91 t4r sr5 new engine low oil pressure?

[d1lyh4n4]

I have a 1991 Toyota 4runner sr5, at, 4x4. In september I had the head gasket blow. I took it to a mechanic recommended by a guy at my work.

The mechanic tore it down and found corrosion on the block. Faced with not knowing how good the lower end of the engine was, considering I bought it used with 153k miles, I opted to buy a new engine. I researched the options and decided to go with a high performance version of the 3vz-e, sold by CHS machine co. out of Portland. It took almost 2 months but we finally got the thing back together.

It came as a long block and touted 200 hp and 220 fpt . Being an almost 30% power increase I thought it would be a good improvement as the stock 3vze is a little under powered. It wound up costing me 2300 for the engine (after core return), and 3789.08 to the mechanic. Making it almost 6100$. I got it back on Tuesday the 26th. When I picked it up I looked it over and listened to it. It sounded and looked good (i.e. no missing, and no visible leaks). I drove it back to work a short distance away. When I went to drive home after my shift I turned it on to warm it up and noticed the oil pressure was a little low. Not thinking anything of it I went back in and waited ten minutes. When I got in it to drive home I noticed the oil pressure was low. I am judging this from the dash guage. For this vehicle it ususally sits dead in the middel of the guage. The needle was sitting at about what I would call 25% of the guage. As im driving home I notice that the pressure is fluctuating 25%-35% guage. At stop lights and such I note the guage showing as low as 10% guage. I was pissed I couldn't think of what it could be. I did some research online and found the various reasons for olow oil pressure and none of them were very comforting. In the morning I turned it on and let it warm this time it went to almost half and then as it got warmer went down to 35% guage and leveled out. When I was almost to work I noticed the it was again back down to 10*25% guage, and it would go up when I would accelerate.

I also noticed that it seemed very under powered and slow to accelerate, taking way to long to get up to freeway speed @ 2k rpm. I checked the oil and it was full. Again no leaks.

I called the mechanic at this point and was like whats up man. He told me hat he believed it was running undernormal operating conditions. And that when I bought it back to have the first of the 3 oill changes I scheduled he would check it with a mechanical guage. This first oil change is supposed to happen at 300 miles.
Im feeling sketched because of the amount money I've put into this project already.

Is there any reason that a new rebuilt engine if in perfect working order and installed correctly would perform like this. I am aware of the breaking in period and am babying it very much not taking it over 3k rpm ever.

-It seems to be fine when cold.
-when warm the oil pressure drops to about half what it should be.
-Oil dip stick reads full
-no leaks
-proffesionally installed
-all new enginge long block, oil pump, water pump, oil filter, cap plugs wires rotor, radiator, Hbalancer, fan bearing bracket, hoses, pressure cleaned oil cooler, throttle position sensor, various vacuum switches, oil, cleaned k@n air filter.
-engine seems to be running fine
-no check engine light

this is really pissing me off considering how much I just paid.

 

[d1lyh4n4]

so what could be causing this issue considering all of the factors.
please help!!!

 

[Kmvreter]

I have a 1991...
... sold by CHS machine co... Making it almost 6100$...
... For this vehicle it ususally sits dead in the middel of the guage... 10*25% guage, and it would go up when I would accelerate...

How long have you owned the truck and was it always at half guage with the old engine? The guage behaviour sounds right from a cold start then dropping as it warms up. The new engine may work at a slightly lower pressure but still be above minimum. What grade of oil are you using and is this the recommended by CHS?
Hopefully the performance issue is a break-in issue and will improve. Have you called CHS to quiz them about your concerns?
Can anyone on here (hopefully with a '91) help with an indication of where their oil pressure guage normally runs?

ps. Not knocking your project, or knowing your circumstances, but I would have put that kind of money on a newer T4R. I understand it's spent now so I hope you get this resolved.

 

[fourwd1]

You're not leaking or burning oil, which is good.
The oil pressure fluctuates, which is normal (but mine are 4 cyl, so I can't comment on your readings).
It seems slow, maybe CHS exagerated the 200 hp ?

 

[Getsum]

If I were you I'd get to the bottom of this as the longer you drive it, the more the mechanic is going to wash his hands of it.

Is your mechanic certified? Did you get any type of warranty on his work?

Have you contacted the company who sold you the engine and asked for their inputs or described the problems? Does the motor have a warranty on it from the factory?

