How bad is this going to be??

[Oliver4R]

1997 4Runner 3.4L V6 - 140K miles - I just found this problem last night while trying to figure out why my 4Runner is lacking power: While checking if my timing marks line up I found that the crank pulley moves at least 15 degrees before the timing belt moves. I don't even know how that's possible? I'm surprised it still ran at all.

These two pictures show how far the crank pulley will go before the cams start turning:

That's probably 20 degrees easy looking at the pictures now. Anyone have any theories on what this could be? There are no signs of metal shavings under the timing cover, and the pulley didn't wobble so hopefully there isn't too much damage.

I thought I could just maybe tighten the crank bolt to spec (184 ft/lbs on the 1997 I believe) but how would I know if it's lined up with the key? I need to get this thing on the road again asap and I'm worried this may not be an easy fix...

 

[wslytoy]

Ok at TDC, are the marks on your timing belt not lined up w/ your cam gears correctly?

 

[psraff]

Just finished my TB... I'm far from an expert, but all I can figure is the key is worn, or missing.

 

[JZiggy]

Broken key. Need to pull the timing belt drive pulley to replace. Get new harmonic balancer and new crank bolt. Sorry.

 

[repo]

https://m.youtube.com/watch?v=KT0TTDeCFzw

https://m.youtube.com/watch?v=9wlvYaMNivs

 

[thegipper]

Bet the crank gear around the key slot is worn like in the videos. At least, that's what makes sense to me.

 

[Oliver4R]

https://m.youtube.com/watch?v=KT0TTDeCFzw

https://m.youtube.com/watch?v=9wlvYaMNivs

Thanks, that’s exactly what mine is doing. Will start stripping it down when I get time in a few days.

 

[Oliver4R]

Thanks for the info especially the video links. That was super helpful. Not the exact news I wanted to hear but I’m excited to have hopefully found the problem. This beauty will be running like new again in the near future.

 

[Moonbandit]

Thanks for the info especially the video links. That was super helpful. Not the exact news I wanted to hear but I’m excited to have hopefully found the problem. This beauty will be running like new again in the near future.

Could you please elaborate on your symptoms?
It runs and drives? but just lacks power?

I have an old runner that just is bogged down - everything on it runs well, just has this insane lack of power when I hit the gas - though when moving it moves more or less fine. I've done all the usual fixes minus checking the TB

Thnx -- and good luck on your runner

 

[JRZEE2000TR4LTD]

Thanks for the info especially the video links. That was super helpful. Not the exact news I wanted to hear but I’m excited to have hopefully found the problem. This beauty will be running like new again in the near future.

Hopefully the keystock and /or the harmonic balancer is the only problem. If your crankshaft slot is compromised or the crankshaft end is worn then you have MUCH bigger problems. Looks like you might have caught it in time since it's not spinning on the crankshaft. Curious to see what it looks like once you get that balancer off.

 

[Oliver4R]

Could you please elaborate on your symptoms?
It runs and drives? but just lacks power?

I have an old runner that just is bogged down - everything on it runs well, just has this insane lack of power when I hit the gas - though when moving it moves more or less fine. I've done all the usual fixes minus checking the TB

Thnx -- and good luck on your runner

Thanks and it is just doesn’t have any power until it hits about 3000rpm and then it gets a bit better. It runs fairly smooth but feels like it’s pulling on 3 cyclinders instead of six. It sort of sounds like what yours is doing. Easy thing to check is to remove your timing belt cover (5 or 6 little bolts) and disconnect your rad hose too remove the timing belt cover. Then turn the crank shaft pulley clock wise by hand (it takes a bit of force) to line up the timing marks on the cams at their marks. Then turn the crank shaft pulley counter clockwise to see if there is any play. I also pulled my fan off (4 bolts) to give me more room. Put the bolts back in after removing it or the pulley and belts will come off as you turn the pulleys.

 

[Oliver4R]

Hopefully the keystock and /or the harmonic balancer is the only problem. If your crankshaft slot is compromised or the crankshaft end is worn then you have MUCH bigger problems. Looks like you might have caught it in time since it's not spinning on the crankshaft. Curious to see what it looks like once you get that balancer off.

I hope so too because the engine has pretty low mileage and runs smooth and quiet. Would be a real shame to have to turf it or rebuild it. Don’t think I even have the time or patience for that right now. Would probably have to sell it as is. I’ll post pics once I have it apart this week.

 

[Oliver4R]

There’s my problem!

 

[Oliver4R]

Surprised to find the shaft in good shape! Phew...

 

[Mark_BC]

Just like in the video. Good thing to note.

 

[Hockeyjock]

Wow you got lucky it do any further damage.

 

[nissanh]

Looks like you'r runner came with VVT-i

 

[jsukey]

Consider yourself fortunate that the key held on! I went through this a few years ago. Ended up replacing the entire engine. Just didn't make sense to completely tear down an engine to replace the crank. I came out better in the longrun price wise, as well as longevity wise.

 

[Oliver4R]

UPDATE: Problem is fixed!!!

I installed a nice used ($30) crank timing gear and woodruff key, new timing belt, water pump, pulleys, and it fired right up and has much more power than any of my previous four 3rd Gens. At least that's what I'm telling myself... Haha!!! Glad that part is done...

I'm taking her on a 6 hour round trip to the mountains/lake this weekend. That should be a good test. Have a great weekend everyone!!!

 

[AntleredRuin]

So the question is how the hell does something like that happen? Someone not torquing the crank bolt to spec?