hq459

ok! on cold start-up the 308 has no oil pressure untill i bring the revs up to 1500,if i let it idle,nothing.if i get it to pump up and let it back to idle,pressure falls off the guage.when hot,it shows real good pressure at idle(the best i've ever seen on the GTS guage and this is the third motor and fifth oil pump)the motor has roller rockers,are they the cause? all help gratefully accepted

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VN V8 Calais

3rd motor with oil issues?

Isn't a faulty gauge?

The oil might be too thin or thick? Friends have had oil issues before from using the wrong oil, did an oil change and it fixed it.

hq459

let me explain,first engine, in the car when i bought it,completely unknown history.drove it for awhile,guage showing not bad while moving,pretty low at hot idle,couple of oil and filter changes with good qual 20w50,one night,guage drops to zero,BIG rattle,shut her down,tow her home replace oilpump with JP high vol.all good again till,acouple of months later,,num.3 ex.lobe leaves camshaft (just like 1978) so engine two bought on fleabay unknown quantity(again)not happy with hot oil pressure,so,another new JP($179)guage is a little better at hot idle but motor still rattles a bit.car is still on the road and a "daily",,one day drops a cyl.,find a collapsed lifter,but have now bought another engine from a mate,so keep driving on num.2 while getting ready for num.3.one day the bad taptaptap stopped and all 8 were back.anyway out it came and in went num.3 which wouldn't pump up pressure when first installed,so primed the pump with vaso,still no pressure so we swapped in the near new pump from num.2 praise the lord all is good apart from the aforementioned slow to pick up pressure when cold.

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76lxhatch

Firstly (its kind of hard to follow your story sorry), are you running a high volume pump with a standard capacity sump? That's a no-no, you'll run out of oil.

Usually you'll get higher oil pressure readings when cold as the oil is a bit thicker, so perhaps you have a blockage in there somewhere - could even be the Vasoline as that won't run until its hot.

ski351

Connect a workshop mechanical oil pressure gauge and then confirm whether the oil pressure is actually abnormal or not. Your gauge (and/or sender?) may be faulty as it seems this is the only thing that has remained the same for 3 engines.

hq459

crikey! sorry for being so verbose yesterday(the power of OLD CROW) i was trying to say that i trust the guage,i've tried two different senders and two oil pumps. so,when cold it will not maintain oil pressure at idle,the guage drops to zero and the rockers start rattling,this condition goes away when up to operating temp,the guage then shows good pressure at idle and the rattle is much quieter.i've not had rollers before and wondered if they might be the cause

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76lxhatch

The roller rockers won't cause it. The fact that they rattle when cold but not so much hot may just be a matter of expansion (especially if solid cam) but could also be an indication that you really aren't getting oil up there when cold. Are you sure that the oiling system including the pump and valves is thoroughly clean?

cunoath

Is it a GTS or just a GTS dash and if so is it the GTS wiring loom or did some one wire the GTS gauges off a standard loom. My advice is same as ski351 connect a mechanical oil pressure gauge as opposed to the electric sender. I always do on a first start up.

Brettly-2008

As 76lxhatch mentioned, rockers (especially rollers) rarely make much noise and it's usually either bad lifters, bad geometry or incorrect oil or a combination of some.

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hq459

she's a kingswood mate,but i've had a good look and imho it looks factory (she's loaded with options,308,m21,full black trim,pwr steer)

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DR327VK

Did you set the Lifter PreLoad correctly when installing the roller rockers?

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hq459

ok,my only problem is when stone cold at idle.will not pick up pressure until revs are bought to 13-1500rpm.if i then let it back to idle,gauge falls to zero and rattle comes back,bring revs back up and rattle goes away and gauge shows GOOD pressure.once hot there is no problem.i will try a mechanical guage but it's got me stumped

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hq459

nah,bought it allready built,and you've completely baffled me,mate.does lifter pre-load affect oil pressure?

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DR327VK

Try a mechanical guage and if it reads less than 10psi at idle you may a have problems!

If you try a thick oil like 40w/70 and it has better pressure at idle you will have problem in the motor! But if its less pressure it is a pickup problem!

Once i have had the valve in the oil pump poped out of its place a had your same problem! Pull the pump out & split it and check the oil valve?

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DR327VK

Sorry i thought you fitted the rockers then soon afterwards had oil problems?

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