Help with 3VZE

Doug,

I think that you may be anticipating problems that you don't yet have. Get it back together; if you still have problems research further at that point.

To address specific points in your post - you didn't remove the spark plugs to check for TDC did you? Sorry for stating the obvious...

You could have sticking or bad valves. In any case it'll be hard to tell whether anything is wrong with the timing belt off. That's a lot of miles/km on the clock I might add.

No, you didn't damage anything. The instant the belt breaks, the engine stops running.

I agree, the cam actually creats a lot of drag to engine rotation my hand and this is normal plus you may have several valves open depending on where cam stalled. I would strongly suggest that you replace idler pully/bearing while in there and consider replacing the water pump too while it is apart if you plan to run it for a while yet.

----------------- The SnoMan

I would agree with replacing the water pump while you are in there, I had to change my belt after my water pump froze up on my 92 pickup. I would be a little concerned about the lack of compression, mine was difficult to turn with the belt off. Remember there are two triangles on the cams for each bank which represent top dead center.

It depends on were his cams stalled at as they could have stopped were there is at least one valve open in each cylinder because the cams are no longer sync'ed

----------------- The SnoMan

Not true, the crank would still spin with the clutch disengauged or over

40MPH if auto. The valves may stop workign straight away but with pistons still travelling up and down out of sequence to valves, serious damage could occur if the valves touch the pistons.

Yeah, but the 3VZE ain't an interference engine, so the pistons can freewheel as they please -- they're not going to touch the valves.

With the clutch disengaged the crank would not spin. I'm sure you meant clutch "engaged," that is to say, foot off the pedal and transmission in gear. In any case, as Andy pointed out, the 3VZE isn't an interference engine.

Per the original post, Doug got the truck stopped as quickly as possible; with any luck had the presence of mind to put the trans in neutral but in any case any wear or damage would have been minimal to nonexistent.

I'd assumed that I didn't need to spell out that I was replying that Doug didn't damage anything, given the particular engine and the circumstances of the failure.

If you're going to have a timing belt break at the top of Pikes Peak and insist on coasting to the bottom of the mountain with the transmission in gear, you might destroy the engine through lack of lubrication. However, Doug didn't so I saw no reason to qualify my statement.

-- Mike Harris Austin, TX

My point wasnt towards the damage side as Im aware that the 3VZE isnt an interference type engine but I was mearly pointing out that the crank will still spin when the belt breaks. Which was what I repost to. :o)

According to the dealer mechanic that did my head gasket, this is not a problem in Toyotas (unlike Hondas) because they don't design the engines with an overlap (of travel) of the pistons and valves. He showed me this when he had the engine apart, and it appeared to be true.

As stated you probably have at least one valve open in most every cylinder since they stopped where they were when the timing belt broke.