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2G Does the crankshaft gear need to be removed to adjust the timing belt?

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Chopperjeff

Probationary Member
14
1
Mar 13, 2025
Danville, California
I ask this as I see a discrepancy between what a trusted auto repair place has told me and what the person who screwed up the timing belt installation on my 1996 Eagle Talon is telling me.

Here's the question...does adjusting the timing of the timing belt involve removing the crankshaft gear?

I don't see why one would have to remove that gear in order to just adjust the timing belt, but then I know nothing about that procedure.
 
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The crankshaft pulley, outside of the timing cover, needs to come off.

The crankshaft sprocket, inside of the cover and “behind” the crankshaft pulley, does not need to come off to adjust the timing belt.
 
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It's a good idea even if you're not going to do the work yourself to have some idea what's involved. That was the idea behind me buying a FSM on day one.

You might want to review the old school VFAQ http://www.vfaq.com/mods/timingbelt-2G.html just so you have a better idea what's involved. Plus your less dependent on what others tell you.
 
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19Eclipse90 said:
The crankshaft pulley, outside of the timing cover, needs to come off.

The crankshaft sprocket, inside of the cover and “behind” the crankshaft pulley, does not need to come off to adjust the timing belt.
Click to expand...

OK, thank you!

Perhaps that is where the misunderstanding is between what the shop was telling me and what the guy who screwed up the timing belt installation was thinking.

Basically, months ago, a guy who does work on engines as a hobby replaced the timing belt on my Eagle Talon. After he did that, the car idled horribly but drove just fine. Somehow, he didn't think his work doing the timing belt caused the idling issue.
Anyways, since it was idling terribly, I had a shop adjust the timing belt. Sure enough, after that, it idled perfectly!

Then, coming home one day from work, the car died, and would only crank but not start.

I took it to back the auto repair shop that had adjusted the timing belt and was told that the crankshaft gear had come loose to the point it was just spinning and not engaging the belt. As a result, I now have two cylinders with bent exhaust valves!
Anyways, the shop told me that they did not touch the crankshaft gear when adjusting the timing belt. When I told them that the guy who replaced my timing belt also replaced the seals behind the crankshaft gear, he then said that he had to have removed the crankshaft gear, thus the issue was caused by him.

Perhaps I should be calling it a "sprocket" and not a "gear"?

Anyways, the car is back into the hands of the guy who screwed it all up in the first place. Yes, scary thought, but it seems I don't have much choice as otherwise, I have to shell out the money to the repair shop to redo the timing belt and fix the valves. At least the guy who screwed it all up is willing to fix it at no cost to me.
 
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Chopperjeff said:
OK, thank you!

Perhaps that is where the misunderstanding is between what the shop was telling me and what the guy who screwed up the timing belt installation was thinking.

Basically, months ago, a guy who does work on engines as a hobby replaced the timing belt on my Eagle Talon. After he did that, the car idled horribly but drove just fine. Somehow, he didn't think his work doing the timing belt caused the idling issue.
Anyways, since it was idling terribly, I had a shop adjust the timing belt. Sure enough, after that, it idled perfectly!

Then, coming home one day from work, the car died, and would only crank but not start.

I took it to back the auto repair shop that had adjusted the timing belt and was told that the crankshaft gear had come loose to the point it was just spinning and not engaging the belt. As a result, I now have two cylinders with bent exhaust valves!
Anyways, the shop told me that they did not touch the crankshaft gear when adjusting the timing belt. When I told them that the guy who replaced my timing belt also replaced the seals behind the crankshaft gear, he then said that he had to have removed the crankshaft gear, thus the issue was caused by him.

Perhaps I should be calling it a "sprocket" and not a "gear"?

Anyways, the car is back into the hands of the guy who screwed it all up in the first place. Yes, scary thought, but it seems I don't have much choice as otherwise, I have to shell out the money to the repair shop to redo the timing belt and fix the valves. At least the guy who screwed it all up is willing to fix it at no cost to me.
Click to expand...

The guy who did it wrong the first time has no chance of doing it right the second time

Do I even want to ask what brand hydraulic tensioner you supplied them with?
 
