I had low oil pressure on my 3.4 v6 so I installed one of the high volume pumps. I still have low pressure, but it is better. It is slightly above the red and occasionally will trip the oil pressure light. Any thoughts?

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[This message has been edited by tshark (edited 09-08-2018).]

I'm in tsharks corner. Don't trust the dash gauge. Pickup or borrow a new automotive pressure gauge. They come with the goodies for attaching it to your engine. Then see what pressure your getting. Now in my humble opinion if your running a Fram oil filter, all bets are off. And your welcome to ask me how I know.

Spoon

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quote Originally posted by tshark: You need to read the computer value to see if the gauge is correct. Have you replaced the oil pressure sending unit? There used to be an oil system flush. You may try that to see if there is a blockage, but also to see if it takes an abnormally long time, as well as if it actually flows. Is the low oil pressure a recent thing, or did this start with the swap?

Computer doesn't know the oil pressure, the sender/gage circuit has no interface to ECU.

A high volume pump does not translate to high pressure.
I would install a mechanical guage and check.

I have checked with a mechanical gauge, and the reading is accurate. This is a new condition, the oil pressure has been getting worse, over the last few months. It is a 3.4 oil pump.

[This message has been edited by Madess (edited 09-25-2017).]

Likely worn bearings. Main and/or rod. The clearances in the engine determine the oil pressure. The pump only supplies volume.

Put 20W-50 and if the pressure increases some then your bearings are shot

Like you I had the same problem with my 2.8 when the mileage went over 100K and using 5w30 oil. It would produce the same symptoms you have. It would not maintain pressure at idle and would sometime cause the oil light to blink. On rare occasions it would turn off the fuel pump and the car would stall. My solution was to increase the oil viscosity I moved to using 10w40 and have never had the problem again and now the mileage is 160K. My wife tried to be nice one time she was using the car and stopped and had the oil changed for me. The shop used 5w30 which the car calls for. It took 1 can of STP for the oil light to stay off at idle.

To test your car you could try adding the STP and see if your problem goes away. If it does then on your next oil change increase the oil viscosity 1 grade.

If you ever get to having to use 20w50 start saving for motor work..

quote Originally posted by 1Packrat: Like you I had the same problem with my 2.8 when the mileage went over 100K and using 5w30 oil. It would produce the same symptoms you have. It would not maintain pressure at idle and would sometime cause the oil light to blink. On rare occasions it would turn off the fuel pump and the car would stall. My solution was to increase the oil viscosity I moved to using 10w40 and have never had the problem again and now the mileage is 160K. My wife tried to be nice one time she was using the car and stopped and had the oil changed for me. The shop used 5w30 which the car calls for. It took 1 can of STP for the oil light to stay off at idle. To test your car you could try adding the STP and see if your problem goes away. If it does then on your next oil change increase the oil viscosity 1 grade. If you ever get to having to use 20w50 start saving for motor work..

If your car shut off from low oil pressure, your fuel pump relay is not working.

This can be verified by disconnecting the OP sender with engine running.

If the car continues to run, the F/P relay is good, your stalling was caused by another issue.

If the engine dies, the F/P relay is bad.

[This message has been edited by olejoedad (edited 09-26-2017).]

Sorry, 2.8 pickup with 3.4 pump

[This message has been edited by Madess (edited 09-26-2017).]

You have a PM.

quote Originally posted by Madess: Sorry, 2.8 pickup with 3.4 pump

If that's the same engine I think it is... when it went together (it was originally a Grooms rebuild - purchased as a long block) the pump that came with it was lots larger than the 2.8 pump. I assumed it was the 3.4 pump.
How many miles are on the engine/car now?

Nah, this is my normally aspirated 3.4. Yours is now turboed.

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[This message has been edited by tshark (edited 09-08-2018).]

So, I took the bolts out of the main bearings, but I can not get the caps off, any thoughts?

Thanks.

Those bits and pieces definitely look like rod or main bearings.

You are gonna have to do a rebuild.

Once the bolts are off the caps, you have to gently tap the caps and they will work loose.

I have heard of people replacing these with the engine in car. They are able to reach around and insert new bearings. But, if you spun a bearing then you crank is scored and needs refinished, and then fitted with the appropriately sized bearing.

Mark the caps!
All Must go back in same place and same way.
if you mess this up now or in the past then expect to have problems again.
Examples:
Flip a cap on same bearing point like 1 rod may look like it fits but very quickly can eat the bearings.
Put cap for X piston on any other rod can do same thing. Might look ok to you but expect to eats bearings.

Been driving w/ bearing in pieces then likely the cap and rod if your lucky are toast. If a main bearing then the cap and block are toast.
Been driving and motor isn't slamming a piston in the head then likely bad main. Bad rod bearings often make very bad knock type noise as piston hits the head but not always. Plus Bad rods often won't make low oil pressure.
Mains in a block maybe can fix but will need to pull engine and take it to a engine shop.
Dead rod then need a new rod. Many OEM wrist pins are pressed in so need a press or just get done by a shop.

Shop won't "fix" just the mains but price a full block restore to rebuild and that cost a lot.
So if main(s) are damage then find a another engine.

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Looks like a bearing for sure. If you decide to rebuild I have standard size rod bearings along with piston rings brand new.

Here is a pic

bad bearings?

Has this bearing been wiped dry? Is the brown color oil, or is it the bearing itself?

The golden color in the very middle is oil, the copper color that runs all the way across is the bearing.

It's worn down to the copper. Those were toast a LONG time ago.

How does the crank look?

Edit: you can even see more copper under each cylinder, where the pressure spikes as the piston is near TDC. Done.

[This message has been edited by Will (edited 01-23-2018).]

no doubt the crank looks like that also. run your fingernail on it, it should be PERFECTLY SMOOTH.

That main bearing is definitely worn. So at the very least, the main and rod bearings should be replaced. But I don't think that explains the chunks of metal in the oil pan. Maybe it chewed up a rod bearing?

[This message has been edited by Blacktree (edited 02-12-2018).]

quote Originally posted by Lou6t4gto: no doubt the crank looks like that also. run your fingernail on it, it should be PERFECTLY SMOOTH.

I've seen rod bearings come out looking like that and worse, while the crank was pristine. New set of bearings and the engine was fine. That's why bearings are SOFT... so that they save the crank.

The motor is coming out in the next few weeks and going to the machine shop. I will let you know what they say. Thank you for the help.

Just a theory: I wonder if one of the rods got bent, then started shaving chunks off the crankshaft thrust bearing. That would explain the metal shavings in the pan. But I'd be surprised if that happened. The stock 2.8 V6 rods should be able to handle about 250 HP. And of course, a stock or even mildly modded 2.8 V6 isn't anywhere close to that.

But I guess we'll see soon enough. Hopefully it isn't anything catastrophic.

quote Originally posted by Madess: The motor is coming out in the next few weeks and going to the machine shop. I will let you know what they say. Thank you for the help.

If it has good compression, I don't see why you'd want to do more than install new bearings, which can be done in the car.

I would think you'd want to align hone it to get all the mains straight. Or you might be doing it again. And clean the oil galleys.

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85 GT 3.4
14.9 @ 90 1.9 60' Old TH125/3.06
Unknown New 4T60/3.42