and spring that is quite softer than the new one. Resulting
n the same high pressure.
This has got me quite puzzled and I ran out of ideas on how to solve this.
Has
nyone experienced the same symptoms and did you find a working solution? I4m
esperate for good advise!
TIA,
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From: [email-masked]
Date: Wed, 15 May 2013 17:49:16 -0400 (EDT)

Magnus
My assumption and info on DW pumps was based on a six cylinder AH.  I just re
read your post and noticed you didn't say which engine.
Aloha
Perry

-----Original Message-----
From: Magnus Karlsson <[email-masked]>
To: Healey Lista <[email-masked]>
Sent: Wed, May 15, 2013 5:14 pm
Subject: [Healeys] Oil pressure

[email-masked]

---

From: Bert Van Brande <[email-masked]>
Date: Wed, 15 May 2013 14:51:41 -0700 (PDT)

On a 4 or 6 cylinder car?  Oil pan gasket installed correctly?  Too much
sealant?  Oil return passage (partially) blocked?  
On a 4 cyl the release
valve opens to a passage to drain oil back to the sump (pan), there is a notch
in the gasket to allow for this.

On an engine that idles the return might be
just big enough to allow for the pressure valve to do it's job but on a faster
revving engine the same return might be obstructing excessive oil return.
Bert

________________________________
 From: Magnus Karlsson
<[email-masked]>
To: Healey Lista <[email-masked]> 
Sent:
Wednesday, May 15, 2013 4:13 PM
Subject: [Healeys] Oil pressure

I have a
problem with an engine that I just restored completely. The oil
pressure gets
too high when revved over 2500. The pressure reaches all the way
up too 80
psi, which of course is way too much. The strange thing is when the
engine is
cold and you rev it, the pressure will not rise above 60 psi. Quite
contrary
to the normal behavior. The oil pump is a new Denis Welch unit, the
oil
pressure release valve and spring are new, all bearings in the engine are
new,
all parts have been machined to the right tolerances. I4ve tried with a
used
release valve and spring that is quite softer than the new one. Resulting
in
the same high pressure.

This has got me quite puzzled and I ran out of ideas
on how to solve this. Has
anyone experienced the same symptoms and did you
find a working solution? I4m
desperate for good advise!

TIA,
www.concourshealeys.com
$12.75
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From: "Patrick & Caroline Quinn" <[email-masked]>
Date: Thu, 16 May 2013 09:26:50 +1000

G'day Magnus

Many years back I had exactly the same problem with a freshly restored 100
engine.

I changed the pressure release valve and spring - Fixed.

Hoo Roo

Patrick Quinn
Blue Mountains, Australia

-----Original Message-----
From: Magnus Karlsson <[email-masked]>
To: Healey Lista <[email-masked]>
Sent: Wed, May 15, 2013 5:14 pm
Subject: [Healeys] Oil pressure

I have a problem with an engine that I just restored completely. The oil
ressure gets too high when revved over 2500. The pressure reaches all the
way p too 80 psi, which of course is way too much. The strange thing is when
the ngine is cold and you rev it, the pressure will not rise above 60 psi.
Quite ontrary to the normal behavior. The oil pump is a new Denis Welch
unit, the il pressure release valve and spring are new, all bearings in the
engine are ew, all parts have been machined to the right tolerances. I4ve
tried with a sed release valve and spring that is quite softer than the new
one. Resulting n the same high pressure.
This has got me quite puzzled and I ran out of ideas on how to solve this.
Has
nyone experienced the same symptoms and did you find a working solution? I4m
esperate for good advise!
TIA,
$12.75
Archive: http://www.team.net/archive

[email-masked]

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---

From: I Erbs <[email-masked]>
Date: Wed, 15 May 2013 17:56:03 -0700

I agree with Patrick. Check the relief valve.

Ira Erbs
Portland, OR
please excuse typos. Sent from my phone
On May 15, 2013 4:26 PM, "Patrick & Caroline Quinn" <[email-masked]>
wrote:

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From: Jose Vicente Vargas <[email-masked]>
Date: Wed, 15 May 2013 19:59:28 -0500

Its the relief valve .....

Sent from my iPhone

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From: Joe and Lenore Armour <[email-masked]>
Date: Thu, 16 May 2013 12:23:59 +1000

Magnus Karlsson wrote:

>pressure gets too high when revved over 2500. The pressure reaches all the way
>up too 80 psi, which of course is way too much. The strange thing is when the
>engine is cold and you rev it, the pressure will not rise above 60 psi.
>  
>

Magnus
BMC pressure relief valves are very basic.  They are constantly open it 
is just a matter of how far.
Remember that the 'relief' valve is a flow ( volume) control valve  
which results in a system pressure.  You do not mention the oil 
viscosity being used .   In my 3000 which has a 15 litre oil sump which 
takes a long time to pass all the oil thro the engine and therefore is 
slow to heat the oil, the viscosity stays high even though I warm the 
engine up for some time.  When I drive off at revs below 2500 rpm the 
pressure remains at say 60psi, if I accelerated early with more revs the 
pressure drops to 40 - 45psi.  I then reduce the revs and wait for more 
time and heat and the oil pressure returns up to 60psi

My theory is that when the oil is cold and you have new and therefore 
close tolerences the volume of the pump output far exceeds the amount of 
oil that is being passed through bearings and  rockers etc.  Consquently 
a large volume of oil is being by-passed back into the sump  and at 
lower revs and pump output the relief valve can still regulate . When 
higher revs and pump volume occur the relief valve is pushed right back 
in the bore against the spring and the now higher volume of thick oil 
by-passing holds the valve back and in effect it is no longer regulating 
the pressure which drops as you are seeing.  In my case when I reduce 
the revs the pressure increases to the nominal 60psi and when the oil 
temp/viscosity changes the relief vale can then regulate the pump volume 
to provide the rated pressure. 

