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v8 2.5 high oil pressure

Steve laud
Posts: 9
Joined: Wed Mar 28, 2018 6:50 pm
Location: Appleby magna, u.k.

v8 2.5 high oil pressure

Post by Steve laud »

Hi my 2.5 saloon as always had good oil pressure,on startup going upto 60 psi and then settleing back to50 psi on normal running and 25 30psi on tick over but at the moment the needle wants Togo off the gauge under normal running and dropping to around 55psi on tickover could it be oil relief valve thanks steve

classiclife
Classic Wise Man
Classic Wise Man
Posts: 1601
Joined: Wed Sep 05, 2018 9:55 am
Location: Ridgewood - East Sussex
Contact:

Re: v8 2.5 high oil pressure

Post by classiclife »

Hello Steve,

That is unusually high for a V8, I presume you have the standard and not a modified oil pump - along the lines that Russ Carpenter sells ??

The oil pressure gauge is an electric unit (sadly) and its reliability is not always spot-on; as such it may be the gauge that is the issue.

Are your other dash gauges performing okay, namely: coolant, fuel and ammeter ?? I mention this because if one of those is also playing up then the voltage stabiliser unit may be defective. If all gauges are good then the issue remains with the oil gauge - is it earthed properly ??

Gauge substitution is the quickest option if you have a spare.

If a spare gauge reads the same then, yes it will be time to look at the oil pump / relief valve.

Out of interest what make and grade of engine oil are you using and do you still run with the paper cartridge or a spin on conversion ??

Hope the above is a "starter for ten" ??

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Steve laud
Posts: 9
Joined: Wed Mar 28, 2018 6:50 pm
Location: Appleby magna, u.k.

Re: v8 2.5 high oil pressure

Post by Steve laud »

Thanks for you reply Richard, yes it is a russ carpenter rebuild about 10yrs ago with approximately 7,500 miles on clock since rebuild,all other clocks working as they should and new oil yesterday

classiclife
Classic Wise Man
Classic Wise Man
Posts: 1601
Joined: Wed Sep 05, 2018 9:55 am
Location: Ridgewood - East Sussex
Contact:

Re: v8 2.5 high oil pressure

Post by classiclife »

Hello Steve,

Under the circumstances, I would be tempted to contact RC as you are using his oil pump and see if he has come across this before. A phone call may save a lot of concern and unnecessary fault searching.

I do know his uprated pumps provide a significant boost in oil pressure - but yours is currently too high and probably beyond what the scope of the pump is designed for IMHO.

What oil ??????

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Steve laud
Posts: 9
Joined: Wed Mar 28, 2018 6:50 pm
Location: Appleby magna, u.k.

Re: v8 2.5 high oil pressure

Post by Steve laud »

Hi Richard,oil was changed yesterday ,the new oil being castrol classic XL 20w/50

classiclife
Classic Wise Man
Classic Wise Man
Posts: 1601
Joined: Wed Sep 05, 2018 9:55 am
Location: Ridgewood - East Sussex
Contact:

Re: v8 2.5 high oil pressure

Post by classiclife »

Hello Steve,

Nowt wrong with that choice of oil.

As mentioned, a call to RC would be my next move and you can then start the investigation from there.

Good luck and I will be interested to hear how this pans out.

Regards.

Richard.
1968 Daimler V8-250 Saloon
DLOC East Sussex Branch Secretary
DLOC 2.5L V8 & V8-250 Registrar - https://www.dloc.org.uk/v8-250
DLOC 2024 International Rally - https://www.dloc.org.uk/rally-2024

Steve laud
Posts: 9
Joined: Wed Mar 28, 2018 6:50 pm
Location: Appleby magna, u.k.

Re: v8 2.5 high oil pressure

Post by Steve laud »

Thanks Richard for your help and advice ,steve

tjt77
Wise Man
Wise Man
Posts: 525
Joined: Wed Mar 23, 2016 7:01 pm

Re: v8 2.5 high oil pressure

Post by tjt77 »

test the pressure with a mechanical gauge.. this is relatively simple to do .. the fitting is 1/8 NPT male to temporarily replace electrical sender for duration of test.. if it reads above 60 PSI you likely have a stuck relief value.. high oil pressures ( above 60 PSI) will add load and hence put excess wear in the bronze drive gear.. and expose leaks in places such as the connections of oil feed pipe to Cylinder heads ..

Chris_R
Wise Man
Wise Man
Posts: 662
Joined: Wed Feb 10, 2016 12:48 pm
Location: Twickenham

Re: v8 2.5 high oil pressure

Post by Chris_R »

I agree with the last suggestion. Temporarily replace with a mechanical gauge to get a reading from that. Otherwise you don't know which end is at fault.

buckfield
Posts: 194
Joined: Wed Feb 10, 2016 11:38 am
Location: south wales

Re: v8 2.5 high oil pressure

Post by buckfield »

Hi, when I tested my engine with the mech gauge, it read just over 40 psi, at idle (cold) 35 psi, when warm and when going up the rev range it never went above 55 psi (warm) but the elec gauge was is reading lower than that, cold idle 25 psi and max 42 psi when warm at 3000 revs. so either both are wrong or just the elec type? Ton

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