No oil pressure after two pumps!!!

[cbuckman5]

I have a 97 Camry 5SFE w/ 205,000mi. I did a complete engine rebuild including pistons(+0.02"), rings, bearings, water and oil pump(Aisin), and all new gaskets. Engine is completely stock minus a trashed balance shaft assembly(BSA) plus a threaded and capped BSA oil feed hole in the block. After everything is back together I prime the oil with several no-fuel crank sessions. I drive it soft for 250miles and get a rod knock. Pull the pan and see #4 crank bearing completely gone and a half chewed up #4 con rod. All crank bearings were scored badly. I also notice each crank bearing closer towards the oil pump was less and less damaged concluding I lost oil pressure. The dummy oil light never came on thru all of this. So I test the oil pressure switch with my air compressor, mechanical gauge, and a voltmeter determining continuity and find the switch opens at 1-2psi!! WTF! Why even have a switch at all when damage can still occur when oil pressure drops under 10psi/1000rpm. I again dismantled the entire engine to clean out debris since about a cup of bearing grit was sitting in the bottom of the pan. So, I pull the engine and do another complete rebuild. I teardown the oil pump and see nothing wrong with seal, bypass, or rotor. So I order a new...everything including a new Toga oil pump and re-assemble. This time I replace the crap oil pressure switch with an electronic oil pressure gage. Now, I have everything running but I noticed the oil pressure bounces around alot. On a warm engine with 5W-30, it jumps from 6-12psi at idle. At a top gear 70mph (~2700rpm)cruise it jumps between 36-55psi constantly very fast. As an aside, I have never seen oil pressure jump around like this at a steady state engine speed. Makes no sense . So I swap the electronic pressure sender with a mechnical gage and see it also jumps around concluding this is really occuring and is not some electrical noise. Not finding any info on oil pressure stability I continue to drive the car another 23,000 miles with no probems until now. Today I do a cold start and hear a metal sqeaking sound from the oil pump area underhood. Couldn't do anything about it since I was 250miles from home. So I proceeded to drive keeping an eye on my pressure gage. 50miles into the drive pressure occasionally dropped from ~45psi down to ~20psi then back up. I pull over and rev the engine in neutral and find around 3000rpm oil pressure completely drops out to ~10psi, yikes!! Still 200miles from home I continue to drive and find myself having to drive slower and slower as oil pressure continues to drop intermittantly until it's consistantly below my 10psi/1000rpm rule of thumb. I pull into a gas station and oil pressure completely dropped to 0psi and I key off. Did I go thru another oil pump? Did my pump strainer inlet fall off in the pan? If I didn't have the oil pressure gage, I would have never known what was going on and would have definetely smoked another engine. So I fell I just repeated the first occurance but hopefully saved the engine. I'm pulling the pan tomorrow and hope to see something obvious but never really concluded what happened the first time other than a mysterious oil pump failure that I couldn't see when I tore everything down. How could I have gone thru two oil pumps. I am an experienced engine builder and know the do's and don't of the trade, but this is just a mind-twister. Thoughts???

[JohnGD]

Sorry to hear that happen to a newly rebuilt engine.

Did you consume any oil? (And should use the thickest approved oil in the temperature range you operate.)

Is any bore/shaft out of round?

Plastigaged all bearing clearances and hopefully they come in at the low end of the specified range?

Primed the oil pump with assembly lube?

Made sure the pick-up tube doesn't have cracks/holes and is properly sealed to the pump? The tube may be picking up air. Was there oil left in the pan?

Might want to power drill up the oil pressure before starting just to check. That should save several seconds of dry start in filling a new filter. Maybe use the following:

http://www.harborfreight.com/cpi/cta...emnumber=98949

[73sport]

Ouch and major Bummer. Sorry.

Lots of things to check. As John suggested, apply all of those. You espcially need to know the clearance between the journals of all rod and crank bearings. Did you check them and do you have the clearance numbers? Did #4 rod got replaced? Did the crank get replaced? Was complete rotating assembly rebalanced?

You state the BSA was trashed. Please explain.

Was there any changes to the top end that would allow large oil leak. Did you swap heads from different year ect??

We will assume these were assemebled with lube and the fact that you mention nothing about the top end being noisey yet the main feeds failed to lube is now up for debate as to wether the top end was getting oil at all too. Look close you may have excessive wear up there too.

