onefiend wrote:Jon11582 wrote:A timing chain (found only on the 2AZ) should last the lifetime of the engine, and will not break from regular wear and tear.
they put a timing chain on the 2GR also. I think all modern engines has timing chains now.
Thats true. I guess that makes the 3MZ a non-modern engine. All the other current Toyota car engines are chain driven now I think, even the lowly xA and Yaris.
The only passenger car engines left are the 3MZ (Solara/Highlander/Sienna) and the 3UZ (GS430/LS430)
Both will be gone soon enough.
Yes our engines are non-interference. Under normal circumstances, if anything breaks, the engine will halt and wont cannibalize itself. But you will be stranded on the side of the road on Monday morning while getting to work in the winter with no heat while it takes AAA 5 hours to get there only to tow you to a gas station garage with no way to get home without calling a cab and waiting another 3 hours, then decideing to walk home but since you have no sense of direction you ended up walking two hours the exactly wrong way when you were only 2 miles from the apartment to begin with.
But the engine will be OK.
EDIT -
FYI, for those that dont know, an "interference engine" means that the valves, when open, occupy the same physical space as the piston when hits top dead center. Normally the valves will always be closed when the piston hits top dead center, except of course if the timing is off If the valves are open and the belt breaks, the piston will keep moving (due to momentum) and crash into the open valves, breaking the valves and/or pistons, if not other things. Non interference means that even if the valves are open and the piston hits top dead center, they still dont collide.
Now this is interesting:
Reading
here
5SFE = Belt/Non interference
2AZ = Chain/? (Its chain driven, so interference shouldnt matter as much)
1MZ = Belt/Non Interference
3MZ = Belt/Interference
That means, if you have a Gen2 V6, change your timing belt on at least the recommended intervals or youll be replacing your internals (Valves and possibly pistons) if the belt snaps. I guess thats the price of displacement, that extra 10% of displacement came from a longer stroke that occupies the same space as the open valves do.
I know this is the Gen1 forum, but maybe we should let the Gen2 V6 guys know this...if they remember when they hit 90K. I think its absolutely stupid to make a belt-driven interference engine in this day and age, but I guess that was Toyota's way of getting "cheap horsepower" out of the 3MZ until the GR engines were ready for prime time passenger car application. I predict we're going to be seeing alot of dead gen2 V6's in a few years from timing belt neglect, and people will be crying foul about Toyota reliability.