engine vibration, 81 diesel pu

Moved your thread to the Older Rabbit Forum where you will get answers usually faster.

When mine did the Vibration it was usually the passenger side motor mount was shot.
But if your timing wasn't spot on, as with use of a Dial Gauge, then your engine wouldn't run as smooth as it can.
Worn shock mounts can cause the vibration as well, and there are thread here and on the VW vortex that tell you how to get a little better mileage out of them.
Check your rear tranny mount, as they can and will go bad quickly as well as the Front grill mount, if it isn't centered it can cause a bit of an idle.

As you didn't say if this was on a colder engine rather than a warm one, that is a possibility, and you said it was a idling issue as if you have some burned out glow plugs that can cause a cold to warm idle issue and vibrations from hades.... but the caveat is that you have to remove them to really see if they are bad, and the number 1 and 2 usually require that you remove the fuel lines to get to those....

Damper on the fan? I do know that the early westys has a negative air displacement issue on the Radiator mounts Bolts at the bottom, and a clip on the top that can lead to ripping the seam of the radiator tanks. But that can be reduced by the installation of the Cabriolet Pin Radiator and the Cabriolet radiator mounts that at the top bolt the fan shroud to the valance. I have a how do I do that on trimming the radiator shroud to make it easier on and off....

First suspect is worn mounts and if you didn't use the HD Diesel ones then the Gassers are more prone to vibrate, and some sellers sell the gasser ones for the diesel.
Second is cold or war? So I would look at GP's all working.
Third is Idle or the injection pump timing with a dial gauge.

briano1234 said:

Moved your thread to the Older Rabbit Forum where you will get answers usually faster.

Check your rear tranny mount, as they can and will go bad quickly as well as the Front grill mount, if it isn't centered it can cause a bit of an idle.

Damper on the fan?

Click to expand...

You could have the Gasser mounts or you could have the diesel ones and just have them out of line. Think of your engine sitting in the bay with two lines going from front to back and side to side. You have a mount under the radiator, a round one and then in back there's the one near the shifter linkage. On the sides you have the one on the transmission and the one from the dark side in the bracket that holds the IP in place. The monster to remove and replace.

But I am going to assume first that you replaced them all and start with a solution there. Getting it aligned is somewhat of a trick. You need to get it on line from front to back and side to side. Tipping the front of the engine up will remove some of the tension being placed on that bracket below the radiator. The bracket has slotted holes in it so you and adjust it. So before you go pulling of pushing on it crawl under there and see what placement you have going. Is there space at the top of the bracket or the bottom?

When you accelerate the engine what happens to that gap? Does it get smaller? Generally the engine puts more pressure on the bottom of the bracket as you accelerate. The engine twists a bit forward. If you currently have a gap at the bottom that will allow the engine to move around some at idle but not under load.

The back bracket is important too. As it controls some of the side to side movement as well. There are adjustments to that one too. So once you have the current setting in mind go ahead and loosen all those bolts. Now push on the transfer case from below. Can you move the engine a bit from side to side? Get it to settle in place then tighten the rear bracket. Move to the front and push up on that bracket with a jack, small hydraulic works well, or ease a floor jack under it, but watch for it hitting other parts. Just raise the bracket enough to slightly lift the front of the engine. Like 1/4 inch or 8mm, Button up the bracket right there.

You can't do much adjusting of the IP bracket mount, as it is pressed in and tightly at that. The orientation of that mount is important so I hope you got it right. If I remember there is a mark on it to line up on.

You can loosen the transmission one and shake the engine at the transmission end to get it to settle into place and not have undo tension that would put pressure on the front and back mounts. Think about that side to side line being shifted to the back or front. That would kick the engine off to the side one way or another.

Another idle shake problem is having too low of an idle. Yes you can time the crap out of it with a gauge and be spot on and that really doesn't help. Why? Because your engine is old, worn and specs are not going to do anything but be a guide now. You need to tweak the settings, both the RPM and Advance or Retard on the timing so the engine mellows out. You can hear and feel it, once you get it to that point then measure the timing and write it down someplace. That is what is right for your engine at this point in its' service life.

Changes can be made from there that will help performance or mileage. But don't think you will get both, fast comes at the expense of fuel so mileage equals less sporty drive, longer seconds to 60 and all of that.

I own two 1981 Rabbits, the 2 door and the PU. I have had to adjust the engine in the mounts several times so far to get them to stop shaking around. Even after putting in new diesel mounts. It is just not something we think of because we are not engines with pistons bouncing up and down in us at 850 RPM at idle.

Let us know when it smooths out.