I am new to this site and looked through some of the threads but failed to find what i was looking for. I was driving my civic home from work when it died with no warning. After pushing it home, i found my timing belt had broke. I know that a few engines, if the timing is off, the pistons will smack the valves causing the need to replace the head. Is my engine one of these engines (i know there is a term for this but i cant think of it)? If not and i can just replace my timing belt and put it back in time, do i need to replace my tensioner pully? my civic has 233k+ miles on it and im pretty sure that the timing belt has never been replaced. my uncle gave me the car and has no mechanical skills at all but im an engineering student and am very mechanically inclined, im just used to working on chevy 350 engines, not honda engines... at least not the internals of the engine. please help.

 

It is an interference engine which means that valve damage is possible if the belt breaks. But sometimes you get lucky and the valves are not damaged. If you can do the work yourself, the simplest way to tell is to put a new belt on and start it up to see if all cylinders still work. Make sure the tensioner and the water pump are not seized up. They certainly should be replaced with that many miles but for now just put a new belt on to see if the engine is OK then you can change the tensioner and water pump.

 

ok thanks for the reply. im a college student and i dont have many tools so my dad and uncle are bringing all the tools down next week so we can work on it. would it be a good idea to see if i can turn my crank gear to make sure nothing is bent? if any valve is bent, the crank should be extremely hard or impossible to turn right?

 

Set the crank 90 degrees off of TDC (all the pistons will be out of the way then) and then it's OK to turn the cam around and around. Make sure the rocker arms go slack but not too slack (which would mean either the valve doesn't come all the way up and / or a piston hit the valve and bent the rocker arm).

You could do a leakdown test with the belt off to check the valves. Prevent the crank from turning so the air pressure doesn't move the pistons.

 

im not sure what a leakdown test is but im sure my uncle does, he is a mechanic. thanks for the help.

 

If my valves are bent because of the pistons, would the pistons most likely be messed up as well? if so, would it be cheaper to buy a new engine/car? like i said, the car has 233,xxx miles on it and is in ok shape.

 

typically (or at least the cases I've heard of) the pistons don't take the damage. The valves do. It might be cheaper to buy a motor if the rest of the car is in decent shape. best bet would be to get the head rebuilt (as far as price goes anyway)

 

Leakdown test is where you use the spark plug hole to fill one of the cylinders with compressed air at about 100 psi and see if it leaks out. Many compression tester sets can do it by connecting to the shop's air compressor.