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Broken Balance Shaft Belt

MX4

Well-known member
Joined
Apr 9, 2001
Messages
780
Location
New Zealand

Hi all,
If anyone can please help with the below problem it would be appreciated. On the car I have the harmonic balancer failed and the balance shaft belt snapped. The cam belt was not effected however the cam belt timing marks dont line up anymore. The engine is able to be turned by hand although it is stiff even with the sparkplugs out. It can be rotated through a full 360degrees and there are no loose rockers with the tappet cover taken off.

Should I just retime it with new belts etc, or remove head for inspection. Any and all ideas appreciated.

Regards,

Ryan
 

turbowop

Well-known member
Joined
Apr 29, 2001
Messages
11,971
Location
Yakima, WA
I would throw a belt on it real quick and do a compression or leakdown test before you pull the head. How far off are the marks?
 

autobahntom

Well-known member
Joined
Feb 8, 2003
Messages
1,250
Location
Delaware
The balance belt breaking probably didn't happen with the harmonic balancer problem-unless the timing cover broke and put pieces into the belt. The balance shaft belt could have been broken for a while and you not known it-just depends on the damage. If the timing belt is six teeth off, then it did jump time-that means there is pieces in there.
Take the belts off, check for damaged/siezed pulleys, put on new belts and rotate the engine over by hand. If nothing out of the 'norm', do a compression test. If that fails by a little; can do a leakdown test to give more info. No rockers off is a good sign though. Could also put a boroscope down the plug holes and see if the valves are completely seated.
Tom
 

1990ggsxnj

Well-known member
Joined
Nov 21, 2008
Messages
525
Location
Blackwood, NJ
Quoting MX4:

...the cam belt timing marks dont line up anymore. The engine is able to be turned by hand although it is stiff even with the sparkplugs out.



Quoting MX4:
Im away from the car now but at a guess maybe 6 teeth each.



Sounds to me like you jumped too much timing and it was difficult to turn because you had valves hitting your pistons. 6 teeth off for both cams may have been something getting in between your crank gear and timing belt unless you are only talking about the left balance shaft which is ok since it's not directly connected to anything. Just my opinion but the checks listed above will let you know for sure. Really hope I'm wrong though.
 
Last edited:

fivestardsm

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Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
I am not disagreeing with any of the afore mentioned statements, but I can think of another isue aswell.

First, did you time the motor previously, or did someone else?

Did the car run a little sluggishly before, and has it been getting worse?


Sounds to me like you had a balance shaft bearing failure. They are pretty common. As for the timming marks, you say they are around 6 teeth each, but wich way...Up or down. If up, then you could have actually been driving the thing like that for awhile.

I had an eclipse brought to me for a tune up because it ran sluggish. When I went through it, It turned out that the timming had been set off about 5 teeth or so. Far enough, that they were opening on the wrong side of the cycle. All I could figure is that some 3 year old helped time it the last time, but there was not a single bent valve on the engine.

This is just an experience I had, and I am not saying yours is the same, so like mentioned, a compression test/leak down test woul be advisable to see what you actually have.

Or you could just tear it down and freshen it up now and do a balance shaft delete. /ubbthreads/images/graemlins/smile.gif
 
Last edited:
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