Crank sprocket change necessary??

[schwar74]

Hey gang,

Thanks for all the info I've already gotten from browsing the forum. I couldn't find an answer to this question.

Is it necessary to change the Crank Sprocket while doing a timing belt change?

I just bought a 90 na with 100k on it that has no known history of a 60k service being done. Obviously its on the top of my list of things to do (would probably do 120k service). In reading write ups of the timing belt change procedure, it seems like getting the crank sprocket off is the worst part of the job. If the front main seal seems to be fine, is it worth the time and potential for injuring the crank shaft or the oil pump housing to chisel it off? Is this part prone to failure? Are the key's prone to breaking? Is teeth wear an issue? Why not just leave it and save the headache? I feel confident that I can get the project done, but this part sounds like a huge PITA!!!

I can see the reasoning behind replacing idlers, water pump, etc, as they have more of a potential for catastrophic failure.

Oh and I'm stuck in the middle of KS, so access to Z shops and Z wrenchers is not available.

Thanks!!!

Scott
Abilene, KS

[t.mcginley.jr]

I just did the timing belt job on my NA while I had the engine out. Same deal, the engine/car has 98k on it, but I have no proof of a 60k service so there was no way I was taking that chance. I replaced the belt, idlers, auto-tensioner, studs (with RameyZ heavy duty ones), water pump, thermostat, and bypass hoses. I didn't replace the crank sprocket. My front seal didn't seem to be leaking at all so I didn't bother. From what I've heard, most people just take it off to replace that front seal and end up busting the sprocket in the process so that's why they replace it. The teeth on it really shouldn't wear out or anything like that.

In the end it's really up to you. If it was leaking oil out of the front then I would say yeah do it.