It sounds like you have an internal leak! Depending on where you tap into the block for pressue it changes everything if theres a leak. Close to the pump and you have higher pressure while further away, it drops. Does anyone have a diagram of oil pressure feeds for this?

You mentioned pulling the counter balance and plugging the feed. I hate to say this again but it seems like there might be more than one feed and maybe it didn't get plugged?

I've had engines pop press in galley plugs on the top end. Like yous they have pressure but its all over the map by load and temperature.
How are these blocks fed? Most engines feed the mains and rods first, secondary is the top end.
This engines needs pulled apart completely and every galley check for obstruction, opens, cracks, flaws, any damage to the pump area, ect. Anything that could promote an oil leak.

Were the cranks Rod and main journals turned? Was the crank bore align-honed?
Did you check, does the main block journal feeds align with the new bearing feeds and do the rod feeds algin with the rod bearing feeds? Don't throw the old bearings away they hold the clue as to what went wrong.

The floating pressure leads me to beleive you had a huge leak. Find that leak.

Hey sorry about all those questions - lots of things to look at.

Let us know what you find.

[cbuckman5]

Many points to touch on here. I welcome all detailed questions.

ok...

As a refresher plus a bit more detail, this car originally came to me with an oil pressure light on, 183k miles, and a nasty squealling sound from the engine. I did a complete teardown and found the balance shaft assembly bearings were destroyed if not missing and the shafts were spinning on the aluminum housing. Before disassembly, I could move one of the shafts back and forth 1/4". This obviously was the source of the squealling. I also saw about a half cup of bearing bits sitting in some nasty sludge in the bottom of the pan.

REBUILD #1
Freeze plugs were pulled and the block was magna-fluxed and hot tanked. I replaced the bearings, oil and water pump, gaskets, rings, pistons, timing belt, and had the crank re-ground and polished. The block was bored and honed correctly. The crankshaft was rebalanced with the new piston assembles. All clearances (bore taper and roundness included)were set to spec values and piston ring gaps were confirmed all with professional calibrated gaging equipment (in an engine build lab at my work). I also checked valve lash, inspected cam journals, and re-lapped the valve seats. I also even re-checked the valve spring rates. I like to do it all while it's all apart.

After asking several people from various sources including an experienced Toyota powertrain engineer here in detroit, I found the balance shaft assembly was a later added peice to smooth out idle and decrease a consumer complained 2000rpm chassis resonance. So, the engine can live fine without it. So I capped off the single oil feed line to the assembly by tapping and loctiting a bolt in place. I also made an adapter so the strainer that normally bolts to the underside of the BSA, could still mount into its exact same orientation. I was very careful about this taking all precautions and validated each change.

Before the first start, the spark plugs were removed and injectors unplugged. The engine was cranked in several 10sec intervals until I could here a tone change suggesting the oil pump was primed.

FIRST FAILURE
Put everything together, drove for a couple hundred miles and everything is fine. Change the oil draining through a cheesecloth to look for any particles. Everything looked great! So I complete the oil change, verify oil level and close things up. The next day I go out for a drive and 10 miles from home I get onto the highway. As I'm cruising at 70mph on cruise control, I notice the trans downshifts to maintain speed then I begin to here a rod knock sound. I immediately key off, jump into neutral and come to a stop. I tow it home and drop the pan to see the oil pump failed from the wear indications stated in my first note.

REBUILD#2

The crank journals were damaged after the first oil pump failure and bearing destruction (beyond regrinding). So it was replaced with a new crank.

The cams and head were also significantly damaged. Those were all replaced with a new fully assembled head.

I also replaced the #4 con rod with a Toyota factory piece. These replacements all took place after I pulled the engine, did a complete teardown, and cleaned and blew out every single oil line (and confirmed with a boroscope). I did not rebalance the crank this time. I also replaced the Aisin oil pump with a Toga pump. I could not find a single thing wrong with the Aisin pump. The bypass worked fine. I did a bench test and drill powered the pump to confirm it was pumping. I hesitated to put that one back in and went ahead and bought a Toga.

This time I swapped the stock oil pressure switch with a oil pressure gage picking up oil pressure as it feeds from the block to lubricate the head. I figure this is a decent "end of the road" location for oil pressure measurement securing that I will at least have the entire cranktrain pressurized if the gage is indicating pressure.

