Help + ideas cam gear pins sheared off. ???

[misterfixit]

Help all please...

When stripping the motor I'm rebuilding the cam gears spun as I was undoing their retaining bolts. Held per the manual but now the pin is flush with the face of the cam.

Any ideas/previous methods of removal. I'm reluctant to go drilling as I don't want to move the dowel position. The other cam the pin started to shear (shift the position).

Tried to grab it and pull but no giving.

Rich

 

Is the cam in the motor? Are you sure that the gear started to spin relative to the cam or did the whole unit rotate inside the head? The cam gear should be held in place by the pin and held down by the bolt, the two should not move together without the cam coming along. If they did, you have a serious problem. See that part on the cam where it looks like you can put a wrench? Put a wrench there and use it to hold the cam still while you break loose the bolt. Don't spare the penetrating oil. Consider heating the bolt with a torch, but be careful you don't set your penetrating oil on fire. I cannot remember if the pin is part of the cam or just set in it, but if it is integral and it is going to shear off, better now than once the motor is in the car, right? If it is integral and it has "started to shear" that means the marks on the cam gears for alignment are no longer valid, if you choose to continue using the cam. You will have to compensate. Once again, if the pin is integral you must replace the cam or the gear will snap it clean through and freewheel under load.

As for getting the gears off the cams, it is a bitch. I recommend a nice plastic nor marking deadblow hammer or a rubber mallet. While it is a pain in the rear, I would consider removing the cam from the motor (if you haven't already) and hitting all around the circumference of the gear until it comes off. If you leave it in the motor, be sure to spin it around as you hit the gear with the mallet or you will just bind it up worse.

If the pin is not integral but shears off flush with the cam, drill it out and replace it. You can get several different styles of broken bolt remover at sears which should work.

 

[jepherz]

Weld something to it, or just replace the cams if they are factory? Are you sure it actually sheared off, or could someone have bolted the gears up wrong onetime and push the pin in?

 

[misterfixit]

No. the one was definately sheared off. theother was starting to shear (offset by about 1mm). Happened before on another 4g6 but I managed to pull them out easily. This motor was a bit of a pain.

Have fixed it though, using two different methods. See pic:


The one that started to shear I took to work. In the dev lab we have a record no.25 vice and a sturdy bench. Clamped the protruding portion of the pin in the vice and squarly and patiently struck the front face of the camshaft to drift it out. Came out loverly /ubbthreads/images/graemlins/wink.gif

The second one was a little trickier. Drilled through with a 3.2mm dia drill then a 4mm dia drill and tapped it through with a bottoming tap to m5. The screw in there was then threaded in snugly and I used a little 2' crowbar to lever the bugger out.

Yes both cams were out of the head.

Phew.. all done. not a fun job.

Rich