Wiring

I now have the wiring well underway. I purchased the GD body loom and dash loom but made the mistake of getting the ls3 engine loom direct from Canems. Not that there is anything wrong with the Canems ls3, on the contrary, it is clearly a quality loom but it is missing the wiring parts that connect directly to the GD body loom via the two Round pin Lucas connectors (9 pin and 5 pin). Since I cant go back in time (which would have been my preferred choice) the only solution was to obtain the Lucas plugs (these need to be purchased as pairs even though I only needed one side). Fortunately Dave at Canems was very helpful in enabling me to figure out his loom and  Luckily I have a pal with a genuine genius in electronics and what may have proved a wee problem for me, was resolved in a couple of hours between Dave and Chris. The new loom additions are now made up and terminated /labelled as well as identifying where and what everything does from the gearbox outputs, fuel pump sensors etc.

s-l1600Lucas Rists 9 Way E Series Circular Sealed Electrical Wiring Connector

Reverse Lockout Solenoid

One problem I can see is that there is no real provision for the reverse lockout wiring.

Here’s the problem00jeep0001_3Downshifting from 6th to 5th presents a distinct possibility of pushing into reverse rather than 5th. OK I appreciate that it would be very hard to push it into gear, more likely there would just be a very unpleasant grinding of gears but that still means something between a very unhealthy situation and a very nast one.

Tremec deliberately make the Reverse position very difficult to push across to to avoid any accidental sloppy driving that may event in such an outcome. and to overcome this they expect the vehicle manufacturer to adopt a control system that energises a solenoid that in effect removes the pressure required to shift across to reverse. Obviously this solenoid should only be activated when it is safe to engage reverse, so the logical control is to use the ecu and a speed sensor that energises the solenoid at speeds at or below circa 3mph.

This is not a problem for the volume car manufacturers indeed its a designed in system for safety.  However this presents a problem for the retrofit market or low volume manufacturers such as ourselves because the system is not technically complete without the control from the ecu to trigger the solenoid at low speed only. It appears there are several workarounds to this problem:-

  1. I guess the most widely adopted is to ignore it.  do nothing,  just use brute force to pull the shift lever across to reverse effectively fighting against the solenoid spring.
  2. Wire it up to the brake switch (and/or the clutch switch).
  3. install momentary switch or switch on timer at the gear knob or appropriately positioned switch to engage the solenoid for a short period whilst the driver wishes to engage reverse.

There are some other variants and combinations of these solutions but in truth they all seem a compromise over how it should work. Additionally, option 1 also apparently leads to excessive wear on the shifter parts that are being forced, probably not a big issue on such low use vehicles. Option 2 is not a real safe solution since you could still be going at high speed when touching the brake and downshifting. Option 3 is just messy.

Further research suggests two better alternatives both of which allow the reverse select mechanism to work as intended.

  1. Aftermarket speed sensor/ reverse lockout control module such as00jeep0001_15 A couple of these units exist unfortunately they are all from the USA and run about $100.
  2. Utilise the ECU. Trigger this from the aftermarket ECU if available. all the above device does is recognise the speed the vehicle, then allows a 12v trigger if that speed is below a set level (say 3mph). I’m not sure if this can be done from the Canems unit but I will be try to find out. It seems such a solution is possible from other ecu units such as Megasuirt, which can capture speed data and output a switch at a determined speed. such an ecu trigger output control that switches on a nitrous pump at a set speed could be hijacked and used. I’ll take this up with Dave At Canems This would be the tidiest and lowest cost solution effectively working like any mass produced car using the tremec’s. If not I’ll probably opt for the aftermarket control unit http://reverselockout.com/

 

 

 

 

Advertisements

Engine Gearbox and Clutch

The LS3 crate engine and Tremec Magnum gearbox has arrived.
Slight problems to resolve.
The yoke I had acquired was a 27 spline yoke from the tremec t56 unfortunately it does not fit the magnum gearbox.
The Yoke needed for a magnum transmission is 31 spline as detailed.

