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oil pressure upon braking...

PostPosted: Tue Mar 29, 2005 7:03 pm
by foggy
On s2 elan motor, In an early coupe:

My oil level was down a little from topped up, and with braking in the
wet, not much decellerative force, oil pressure was zero.

New to ownership... Is this normal? what's the fix? what should level
be down from dipstick entry hole?

Cork gasket for cam cover very leaky... Is thre a better gasket made?
What's suggested routine for no leaks? (hopefully not an oximoron...)

I was on Lime Rock in wet, so not braking hard. Interesting additional
question, I pressed brake pedal and got accelerator stepped on, too.
Is there a part of accel pedal up above the brake pedal, I haven't seen
yet?

thanks, all,
Steve

oil pressure upon braking...

PostPosted: Wed Mar 30, 2005 10:00 am
by rgh0
Steve

You should not loose oil pressure under straight line braking even
with a little low oil level. A few possible areas assuming you have
normal reading of 30 to 40 psi at 3000 rpm with a hot motor.

1. Gauge is faulty and reads at bit low by say 10 psi, oil pressure
will drop at idle, especially under racing conditions of hot oil to
around 10 psi. So a low reading guage combined with low presure at
near idle while breking could look like total loss of pressure.

2. Pickup not installed properly in sump so to high and not picking
up oil properly

3. Dip stick locating tube installed to high so oil level really
lower than indicated


As for hitting accelerator under brakes, probably due just to the
close placement of the 2 pedals. Not sure about the lever arm
location for the accelerator cable on the LHD cars but on RHD cars
not possible to hit while braking.

Rohan

oil pressure upon braking...

PostPosted: Wed Mar 30, 2005 12:55 pm
by Rob_LaMoreaux
As Rohan said this normally does not happen in straight line braking, but it
is common during cornering since the drain back path from the head is too
slow and much of the oil stays up on top too long emptying the sump too
much. Some times the dipstick tube gets pushed in too far and then reads
that your engine is fuller than it really is. On my car I found that it
wants to have the level read about 3/8th inch higher than the full mark to
prevent starvation of the pickup on corners.

Properly set up the throttle should be just below the brake pedal when the
pedal is fully pressed, but during a track day the brake pedal may find a
lower low point due to heat and wear. On my car the throttle is just below
the brake pedal so I can easily heel-toe, but occasionally my foot rotates a
little more than I want and I get a little throttle when I just want brake.
So I rotate my foot back. Of course you can also adjust the throttle cable
so the throttle pedal is a bit lower, but you still get full throttle just
before the adjustable stop on the back of the pedal hits the floor.

As far as a leak free engine, it can be done by proper and careful assembly.
The cork gasket for the cam cover shouldn't be much of a problem if it is
put on properly. Get a new one and attach it to the cover with good rtv.
After the RTV has cured use a gasket sealer like permatex Aircraft flange
seal on the surface and put it on the engine. This should keep the leaks out
from the cam cover.

No getting the leak where the head meets the block and the front cover is a
different story that I need to get right the next time I have the engine
apart.

Rob LaMoreaux
Ann Arbor, MI USA
(734)-971-5583
Cell (734)-604-9280
Email: ***@***.***
Too many Hobbies.... Too Little Time
1969 Lotus Elan....It's not a restoration, it's a never-ending adventure.

oil pressure upon braking...

PostPosted: Wed Mar 30, 2005 1:12 pm
by john.p.clegg
Rob,Steve
the oil pressure guage is a sluggish thing,try fitting an oil pressure switch to a red light on your dash,then you'll know what frightening is when taking those long curves

John


rob_lamoreaux <***@***.***> wrote:

, but it is common during cornering

oil pressure upon braking...

PostPosted: Wed Mar 30, 2005 1:25 pm
by BillGavin
Hi Steve

As Rohan said, you should not be losing oil pressure when braking
in a straight line - check his list to be sure your car is set up to
original spec.

I used to have problems in the wet at Lime Rock and Bryar with the
engine in my Mini stalling under braking - there wasn't enough traction
in some areas, the brakes would lock up the driveline, the engine would
stop, and the oil pressure would go to zero. As soon as I released the
brakes, the engine would restart and the oil pressure would return. Very
gentle application of the brakes, and avoiding standing water, minimized
the problem.

Next time you have the problem, check if your tachometer is going to
zero as well.

- Bill

At 02:01 PM 3/29/2005, you wrote:


oil pressure upon braking...

PostPosted: Wed Mar 30, 2005 3:13 pm
by Frank Howard
In a message dated 3/30/05 04:01:27 AM, ***@***.***es:

<< 3. Dip stick locating tube installed to high so oil level really lower
than indicated >>

Steve,

With all due respect to Rohan, I think he meant to say, "Dip stick locating
tube installed too low so oil level really lower than indicated."

Frank Howard
'71 S4 SE
Minnesota

oil pressure upon braking...

PostPosted: Fri Apr 01, 2005 11:14 am
by rgh0


Frank

You are right of course. Hard to keep you ups and downs straight when
you live in Oz "down under" and spend all you time standing on your
head !!

Rohan