1G Brand new and.... Kaboom.

[YawnY]

First drive this spring to do a base tune, had driven the car in the fall to get gas before winter then parked. Ran car in the garage afew times and had no issues. Set idle, timing, base afr. Go for a quick drive.
Did a small pull, hit 7 psi and then she let go.
Brand new gates belt, brand new tensioner. Less than 3 km on it.

You must be logged in to view this image or video.

 

[motomattx]

Since it looks still intact, as in the belt has not completely broke in two pieces, it would be important to look at the actual tensioner and the actual tension still on the belt to see if it is loose on the pulleys, that will tell more about what gave out on it, and then see if the tensioner is able to be pushed back in easier than it should be, of course even a bad one will be hard enough to push in that it wont be easy.

 

[GST with PSI]

I don’t say it often as someone will almost always try to argue with me about it, but I also have ran nothing but Gates auto tensioners for a long time.

In the 20ish years I've been dicking with the 4G63, I've never had a tensioner fail. I've probably ran more Gates tensioners than anything else. Additionally, if you tension the belt properly with the tensioner pulley, the belt will typically retain tension for a while even if the auto-tensioner fails.

If my car sits for any extended period, I'll crank it over a few times before I run it and double check the belt tension to ensure nothing crazy happened over time.

I've never been a believer in the OEM tensioners being any better or worse than the aftermarket stuff, and my personal experience has reinforced that fact for me.

@YawnY, take some pics of the tensioners (auto and pulley arm) installed when you get the cover off and post them up. That should be pretty telling as to what went wrong. Hopefully your head isn't too f***ed up.

 

[99dsmer4g63]

I opted for an oem belt as the standard gates belt is recommended for low boost/stock rebuilds. At least that’s what I’ve seen/heard. Oem belt isn’t much more money than the gates anyway. I do run all gates accessory belts though and water pump.

Sorry to hear about the failure. If @enriquez2000 is right about it being in the air I’m not getting mine out anytime soon.

-Daniel

 

[YawnY]

In the 20ish years I've been dicking with the 4G63, I've never had a tensioner fail. I've probably ran more Gates tensioners than anything else. Additionally, if you tension the belt properly with the tensioner pulley, the belt will typically retain tension for a while even if the auto-tensioner fails.

If my car sits for any extended period, I'll crank it over a few times before I run it and double check the belt tension to ensure nothing crazy happened over time.

I've never been a believer in the OEM tensioners being any better or worse than the aftermarket stuff, and my personal experience has reinforced that fact for me.

@YawnY, take some pics of the tensioners (auto and pulley arm) installed when you get the cover off and post them up. That should be pretty telling as to what went wrong. Hopefully your head isn't too f***ed up.

We ended up cutting the top of the belt, setting the engine so we could move the cams and doing a leak down test to see which valves could be damaged. #3 is forsure dead. I'll post pictures of rest.

 

[Mech Addict]

Big bummer!
I did my tbelt yesterday, so reading this morning about a mystery failure is just not reassuring. I hope you track down the cause so we all feel a little better.
From the one photo the one thing I noted was the color if the “thread” layer in your timing belt looks brown, where the accessory belts in the photo look white still. Could have happened as things were coming apart, but perhaps a clue to belt internal belt disintegration? Need more photos of the aftermath. Some fluid or other contaminant got on it?

 

[YawnY]

Big bummer!
I did my tbelt yesterday, so reading this morning about a mystery failure is just not reassuring. I hope you track down the cause so we all feel a little better.
From the one photo the one thing I noted was the color if the “thread” layer in your timing belt looks brown, where the accessory belts in the photo look white still. Could have happened as things were coming apart, but perhaps a clue to belt internal belt disintegration? Need more photos of the aftermath. Some fluid or other contaminant got on it?

No contamination. The engine maybe had 1 hour of run time.

 

[Mech Addict]

Hummm.
But can you confirm my observation: does that inner belt layer seem odd in terms of color?

 

[YawnY]

Hummm.
But can you confirm my observation: does that inner belt layer seem odd in terms of color?

