1993 Mazda 626 Camshaft Sprockets Will Not Rotate

Tiny
DIGITALSTORM
  • MEMBER
  • 1993 MAZDA 626
Engine Mechanical problem
1993 Mazda 626 6 cyl Front Wheel Drive Automatic

During a timing belt replacement, the crankshaft sprocket and both camshaft sprockets lined up properly with their respective marks when rotating the engine from the crankshaft bolt. With the old belt on, the crankshaft and camshafts rotated with relative ease. Once I removed the old belt in order to replace it, the right camshaft sprocket jumped counterclockwise almost a 1/4 of a turn on its own. When I try to turn the right camshaft sprocket clockwise back into position, it turns slightly forward then falls back to its original position. As if there is compression holding it back. The right camshaft sprocket remained aligned when this incident first occurred with the left camshaft sprocket and it continues to remain aligned although it now also exibits the same compression behavior as the left camshaft sprocket.

This is the 6 cylinder, 2.5 litre engine which is reported to be a non-interference engine although I am wondering if damage could have resulted when the left camshaft spocket initially sprang counterclockwise. Any advice would be greatly appreciated and thank you very much in advance.
Do you
have the same problem?
Yes
No
Thursday, September 3rd, 2009 AT 4:33 PM

3 Replies

Tiny
MHPAUTOS
  • EXPERT
Hi there,

Valve spring pressure is causing the can to kick, if these are an non interference type engine, (i don't have my cam belt info to hand just now to check) there will be no damage, you will need someone to assist you by holding the drive gear in position while you re set the timing.

Mark (mhpautos)
Was this
answer
helpful?
Yes
No
Thursday, September 3rd, 2009 AT 6:50 PM
Tiny
DIGITALSTORM
  • MEMBER
Hi Mark,

Thank you so much for such a speedy response. I am quite amazed and will be sure to make a donation.

With respect to your response, it certainly answers why the camshaft kicked counterclockwise although I am wondering why both cams turned so easily by hand when rotating with the belt on and now I cannot overcome the valve spring pressure of a single cam without feeling like I am going to damage the engine. I just need to rotate the right cam less than a quarter of a turn to line up the marks. How much force is acceptable in order to rotate the camshaft without considering that something else may be wrong?

Also, how do you hold the drive gear in position on an automatic transmission and how would this help to overcome the tremendous valve spring pressure that I am experiencing?

Once again, thank you so much.

Mike
Was this
answer
helpful?
Yes
No
Thursday, September 3rd, 2009 AT 11:36 PM
Tiny
DIGITALSTORM
  • MEMBER
Disregard this post since I solved the problem. Once I verified for sure that my V6, 2.5 litre engine is a non-interference engine, I applied a little extra rotational force on the camshaft sprocket to overcome the valve spring pressure and was able to line up the timing marks. I then properly installed and tested the new timing belt, idlers, water pump, etc. This engine now runs like new again.
Was this
answer
helpful?
Yes
No
Saturday, September 5th, 2009 AT 11:04 AM

Please login or register to post a reply.

Recommended Guides