Sudden loss of oil pressure in fresh built 8BA engine
 

I have just completed a rebuild of an 8BA. At start up oil pressure 40-60psi, several starts later, same oil pressure 40-60psi. Running a new melling oil pump. At last start this afternoon, no oil pressure at all. Removed oil gauge line from rear of block and cranked over the engine, no oil pumped out. Sump has oil and at full on dip stick. Never had this happen before in all the builds I have done (20+ over 7 years)

Any idea what the issue might be? Oil pump drive/shaft issue? Cam shaft oil pump drive gear?

Any assistance would be greatly appreciated. Thanks David

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Let's say that someone magically guesses what the problem is.
You are still going to have to do the same thing, most likely, and that is to dis-assemble and inspect.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Yeah, you are correct. I plan to drop the sump tomorrow and check the oil pump first off. If not that then I will drop the transmission and inspect the cam gear. I can't think of any other reason for sudden lack of pressure.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

The 8ba has a flat on the cam gear. Also the pressure was quite high for some reason, was this the M19 pump??I never use Mellings pumps, always had troube with them.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Ron, The new melling pump is a standard pump. Cam was reground 8BA mild .325" lift. Any insights as to what could be wrong?

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Oil pressure was under moderate revs, not idle

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

If you are on a test stand then remove the plate at the back and start diagnosing from there. I've heard of those gears coming loose on the end of the cam. If the engine is in the car, then remove the pan and inspect the pump. You'll find it in probably either of those places.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Thanks, Engine is in the car. Plan to drop the sump and inspect the oil pump 1st. If not the pump then will drop the transmission. Thanks David

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Maybe the pickup tube is loose?

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

That waz my first guess.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

One mistake even a veteran will make I know from experience decades ago is installing the oil pump idler gear backwards the gears will mesh but have ever so little engagement that wears away quickly then all of a sudden no oil pressure. Heres another example. One time on a fresh build prior to starting I tried to get the oil pressure up no matter what I did no luck getting any oil to flow. Finally removed the oil pan removed the new oil pump looked up into the pump hole and with help turning the engine in the front looked into the pump hole discovering the idler gear was not turning. The cam I used was a NOS 8-BA cam. When I removed the cam I found the gear on the end of the cam had fallen off it was sitting in the oil idler gear compartment. The cam did not have a flat area to hold the gear from turning so not all late cams have that flat that NOS gear was extremely loose never expected something like that to happen with a cam I removed from the factory applied cosmoline and burlap type covering. If you could remove the oil pan and look at things that should help you figure out whats wrong.
Ronnieroadster

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Excellent advise, thanks. I will pull the pan this morning and post results, thanks.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Well the problem turned out to be relatively simple to fix. Faulty oil pickup unit replaced and engine back together ready to refit into the vehicle. Thanks to all for your advice.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Glad you found the problem. How was the oil pickup faulty?

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

How was it faulty? :confused:

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

I had exactly the same thing last year on a rebuild with a new melling oil pump. Oil pressure was fine but after a few starts I had no oil pressure at all. Dropped the pan and removed the oil pump only to find the pump drive shaft had snapped in two. The oil pump itself had no binds at all. it must have been a weak shaft from the factory although the break was clean. I installed another oil pump (not Melling) and everything has been fine since.

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Oil pick up had a fracture in the bronze weld which opened up. In the bin and a replacement fitted

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Thanks for the follow-up....

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Looks like Mr 42 nailed it!

Re: Sudden loss of oil pressure in fresh built 8BA engine
 

Thanks ford1933-2008 for the feedback-
:)