turbokinetic
Registered User
Hey folks. I'm new here, and have a very unique project going on. I chose the 6.2 forum because it seems the closest to the type of engine I have. If there's a better place, it won't hurt my feelings if the admins move it.
I'm working on a 1984 Oldsmobile Cutlass Ciera with the 4.3L Olds Diesel V6 engine. The car belongs to a friend, and it has sentimental value to him. His mom (who has passed) had one when he was younger. This is a labor of love project, so please understand the reason for repairing this car.
This engine is an indirect injected engine using a Stanadyne DB2 injection pump, and glowplug system very similar to the 6.2 IDI.
The engine was in terrible shape when I got it. These 4.3V6 diesels were not known for a long life; although this one lasted more than 30 years. The previous owner had apparently run it very hot and both of the aluminum heads were cracked beyond repair. A local machine shop actually had a spare set of core heads! They rebuilt the cores they had.
The engine is obsolete, and it's very difficult to get parts for it. Pistons are completely unavailable and gaskets are very very difficult to obtain.
During the engine repairs, I found a couple of cracked pistons (skirt cracking) and replaced them with used pistons from another engine I had here. The pistons are letter-coded as to bore size, and I matched the letters.
The Olds 4.3V6 diesel is a roller-lifter engine. All the lifters were in serviceable shape as far as galling on the rollers, scoring on the lifter body etc.
After putting the engine together, it runs very well and starts easily. There's not any significant smoke from the exhaust. There is not any bupping or chuffing from the intake or exhaust.
The only problem is a very loud tapping noise. The tapping noise is strange in that it fades in and out. When the engine is started cold, the timing advance causes it to be clattery as expected, but I can hear the tapping on top of the fuel combustion sound. As the engine warms up, it runs smooth. There is no missing or any sign of a problem; other than the tapping.
When the engine is run on the road, the tapping is very noticeable in the car. After coming to a stop, the tapping is still just as loud as it was going down the road. If I let the engine idle, after about 5 minutes, the tapping will gradually fade away. If I revv the engine, the tapping comes back then takes a little while to fade away again at idle.
If I shutdown the engine while it's fully warmed up, then re-start it after a few minutes - the tapping will be gone until the engine has been revved up again.
During the engine repairs, I changed all bearings (the old ones were not destroyed and all were standard).
In troubleshooting this, I have done the following:
- Turn off the ignition while the car is moving, thereby cutting off the fuel. The tapping continues as long as the engine is rotating and the car is coasting in gear.
- Disconnect fuel injection lines one at a time trying to change or eliminate the tapping. Can not change the noise, and the engine runs the same way for each line disconnected. In other words, all cylinders working.
The above make me think it's a mechanical problem; and not a fuel combustion knock.
I further did the following:
-Remove valvecovers. Run the engine and observe the motion of the rocker arms. They all appear (by eyeball) to be moving the same distance.
-Press down on the rocker at the pushrod end and the valvestem end, with engine running. I used a piece of 5/8" heater hose to do this. I was not able to "Feel" any difference in the movement of any valve. I also noticed NO change in the engine sound when pressing down on any valvetrain component.
The engine has 40 PSI oil pressure when going down the road. It has 15 or 20 at idle.
The sound appears to be coming from the "middle" of the engine. I just don't know what it could be and I am hoping for any insight. The problem is the gaskets are very hard to get. So I need to minimize the number of times I dismantle the engine.
Here is a video where I am testing an electronic part I built. If you go to the end of the video, you can hear the tapping noise gone after I re-start it. That point is about at 7:30 in the video.
https://www.youtube.com/watch?v=qb7FcNfRbLc
Here is a thread concerning the car and its engine, with engine build pictures:
http://www.a-body.net/forums/showth...s-Ciera-Diesel-Engine-repairs-and-restoration
Thanks in advance for any insight.
Sincerely,
David
I'm working on a 1984 Oldsmobile Cutlass Ciera with the 4.3L Olds Diesel V6 engine. The car belongs to a friend, and it has sentimental value to him. His mom (who has passed) had one when he was younger. This is a labor of love project, so please understand the reason for repairing this car.
This engine is an indirect injected engine using a Stanadyne DB2 injection pump, and glowplug system very similar to the 6.2 IDI.
The engine was in terrible shape when I got it. These 4.3V6 diesels were not known for a long life; although this one lasted more than 30 years. The previous owner had apparently run it very hot and both of the aluminum heads were cracked beyond repair. A local machine shop actually had a spare set of core heads! They rebuilt the cores they had.
The engine is obsolete, and it's very difficult to get parts for it. Pistons are completely unavailable and gaskets are very very difficult to obtain.
During the engine repairs, I found a couple of cracked pistons (skirt cracking) and replaced them with used pistons from another engine I had here. The pistons are letter-coded as to bore size, and I matched the letters.
The Olds 4.3V6 diesel is a roller-lifter engine. All the lifters were in serviceable shape as far as galling on the rollers, scoring on the lifter body etc.
After putting the engine together, it runs very well and starts easily. There's not any significant smoke from the exhaust. There is not any bupping or chuffing from the intake or exhaust.
The only problem is a very loud tapping noise. The tapping noise is strange in that it fades in and out. When the engine is started cold, the timing advance causes it to be clattery as expected, but I can hear the tapping on top of the fuel combustion sound. As the engine warms up, it runs smooth. There is no missing or any sign of a problem; other than the tapping.
When the engine is run on the road, the tapping is very noticeable in the car. After coming to a stop, the tapping is still just as loud as it was going down the road. If I let the engine idle, after about 5 minutes, the tapping will gradually fade away. If I revv the engine, the tapping comes back then takes a little while to fade away again at idle.
If I shutdown the engine while it's fully warmed up, then re-start it after a few minutes - the tapping will be gone until the engine has been revved up again.
During the engine repairs, I changed all bearings (the old ones were not destroyed and all were standard).
In troubleshooting this, I have done the following:
- Turn off the ignition while the car is moving, thereby cutting off the fuel. The tapping continues as long as the engine is rotating and the car is coasting in gear.
- Disconnect fuel injection lines one at a time trying to change or eliminate the tapping. Can not change the noise, and the engine runs the same way for each line disconnected. In other words, all cylinders working.
The above make me think it's a mechanical problem; and not a fuel combustion knock.
I further did the following:
-Remove valvecovers. Run the engine and observe the motion of the rocker arms. They all appear (by eyeball) to be moving the same distance.
-Press down on the rocker at the pushrod end and the valvestem end, with engine running. I used a piece of 5/8" heater hose to do this. I was not able to "Feel" any difference in the movement of any valve. I also noticed NO change in the engine sound when pressing down on any valvetrain component.
The engine has 40 PSI oil pressure when going down the road. It has 15 or 20 at idle.
The sound appears to be coming from the "middle" of the engine. I just don't know what it could be and I am hoping for any insight. The problem is the gaskets are very hard to get. So I need to minimize the number of times I dismantle the engine.
Here is a video where I am testing an electronic part I built. If you go to the end of the video, you can hear the tapping noise gone after I re-start it. That point is about at 7:30 in the video.
https://www.youtube.com/watch?v=qb7FcNfRbLc
Here is a thread concerning the car and its engine, with engine build pictures:
http://www.a-body.net/forums/showth...s-Ciera-Diesel-Engine-repairs-and-restoration
Thanks in advance for any insight.
Sincerely,
David