Upvote0
Chopperjeff said:
OK, thank you!

Perhaps that is where the misunderstanding is between what the shop was telling me and what the guy who screwed up the timing belt installation was thinking.

Basically, months ago, a guy who does work on engines as a hobby replaced the timing belt on my Eagle Talon. After he did that, the car idled horribly but drove just fine. Somehow, he didn't think his work doing the timing belt caused the idling issue.
Anyways, since it was idling terribly, I had a shop adjust the timing belt. Sure enough, after that, it idled perfectly!

Then, coming home one day from work, the car died, and would only crank but not start.

I took it to back the auto repair shop that had adjusted the timing belt and was told that the crankshaft gear had come loose to the point it was just spinning and not engaging the belt. As a result, I now have two cylinders with bent exhaust valves!
Anyways, the shop told me that they did not touch the crankshaft gear when adjusting the timing belt. When I told them that the guy who replaced my timing belt also replaced the seals behind the crankshaft gear, he then said that he had to have removed the crankshaft gear, thus the issue was caused by him.

Perhaps I should be calling it a "sprocket" and not a "gear"?

Anyways, the car is back into the hands of the guy who screwed it all up in the first place. Yes, scary thought, but it seems I don't have much choice as otherwise, I have to shell out the money to the repair shop to redo the timing belt and fix the valves. At least the guy who screwed it all up is willing to fix it at no cost to me.
Click to expand...
The guy offering to fix it at no cost is wrong and you should run away, fast. Done over a hundred timing belts on a variety of cars and never have I removed any sprockets, gears, etc.

With bent valves the head has to come off and be checked to ensure the integrity of the head, to include seeing if the head needs to be machined. Even if you do the work yourself you're looking at several hundred dollars minimum just in parts, gaskets, and machine shop fees. Take the car to a reputable shop to ensure the job is done right. If anything is cheaped out (not machining the head, reusing the head bolts or timing belt, using cheap parts, etc.) you are taking a serious gamble.
 
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Upvote0
CKOPOCT said:
With bent valves the head has to come off and be machined.
Click to expand...
This is not an absolute.

It needs to be inspected, the valves and guides checked, the flatness of both the head and block checked and machined as needed. If the surface RA isn't up to the spec for the head gasket to be used then the surfaces may need machining even if they are otherwise flat.

You can't put that material back so you should only remove it when required.
 
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steve said:
This is not an absolute.

It needs to be inspected, the valves and guides checked, the flatness of both the head and block checked and machined as needed. If the surface RA isn't up to the spec for the head gasket to be used then the surfaces may need machining even if they are otherwise flat.

You can't put that material back so you should only remove it when required.
Click to expand...
True. I should have said "sent to a machine shop to be inspected." Most heads I've done have had to be machined, so I errantly lumped it all in. I'll edit my post to ensure folks aren't misled. Thanks, Steve.
 
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If the sprocket was free spinning I'm expecting that the sprocket woodruff key is not installed or broken. I would strongly suggest dealing with a proper professional and doing a full look over of all of the components.
 
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chrysler kid said:
The guy who did it wrong the first time has no chance of doing it right the second time

Do I even want to ask what brand hydraulic tensioner you supplied them with?
Click to expand...
Yeah, that's the thing in that since he screwed it up the timing the first time, and refuses to admit he screwed it up tells me that he will most likely screw it up again.
It was damn near comical when I explained to him in a very logical fashion that since the car was idling perfectly before he replaced the timing belt, then idled like crap afterwards, plainly points to the timing belt work has caused the issue, he launched into saying "Well, if the timing was off, then it would be mis-firing and overall would run poorly when accelerating, which it wasn't doing".
I was quite literally left speechless! I mean, how can anyone be that stupid?

Then he seems to bounce around between saying that he's worked on machining heads before to then saying that only a reputable shop should do the head work.

My last text message to him was basically telling him that if he can show that the shop that corrected his timing belt adjustments are the ones that screwed up the crankshaft sprocket, resulting in the failure of the engine and bent valves, then fine, we will have the car towed back to them and have them repair it. However, that shop has assured me that they never touched the crankshaft sprocket when they adjusted the timing.

