Timing belt replacement

[Guest rocketdriver]

Having read the tale of the recent forced landing which was possibly occasioned by a timing belt failure in an auto conversion engine, what is recomended?

 

Do we work out a replacement shedule based upon how many hours the Auto engine would have to run at 80 kph to get to (say 100,000 Km if that is the manufacturer's recomended shedule) or are there some more informed recommendations?

 

Would appreciate some advice as I am soon to take delivery of an imported aeroplane with an auto conversion motor driving the fan.

 

 

[will kirkbride]

Have had a bit to do with the Subaru EJ20 and EJ25 engines in the likes of the WRX and Forrester autos.

 

The problem as I see it is not so much the belt itself,rather the other items which are in the belt run such as the tensioner which is a bearing on a moving arm set up with a hydraulic finger to keep the tension. there is also the water pump and up to 4 other idler bearings in the mix.

 

I have seen the hydraulic push rod assembly leak oil and therefor lose pressure causing the belt to skip a few teeth with disasterous results as in the later engines, the valves will hit the pistons if the belt skips more than 3 or so teeth.

 

Also, this set up does not like to be wound in the reverse direction. this causes the tensioner to "back off" from the pressure put on it by the belt.

 

Hope this helps.