Cross Threaded Timing Belt Tensioner Bolt (1 Viewer)

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Glad you got it all figured out!
Anyone reading this in future: most O'reilly would lend you a thread chaser kit for free.
 
How's the helicoil repair holding up?
funny you should ask. Failed in February. lasted slightly less than four years and ~45,000 miles. Ultimately the tensioner didn't have full range of motion due to the helicoil, probably from user error aka me installing it. Eventually the belt got loose and rubbed until it jumped timing. replaced it with a timesert. wish i knew about the timesert the first time around! we will see how long it goes now. about ~320k on the clock now.
 
Darn it! Reading yours helicoil failed at 45K, is concerning. Failure in a 4.7L VVti is engine killer. Anyone been successful, repairing in place with time sert or such?

I'm doing a T-belt R&R in a 4.7L VVti w/265K miles. Found last guy in cross threaded tensioner pulley bolt during install. It felt strangely tight coming out, I'd hope just thread sealer. NOPE!.

I'm leaning toward replacing the oil pump. But I really don't want the extra 20 hours labor.

But, I see 3 issues with helicoil or time-sert or any that need drilling & tapping.
1) I see hole passes through. Which drilling and tapping, risk aluminum shavings going into oil pan.
2) Not alot a lot of metal in capture nut casting, would remain for strength after drilled and tapped.
3) Drilling the bore square, is problematic.

Oil pump housing, I've on the shelf. The yellow circle is the capture nut w/ bolt Tensioner bolt in it from viewed from backside.
Oil Pump (12).JPG
 
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Darn it! Reading yours helicoil failed at 45K, is concerning. Failure in a 4.7L VVti is engine killer. Anyone been successful, repairing in place with time sert or such?

I'm doing a T-belt R&R in a 4.7L VVti w/265K miles. Found last guy in cross threaded tensioner pulley bolt during install. It felt strangely tight coming out, I'd hope just thread sealer. NOPE!.

I'm leaning toward replacing the oil pump. But I really don't want the extra 20 hours labor.

But, I see 3 issues with helicoil or time-sert or any that need drilling & tapping.
1) I see hole passes through. Which drilling and tapping, risk aluminum shavings going into oil pan.
2) Not alot a lot of metal in capture nut casting, would remain for strength after drilled and tapped.
3) Drilling the bore square, is problematic.

Oil pump housing, I've on the shelf. The yellow circle is the capture nut w/ bolt Tensioner bolt in it from viewed from backside.
View attachment 3792282


Right now I probably have one good thread holding my tensioner in place, I put lock tight on it to keep it from backing out, but I don't have the warm and fuzzes about this holding up for another 100k miles.

Back story is 2 timing belt changes ago, I removed the tension bolt and it removed the aluminum for me (uh oh), I didn't have time to explore options so I put a slightly slimmer washer on the bolt, caught a couple of threads, lightly torqued it, and drove it for 130k miles no issue.

Yesterday I replaced the timing belt again, also needed to wrap the job up bc needed the truck today, but this time I only felt one-ish decent thread holding it in there, so applied the thread lock but I'm not sure about pushing this another 100k like I did last time.

I'd REALLY like to avoid all the work associated with removing the oil pump. That's just more work than I really want to bite off in my garage.

I don't totally understand the flow path for the oil, but if I did tap it for a new timesert or helicoil, and I was worried about shavings, could I pump some oil into the hole and open up the pan drain plug to get the shavings out?
 
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funny you should ask. Failed in February. lasted slightly less than four years and ~45,000 miles. Ultimately the tensioner didn't have full range of motion due to the helicoil, probably from user error aka me installing it. Eventually the belt got loose and rubbed until it jumped timing. replaced it with a timesert. wish i knew about the timesert the first time around! we will see how long it goes now. about ~320k on the clock now.

I'll have to research timesert, but you can test the range of motion before you button up right? I was tempted to install the tensioner with no washer to get a couple of extra threads of engagement but could tell it was gonna run against the back plate. Would the helicoil have worked otherwise? This is such a s*** repair to have to do.
 
