Engine Bay Completion - Part 2

I jumped the gun with the title of my last post.... To really complete the engine bay, I have some more important tasks to complete such as:

• Welding up a custom fabricated aluminium external dry-sump reservoir.
• Install an oil priming pump.
• Wrap up the starter motor and coil packs in heat shielding.
• Re-install my shock tower bracing.

For the external dry-sump tank, I am using the space previously used by the battery (which is now in the trunk) as its new location. And seeing that this engine-bay panel had the typical rust associated with a battery leak in a previous life, I have cut out the rust to create a large hole in the spot where the battery tray used to bolt up to. This lets me extend the height of my external oil tank (downwards thru this hole) which gives me advantages in building a tank that efficiently removes air from my scavenged dry-sump oil. Here are some "in progress" photos.



I used a cardboard template to get the outside dimensions done and then added baffles from there. One of which I took a photo of.


















Here is a trial fit to make sure the hoses all worked together.

And here you can see how I've cut out the bottom of the battery tray to give the tonk some extra height. Plus include a convenient drain plug.

Never having built one of these things before I did so based on the following thoughts.....

• Ensure the oil tank outlet is at the lower-rear of the tank (so oil naturally moves towards this outlet under acceleration rather than away from it - and then risk sucking air).
• Baffle the tank (horizontally) so that oil can't slosh up the back face of the tank and expose the outlet to air.
• Make the tank itself as high as possible (compared to diameter) so there is a nice column of oil sitting above the outlet.
• For the scavenge inlet, make this (foamy) scavenged oil-air mix flow over a smooth surface and thru a meshed sieve (similar to a funnel with a sieve filter in the bottom) - to promote air bubbles to come to the surface and "pop" (disappear).
• Include an oil-level "sight" column, an oil filler neck, drain hole and tank breather.

This tank holds 8 litres when full, but when the engine is running it will  have about 4 litres in it, while the rest of the dry sum plumbing (oil pump, hoses, oil cooler, filter, etc) holds another 4 litres. These next couple of shots show the results of my first prototype. You will see a couple of  blocked off ports that I had to weld over after finding out the radiator hoses got in the way.....

This next bit may be seen as overkill by some, but I've also included a remote (electric) oil pump that allows me to press a "momentary" switch to pressurise the oil system before I hit the start button. In fact, once complete, i'll wire it all up such that the engine wont fire unless there is some oil pressure. I'm thinking that I can use an oil pressure warning light (warning of low pressure) as the trigger to allow the ignition the fire. A benefit is that if I get low oil pressure for any reason while racing and I'm distracted and don't see the warning light - it will automatically cut ignition to protect the motor. A bit of a fail-safe really. This little electric oil pump is just a diff/transmission remote oil cooler pump and wont need to run for any long duration - just long enough to pressurised things until the dry-sump pump takes over. Too easy I say.

One design flaw I've found (that I should have thought of while building the external tank), is that the oil priming pump sucks air through the joint "T" fitting it has with the oil level sigh column. Bummer. I have a couple of options to fix this: either have dedicated separate fittings for both the priming pump and sight level, or, I can insert a small plastic ball into the clear sight tube. For this second option I need a ball that's light enough to float on oil, but small enough so it can just slide up/down within the clear sight-tube, as well as being too big to fit through the lower AN-6 hose-spike fitting. This way, when the priming pump sucks oil (and oil in the sight level drops), this ball drops down to jam against the open end of the hose spike fitting and blocks this passage off. If I can find a "high viz" ball, then this will aid in reading the oil level too.