I would also do a compression test on the cylinders as well as install a manual oil pressure gauge to get an accurate oil pressure reading...the dash gauges are notoriously off. His idea of continuing to drive the truck with low oil pressure is downright WRONG! He is assuming your pressure is fine, you need to know NOW before you destroy your engine. Ask him if a high volume pump was installed or if one is needed...this may be a question for the people you bought the engine from.

Is there anyway you can do a horsepower check to see what the actual HP is? Some speed shops have setups and don't usually charge that much. Having an engine at 150hp when they advertised 200 is grounds for a return or replacement....again, depending on your warranty.

Last point...BE PROACTIVE! No one is going to take care of you as good as you are. Look after your investment and demand satisfaction. They are just HOPING that you simply go away...DON'T.

 

[rustyrazor]

Oil Pressure

Here's a few thoughts.

My oil pressure shows up really low if I use standard 10w30 oil. I've heard this from others also about the 3L V6. It's just like you say. It would start at normal pressure when cold and then drop way down once it warmed up.

My solution was to start using the Mobil 1 20w50 full synthetic oil. It's about $26 at wallmart in the USA. Some people might think the oil is too heavy or whatever and that it's meant for racecars, won't flow in the cold etc, etc. This doesn't apply to fully synthetic oils so cold starting is not a concern.

With the Mobil1 20w50 the pressure is always dead centre. Nothing short of a nuclear reactor will affect the viscosity/lubricity or whatever of that stuff.

It sounds like it's too late but you could have checked with toyota to see if your headgasket was replaced under the recall yet or not.

As for the power the 3L V6 combined with the automatic tranny seems to be a really gutless combination.

 

[Getsum]

Here's a few thoughts.

My oil pressure shows up really low if I use standard 10w30 oil. I've heard this before about the 3L V6. It would start at normal pressure when cold and then drop.

My solution was to start using the Mobil 1 20w50 full synthetic oil. It's about $26 at wallmart in the USA. Some people might think the oil is too heavy or whatever and that it's meant for racecars, won't flow in the cold etc, etc. This doesn't apply to fully synthetic oils so cold starting is not a concern.

It sounds like it's too late but you could have checked with toyota to see if your headgasket was replaced under the recall yet or not.

As for the power the 3L V6 combined with the automatic tranny seems to be a really gutless combination.

Did you read his post? He replaced his entire motor with a high performance engine...the entire thing. What would checking with Toyota about a headgasket do?

 

[rustyrazor]

Did you read his post? He replaced his entire motor with a high performance engine...the entire thing. What would checking with Toyota about a headgasket do?

I realize that it's too late for him but if some other people search "blown head gasket" on this forum and this thread comes up then the information is there. Maybe he did check with Toyota, I don't know. All I'm saying is that anytime anyone mentions a blown head gasket I'm going to mention the Toyota recall that is still active. I had my head gasket replaced just over 1 year ago under the recall.

 

[Savage]

my gauge reads low at idle and rises as the rpm's increase. Different than most other gauges I've experienced but seems normal for this vehicle. I tend to trust my ears and feel to interpret this kind of situation. If the engine doesn't sound like it's starved for oil and temp's don't increase it probably is the gauge. I would suggest trying to bypass your indash gauge with an aftermarket and double check the pressure reading from your sending unit...this is where I would start based on others here also verifying a low reading as some what typical. There are many things that could cause actual low pressure though. GL!! Oh, and as previously suggested, I would be all over this mechanic guy to get this FIXED before I drove another #$%^& mile in it!!!!

 

[n8buddy]

did you mechanic re-use the old oil pressure sending unit? my guess is that the sending unit or gauge wears out over time and gradually reads lower. I have owned my truck for 5 years and when i first got it the guage read normal and has gradually read lower over the years and now reads almost zero at idle. I had the techs at toyota checked it and it was fine.

 

[wolfgang]

Surpized mechanic's bill was so high. I'd have him replace the sending unit to give you peace of mind. Can't be but $25 for sender. If that doesn't impact it - I'd start complaining loudly as it won't get any better.

 

[1stgen]

Few things to consider before you run out freaking:
1. What kind of oil is in there? Generally for break-in the oil used is lower weight.
2. Is it the same oil sending unit. If it's not you have nothing to compare it to.

If I was you, I would take it to the mechanic, get them to check the factory manual for the operating oil pressure. Put an actual gauge on it and see if it's withing the range. The stock dash gauge is basically a pressure/no pressure gauge as it can change based on the oil you have, the temperature, and the humidity (it's an old gauge, has a spring coil in it).