To top off all of this frustration, this guy has now had my car in his possesion for two weeks, and NOTHING has been done to it so far!

twicks69 said:
If the sprocket was free spinning I'm expecting that the sprocket woodruff key is not installed or broken. I would strongly suggest dealing with a proper professional and doing a full look over of all of the components.
Click to expand...
If I allow this guy to do the work, I do plan on taking it back to the repair shop that corrected his previous timing belt screwup to check that the sprocket is installed correctly.
 
Upvote0
twicks69 said:
If the sprocket was free spinning I'm expecting that the sprocket woodruff key is not installed or broken. I would strongly suggest dealing with a proper professional and doing a full look over of all of the components.
Click to expand...
Was just texting the guy who screwed up the timing in the first place, and he is claiming that in order to adjust the timing of the timing belt, the woodruff key needs to be removed. But that is not what I'm understanding from what I have read.
Then again, someone said this: "On my 2G, the crankshaft sprocket BOLT needs to come out otherwise there is no room to slide the crankshaft pulley off because of interference with the frame. It's one annoying thing between my 2G and 1G/GVR4 I have owned."
But is that required for just ADJUSTING the belt? The belt was already fully installed, and just needed its timing set correctly as it was off a tad.
 
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Upvote0
To adjust the belt you take it off and put in on correctly. That's how you do it.

I'm scratching my head thinking about how you would get the key back in if you tried that. Without it the crank sprocket is going to spin under load and since the belt and sprockets are toothed they only go on one way correctly.

You need to check the timing marks on each as you put the belt on making sure you don't leave slack in the belt between the previous sprocket and the current on. One important fact is that the oil pump sprocket has to be in the correct phase when the mark aligns. It can be out of phase and cause vibrations. The last thing is you need to adjust the tensioner arm and pulley correctly to apply the preload to the belt and take up the slack at the end. If you messed up with the alignment and left slack in the belt as you went around the sprockets it will show up here and the timing marks will no longer line up. If so you get to try again!

This all may seem daunting but it's really not after you done it one of twice.
 
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Chopperjeff said:
Which involves removing the crankshaft sprocket?
Click to expand...
Nope, you have to remove the crank pulley/harmonic dampener but the sprocket stays on the crankshaft.

crank pulley/harmonic dampener
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crank sprocket
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You may need to remove the crankshaft bolt to get the crank pulley off but it usually goes right back on until you ready to put the pull back on at the end. At that point you also need to torque it down.
 

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steve said:
Nope, you have to remove the crank pulley/harmonic dampener but the sprocket stays on the crankshaft.

crank pulley/harmonic dampener
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crank sprocket
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You may need to remove the crankshaft bolt to get the crank pulley off but it usually goes right back on until you ready to put the pull back on at the end. At that point you also need to torque it down.
Click to expand...
OK, thank you for all that! Much appreciated.
 
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To be sure there's no misunderstanding, the timing belt doesn't really get "adjusted." It's not like an alternator belt, where if it squeals you just tighten it and all's good, or your leather belt... where if you had too much cake you just back it off a notch. The timing belt connects the camshafts and the crankshaft together in perfect sync. When installed correctly all of the timing marks on the cam gears and the crank gear (sprockets) line up perfectly, and all slack has been removed (to factory spec), so there's no slop in the belt. The tension ensures the cams and crank stay in sync... that one of the cams doesn't "jump a tooth" - causing the system to no longer be in sync (or bend valves).

The shop that corrected your timing belt most likely lined the crank up to top dead center (compression stroke), then took the top timing cover off and looked to see if the marks on the cam sprockets lined up correctly. Noticing they were off, they took the belt off, lined everything up properly, then reinstalled the belt.

To change the timing belt you have to remove components to expose the sprockets (timing belt covers, crank pulley, motor mount...) so you can access the belt. But the sprockets stay on the car.

Changing the timing belt correctly on a DSM isn't terribly difficult, but it is more involved than many other cars. People who "work on engines" sometimes will just assume the 4G63 is just like any run-of-the-mill timing belt job, and end up not doing things correctly - like setting the tension. Not uncommon, unfortunately. But with a trusty Factory Service Manual at hand and DSMTuners app at the ready (plus tools and determination) you can do the job perfectly.
 
