[Nothern Toyota]

Hello Toyota Nation.
My almost 20 year old Tundra 4.7 failed today. It started normally but idled a bit wierd then shut down and failed to re-start during cranking. I could hear that the compression wasn't normal when it turned over. A random misfire and camshaft sensor code came up. After referring to a dealership it was determined that the timing belt failed by opening the passenger side cover just in front of the valve cover.
My main concern all along was the rubber timing belt which was changed twice before at 95 then again at 210 thousand kms. I currently have about 280 thousand on the old truck.
I'm curious if any other owners had a similiar type of timing belt failure and if it caused damages to pistons or valves? I want to fix this but my dilemma...is it worth it if there is further damage to cylinder and head parts.
Thanks for any reply.

 

[sdspeed]

I believe that's considered a interference motor. I've seen pics of belts that broke with 50k miles on them and others that were fine with well over 100k on them. That being said you won't know the type or amount of any damage until you take it apart. You might want to try a borescope 1st to get a general idea, but the best way is to pop the heads off. It really doesn't have that many miles on it. I guess it comes down to the condition of the rest of the truck. No need to put a fresh engine in a tired shipping crate

 

[Nothern Toyota]

Thanks sdspeed , I was hopeful since i had almost no wear or cracks the first 2 timing belt jobs that it would hold out to another 100K. Great idea, I will look into this tool before moving forward.

 

[sdspeed]

Might consider something like this, lots to pic from cheap. Some parts stores still have units they rent or loan out. Ya just need to see the condition of the piston and if possible the cylinder wall.
Some guys on the Corvette forum were able to twist ones like this around and get a glimse of the valves. Late model corvettes had a bad habit of dropping valves for fun,UGH!

LETSCOM Wireless Endoscope 2.0 MP HD Inspection Camera, IP68 Waterproof 5.5mm WiFi Snake Camera with Telescopic Stick Semi-Rigid Cable Wireless Borescope for Android & iOS Smartphone-11.5Ft: Amazon.com: Industrial & Scientific

LETSCOM Wireless Endoscope 2.0 MP HD Inspection Camera, IP68 Waterproof 5.5mm WiFi Snake Camera with Telescopic Stick Semi-Rigid Cable Wireless Borescope for Android & iOS Smartphone-11.5Ft: Amazon.com: Industrial & Scientific

www.amazon.com

 

[Sejmon]

unfortunately there are wear and tear cracks that we can't detect right away. We don't look under the hood once an hour. Cracks can appear suddenly on a run like yours.

 

[Sejmon]

I do, but I don't think it's that bad. If your master is a pro then he can save your Tundra

 

[Nothern Toyota]

After a few weeks considering if one should fix an old truck I took the plunge and changed the timing belt, water pump and tensioners on my Tundra.
Thanks to YouTube DIY videos.
After a few dramatic moments at start up I.E. failed ignition coil on cylinder 1 the old truck was back in service.
Thanks sdspeed for your idea on scoping the cylinders. That helped me to verify if any valves were bent or not.

 

[sdspeed]

Glad to hear it worked out.