We cut the belt to do a leak down test. That's why it's split.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[motomattx]

In the 20ish years I've been dicking with the 4G63, I've never had a tensioner fail. I've probably ran more Gates tensioners than anything else. Additionally, if you tension the belt properly with the tensioner pulley, the belt will typically retain tension for a while even if the auto-tensioner fails.

If my car sits for any extended period, I'll crank it over a few times before I run it and double check the belt tension to ensure nothing crazy happened over time.

I've never been a believer in the OEM tensioners being any better or worse than the aftermarket stuff, and my personal experience has reinforced that fact for me.

@YawnY, take some pics of the tensioners (auto and pulley arm) installed when you get the cover off and post them up. That should be pretty telling as to what went wrong. Hopefully your head isn't too f***ed up.

This is absolutely correct, even with NO autotensioner installed the engine should run fine until the initial belt stretch happens which should be a good bit of mileage if the belt was properly pretensioned and all pulleys were good and installed right, and by right I mean tightened down right and with the tension pulley in the proper orientation, I have seen tensioner pulleys swung in the wrong direction to pretension the belt and if this is done the pulley will work itself loose during operation.

 

[Justin DuBois]

Does the oil pump spin?

 

[YawnY]

Does the oil pump spin?

You got. Oil pump locked up solid.

Sorry for the late update. I have a 9 month old baby. I finally got into the garage. Tore the head off, found #3 made contact. Got to the timing belt and found the oil pump locked up solid.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[Dericsh]

I’m having a hard time seeing if you have a balance shaft belt on there or not, but I’m wondering if you had a delete with the no-groove stub shaft ?

 

[YawnY]

I’m having a hard time seeing if you have a balance shaft belt on there or not, but I’m wondering if you had a delete with the no-groove stub shaft ?

I never installed a balance shaft belt, it wasn't installed from when I bought the motor used and did a refresh so I never installed a new one. It was sitting in a guys garage for many years and came out of his 1g that rotted out.

 

[Dericsh]

I never installed a balance shaft belt, it wasn't installed from when I bought the motor used and did a refresh so I never installed a new one. It was sitting in a guys garage for many years and came out of his 1g that rotted out.

Im afraid you may find out you were running a shaft like the one in this post.

https://www.dsmtuners.com/threads/bse-a-look-at-stubby-shafts.468879/

 

[YawnY]

Im afraid you may find out you were running a shaft like the one in this post.

https://www.dsmtuners.com/threads/bse-a-look-at-stubby-shafts.468879/

Thankfully I have 2 short blocks that are bone stock. Never touched. I'll take the pump off one and inspect it and hopefully it's good.

 

[chrisman287]

I’ll definitely be checking the stubby shaft on mine while it’s apart. Wouldn’t have ever thought to.

This car spun a bearing but thing was damn near seized

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[99dsmer4g63]

Looks like you have junk stub shaft too.

-Daniel

 

[YawnY]

Did abit more digging today, looks like I have the right stub shaft but the main oil pump drive locked up. No clue why that locked up. I'm going to replace the oil pump assembly and check all the bearings.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[curt-s]

What brand was the case? Topline, ACL, or OEM?

 

[Justin DuBois]

Did abit more digging today, looks like I have the right stub shaft but the main oil pump drive locked up. No clue why that locked up. I'm going to replace the oil pump assembly and check all the bearings.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

Check the stub on the other gear.

Justin

 

[YawnY]

Check the stub on the other gear.

Justin

The stub in the other gear is the proper oem stub. I can go grab a picture of it if you want.

 

[Justin DuBois]

The stub in the other gear is the proper oem stub. I can go grab a picture of it if you want.

Lets confirm

 

[YawnY]

Lets confirm

You must be logged in to view this image or video.

 

[Justin DuBois]

You must be logged in to view this image or video.

Interesting - is that a chunk missing out of one tooth? It looks like the right stub. It does not look like the original point of failure.

 

[YawnY]

Interesting - is that a chunk missing out of one tooth? It looks like the right stub. It does not look like the original point of failure.

The gear looks brand new, I guess it's just the picture. No clue why the pump locked up. I'm stumped.