Oil pressure issue - Mocal pump cover take off

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Scott marsden
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Oil pressure issue - Mocal pump cover take off

Post by Scott marsden »

Hello everyone,

1st post here so go easy. Looking to pick your brains...I have an oil pressure of 20 to 25 psi that varies little with rpm changes.

My engine block is a p6 with code starting 48105

I have checked the gauge and the sender and then used a manual pressure gauge and the reading match the gauge when taken from locations on the pump cover and at the remote filter head. So everything after the pump is reading 25 ish psi. I have changed the pressure relief plunger and uprated the spring. Plunger is moving freely.

I am using rimmerbros item R01105 which is a mocal pump cover take off with pipes going under the sump to the other side of the block where the filter housing is located. I now see this is listed for later sd1 engines not suitable for early engines.

My concern is I see rimmerbros do item BHH998 for an early p6 engine setup( originally used on mgb gt v8 engines) which potentially means I have fitted a late style mocal one on my engine!!! Is it even
possible to fit the wrong one and could it have the effect that I am seeing with my oil pressure?

To add to my concern I was worried that someone could have changed the timing cover to allow them to use the later larger pump heats or even done the modification to use later pump gears in an early timing cover.

Any help before I purchase parts would be much appreciated.

Additional note: it runs a mallory dual point distributor regarding the distributor drive onto the pump gear if that helps identify anything.

I will post some pics in the morning of the setup.

Kind regards
Scott Marsden



Scott marsden
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Re: Oil pressure issue - Mocal pump cover take off

Post by Scott marsden »

Just to add,

The oil pressure of about 25psi is from cold on tickover which only twitches slightly on revving.
When warm at tick over it drops by about 5psi and again on revving only twitches slightly.

Cheers

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ChrisJC
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Re: Oil pressure issue - Mocal pump cover take off

Post by ChrisJC »

Are you concerned about the 25psi? I am presuming you are expecting more pressure.

Are you absolutely sure you have oil flow? (can you see it weeping from the rocker shafts)?

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

Scott marsden
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Re: Oil pressure issue - Mocal pump cover take off

Post by Scott marsden »

Hi,

Yes I was expecting more pressure. I was definitely expecting it to fluctuate more with revs.

My explanation was a little misleading as I have not yet changed the oil pressure piston. Having inspected the original one it appears to have score marks along it. I presumed it was not stuck as it came out easily. Having done some reading this is not always the case as they can get jammed up quite easily. I am going to remove my pump cover tonight and polish the bore and polish up the replacement piston. I will then refill with oil and add a new filter and let you know the outcome.

I also have a new pressure spring. Compared to the one that I removed it is shorter bit the wire gauge looks heavier. It is the updated version from rimmerbros.

I will let you know.

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