Its just, the bolt that is in the hole. Seen from back side of oil pump. You must have threads sealer on the bolts threads. If it hold torque of 25ft-lbf, you're good to go.

I would not assemble T-belt tensioner pulley assy., without washer( spacer) on back side.

If tensioner fails. Being and 2002, engine will "likely" be okay. Meaning, valves not likely, hit piston. But be warned, Toyota states it is an interference engine.
 
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Alright, I did the repair tonight. It went exceedingly well.
I drained the oil and coolant. Removed fan, shroud, and radiator. Then I removed the crank pully and the timing belt cover down there, didn't have to remove any other components or covers thankfully. Remove the tensioner and pully bolt and then you can kinda wiggle the tensioner pulley out of it's slot and get to the pulley bolt hole.
You want the standard M10 x 1.25 kit here,

Once the pulley is out of the way, you can just zip tie the timing belt to get clearance to the hole.
PXL_20250329_214620032.jpg


Bc I removed the radiator, I was able to get my entire body into the engine bay from the bottom with my drill so I could keep a really close eye on keeping things square when drilling out the threads.

After drilling out the old threads, you use the kit's counter bore attachment so that the threaded insert sits right below flush and doesn't interfere with the mobility of the pulley.

Then take your time, and tap the threads. I HIGHLY recommend using the little extra "tap guide", a few bucks and really takes the pressure off when you're tapping the new threads, keeps things nice and square. (see it below on the tap). When you're done, you'll have new threads for the external portion of the insert with a nice counterbore for just below flush fit.
PXL_20250329_223811406.jpg



After that, put some high temp sealant on the external threads of the insert.

PXL_20250329_224229932.jpg

PXL_20250329_224744543.jpg


Once you've screwed in the insert, you'll have this new lovely set of threads, that can easily take the 25 ft-lbs you need. Considering where I'm at with mileage, this likely only needs to last me 1 more timing belt change at most. I've been very impressed with this kit. If anyone needs it, I'll sell at a great discount! lol.

PXL_20250329_225010347.jpg
 
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View attachment 3872783View attachment 3872782View attachment 3872781
A few extra pics of the thread sealer and the insert. And then pulley re-installed. Letting it all cure for 72 hrs before I introduce oil and heat to the threads.
This is timely as I had the threads came out of mine when removing the tensioner about an hour ago. Thanks for all the info, this is really helping with my panic.

How much would you want for the kit? Happy to take it off your hands and put it to use.

What did you do to flush the swag out of the oil post install?
 
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This is timely as I had the threads come out of mine when removing the tensioner about an hour ago. Thanks for all the info, this is really helping with my panic.

How much would you want for the kit? Happy to take it off your hands and put it to use.

What did you do to flush the swag out of the oil post install?
One thing I've heard to help capture the chips from tapping is to pack the tap flutes with grease - you have to back out and clean the flutes more often, but shouldn't be an issue for job like this. The grease helps make sure the chips stay in the flutes.
 
This is timely as I had the threads came out of mine when removing the tensioner about an hour ago. Thanks for all the info, this is really helping with my panic.

How much would you want for the kit? Happy to take it off your hands and put it to use.

What did you do to flush the swag out of the oil post install?
I actually sold it already to @cruiserbrett, but I only used one of the 5 inserts it came with. If he only uses one or two, maybe see if you can buy the kit from him. Keep passing it on haha.

And yeah similar to the suggestion I just used tap oil on all the parts and cleaned often. Most of the bits fell to the outside anyways, I did vacuum around the hole at the end too, I wouldnt worry too much about a few tiny aluminum shavings personally.
 
I actually sold it already to @cruiserbrett, but I only used one of the 5 inserts it came with. If he only uses one or two, maybe see if you can buy the kit from him. Keep passing it on haha.

And yeah similar to the suggestion I just used tap oil on all the parts and cleaned often. Most of the bits fell to the outside anyways, I did vacuum around the hole at the end too, I wouldnt worry too much about a few tiny aluminum shavings personally.
Awesome. Thanks for the additional info.

We need a communal tool kit for oddities like this. lol!!
 

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