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Mazda 2.0L \  Camshaft problems. Need opinions.

Camshaft problems. Need opinions.

Mazda 2.0L Mazda Engine Mazda Tech
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replies 17
following 5
 
anguswilly   +1y


Here is the correct listing, the pic is still wrong, but they should send you the right part according to the listing.
emjay   +1y
Correct Angus that is the right cam.
man of tercel   +1y
Okay I have the new cam shaft. Any body have the torque specs for the bolt that holds the sprocket on? And also the rocker assembly bolts.
mazdatweaker_2   +1y
When you take off the old cam check the journals really carefully for galling. The old cam may have been starved for oil and seized up. That would explain why the gear got screwed with the timing belt. If that is the case plan on putting a head on it, too.

How many miles are on the vehicle?

(added edit)
Before going too far on this project you might want to check the engine to see if there is any oil in the crankcase. You might need a whole motor if the level dropped too far on the way to a shredded timing belt.
man of tercel   +1y
Iirc it's 160k. But please tell me the journals that you are talking about are the two on either end. Cuz they're fine. But the others are not.
mazdatweaker_2   +1y
The journals are what the camshaft sits on while it rotates;the half_moons. If the two inside ones ran dry first this is where the cam started to stick and metal to metal contact and metal transfer would have started to occur on the way to cam failure. The journals are line bored at the factory so they are supposed to be matched during service work

The bottom end might be seized but you can check for that by putting a socket on the crank bolt and trying to rotate the engine. It may not be stuck but if it is you will be up against a seized motor. Because the engine is non-interference and has the cam out of it right now you can try to rotate the engine with the starter. If you just get a loud click and no engine rotation that is another clue that the bottom end is DOA.

There is a chance that the self destruction of the top end may have saved the bottom end, in that the engine wouldn't have run long if / when the cam seized and the belt stripped.

I hate to be the bringer of bad news but you kind of need to know what you are up against.

Posting pictures would help. Replacing parts is sometimes a judgment call based on perceptions.
anguswilly   +1y
This requires you to post pics, if the cam journals are bad, it depends how bad, some can be smoothed out with emery - some cannot.
mazdatweaker_2   +1y
It would help if someone could post a picture or two of a non-damaged head with the journals exposed for point of view. I would if I had a head available.

The problem isn't so much the journals, but the oil galley holes getting blocked from metal smear from the prior damage and then they block off oil flow to the replacement cam if they aren't drilled out. The shavings / filings are another issue entirely. Time with a slow speed drill, some grease, and hope that the bit doesn't break off.

All of this is doable but for many the easiest route is to replace the head if the engine is otherwise ok.