3 Cyl Interference Engine Debate

The offical workshop manual says that a piston would strike a valve if engine is turned over without its belt on. Gates Belt Co. rep says it won't. Anybody know for sure?

well in the past I have found that they are a interference motor
JT

It really depends. Technically, a non interference engine can strike a valve if the RPM's are high enough when the belt breaks.

With a Metro, the exhaust valves are usually due for replacement at around 100,000 miles of service in my opinion.

I went thru this conversation a year or so ago on this forum.

As I remember, it was concluded that the 3 cyl Metro engine is non-interference.

However, if you have the Head off of the engine, it should be a simple matter to
do some measurements of how close the piston gets to the top of the Block and
how far down the Valves travel when the cam shaft is turned.

Then add the thickness of the Head Gasket all compressed between.....

No?

Anybody ever done that while the Head was off?

We could solve this entire controversy once and for all!

Same for any engine.

DoctorBill

After breaking a timing belt at 75 MPH on the freeway, I can definitively state that the 95 3 cylinder Suzuki engine is a non interference engine. Replaced the timing belt, aligned the timing marks, and drove away!!

The three cylinder is definitely not interference. Four cylinder, some are some aren't, depends on which of the four different heads you have. Manufacturer puts that warning in every manual just to be safe.