Yanmar 6LPA-STP Timing Belt

[johnmurray]

I am in the process of arranging for a mechanic to replace the timing belt in my Yanmar 6LPA-STP engine. (I have only about 630 hours, but am approaching the seven year mark.)
In the meanwhile I have heard horror stories that the 6LPA-STP is an "interfering engine" and if the timing belt breaks the pistons and valves can crash into each other and badly damage or destroy the engine. Someone else said this is not true, a broken timing belt will stop the engine, but not cause any damage (unless you run into something). Apparently there is another model of Yanmar that does have the interfering engine, but it is not the 6LPA-STP.
Does anyone know the right answer to this question?

[Maid Marian]

The 6LPA-STP is a interference engine. I found out around 500 hours when the valves started hanging open and the pistons would slam shut due to lubrication issues with the valve seals. I was fortunate that no damage was done and the issue was repaired free by a yanmar service center. As far as timing belts go, I just repalced them after 10 years and 1400 hours. BTW, there was no signs of wear or cracking.

Good Luck,
Steve

[johnmurray]

I had my timing belt replaced to-day (7 years and 658 hours). It took the mechanic about four hours in total. He had to remove the forward hatch to facilitate access. The job was made more difficult because he had to remove part of the engine coolant system before he could remove the timing belt cover. The actual exhange of the belts was not difficult. As has been the experience of others, the "old" timing belt looked like new!
While he was at it he replaced the two drive belts. They looked due for replacing.