GD427 in action

GD427 in action

Saturday, 9 April 2011

Guess what I did today... :-)

I must admit, the first attempt didn't go so well, I hadn't put enough fuel in the tank so whilst it started it was very rough and wouldn't idle, hence the "jaunty" angle of the tank in the video to make sure the fuel level was high enough on that side so the pump wasn't sucking air. This was the very next try though...




In this next clip you can see the box I made with the basic electrical connections to start the engine, along with the accelerator pedal.


Thursday, 7 April 2011

Electrical musings

The Tremec T56 gearbox comes with a reverse lockout solenoid designed to prevent you accidentally selecting reverse during forward motion. On a modern vehicle this is controlled by the ECU which effectively locks the car out of reverse once the vehicle speed exceeds a certain value say, 3mph. There has to be a failsafe in case of a malfunction so in fact the lockout can be overcome with a bit of brute force against the spring loaded plunger. The ECU I’m using doesn’t have provision for this functionality so I’m left with either using a bit of force each time I want reverse or rig something else up. I’ve decided to go with the “rig something else up” option although I understand many choose to use brute force or even take the mechanism off altogether. The problem with removing it comes with the reverse selection being across to the right and forward which could potentially lead to problems from an enthusiastic shift from fourth to fifth if you miss the gate and crash into reverse. The other option is to mount a switch somewhere that needs to be pressed before you select reverse but this option doesn't really appeal. The spring is quite stiff and so as an experiment i’ve temporarily wired the solenoid and powered it direct and it does make shifting into reverse so much easier so I think it’s something worth pursuing.

Another aspect I’ve come across in relation to the engine management system is the use of a Neutral Safety Switch (NSS), again a modern “gadget” to ensure that you’re either in neutral with an auto box or have the clutch depressed in a manual before you can start the engine. Again, it can be overcome, the ecu provides an output which must be grounded to allow the engine to start, you could just permanently ground the wire but I’ve decided to make use of it and fit a switch to the clutch pedal requiring the clutch to be depressed (grounding the wire) before the engine will start thus avoiding the accidental lurch forward when you’ve forgotton you left it in gear.

This is where it gets interesting, I’ve going to try and power the reverse lockout solenoid on the gearbox from the brake light switch on the brake pedal and ground it through the safety switch on the clutch pedal. This will mean it’s only possible to select reverse (without brute force) whilst the brakes are on (providing power) and the clutch is depressed (providing an earth) which is generally a good position to be in before you put the car in reverse! I guess there’s still a possibility of a mis-shift whilst changing down and on the brakes but in this scenario I’ll be shifting away from the reverse position i.e. right to left. The other benefit is that by grounding the solenoid through the switch on the clutch, it won’t keep being activated each time you brake during normal driving. There’s a little bit of figuring out to do with the wiring, I don’t know yet the output voltage from the ECU for the NSS and don’t want to risk the solenoid trying to earth itself back through the ECU so I’ll have to fit some diodes in place to limit the direction of the current. Once I’ve got it all figured out I’ll post some more details

Sunday, 27 March 2011

Fuel Lines tightened... wheels arrived

I've fitted the sensor on the intake and tightened all the fuel lines after having to remake one of them after mistakenly cutting it to length when it was supposed to be a bit long .....!

I've also picked up and fitted my own wheels after having Andy's factory wheels on loan until mine were ready. Hopefully next weekend I'll get a chance to connect the battery and add some fuel and we'll be running. That'll be a bit of a milestone for me and then tidy up a few wires (p-clips on order) and it's on with the body and cutting holes in the rear deck for the roll hoops. If you've followed this blog from the early days, rest assured I'll be using the correct size holesaw :-)






Thursday, 17 March 2011

Preparing to start the engine

Had a little tinker today and mocked up the fuel lines from the pump/regulator to the tank and from the fixed fuel line to the engine. I'm going to start the engine before I put the body on partly to satisfy my curiosity but also to check for leaks in the fuel line. All the joints can be accessed once the body is on but I'd probably have to do it from underneath.



I've also built a "starting box" housing water temp gauge, oil pressure gauge and rev counter along with several switches rigged up to mimic the the action of an ignition switch i.e. power on and start but also the action of holding the clutch down. My system includes a switch similar to that found in modern vehicles which requires either the gearbox is in neutral if automatic or the clucth held down if manual. This often referred to as a neutral safety switch and is the switch labelled NSS on the box.





I've also loosely mocked up the air filter assembly and you can see how the GD system draws cool air from in front of the radiator which should help performance. The air box will be bonded into the body when it finally goes on.





This was the first time that I've moved the body whilst on it's new frame which has been designed to allow me to move either the body or chassis out of the garage independently on each other.



I also wired the fan and fuel pump. Next job will be to tighten all the fuel lines, put some petrol in the tank, connect the battery and it should fire right up !

Sunday, 13 February 2011

Screen demist pipes

Weather was rubbish today so spent some time inside putting some waste pipe together for the screen demisters. These pipes which I made into "T" pieces, take the warm air from the heater and split this to the screen demisters and the footwell, one for each side. The "T" pieces are joined to the various components by flexible tubing. I found a website which allowed me to print some templates for joining two pieces of pipe together.

It was actually designed for much more complicated joins that I was attempting i.e different sizes, angles, offset etc. but very handy nonetheless.
After cutting out the template and marking the pipe accordingly, I made the cuts and glued them together. Once dry, I'll rub down the joints a little and paint them black...... don't know why, you'll never see them but it just seems like the right thing to do :-)

Sunday, 30 January 2011

A little bit of plumbing

Grabbed a little garage time today and started to put the main hoses together for the cooling system.

Before..



After...




I still need to run some additional hoses for the heater pipes but got drawn in and bought the bling polished pipes from GD. These mount to the chassis rails and just need hose connected at each end rather than a continous run of hose all the way round the front of the engine. I'll need to fix these solidly to the chassis so I'll do a little planning where to drill the holes and fit these next time.

Friday, 21 January 2011