E-Type V12 very low oil pressure - new rebuild

[nissanite]

my friend has a V12 that he has owned sinsce new. The heads needed to come off. Yadda yadda he had to get a new engine. He found the proper engine & had it rebuilt.
Now, the engine runs but only has 9 lbs of oil pressure. He used a new gauge to test the cars gauge, same reading.

A club member mentioned 20 quarts of oil but could not remember the rest of the story. This has been going on for about 3 years at 3 different shops.

S.O.S. Please help!!!!!

 

[jessebogan]

Did he use a direct guage plumbed in where the sender goes? I mean a screw in fitting, with a tube to a decent test guage. Does the oil light come on at idle?If he really has 9 psi of oil pressure it is too low.Either the oil pump or bearing clearance is out of spec.
However, the V12 is a high oil volume, not high pressure engine. The factory guages are notorious for erroneous readings, and should be treated as a suggestion.

What weight oil is he using? Is the pressure reading hot or cold, at idle? More details please.

 

[DrEntropy]

If a "hard" gauge was put on it and read 9 PSI, I'd not be running it until the problem is solved. If it wasn't checked with a pressure gauge, that needs doing first. The sender could be at fault.

"Had it rebuilt" raises a red flag here but after three years there's not much recourse. It needs to be opened up and all checked with mic's and such if a hard gauge reading is 9 PSI.

 

[PhilW]

I'll need Jesse to OK this, as V12's are not my strong suit.

On the 6 cyl. E's, there's a brass valve and spring screwed into the oil filter housing. It regulates the pressure into the system. The oil pumps upwards of 70-80 pounds of pressure. That valve opens at around 40 pounds to send the excess back into the oil pan while keeping 40 lbs. in the system. If a small piece of dirt (common after a rebuild) gets caught under the brass valve, then the 40 lb. threshold won't be met and the pressure will be low.

But, on the 6 cyl. cars with this problem, the cold oil will have decent pressure and will drop alarmingly as the oil gets hot and thinner.

If it's 9 lb. with cold oil and a non-electric oil gauge in line, i'd say you have pump problems.

If the donor engine was from an XJ and you're putting it into an E-type, the pumps are different and the in and out oil tubes need a bit of changing to get things connecting and working properly.

See if you can get the stamped on block numbers to let us determine the donor and also what did this go into - XKE or XJ.

Phil.

 

[jessebogan]

While on the subject of the pipes... There are O rings that seal them to the pump inlet and outlet, and the cooler/oil filter on an E type. Air leaks on the suction side will suck air in, also causing low pressure. I agree with Doc, do not operate until actual pressure is established. There is a relief valve (thanks Phil), on the left rear area of the block (XJs) and in the filter housing (IIRC) on Etypes. Let us know what car the engine is fitted in, and we should be able to direct the diagnosis accordingly.

 

[DrEntropy]

Speakin' on oil systems, who has the corect oval filter insert for E-Type V-12's? Gone thru XK's etc. and always get the round one. :madder:

 

[jessebogan]

Hey Doc, I have a few. Far eastern manufacture, but they seem OK in use. All I could find when I bought them. PM me if you want one

 

[nissanite]

Thanks for all of the imput.
Yes an actual hard lined aftermarket gauge was tried.
My friend said the relief valve had not been cleaned during the rebuild & was very dirty.
I will check the serial # this week.

 

[nissanite]

We found the problem!
Lowe's Automotive in Sarasota,FL checked the oil passage in the manual, then traced the problem & repaired it. There is a bolt that was not installed above the oil level. I should have been installed during the rebuild & goes from top down so it was out of site with the pan off.
Car is running & driving perfectly.

 

[DrEntropy]

YIKES!

At least it was found before there was any bearing damage.

Thanks for reporting back, too!

A pal and I wrenched on old "Euro-trash" in Sarasota for years. Still take care of a few of the valued clients. I'm 50 miles north, made the commute daily for a decade or so.

 

[Grantura_MKI]

All oil passage plugs and the oil relief valve, should have been removed prior to the re-build. Lump should have been hot tanked...more problems will occur is my feeling. There is no reason for dirty oil on a new engine, except lack of cleaning or a dirty enviroment.

 

[DrEntropy]

<fingers crossed>

That's what my first thought was.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]
"Had it rebuilt" raises a red flag here but after three years there's not much recourse. It needs to be opened up and all checked with mic's and such if a hard gauge reading is 9 PSI. [/QUOTE]

Not trying to throw rocks, but... any proper rebuilder would tank the block as a matter of course. "Hospital clean" is the only way to conduct an engine rebuild, especially one of those mills.