By design the oil pump output at all revs and temperatures should exceed 
the volume of oil that is being accepted into the engine lubrication 
galleries and therefore the relief valve is regulation the oil volume to 
control the pressure.  High oil pressure does not guarantee oil is 
getting to the metal requiring lubrication.

Pressure ,  Volume  and Temperature  are related.
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From: Chris Dimmock <[email-masked]>
Date: Thu, 16 May 2013 13:59:53 +1000

Hi Magnus
The only other suggestion I can offer, that hasn't already been suggested, is
that there are 2 types of camshafts for the C series engine.
One camshaft, typically used in low revving C Series sedans, and possibly
early 100/6's etc has 13 teeth to drive the oil pump. The oil pump gear and
the camshaft gear on the cam are the same size. This camshaft drives the oil
pump faster.
The other camshaft, typically found in later C Series engines and most 6 cyl
Healey's, has 12 teeth to drive the oil pump (and still 13 to drive the
distributor). Easily identifiable because the two gears on the camshaft are
different diameters. It drives the oil pump slower than the "sedan" cam.
Typically, the sedan cams have little wear on the lobes, and typically have
never been reground. So the initial reaction when you look at a pile of old
cams is you select the one with the best lobes, that hasn't been reground...
Often, a sedan cam.. And that's where the problem starts...
If you use a sedan cam, with a Denis Welch hi volume pump, you will have huge
oil pressure. And if you rev the engine at around 6,000 or more for any
prolonged length of time, the oil pump gear on the cam will strip and you'll
have no oil pressure, as the cam gear that drives the oil pump has very poor
lubrication, and you are driving the oil pump faster....
At least 3 people encountered the stripped oil pump cam gear problem at
Bathurst in 1998 and 1999.
Of course, this all only applies to reground, original BMC cams. The
remanufactured, gun drilled cams solve the whole cam lubrication issue. E.g
the Denis Welch remanufactured cams. They make the cam part of the lubrication
system, lubricating the gears and the lobes by oil ways in the cam.
Hope this helps
Chris
P.S Patrick Quinn. I'll write this up for you as an article. ;-) Promise
Sent from my iPhone

> engine is cold and you rev it, the pressure will not rise above 60 psi.
Quite
> contrary to the normal behavior. The oil pump is a new Denis Welch unit,
the
> oil pressure release valve and spring are new, all bearings in the engine
are
> new, all parts have been machined to the right tolerances. I4ve tried with
a
> used release valve and spring that is quite softer than the new one.
Resulting
> in the same high pressure.

[email-masked]

---

From: Austin Healey <[email-masked]>
Date: Thu, 16 May 2013 07:10:32 +0200

Thats quite strange.
My only suggession is that the relief valve is a bit tight in its bore. Are
there any scoring marks on the relief valve(s)? Maybe You could try
polishing some 0.1mms off the valve and retry it.

Gergo

2013/5/16 Chris Dimmock <[email-masked]>

> > pressure gets too high when revved over 2500. The pressure reaches all
> the
> way
> http://autox.team.net/mailman/options/healeys/[email-masked]

[email-masked]

---

From: Michael Salter <[email-masked]>
Date: Thu, 16 May 2013 10:40:20 -0400

Hi Magnus,
We had similar although not identical problems with one of our race engines
after a cam failure.
In order to make the next day's racing we replaced a badly worn cam and
lifters and after that the pressure became very erratic.
We solved the problem in the short term by replacing the oil pressure valve
plunger with a ball (an old "A" series trick) and the problem went away.
The problem was, of course, caused by little flakes of cam lobe jamming the
plunger in the bore.
The engine survived the days racing but the bearings and crank were a real
mess when we did strip it.

Michael S

On Wed, May 15, 2013 at 5:13 PM, Magnus Karlsson
<[email-masked]>wrote:

> anyone experienced the same symptoms and did you find a working solution?
> I4m
> http://autox.team.net/mailman/options/healeys/[email-masked]
>
>

-- 
Michael Salter

[email-masked]

---

From: Magnus Karlsson <[email-masked]>
Date: Thu, 16 May 2013 20:56:40 +0200

Many thanks to everyone who answered my somewhat desperate question.

Today I removed the aluminium sump. One of a lesser quality, which made me
suspect that  maybe the pipe from the relase valve got blocked by the thick
sump bottom. As it turned out this was not the case I simply cut the spring by
2.5 coils, which restored the pressure to the correct range.

I had previously sleeved the oil passages to prevent the dreaded crack in the
block that lets oil into the water. So my conclusion is that either this
restricton caused the increased pressure or a faulty spring. Lots of work but
all worth while.

Once again many thanks to all helpful fellows on this list!

Magnus Karlsson
Sweden

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