Main Belt Tensioner

The main belt tensioner was an idea I grabbed off a member on the Ausmini forums. What people had done previously was purchase a belt that would fit around the main crank and the water pump and slip it on, meaning it wasn't easy to get on or off. The pulley used by the Ausmini member Amos is from the AE92 Toyota Corolla's air con, but after calling up several wreckers who weren't interested in small business, I was informed by my friend Alan that the idler pulley from the Nissan SR20 engine was the same 4pk belt.

Once purchasing one of these from KYP in Welshpool for $15 I took it back to trial fit it. The bad news was that the pulley was definitely too big (close to 90mm) for the space I had to work with, although the AE92 Corolla used a smaller 69mm pulley. So I ended up ordering a brand new AE92 Nuline replacement pulley with bearing from Coventrys which sat perfectly in the idler bracket from the SR20. The good news was that KYP had sold me the idler pulley and whole bracket that it was attached to. I was able to cut the tensioning part off with a grinder and use that instead of recreating something else.

The next part was attaching the bracket to the block of the engine. This was simply done by using the two bolts on the back of the block where the layshaft bracket was mounted and just bolting on top of it. I did think of welding it to the layshaft bracket but it would be more convenient having them separate. After I held the pulley bracket in place with an old Glanza belt, I could line up the 3 pulleys (main crank, water pump, idler tensioner) and tack weld the brackets together.

With the bracket attached and self supporting I tested out the tensioning of the idler pulley which didn't work as well without having a belt that fit. To measure which belt would work I used a piece of string around all pulleys with the idler at its minimum to maximize the tensioning of the idler pulley. The belt I think ill be using is a 4PK0705, but I'm yet to try this as I'm working away at the moment.

This is what was created, but still needs to be cut down and properly welded.