Before the timing belt install, I wired up the oil pressure gage and drill powered the Toga pump. It did take about 5 second to prime, but when it did, I noticed a nice steady oil pressure at the gage. I also saw oil weeping from the camshaft journals all the way up to the last ones by the sprockets.

So I drop the engine back in and repeat the start up process minus the oil pump priming and she fired right up nice and smooth except for the oil pressure. It quickly bounced back and forth maybe 10times/sec but averaged out at safe pressure. I drove it 23000 miles without a problem. At about 2000miles, I checked the valve lash because at fully warm, it was ticking quite a bit. I checked and confirmed (cold) that everything was right in spec- another wierd thing.


SECOND FAILURE
This last Sunday is when the oil pressure started to drop out and I pulled over to a gas station. Here's an important note, when I did the slow reving test (where I continuously increased engine speed in neutral and watched oil pressure), the "valve ticking" completely went away when oil pressure dropped out. So maybe that valve ticking wasn't lash, maybe it was some other oil pressure affecting occurance.


NOTES ON QUESTIONS
I do recall inspecting the oil inlet tube/strainer and making sure it mounted correctly to the oil pump.

When I replaced the trashed head with the new head, I checked every feature making sure this head was an exact replacement.

I wish someone had a pressure vs. engine speed curve (hot) of this oil pump sampled at the location of the stock oil pressure switch and could tell me the pressure variance. I feel when I capped off the oil feed to the BSA (which that same line runs up to the cylinder head/pressure sensor location), I took out some volume in the circuit that could be damping pressure oscillations. But, I do remember during the oil pump priming, oil pressure was very steady. That would tell me the oscillations are induced from something in the cranktrain or valvetrain rotating and varying a restriction (like an out of round crank main journal). Those were all checked.

This does sound like the oil pump inlet has a new leak that grew in that last drive home to the point where it's now just sucking air. Oil pressure remains at zero when spinning the engine.

I can't get to pulling the pan until Saturday. We'll see then. I better find something this time or this car is going into the Detroit River!

[73sport]

Thanks for all the details. I'm thinking. . . .

Were any of the oil pumps burned, galled, damaged or show signs of metal debris going through them?

Can you pressurize them and see where (what PSI) the relief valve opens at?

Did they fail in anyway?

My earlier questions about the bearings. Any thoughts? Can you confirm that all the feed holes aligned in the block? How it would make it 23k with an issue is beyond me but then again I found a drill bit in a crank throw of a GM motor with 150,000 miles on it. It was built that way! I should have kept it!

[cbuckman5]

Update on teardown:

I pulled the oil pan this morning hoping to find something obvious. I found nothing. When draining the oil I drained it through a cheesecloth to catch any particles. I didn't find a single sliver of oil, which is good news that bearings may be ok. I dropped the pan and saw everything was in it's proper place. No metal shavings or debris in the bottom of the pan. The loctited bolt I used to cap the removed balance shaft assembly was still tightly torqued. The strainer was properly secured it's support mount and to the pump inlet. I removed it and did not see any crack or break in the tube. The strainer's gasket on the pump inlet sealed perfectly. Can find anything wrong down there. Going to now remove the timing belt and drill spin the pump.
I'm wondering if the gasket between the block and oil pump fails, wouldn't that create a leak path from the high pressure outlet back to low pressure? We'll see....

[cbuckman5]

Found the problem! In pulling the lower timing belt cover, I found the oil pump pulley spun on it's shaft. Cheap power metal pulley wheel that came with the new Toga oil pump. I have another new Toga pump I just looked at and found they put too small of a slot on the shaft and pulley to couple them. I'm just going to replace it with an OEM part. I'm really lucky that I didn't loose the timing belt. That would have been a disaster.

[73sport]

Originally Posted by cbuckman5

Update on teardown:

I'm wondering if the gasket between the block and oil pump fails, wouldn't that create a leak path from the high pressure outlet back to low pressure? We'll see....

YES, this will do it to!

If you decide to use a gasket between the pump & block, spray it with Permatex Copper Coat on both sides and all edges! This seals it, strengthins it, and makes it less permiable to the oil. ITS GOOD STUFF!

As for your findings - that is STRANGE! Anyway the pump seized and spun the shaft? INSPECT IT! What do you mean about "too small of a slot?"

I still think it sucked air. I'm not familar with this engine, pressure test the pickup tub assembly and make certain there are no holes in the screen.

I'd pop the rods and main farthest from the pump and inspect them too . .