V8 problems

I am posting this on behalf of a contact in Venezuela, as he does not
speak English.


Vehicle RR Classic 1977 3.5 V8

The problem started when the oil was changed and due to the oil filter
not being correctly installed, it lost about 3l of oil and the tappets
got very noisy when the engine warmed up.
He rebuilt the engine with new bearings throughout, new hydraulic
tappets tappets and oil pressure gauge. The old guage showed normal
pressure pressure even when disconnected from the engine.

The problem is that now when the engine is started, everything is OK,
oil pressure at 50 PSI. After 5 minutes or so, oil pressure drops to
zero at 900rpm and on increasing to 2000rpm the oil pressure goes up to
only 25PSI max. The oil temp is 60 deg and increasing and the tappets
are noisy due to lack of oil pressure. The oil pump has also been
rebuilt with new internals.

Any and all suggestions welcome


Tim
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"TimL" <[email protected]> wrote in message
news:[email protected]...
>I am posting this on behalf of a contact in Venezuela, as he does not speak
>English.
>
>
> Vehicle RR Classic 1977 3.5 V8
>
> The problem started when the oil was changed and due to the oil filter not
> being correctly installed, it lost about 3l of oil and the tappets got
> very noisy when the engine warmed up.
> He rebuilt the engine with new bearings throughout, new hydraulic tappets
> tappets and oil pressure gauge. The old guage showed normal pressure
> pressure even when disconnected from the engine.
>
> The problem is that now when the engine is started, everything is OK, oil
> pressure at 50 PSI. After 5 minutes or so, oil pressure drops to zero at
> 900rpm and on increasing to 2000rpm the oil pressure goes up to only 25PSI
> max. The oil temp is 60 deg and increasing and the tappets are noisy due
> to lack of oil pressure. The oil pump has also been rebuilt with new
> internals.
>
> Any and all suggestions welcome
>
DO NOT trust electric gauges, if that's what is fitted. They are notoriously
inaccurate, fit a decent mechanical gauge. Is the oil low pressure lamp
coming on at idle?
Are the rocker shafts installed the right way up? Check the oil hole
positions if they were stripped.
Did he replace the cam bearings as well? If so, did he peen or loctite them
in position to prevent movement?
Has a cam bearing possibly shifted due to the previous heating-up internally
of the bearings due to low supply?
What condition are the oil pump gears, pump cover face and housing, and
relief valve and its spring?
Has he somehow introduced debris into the engine that has now wrecked the
new crank bearings?
Did he check the crank journal dimensions prior to fitting new bearings?
Correct pressure should be 35psi + or- 5psi at 2400rpm, hot. (Hot = oil temp
of 86 degrees centigrade), and no oil warning lamp at idle (i.e. more than 3
or 4psi at idle, preferably 10-15psi.) The pressure will be considerably
higher when cold, due to the oil being thicker and hence providing a greater
resistance to flow.

Badger.

the oil pressure on rover v8 engines of the early years was on the low side .

the main problem was in the face of the oil pump filter casting , its aluminium
with steel gears running up to it .

you can tell if you have oil pump low pressure problems because after say
30mins of engine running it will start to missfire and eventually stop running
completely .

what you can do with the pump filter housing is to change the pressure relief
spring and fit a pump" booster plate ".

this is an anodised aluminium plate that is sandwiched between the filter
housing and the main part of oil pump .

some pumps you need to drill or cut a groove in them but its not very difficult
to do .

try KENNE BELL BUICK for a pump booster plate kit or POSTON ENTERPRISES in
alabama .
also look at TA PERFORMANCE , i think they do 215cu in and rover v-8 parts .
..

the early rover v-8 engine was originally a buick 215 cu in and rover bought
the design from buick in the 1960s .

the later SD1 engines have improved oiling system but can still benefit from
the sandwich plate kit .

REAL STEEL in the UK sell oil pump booster plate kits and gear sets for
later range rover v-8 engines of 3.5litre variety .

also look at www.v8tuner.co.uk for oil pump booster plate kit

"TimL" <[email protected]> wrote in message
news:[email protected]...
>I am posting this on behalf of a contact in Venezuela, as he does not speak
>English.
>
>
> Vehicle RR Classic 1977 3.5 V8
>
> The problem started when the oil was changed and due to the oil filter not
> being correctly installed, it lost about 3l of oil and the tappets got
> very noisy when the engine warmed up.
> He rebuilt the engine with new bearings throughout, new hydraulic tappets
> tappets and oil pressure gauge. The old guage showed normal pressure
> pressure even when disconnected from the engine.
>
> The problem is that now when the engine is started, everything is OK, oil
> pressure at 50 PSI. After 5 minutes or so, oil pressure drops to zero at
> 900rpm and on increasing to 2000rpm the oil pressure goes up to only 25PSI
> max. The oil temp is 60 deg and increasing and the tappets are noisy due
> to lack of oil pressure. The oil pump has also been rebuilt with new
> internals.
>
> Any and all suggestions welcome
>
>
> Tim
> --
> Delete "removethisbit." to get valid address


Sounds very much like the oil pressure relief valve sticking open. Tapping
the pump housing with a hammer sometimes temporarily un sticks it.
I had this happen with my V8 its a fairly common problem.
The relief valve will be pushed fully open by the cold oil but as the oil
warms up and thins out the valve gets stuck in the bore for some reason and
the spring cannot push it closed.
The best thing to do is to make sure that the valve bore is OK and the valve
can move freely, if there's still a problem replace the standard valve with
a tadpole type from someone like www.jeengineering.co.uk (about £20) fitted
one to my engine (no modifications needed) it cured the problem straightaway
(20psi at idle, above 2000rpm 50psi).
There's a picture of the valve on my web site
www.sumpoil.pwp.blueyonder.co.uk/oilpress.html

Regards

Liam

Thanks all, I shall pass these replies on

Tim


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