1986 C4 with engine problems 0 psi Oil pressure
Thread Starter
Heel & Toe
Joined: Sep 2022
Posts: 18
Likes: 0
From: New Mexico
1986 C4 with engine problems 0 psi Oil pressure
Hello I have a 1986 c4 corvette with the small block 350 bored out. It was my dads and before he got it someone bored it out also mentioned he bent a push rod and replaced it but doesnt know how good of a job it was. The car rn has two knocks in the motor, one may be a push rod and the other idk what it is. The car starts fine and drives fine when easy on the throttle, with oil pressure at 40 psi or normal psi but when it gets warm it starts to drop, It will get to 0 psi at idle and stay there untill I get back on it and get 20 psi under load. Just replaced the two Oil pressure switch/sensor and got the same readings so I belive its not that. I feel like when its cooler it gets more power and when warm/hot has lack of power but makes sence bc the oil pressure idrk. When I get on it feels like a huge lack of power, but if I ease on to it i feel more power it hard to explain. Now Im not sure if my motor is going out or theres a possible fix, considered swaping the engine.
Anything helps Thanks
Video of the knock in motor
Main knock when warm at 0 psi
Video of cold start with old Oil pressure gauge switch/sensor
Dash showing 48-50 psi when cold
Anything helps Thanks
Video of the knock in motor
Main knock when warm at 0 psi
Video of cold start with old Oil pressure gauge switch/sensor
Dash showing 48-50 psi when cold
Racer
Joined: Oct 2023
Posts: 383
Likes: 124
From: St. Petersburg, FL
When it dropped to zero did the engine make a lot of valve noise ? If not maybe your gauge is bad ? I have a hard time believing that if your oil pressure was at zero for as long as you mentioned the engine wouldn’t make a bunch of noise or have started to seize. I know you said you replaced the sending unit but it might be faulty, or the sensor might not be making proper ground. I would put an external oil pressure gauge on it just to see if the readings are what you saw on the dash gauge and go from there.
Thread Starter
Heel & Toe
Joined: Sep 2022
Posts: 18
Likes: 0
From: New Mexico
Thanks man, when it dropped to zero I dont belive it was making valve nosies, I peeped at the valves and they seemed normal and wet.
I'm working on it at my school that I graduated from, they unfortunately didnt have the oil pressure gauge. I'll go ahead and buy that and try it out on monday hopefully.
I'm working on it at my school that I graduated from, they unfortunately didnt have the oil pressure gauge. I'll go ahead and buy that and try it out on monday hopefully.
Drifting
Joined: Jun 2020
Posts: 1,716
Likes: 744
From: Stay dangerous my friends
When bearing clearances are increasing due to excessive wear, the oil pressure drops. But not to zero.
what metal bits or sparkles are in the oil filter?
one distinct quality of rod knock is that it is louder when theres no load on the engine, compared to higher loads.
what metal bits or sparkles are in the oil filter?
one distinct quality of rod knock is that it is louder when theres no load on the engine, compared to higher loads.
Thread Starter
Heel & Toe
Joined: Sep 2022
Posts: 18
Likes: 0
From: New Mexico
When bearing clearances are increasing due to excessive wear, the oil pressure drops. But not to zero.
what metal bits or sparkles are in the oil filter?
-I haven’t checked the oil filter to see if there’s anything
one distinct quality of rod knock is that it is louder when theres no load on the engine, compared to higher loads.
what metal bits or sparkles are in the oil filter?
-I haven’t checked the oil filter to see if there’s anything
one distinct quality of rod knock is that it is louder when theres no load on the engine, compared to higher loads.
Thread Starter
Heel & Toe
Joined: Sep 2022
Posts: 18
Likes: 0
From: New Mexico
So I did the oil pressure test with a gauge and it was showing normal psi, even when warm/hot.
Cold start psi and when warm
What could casue my new oil pressure gauge and switch/sensor to read 0 psi? Possibly a ground when it gets hot?
Now Im wondering what that knocking is? Im going to remove my filter to see if I can find anything next week.
Cold start psi and when warm
What could casue my new oil pressure gauge and switch/sensor to read 0 psi? Possibly a ground when it gets hot?
Now Im wondering what that knocking is? Im going to remove my filter to see if I can find anything next week.
