2005-10-23

2005-10-23

I ordered a couple more plumbing bits to help me finish the plumbing in the back of the car. I've nearly finished it, but in order to get it done, I need to make some progress on the front.

Spent yesterday on the car. Cleared up the table, dropped the car back flat on the table, and started measuring it up for the new-new-new-new-front end.

I'm going to build it with a structurally strong transmission tunnel, and I'm going to link it into the cage for increased strength and safety. The front end/tunnel will also be optimised for engine removal, maintenance access, and driver/passenger space is a final consideration.

As the engine/gearbox/bellhousing are american, The starter motor and sump pump sit on the right hand side of the engine. Unfortunately, this is also where I want to sit, soI'm thinking about making the car LHD as there could potentially be more space for the drivers legs. Having tried sitting in both sides with pedals and a phantom steering wheel, there really isn't much in it once the position is comfortable. The biggest difference it makes is in how far back I can push the engine, as the starter motor hits the RHS seat. The side difference may be more promenent when the engine mounts are in, as they're exactly at foot level. This mas migrated the engine mounts up to the top of the todo list!

In order to mount the engine in the right place and make the engine mounts, I need to move the dash bar on the roll cage up about 3". This is because the gearbox is deeper than the engine! I'm going for at least a 3" raise as the engine will be immediately underneath it, so I want some decent access, and to gain space for engine removal.

I've been contemplating solid mounting the engine, but I've come to the conclusion that the car will shake itself to bits if I do so I'm going to go with conventional rubber bushes. I've got mk2 escort leaf spring bushes, and also some manta training arm bushes to choose from.

I'm also going to need to build the bottom of the tunnel because that's what the engine mounts are going to sit on. It is critical to get this right as it's what's tripped me up a few times now. This needs to allow enough space to take the engine out easily, work on the engine in situ easily, be very strong as all the twisting force of the engine will be going through the tunnel, support the weight of the engine and gearbox, take the suspension and shock loads and transfer them into the external spaceframel, and allow enough space for the driver and passenger to fit in! not an easy task.

Most of my time at the garage was spent playing with bits of metal as an aid to visualise the overall structure, and after a few hours, I had a concept I liked, and allowed me to do everything I wanted. It's symetrical so I'm not tied to having the driver on one side only, allows loads of access, and the driver/passenger have enough space to be reasonably comfortable. It's no Lexus ;-). I've left the rails at the front of the chassis sticking out 55cm ahead of the axle line so the lower wishbonse can mount to it. If the design I do means that they're in the wrong place, I can easily lop them off and move them, but if I left them too short it'd be much harder to lengthen them.

I decided to start making the bits of engine mount that bolt to the engine. I've made the first one out of aluminum.

I'm unsure about it as I can see it stress fracturing around the bolt holes. I'm a bit stuck for space that side as the dry sump pump covers two of the mounting holes and severly restrict any strengthening ribs I can put on mount. I think I'll remake this mount in steel for this side, and add some more strengthening to this one and move it to the other side where's there's plenty of space.

The chassis part of the engine mount will be a U shaped bracket that will go between the bottom and top chassis rails. I'm going to try and link this directly into the outer spaceframe as there'll be a lot of force going through this, and the more I can soread it out, the stronger the structure will be.

Next weekend I'm working both saturday and sunday, so probably won't get much more done till the weekend after. This gives me plenty of time to finish the suspension design (I'm still working on it). I'm having great fun playing with the different possibilities. One thing I have found is that the Manta upright would be vastly improved if the lower ball joint was about 10cm lower….. I wonder how easy it is to make or modify uprights. Apart from that, it's just messing about until I have something that has good camber curves, a stable roll centre, a small amount of scrub, not a huge amount of castor, minumal bump steer and fits in the space available!

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