Oil pump non return? SB318

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TIB3300
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Oil pump non return? SB318

Post by TIB3300 »

Good day chaps

Iam after a liitle info please

Doe's the 318 oil pump have a non return valve?
As on start up the oil pressure takes a while to build up. I have changed the oil filter just to make sure its not that.

This didnt happen for the first 1000 miles or so :-k
Thanks in advance :thumbright:
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Dave999
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Re: Oil pump non return? SB318

Post by Dave999 »

good day fine sir

in most cases there is a bypass valve in the pump it bleeds off pressure when it gets high enough to overcome the strength of the spring behind the piston. saves your Pump drive from excessive wear

if this piston and spring set up gets stuck you have no oil pressure.....
you have oil presure eventually so its probably NOT this.

an oil filter can be purchased with or without a none return valve

you would use one without a none return valve if the filter is large capacity AND the oil enters and exits the top of it.
you get better oil flow for a lower pressure without a none return valve.....
and a filter in that orientation does the none return job adequatly on its own.

if the filter is on its side or dome side up you need one with a none return valve otherwise the oil just percolates back into the sump when yoiu stop the car.
and the amount that dissapears back to the sump increases as your lifter bore bearings etc wear becasue air can be drawn in.
leaving the car for weeks on end rather than drving it regularly it will take longer to pump up when you start it.

if you run hydraulic lifters and the car sits for months doing nothing expect any that are off the base circle and under valve spring pressure to bleed down. this can take HOURs or WEEKs or anywhere in between.
obviously when you start those rockers will clack and oil is flowing freely into those lifters. preasure will take a while to get up to normal. usually just longer than you think is reasonable... :)

starting the car at 0* will take longer to get pressure than at 25* cold oil, cold motor bit more drag even if the oil is good and its summer/winter viscosity modifier works. worse with straight SAE30 or 40 less so with multigrade

if you look at your filter if you can see what looks like a rubber flap below the ring of smaller holes in most cases that is a filter with a none return valve... and they are bit crap and they do fail. none return valve is a very grand name for a rubber washer...!

if these holes are just open and you can see nothing below you don't have one

mine has a none return valve and they are not exactly that effective. leave it two months and it takes a while to show pressure

remote filter head or a 90* adapter might get you a filter with big capcity and with the domed end pointing down. no small drain back is going to be able to lift a filters worth of oil out of it and down to the sump

Dave
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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TIB3300
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Re: Oil pump non return? SB318

Post by TIB3300 »

Thanks DAVE
It’s strange as when I first built the engine, the oil pressure light would go out quicker than it does now. Let’s say it took 4 to 6 seconds of just cranking the engine to turn out the oil light. it now it takes 10. 15 seconds of cranking.

I have always tested engines for good oil presser by cranking engine until the oil light goes out. Then immediately turning the key back to the off position, then back on again to see how long it takes the oil light to come back on?. This then gives an indication of how tight the engine tolerances are.

With mine it now takes more cranking to turn off the oil light, but still keeps good oil pressure for about 5’ 8 seconds before the light come back on to come back on after cranking , telling me the engine is nice and tight
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Dave999
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Re: Oil pump non return? SB318

Post by Dave999 »

yeah id guess if you had a bad bearing or if the oil was escaping past a gallery plug or some such you'd loose that pressure faster...

you'd know about it anyway

i think you will just have to an eye on it.

to be honest unless it carries on getting worse.... probably ok.

mine will either come up quick
or it will stay low on the starter and once it starts it will come up and be about 40flb -50Ftlb when cold but the preasure releif kicks in at 50
manages about 15- 20 ftlb when hot at idle
hemi 6 pump is considerd by many a weak point too small for the motor

the chrysler pumps are all much the same style. your 318 one has more depth to the impellor section
Mine is in the sump
is yours accessible from the outside or in the sump also?
if the motor is out it may be worth just pulling it and checking the relief valve doesn't stick either open or shut and the spring is still springy
take out spring and Valve piston on mine these are in a bore in the mounting face of the pump

clean them lightly oil the piston

Bananarama! down the bore fully
turn pump upisde down
piston should slowly fall out under gravity
twist it round 20 or 30 dgrees and try again
if it doesn't come out eaily of it own accord
wash the pump and piston
polish the piston
bottle Bananarama! bore with petrol or some such

try again

when happy that it doesn't stick and can't hang up in the bore, due to damage corrosion or varnish
put it back as it was.

taking off the sump will also let you look for the kind of debris that you don't wanna see....

if the Motor is now back in a newly painted engine bay i'd just keep an eye on it... what more can you do. if you were chewing up bearings the oil pressure light would eventually join you while drving

cheap gauge and sender might be useful..... it won't read right but for comparison would be ok.


Dave
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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TIB3300
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Re: Oil pump non return? SB318

Post by TIB3300 »

Cheers :thumbright:

Engine is still out, I was thinking it could be the pump not sucking quick enough ? :-k
It was a new pump i got with the half built engine

Am gona strip it and have a look, but will probably buy a new one
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Dave999
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Re: Oil pump non return? SB318

Post by Dave999 »

The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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TIB3300
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Re: Oil pump non return? SB318

Post by TIB3300 »

Dave999 wrote: Wed Jan 18, 23 2:10 pm spotted this and thought of you...

https://www.forabodiesonly.com/mopar/th ... re.533675/
Cheers
Yes certainly worth investigating :thumbright:
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