89 740 crank sprocket key

nisan17 · Post by **nisan17** » 22 May 2012, 14:51

Hi Group:

This car must have a demon in it??!! I replaced my timing belt and seals with success. I did a test start with just the Harmonic Balancer/pulley on the end of the crank with the bolt snug. Now, that key from the sprocket that holds and aligns the HB/pulley sheared because my test start caused the bolt to loosen. WTH!!

Question: Can I tighten the pulley to the crank and align what little sheared key is left? Or shall I get another intact sprocket? Or, can I run a bead on there from a welder or where can i get a new/used sprocket?

Then I will bless this thing!!!!

Thanks again,

bwta · Post by **bwta** » 22 May 2012, 22:23

try tighting the bolt with whats left of the key, it just may work
good luck

Post by **billofdurham** » 23 May 2012, 13:13

Kevin, it depends on how much of the key is left and how tight it fits into the groove. Putting a weld on is not a good idea - not only my opinion but that of a friend of 40+ years who is a master coach builder and can weld just about anything. His opinion is the weld would not have enough strength to last for very long.

I would be trying to source a used one or failing that going for a new one.

In case your old book doesn't have this the torque setting on this bolt to 60nm (45 ft-lb) plus an additional 60 degrees (1/6 turn).

Bill.

nisan17 · Post by **nisan17** » 29 May 2012, 21:56

Bill, got a used sprocket/gear and got it all together and going. Now, I still have a check engine light even though I disconnected the battery prior to starting. When starting off from a stop sign, the cars seems to not quite have enough, I have to let the car slowly rev up to get going. But it is in very short order, meaning it gets going quickly. I don't want to have it backfire again and blow out a seal or two again!

I've replaced my throttle switch, flame arrestor, cleaned the MAF, throttle body, replaced the air filter, airbox thermostat valve. What could be causing the light to come on? I'll do the OBD in the next day or so. Shall I check the timing? I haven't checked it after the belt change. Thanks again,

Post by **billofdurham** » 30 May 2012, 12:40

I am assuming you had the CEL before you did the timing belt. Did you erase it? I have found that only disconnecting the battery doesn't always erase the codes.

My first job would be to check the OBD and erase any codes found. Then run the car and see if they return.

If you had everything set up correctly there should be no need to check the timing.

Bill.

nisan17 · Post by **nisan17** » 30 May 2012, 13:54

Bill,

Yes, I had the CEL prior to the timing belt change. The OBD showed a throttle control switch.(a couple months back) I changed the belt due to being oil soaked at the expense of a blown seal.

Thanks again.