March 6, 2014
On and on………
At the beginning of March in a seemingly endless winter, here we are making parts and getting cranky.
A few processes and order of operations got changed around and it seems to have streamlined the machining process a bit. It is always interesting to go from a fixture plate to a tilt table to the lathe and then to a rotary table, all in the span of a few hours. We have included a few more photos to show some of the steps not specifically talked about earlier.
The big pucker moment was when I set it on the lower end to check the fit. Now this can’t be done until nearly all the machining is completed as there needs to be clearance round the base of the cylinder to miss the fins and case recess of the 999. So with over 9 hours of machine time invested already, the initial test occurred. Imagine the awful feeling in your throat (among other places) when the cylinder went down and didn’t sit flush on the locating dowels. Now imagine the chagrin when you realize you have put it on backwards. For cryin’ out loud! Reversing the cylinder yielded the desired results. Phew!!
After all the dimensional machining was completed, the finishing needed to be done for good appearance. This takes another 1 ½ hours, with most of it handwork. As you can see, they look a lot alike, so much so that we need to stamp appropriate identifying numbers on the parts to differentiate them. They are visibly a bit different, but tracing which one was which in the future is critical to let us know that the variations in the process were good or not. It is also part of the maintenance to know what goes on with each in the servicing process.
We also determined that the BIG blower will fit in the V of the 999 with careful attention to intake manifolding. There will be photos as this project takes shape. The next step is a complete mapping of the left side of a 999 engine case, including crank, half-time shaft and output shaft locations (in addition to every screw and locator dowel as well). I can assure you this will happen in the dead of night or very early in the morning before the phones and questions begin. It is a rather imposing powerplant with the blower sitting there looking somewhat threatening.
Well, off to the back to build a customer exhaust and try to stay warm.
April 8, 2014 Cylinder fun still
Having received the ductile iron sleeves, setting up the billet cylinders was the next step. This required boring and counterboring for the step in the sleeve. These sleeves differ from conventional design in that they are thicker for the top inch to counteract the distortion that accompanies the high combustion chamber pressures encountered in high output motors. The extra thickness reduces the distortion and helps the cylinder stay rounder for a better ing seal and thus more power and less blowby. This also helps keep the crankcase oil less diluted in a nitro-powered platform.
A few compromises are always the order of the day in any project and the trade-off between the outside diameter of the sleeve, the thickness of the snout of the sleeve and the flat area surrounding the boundary is a balancing act that few besides the top fuel cars need to consider. The clamping force of the o-ringed head gasket area on the tis boundary area needs enough bearing surface to keep the sleeve from being crushed into the aluminum, dropping down, reducing the clamping force and allowing for a blown head gasket. You may have seen this on a top fuel dragster, attended by a flash of green from the burning of the copper head gasket. Not good.
Well off to the mill, setting up a .006” interference on the main outside diameter and a slight drag fit on the flange.
Once the machining was done, sleeves in the 30 degree outside air and the cylinder in the 350 degree oven. When 20 minutes passed, you run up the stairs with the sleeve while Nick holds the cylinder with special gloves and you carefully guide the sleeve in and drop it in place, being careful to not have it bounce back up and stick as the cylinder cools and it grips the sleeve. Into the press to hold it and on to the next one.
Relieving the sleeve for the dowels and stud clearance is next and after that, boring honing and o-ringing.
Now that the testing on the turbo dragbike is basically done we will have to settle for a 260 hp platform. Wiring in the 2-step launch control, the dragslick with a new gear ratio, slider installation and a plenum shroud with a bit of ballistic Kevlar in it is the precursor to the first test date tentatively set for April 27 at Byron Dragway. Hopefully it won’t be snowing.
While this doesn’t appear directly related to the Bonneville turbo project, the Motec conversion and the billet cylinders will allow a better ignition control and ring sealing for the nitro 749 going to the salt.
While the time until we head west may seem like a short forever, the amount of development and testing, combined with the necessary preparation will make for a surprisingly short span of days. One step leads to another and must be completed to allow for the movement forward to the next.