Completed Changing of MFI Injection Pump Belt, If anyone ever wants the skinny....

[IAN]

If anyone ever seems a bit freaked out by this task, let me know.

I learned several things that I'm sure would make it much easier for the 1st timer....

Otherwise I won't bore anyone....

Thanks.

[Tim Walsh]

post it anyway I'm sure someone's going to ask. I would like to know just for curiosity's sake.

[72 four door]

Yes please post it I want to know too

[Rot 911]

Here's a pic to go along with any info Ian may provide:

[widebody911]

Here's my 2 cents - if you have the engine out for any reason - REPLACE THE DAMN BELT! Years ago, I had a new clutch installed on my '72T. About a month later, the belt broke! I had *planned* on replacing the belt, but forgot to order it when I ordered the clutch bits.

[IAN]

My injection pump belt broke while I setting the timing in my garage. I'm very lucky it broke in my garage, it would have been a tow truck otherwise for sure.

Here is the lowdown:

1) Jack up Car, you could do this by the side of the road without jacking up the car but it would be a bit brutal.

2) Remove rear left wheel.

3) Use 10MM wrench to remove 4 bolts that attach a tear drop shaped piece of sheet metal that sits directly in front of the cam on the left side of the engine.

4) Pull sheet metal piece down a bit, you do not need to entirely remove it. The accelerator linkage runs directly through this piece of sheet metal so it will basically hang in place while you work.

5) Get out your 22MM wrench and rotate your fan pulley to TDC cylinder1, then go 360 degrees to cylinder 4. Then rotate a bit more until you see the FE mark on the pulley. Leave the engine at the FE mark.

6) Remove the air filter assembly if you haven't already and get a paper towel and wipe off the cog of the pump the best you can.

7) Loosen the (2) 12mm nuts on the right side of the pump. Take the nuts and washers completely off the right side. The left side is harder to get at. Keep in mind that the pump bolts form a square, keeping this in mind makes it a bit easier to find them when trying to undo the left side. The front left bolt is easy. The rear left bolt really sucks. I removed a section of linkage to get better access. Use a box wrench that gets passed through the middle of the throttle body. The rear left bolt on the pump can take a while, if you have a temper like a do you might want to make sure there aren't any kids around. You do not have take of the nuts entirely off on the left side, actually I would not do this as it will make it even worse to put back together.

8) Get a mirror, I used one from my wife's make up kit. Arrange the mirror so you can see the cog of the pump well. You will notice a vertical line that runs down the brownish area on the back of the pump itself. If you keep spinning the cog on the pump while looking in the mirror you will also notice a small line between 2 teeth on the pump cog. Line up these 2 lines.

9) Now that the bolts are off the right side of the pump you can see how far you have to slide the pump to the left to get the belt in place. You will notice that there is less less than 1/3 of inch to slide the pump. I was alone when I did this so I put the washers and nuts back on the right side of the pump. I then placed a crowsfoot on the right side of the pump behind the breather assembly and gently pryed the pump to the left. I then tightened the nuts in place.

10) Then I placed the belt through the slot in the sheet metal from the top. I then walked to the rear left wheel well and placed the belt on the cog directly in front of the cam.

11) This was the key part for me. After tugging for what seemed like an eternity trying to get the belt in place I realized that the throttle linkage needs to pass directly through the center of the belt. I did not realize this was the case because when my belt broke I just pulled it out. I wasn't sure about this at first but now I'm sure. So take the throttle linkage that runs from the front of the car off and pass it through the center of the belt. Put the linkage back on.

12) Take your mirror and check your marks on the pump. Check the fan pulley and make sure you are still on FE, should be unless you moved it.

13) Pull on the belt and place it on the wheel of the cog on the pump making sure to not turn the cog on the pump. Once I passed the throttle linkage through the center of the belt it want on pretty smoothly. Re-check your marks on the pump and make sure you are still lined up. If you are not lined, do it again. If you keep doing it and continue to be off by 1/2 tooth you will need to take a 4.0mm allen wrench and undo the 3 screws on the front of the pump cog and rotate your cog a bit. I did not have to do this.

14) Loosen the nuts on the right side of the pump. Then put your crows foot on the left side of the pump and gently pry the pump towards the right of the car. Be careful of throttle bodies, fuel injection lines, etc. Tighten nuts on right side of pump.

15) Check the tension on your belt. It should turn about 90 degrees in the center of the belt. I think what you get is what you get. The adjustment range is very small with the pump.

16) Rotate your engine with the fan pulley 2 complete revolutions and stop again exactly on the FE mark. Get out your mirror and check the marks on the pump. You should still be on. If not, somehow you skipped a tooth or something. I also watched the belt very carefully while rotating the engine to make sure that the belt was not walking off the end of the pump cog. It didn't.

17) Put it all back together.

18) With the engine running. I looked very carefully again at the belt to make sure it was not wobbling or walking off the cog.

Hope this helps someone.