Stuck timing belt sprocket

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Yaut
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My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Stuck timing belt sprocket

Post by Yaut » Thu Apr 30, 2020 7:20 pm

This post is sort of dual purpose. I wish the express my annoyance but wouldn't mind hearing any tips on how to approach this.

Today I began the simple task of replacing my very worn timing belt. I took everything apart to get down to the belt and removed the balancer of course. I noticed that the timing belt sprocket on the crankshaft was quite worn (not sure how a rubber belt wears out a metal sprocket but this car did live a large part of it's life on dusty gravel roads and was missing the timing cover gasket). To my annoyance, I could not slide the sprocket off. I lubed the shaft up with penetrating oil and figured a three jaw puller could easily remove the stubborn sprocket. There is very little room between the block/front plate and the sprocket and was just barley able to get the jaws on it. For extra insurance, I heated up the sprocket with a torch but not so much as to damage the front main seal. I also tapped the key down with a punch in case it was sticking up and binding on the sprocket. No go. The puller managed to severely bend the ring on the back side of the sprocket. When I took the puller off, to my dismay, the ring on the back of the sprocket was now not only twisted but detached from the sprocket itself. I was quite annoyed and couldn't leave this on the car in this state. Further more, now my timing mark (which was on this ring), was no longer valid. Even further more, this ring being loose between the engine and sprocket made it completely impossible to get the puller on anymore. My replacement sprocket off of a previous year 3A-C engine appears to be one solid machined piece whereas the one on my car seemed to have the ring that has the timing mark on it just pressed onto the sprocket somehow. If I had known that, I wouldn't have put a puller on it but I was going off what my replacement sprocket looked like.

In the end, I managed to cut the ring off with some side cutters and installed the belt anyway even though this ring probably is also important as a guide to keep the belt in place. Since my timing mark was now removed and destroyed, I used my replacement sprocket as reference to set my engine in time. I feel bad if anyone else other than me has to replace a timing belt and wonder where the hell the timing mark is lol. If anyone has any suggestions on how to get this stuck sprocket off, please let me know.


Replacement sprocket next to the ring that would normally be a part of the sprocket that I had to cut off of the crank. The one I cut off is clearly thinner and was not machined as one piece as it was on my replacement sprocket (which came off a one year older engine).
2020-04-30 19.47.51.jpg
2020-04-30 19.47.43.jpg
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'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: Stuck timing belt sprocket

Post by Petros » Thu Apr 30, 2020 7:52 pm

wow, looks like you had quite the ordeal with that one. I have found that tapping the sprocket with a hard plastic hammer usually breaks it free. after soaking in penetrating oil, heating it up, and than giving it a number of hard whacks, it usually can be made to begin to move off, a bit at a time, until you can get something behind it, like a lever or puller jaws. only once, when there was a lot of rust on the nose of the crank, did it take much more than that.

often it can seem really stuck, but one it takes several hard impacts, it will start to move off. Most of the time, after a few good whacks, I can wiggle it off by hand. Even on ancient Tercels that may have never had it off before. I seldom have to use a puller doing it that way.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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Yaut
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My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Re: Stuck timing belt sprocket

Post by Yaut » Thu Apr 30, 2020 8:16 pm

Petros,

Thank you. I suppose my main issue was the lack of room in the engine compartment. I of course had removed the radiator but perhaps I should have removed the radiator support to gain more room. I found that I barely had room to swing even a small hammer although I did manage to tap on it quite a bit to no avail. Perhaps I will just leave it they way it is until further repair is required. It seems as though when the car is running, it tries to pull the timing belt towards the front of the car and not back towards the engine so the fact that this ring is missing probably doesn't cause any harm. The sprocket was quite worn but not to the point that it should slip a tooth or anything for quite some time. I think it more likely that I will need replace the front seal at some point which will force my hand.

Diarmait
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
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Re: Stuck timing belt sprocket

Post by xirdneh » Thu Apr 30, 2020 9:22 pm

Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Yaut
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Joined: Thu Jan 10, 2019 5:34 pm
My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Re: Stuck timing belt sprocket

Post by Yaut » Thu Apr 30, 2020 9:43 pm

Nice! I'll make one
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Stuck timing belt sprocket

Post by Petros » Fri May 01, 2020 6:18 pm

the timing belt sprocket and drive gear tent to get pitted when people think it is "cool" to keep the over off to show off the timing belt. it is not just foolishly dangerous to work around an engine when running like that, sand and gravel will pit and wear away the metal parts, and erode away the belt. best find a replacement when you have a chance, a pitted gear may wear out a new belt faster.

I just removed the radiator and all the normal parts to access the belt, and find there is just enough room to swing a plastic hammer to strike it hard enough to break it free. I can only get one angle with an outward blow as I recall, and it is a rather obleak angle at that, but it does the job. Even striking it side to side should help break it free. the only exception is if there is a lot of rust in there, which normally does not happen. or if some fool used loc-tight on it, or some such adhesive. a good puller will do it, which is always a last resort for me.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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