How can I tell an oil pump is bad?

TennLee · 04-14-2001, 08:47 PM

Let me explain my situation. Unlike a lot of people who put a late model 5.0 engine in their fake cobras, I decided to build a carbed 302. So, I procured a block, and added new crank, pistons, Edelbrock cam, heads, manifold, and carb. The block is from a '72, and so is the oil pan, with dipstick. I bought a regular oil pump (not HV or HP) from Autozone, and put an Accel distributor on top.

Here's my symptoms:

1. When I spin the oil pump in a bucket of oil, it squirts oil like a fountain.
2. When in the motor, and using a drill to prime it, and get oil out of the passenger side backmost rocker, and no others. Autometer mech gauge (new) reads near zero.
3. When I ran the motor (maybe not too smart, here), I get still next to no oil pressure. Didn't run it very long, just a few secs.
4. Was advised I might not have an oil galley plug in the back of the lifter valley. I pulled the manifold and the plug is there. I have no fluid leaks, nor any smoke at all when I ran the motor.

Could my oil pump be bad but still make the "geyser" in the bucket? What could I be overlooking? Should I give $50 to Autozone for a high pressure model oil pump? I suspect that's not it since all the bearings are new, and I shouldn't need a HP pump?

Sorry about the long winded story, but I'm stumped.

Thanks

Lee

------------------
Lee
'66 FFR Cobra (Replica)

04-14-2001, 09:12 PM

Man, that sucks, here's my only theory:
Did you clean out the oil passages in the crank when you got it. I rebuilt an engine in school about 2 months ago and we got a brand new crank. Just for the fun of it i took a wire brush and found an insane amount of metal shavings and crud inside the passages that wasn't cleaned out. Main bearing oil pressure determines overall oil pressure, and if you're getting no oil through the mains, none of it is getting to the galleries and that is where (if i'm not mistaken), where the oil pressure is measured. I assume since you took out the plugs (from what it sounds like) from the oil galleries that you cleaned out the galleries, that's another possible thing to be plugged as well. IF i were you i'd go ahead and take the block back out, clean out all the passageways, and check to see if the bearings are toast. If you cleaned all this stuff out, then i'm stumped also, but if it's an old high mileage block then the most likely culprit is sludge buildup (i found an unbelievable amount of sludge in my 150,000 mile 302 and all older 302's i've seen are caked with sludge). Good luck man, i feel for 'ya.

------------------
'84 Mustang 5.0 T5, FMS aluminum radiator & 180* t-stat, 1 5/8 shortys/2.5" duals, '88 GT tail lights and wheels, Holley 4160 4 BBL, FMS smog pump idler

PurgingPony · 04-15-2001, 09:51 PM

Did you by chance plastigage your main bearings? What all is done to your engine? Is it just rings and bearings or is everything new or is everything turned down?

------------------
88LX 5.0,C4,3200stall,TFS stg 1 cam, ported E7's, BBK LT's, Race magnum bullets, ASP 3" pulley, 3.73's, 75hp NOS Dry Kit, Explorer intake
7.94@85 N/A 1/8th C4
7.61@89 N2O 1/8th T-5 http://www.angelfire.com/ns/PurgingPony/50mainpage.html

04-14-2001, 08:47 PM	#1
TennLee Registered Member Join Date: Apr 2001 Location: Knoxville, TN Posts: 1	How can I tell an oil pump is bad? Let me explain my situation. Unlike a lot of people who put a late model 5.0 engine in their fake cobras, I decided to build a carbed 302. So, I procured a block, and added new crank, pistons, Edelbrock cam, heads, manifold, and carb. The block is from a '72, and so is the oil pan, with dipstick. I bought a regular oil pump (not HV or HP) from Autozone, and put an Accel distributor on top. Here's my symptoms: 1. When I spin the oil pump in a bucket of oil, it squirts oil like a fountain. 2. When in the motor, and using a drill to prime it, and get oil out of the passenger side backmost rocker, and no others. Autometer mech gauge (new) reads near zero. 3. When I ran the motor (maybe not too smart, here), I get still next to no oil pressure. Didn't run it very long, just a few secs. 4. Was advised I might not have an oil galley plug in the back of the lifter valley. I pulled the manifold and the plug is there. I have no fluid leaks, nor any smoke at all when I ran the motor. Could my oil pump be bad but still make the "geyser" in the bucket? What could I be overlooking? Should I give $50 to Autozone for a high pressure model oil pump? I suspect that's not it since all the bearings are new, and I shouldn't need a HP pump? Sorry about the long winded story, but I'm stumped. Thanks Lee ------------------ Lee '66 FFR Cobra (Replica)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Confused, I need help on different fuel pump wiring methods.	5.0 Fiend	Windsor Power	12	10-14-2004 06:43 PM
oil pump installation question	82 GT	Windsor Power	3	07-03-2003 02:03 PM
Fuel pump relay questions	Big Bopper	Windsor Power	1	11-10-2002 10:20 PM
STEWART Water Pump issues :( ??	LOBE_50	Windsor Power	6	05-15-2002 08:34 AM
Lost another oil pump	oldman	Windsor Power	2	10-20-2001 11:14 AM

04-14-2001, 09:12 PM	#2
84stangLX Guest Posts: n/a	Man, that sucks, here's my only theory: Did you clean out the oil passages in the crank when you got it. I rebuilt an engine in school about 2 months ago and we got a brand new crank. Just for the fun of it i took a wire brush and found an insane amount of metal shavings and crud inside the passages that wasn't cleaned out. Main bearing oil pressure determines overall oil pressure, and if you're getting no oil through the mains, none of it is getting to the galleries and that is where (if i'm not mistaken), where the oil pressure is measured. I assume since you took out the plugs (from what it sounds like) from the oil galleries that you cleaned out the galleries, that's another possible thing to be plugged as well. IF i were you i'd go ahead and take the block back out, clean out all the passageways, and check to see if the bearings are toast. If you cleaned all this stuff out, then i'm stumped also, but if it's an old high mileage block then the most likely culprit is sludge buildup (i found an unbelievable amount of sludge in my 150,000 mile 302 and all older 302's i've seen are caked with sludge). Good luck man, i feel for 'ya. ------------------ '84 Mustang 5.0 T5, FMS aluminum radiator & 180* t-stat, 1 5/8 shortys/2.5" duals, '88 GT tail lights and wheels, Holley 4160 4 BBL, FMS smog pump idler

04-15-2001, 09:51 PM	#3
PurgingPony Registered Member Join Date: Dec 1999 Location: Naples, Fl Posts: 113	Did you by chance plastigage your main bearings? What all is done to your engine? Is it just rings and bearings or is everything new or is everything turned down? ------------------ 88LX 5.0,C4,3200stall,TFS stg 1 cam, ported E7's, BBK LT's, Race magnum bullets, ASP 3" pulley, 3.73's, 75hp NOS Dry Kit, Explorer intake 7.94@85 N/A 1/8th C4 7.61@89 N2O 1/8th T-5 http://www.angelfire.com/ns/PurgingPony/50mainpage.html