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.

Hi. Just wondering if anyone can tell me the out side diameter and wall thickness of the prop drive shafts used on most popular 100 HP engines with reduction drive eg. Rotax

Subaru EA81

Hi there. I to have decided to power my future kit aircraft with the Subaru EA81 engine after much research and indecision over the power plant. Like others on this forum,I looked at the Rotax 912uls 100hp. Great engine, but out of my price range. Jabaru 3300, same. I wanted around 80 to 100 reliable horse power.

The Subaru has a proven record for reliability as well as the following .

simple design .. one piece crankcase and cylinder assembly...no leaks from cylinder base gaskets

push rod engine meaning less complicated......parts are still available at a reasonable cost.......the parts needed for reconditioning are in some ways superior than the original because of advances in production techniques and materials (gaskets,pistons and rings and bearings). This engine has less bolts holding it together than almost any other engine i have come across, meaning that it goes together really well and is easy to maintain.

If anyone is interested,I can provide a step by step record of my engine from the strip down to the final completed item with accompanying photos on this thread