So a few days ago I discovered the engine cradle I built had an issue - the engine was sitting two low relative to the subframe resulting in the differential being too close to the engines front sprocket which in turn would result in a very short chain and poor ground clearance.
One approach would be extending the current cradle by adding in the required extra metal but the question is how much higher did the engine need to sit and would I be happy hacking the current cradle around.
I decided to start again and take the opportunity to build a better cradle. I was never happy with the look of the first one anyway and the overall finish is still important even if it was functional.
Not having a finished install to hand or knowing anyone with one I couldn't simply ask someone to measure their setup so I started studying photos and discovered that the front mounted oil cooler bolt was approx 5mm lower than the top of the front subframe cross-member.
I fashioned a plinth for the engine to sit on using scrap wood and window fitting packers that come in various thicknesses (1mm-6mm) and have proven very handy. I figured I needed the engine to sit 30mm higher than the lowest part of the subframe. I also picked the front of the engine up slightly (an extra 6mm) to improve clearance on the cars front cross panel.
I found the front upper engine mounts were a good place to start with the new fabrication. I was happy with the design on the old one so I cut some tube to the same length and tack welded some 2mm washers onto them. The bolt in the above picture was used to hold the washer in the correct position and acted as a ground for the welder.
The main cradle structure is made of a back-bone that spans the engine from left-to-right. It's position is critical to ensure all the other struts and brackets go in the correct place. On the previous cradle I had a gap that was too big between the steel and the engine which caused clearance issues when the throttle bodies were fitted. This time I made sure I positioned it lower and I checked the throttle bodies before welding up.
I cut the steel pieces using a metal chopsaw. The sizes were approx the same as the last time although the design is different this time which I had to take into account.
I used a 20mm hole saw in a drill press to cut the holes in the end of the box section.
A wooden jig was built that is the exact width of the R1 engine. This was used to ensure everything was held square and in the correct position during welding.
I managed to salvage the lowest part in this picture from the old cradle. It wasn't much but saved me from having to fabricate brackets again. The "ribs" are new and fit much better than the last one, partly due to using smaller 20mm box section where the rest of the cradle is 25mm. I also changed the angle of the cuts to 30 degrees and the revised back-bone angle helped.
The right-hand upright was tackled first. It was very tricky due to the various angles of all the intersecting pieces. The point it touches the subframe mount is at different angle on all 4 sides of the box section.
The mount onto the cradle back-bone was achieved by drilling offset 20mm holes in the box section so that a piece of round tube would be parallel to the back-bone once installed in the correct position.
The left-hand upright tacked into place and the bulk of the cradle is almost finished. I have got to add a supporting piece to the left-hand upright and I have lower mounts to add once I am happy with the differential position.
Next job is differential mount.