Fity
30th March 2012, 01:45 PM
I recently bought a 2000 GU with what was supposed to be a dead ZD30. The previous owner told me it just died while driving so they replaced the injector pump and it still won't start. When cranked over you can hear air coming out of the intake. So as you would assume the grenade as gone off. You can't always trust what previous owner say when trying to get the most for their car and it had NADS fitted so he knew about the grenade. I didn't care as I am planning on fitting a TD42 anyway.
I get it home (via tilt tray) and figure I should just confirm that it is in fact got low compression. Without taking it apart I could turn the crank over relatively easy by hand. I thought I should just check that the fuel pump was installed and timed correctly.
I pull the front timing cove off noting that it had been recently removed and had fresh gasket silastic everywhere. To my surprise it was not timed correctly and was a few teeth out! Now any one familiar with ZD30 knows that the cams are driven from a timing chain off the injector pump gear, so if the injector pump is out so are the cams. I checked the cams and they were out too, but to a different degree to the injector pump. So I precede to time it correctly and noticed that a locating pin on the cam sprocket had sheared off. My guess is that the valves hit the pistons after being incorrectly timed. So bent valves I hear you ask? I pulled the cams out and all the lifters are sitting flush, so put it back together correctly with a new pin for the sprocket and turn the key. It cranked, then coughed, then fired, then purred like a kitten.
I think the locating pin on the cam sprocket may be a design feature to save the valves in case of a chain failure. I hope that this helps some else and saves then thousands of $$$ on a rebuild instead of a 50 cent part. :)
So now I have a cheap GU with a perfect motor. The TD42 is still going and I have the running ZD30 to fund it.
I get it home (via tilt tray) and figure I should just confirm that it is in fact got low compression. Without taking it apart I could turn the crank over relatively easy by hand. I thought I should just check that the fuel pump was installed and timed correctly.
I pull the front timing cove off noting that it had been recently removed and had fresh gasket silastic everywhere. To my surprise it was not timed correctly and was a few teeth out! Now any one familiar with ZD30 knows that the cams are driven from a timing chain off the injector pump gear, so if the injector pump is out so are the cams. I checked the cams and they were out too, but to a different degree to the injector pump. So I precede to time it correctly and noticed that a locating pin on the cam sprocket had sheared off. My guess is that the valves hit the pistons after being incorrectly timed. So bent valves I hear you ask? I pulled the cams out and all the lifters are sitting flush, so put it back together correctly with a new pin for the sprocket and turn the key. It cranked, then coughed, then fired, then purred like a kitten.
I think the locating pin on the cam sprocket may be a design feature to save the valves in case of a chain failure. I hope that this helps some else and saves then thousands of $$$ on a rebuild instead of a 50 cent part. :)
So now I have a cheap GU with a perfect motor. The TD42 is still going and I have the running ZD30 to fund it.