4.0 chain break

My timing chain broke this morning. Not sure on damage. It has 230,000 miles. Any suggestions?

 

I don't know whether this engine is an interference design or not. It probably is. If so, you likely have damaged valves. With that many miles, I would look for a lower mileage used engine and call it a day. If the valves escaped damage, you could replace the chain and gears.

 

It isn’t an interference engine.
https://www.toyotanation.com/threads/tacoma-4-0-v6.147979/

But there still could be gear, guide, and timing cover damage.
You’d still need to pull the timing cover at a minimum to see “what’s damaged”.

 

Pretty sure it is just going by the compression ratio. Also 4 valves per cylinder right??@Torspd will know for sure as he’s had several apart

 

Typically, it is the valve that smacks the piston on an “interference” engine. (Not referring to valve float here)
At least that’s my teaching. (I did own a Honda)
Anyways you are most correct in saying “Torspd will know”.
That guys is a wealth of information on these engines.

 

@Torspd

 

I’ve found conflicting info.
This indicates it is Not Interference
https://www.tacomaworld.com/threads/interference-or-non-interference.39539/

This says it Is
https://www.tacomaworld.com/threads/fj-cruiser-owner-needs-help-with-4-0l-pics.96989/page-4#post-1898426

I guess we’ll have to wait on the guys that really know?

 

With high compression you typically also have a smaller combustion chamber necessitating the interference design which is why a brought that up. And I didn’t mean valve float but that the intake and exhaust valves could potentially (again, not sure 100% on this engine) hit each other if the secondary timing chain is also kaputt.

 

You need to remove it and tear it down. Or simply find a low mileage used motor. Start phoning wreckers and make sure to get some kind of warranty.

 

Are you sure that the chain is broken?

I'm not saying that it isn't, but in my short lifetime I have never seen a chain actually break. Stretch and slip a tooth yes, break a chain no.

 

Tacos are non interference. Thats one reason I prefer them. Your motor was probably not damaged. Replacement of the chain should get it back to normal.

 

In case some are following this thread, The OP posted he is looking for a donor engine.

https://www.tacomaworld.com/threads/4-0-motor-swap.710935/

Looks like the chain jumped timing ( not broken ) and damaged his engine...

 

Any pics OP?

 

Right, I've read conflicting things too, and I don't have first hand knowledge about this. That's why I just proposed it as something to consider.