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The crank shaft sprocket only comes off to replace the balance shaft belt. Behind the crank shaft sprocket is the crank trigger plate which behind that has the balance shaft belt

If the shop corrected the timing, the timing was off to begin with, and it ran better afterwards, then it makes no sense to their excuse of why it stopped working. The easiest answer to both situations is that the first mechanic slapped a belt on there and it was off a tooth, the second shop corrected the belt being off a tooth, but the hydraulic tension on the belt was never set correctly by either shop

There are specialty tools that are 100% needed in order to correctly set timing belt tension. There is no chance either mechanic set the belt tension properly or ever touched the factory service manual for the timing belt procedure.

On 99% of cars with a timing belt there is no specific procedure. On Hondas and Toyotas you pull the grenade pin on the tensioner and the belt sets itself to the proper tension with no adjustment. The 4g63 motor has an adjustable tensioner pulley that needs to be clocked correctly to a set depth on the tensioner arm which is moved by a hydraulic tensioner

99.99% of shops will never do the procedure correctly. They don’t have the tools, and for their entire career simply eyeballing a timing belt works every time. The 4g63 isn’t one of those cars where you can just have a random technician eyeball the install

Don’t bring the car back to either shop. Do the job right, do it yourself. The only person who cares about doing the job correctly is you, the shop only cares about doing it quickly.

(Ok technically you don’t need the special tools, but let’s be honest most shops are going to under tension the pulley and then pull the grenade pin without thinking twice)
 
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chrysler kid said:
The crank shaft sprocket only comes off to replace the balance shaft belt. Behind the crank shaft sprocket is the crank trigger plate which behind that has the balance shaft belt

If the shop corrected the timing, the timing was off to begin with, and it ran better afterwards, then it makes no sense to their excuse of why it stopped working. The easiest answer to both situations is that the first mechanic slapped a belt on there and it was off a tooth, the second shop corrected the belt being off a tooth, but the hydraulic tension on the belt was never set correctly by either shop

There are specialty tools that are 100% needed in order to correctly set timing belt tension. There is no chance either mechanic set the belt tension properly or ever touched the factory service manual for the timing belt procedure.

On 99% of cars with a timing belt there is no specific procedure. On Hondas and Toyotas you pull the grenade pin on the tensioner and the belt sets itself to the proper tension with no adjustment. The 4g63 motor has an adjustable tensioner pulley that needs to be clocked correctly to a set depth on the tensioner arm which is moved by a hydraulic tensioner

99.99% of shops will never do the procedure correctly. They don’t have the tools, and for their entire career simply eyeballing a timing belt works every time. The 4g63 isn’t one of those cars where you can just have a random technician eyeball the install

Don’t bring the car back to either shop. Do the job right, do it yourself. The only person who cares about doing the job correctly is you, the shop only cares about doing it quickly.

(Ok technically you don’t need the special tools, but let’s be honest most shops are going to under tension the pulley and then pull the grenade pin without thinking twice)
Click to expand...
Thank you for your detailed reply!

I'm confused though when you said "the hydraulic tension on the belt was never set correctly". Even if it wasn't set correctly, how would that cause the crankshaft sprocket to completely fail to the point it was just spinning, and not engaging the belt anymore? Are you saying that the belt completely came off the crankshaft pully? However, they are NOT saying that it came off the sprocket and instead are saying the crankshaft sprocket itself has apparently come off, as if it wasn't tightened enough.

And, since they never touched the crankshaft sprocket when they adjusted the timing, they figure the fault is on the person who replaced the timing belt in the first place as he definitely did remove the crankshaft sprocket as he not only replaced the seals behind the timing belt, but he also replaced the balancer belt.

At this point I will just have to wait and see what the person comes up with who originally did the timing belt. Very unnerving as I think about the fact that he didn't set the timing correctly the first time, so what are the chances it will be done correctly the second time, but perhaps, hopefully, he has learned something and will get it right.

As for doing the timing belt myself, there is a zero percent chance of that happening as I am just not that mechanically inclined, and would have zero patience for it.

Anyways, again, thank you so much for the input.
 
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