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V8 250 Significant Change in Oil Pressure

classiclife
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Re: V8 250 Significant Change in Oil Pressure

Post by classiclife » Fri Dec 14, 2018 10:38 pm

Hello Dave,

Your cannister is approx. 123mm and the type Nick and I have flagged is 85mm - so you certainly have an extra capacity filter.

I doubt it will make much difference other than requiring a tad more oil to fill it. Why not try one of the type that Nick and I have flagged ??

The air bubble you mention will make negligible difference to the reading as the oil pressure will compress that.

I agree that too much fear is pinned on oil pressure and quite often gauges are not as accurate as one might expect. As mentioned, if the pressure registers swiftly and stays put within reason then I am sure you will be fine. It is not as though you have a race engine where the revs are often in the 7-8K bracket; you would soon know about poor quality oil then !!!

Your current pressure will not do harm, but I understand your concern - worth trying the options mentioned I feel.

Regards.

Richard.

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captain bobo
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Re: V8 250 Significant Change in Oil Pressure

Post by captain bobo » Mon Dec 17, 2018 8:45 pm

I spoke to Flexolite today about suitable or recommended filters for the V8 250 conversion. It occurs to me that others might find the information useful so here is the information from Flexolite:-
Mann WE916/1
Fram PH2857A
Crosland 357
Any similar compatible high quality oil filter with a 3/4 inch UNF fitting.

They added: remember to fill it with oil and to grease the seal before fitting. Change every 6000 miles or sooner if needed.

I hope others find this interesting or useful.
Best wishes, Dave B

classiclife
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Re: V8 250 Significant Change in Oil Pressure

Post by classiclife » Mon Dec 17, 2018 10:15 pm

Hello Dave,

Useful update.

The fitting / instruction sheet that Flexolite send out with their Daimler V8-250 oil filter conversion lists those filters you have mentioned.

The Flexolite oil filter adaptor conversion (V8-250) part number is FA026; whereas for the Dart / SP250 it is FA025.

Regards.

Richard.

Chris_R
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Re: V8 250 Significant Change in Oil Pressure

Post by Chris_R » Thu Dec 20, 2018 11:26 am

Richard, I sent you an email off the forum. Did you receive it? Regards, Chris.

classiclife
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Re: V8 250 Significant Change in Oil Pressure

Post by classiclife » Thu Dec 20, 2018 7:01 pm

Hello Chris,

Sorry to say, no trace at the moment.

Regards.

Richard.

Chris_R
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Re: V8 250 Significant Change in Oil Pressure

Post by Chris_R » Fri Dec 21, 2018 11:16 am

Richard, have sent you a PM instead then! Chris.

tjt77
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Re: V8 250 Significant Change in Oil Pressure

Post by tjt77 » Sat Dec 22, 2018 4:05 pm

given the electric pressure senders are notorious for giving unreliable readings the best way to know what your oil pressure is in actuality, would be to plumb in a mechanical oil pressure guage to do a back up test .. these are readily available from car parts stores (Halfords in UK would be one outlet) and should come with the required fittings.. you can uses the existing fitting for the electric sender, if you remove the sender (which has an 1/8"male pipe thread)
Its doubtable that a simple oil and filter change would make any major difference in oil pressure...but the sender can and does play up quite suddenly and a change in oil viscosity can be the thing that tips it over the edge.. the normal scenario is low reading when they start to fail.
As for additives in oil.. ZDDP or an equivalent is something I consider essential for our engines..the tappet designs impart high loads that need a good lube film... which is why I used oils specified for diesel engines :- Chevron Delo of Shell Rotella being the most readily available in my area in 15/40 multigrade.

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captain bobo
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Re: V8 250 Significant Change in Oil Pressure

Post by captain bobo » Thu Dec 27, 2018 8:40 pm

I ended up fitting a Mann WE916/1 filter to replace the existing screw on filter.

As a consequence the oil pressure gauge shows readings (both hot and cold) better than the existing filter but still slightly lower than the readings the gauge showed before the oil change.

Can any forum member explain to me me in simple language how the V8 250 oil pressure sender actually works? How does pressure change translate to a change in electrical signal?

I'm tempted to follow the route of getting an accessory device to accurately measure the oil pressure; I could use it to assess the accuracy of the sender / gauge combination. Just for interest's sake.

Belatedly - seasonal salutations to forum members; may your pistons not slap, your bearings not wear, your fuses not blow, your oil not leak, your exhausts not smoke and your wheels not wobble!
Best wishes, Dave B

classiclife
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Re: V8 250 Significant Change in Oil Pressure

Post by classiclife » Fri Dec 28, 2018 10:47 am

Hello Dave,

As Nick and I pointed out earlier in the thread and to which you later eluded too, the Mann 916/1 is the correct filter size for your engine - the improved reading in the oil pressure certainly points to that.

Allowing for some slight inaccuracy in the gauge I suggest your oil pressure is probably spot-on, but the fact you wish to determine a "second opinion oil pressure reading" is worth doing if only as a matter of interest.

I look forward to hearing how this progresses and thanks for sharing the issue.

Good luck.

Richard.

Ian Slade
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Re: V8 250 Significant Change in Oil Pressure

Post by Ian Slade » Fri Dec 28, 2018 3:19 pm

The sensor works with an carbon pile within the sensor casing, the pile consists of carbon discs as pressure is increased the resistance decreases thus allowing a greater voltage thus moving the needle higher up the scale similar to the fuel gage and unfortunately just as accurate.
Owner since the 70's, Genghis is slightly to my left.

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