Dana Spicer 3-3-5961X
1350 Series Slip Yoke 31 Spline fits Tremec T56 MAGNUM and TKO 600 Transmission
Length to center of u-joint… Dimension #1 = 6 1/2 inches
Barrel Diameter… Dimension #2 = 1 11/16 inches
Barrel Length… Dimension #3 = 4 1/2 inches
U-joint cap diameter… Dimension #4 = 1 3/16 inches
U-joint width… Dimension #5 = 3 5/8 inches
Series… 1350
Spline count… 31

magnum yoke

Good news – called GD and sounds like they have one in stock. Ill order up a full propshaft from GD as soon as I do a trial fit of the engine.

Tried the engine and transmission in for size and works out the prop gap is about 366mm I guess the actual prop length will be something a little shorter than this with an allowance for a bit of clearance on the sliding spline.

Clutch Trial Fit

What on earth was I doing a clutch trial fit for you may well ask, well the truth is I wasn’t  meant to but after fitting the clutch and pressure plate housing I started to do a bit of reading up to find out what the odd looking connection was on the slave cylinder. Whilst searching for information on the slave cylinder fluid input fitting which turns out to be “Quick Disconnect Fitting” I also discovered that I had inserted the pilot bearing the wrong way around. It said nothing on the instructions I received with the installation kit about direction for the pilot bearing and although I did notice it had a slight difference I chose to put it in with the needle bearings visible and closest to the transmission. My logic was simply to get the needle bearings further along the shaft end.

Turns out my logic was wrong and the bearing goes in with the closed end towards the tranny, obvious when you realise that this is the grease seal end.  OK so the clutch has to come back off – no big deal but how the heck will I get the pilot bearing out that i just drifted in with a 3lb hammer?  My first thought was, OK its just going to get butchered out and buy a new pilot bearing but a quick google check and low and behold some genius on youtube had figured out a 3 minute solution. All I had to do was pack the centre of the bearing with grease and insert a close fit (15mm) drift through the centre of the bearing, strike it with a hammer a few times and low and behold the bearing jumps out. Extreme Hydraulic pressure pushes it out from behind – what a good trick –  and it works – youtube to my rescue!DSC_0302

Now on to the problem of that Quick Disconnect which got me searching in the first place. Apparently these fittings are used quite extensively in the USA and the idea is to enable disconnection of the slave cylinder for removal of transmission during clutch service etc. without introducing air into the system so alleviating the need to bleed.DSC_0298

The Quick Disconnect is the big orange part in the picture. The other opening is for the bleed nipple which is lengthy so it can just be bled from the bellhousing opening. I’m going to fit external bleed flexi pipes so I plan to modify both of these fittings. Pretty easy on the bleed side since its just an m10 fitting, so a standard male end of a flexi would work here but the quick disconnect is not so simple since its fitted into the slave cylinder aluminium casing with a flat o ring and groove, held in place with a roll pin. I think the simplest method here may be to cut this orange bit off and have the blank pipe end threaded to m10 with a taper. That way I could fit an m10 female/female extension fitting, effectively replacing the orange part with this.

m10 female

I’ll figure this out over the next couple of days and report my solution here.

Trial fit to get prop lengthDSC_0312

Things are starting to get heavy  LS3 and Tremec Magnum in place.

Engine back out to sort the clutch slave issue here’s a pic of the new fittings. The banjo fitting on top is for the remote bleed flexi this replaces the long brass bleed screw (above). The setup on the lower input shows the new fitting that replaces the ‘quick disconnect’ (orange plug above). It was easier to turn this fitting with a standard male metric brake end as shown, but since I already had my flexi pipe with a male end just adding a standard female/female coupling in between joins it all together.

clutch slave fitting

With this complete I can re-install the engine and gearbox in the chassis.