RV* 4.6 Serpentine Trigger Wheel

stevieturbo · Post by **stevieturbo** » Tue Feb 16, 2016 12:02 pm

Adapt and overcome.

SuperV8 · Post by **SuperV8** » Wed Mar 02, 2016 9:33 am

My solution:
Ignore the pulley bolted to the front for the supercharger. My crank pulley is the same as yours from the later GEMS engines. Trigger wheel is the standard trigger wheel used on the earlier engines.
I found it easier to make a simple aluminium spacer than machining my pulley.

garrycol · Post by **garrycol** » Thu Mar 24, 2016 11:17 am

Ok - got my trigger wheel and had the back of the crank pulley turned down.

The diameter of the trigger wheel is about 1mm larger than the diameter of the pulley. When installed on the pulley the trigger wheel runs about 5mm clear of the pulley. I assume that is enough clearance.

However when installed on the crankshaft the trigger wheel just touches the water pump housing.

Now the obvious solution is to grind a little off the water pump housing (it should be about 3-4mm thick there but I I would prefer not to do that if possible.

The other solution is to send the pulley back to the machine shop and pay to get a few more mm of the pulley. But I am not sure how much.

So, given the trigger wheel is basically the same diameter as the pulley, how close can the teeth on the wheel be to the metal pulley and still allow the EDIS 8 sensor to provide the appropriate signal to the ECU.

I am just concerned that if the teeth are too close there will be electrical noise between the trigger pulses because the EDIS 8 sensor will also pick up the steel in the rotating pulley.

So, what is the min distance the trigger wheel teeth must be away from the metal pulley in an EDIS 8 system.

Thanks

garry

stevieturbo · Post by **stevieturbo** » Thu Mar 24, 2016 11:47 am

Those teeth look huge, don't see any problem removing a few mm from them, and/or some from the pump.

Air gap will still need to be appropriate for the sensor.

Trigger wheel looks miles away from the pulley, so no problem there.

garrycol · Post by **garrycol** » Thu Mar 24, 2016 12:15 pm

Thanks - that is another thing I am yet to determine is what the air gap should be for EDIS 8.

The sensor magnet is 8mm across so I dont think I can move the trigger wheel much closer to the rim of the pulley without the sensor also picking up the rotating pulley as well as the trigger teeth.

I agree - maybe a little off the water pump housing and 1/2mm off the trigger might work.

garry

stevieturbo · Post by **stevieturbo** » Thu Mar 24, 2016 12:43 pm

Air gap is down to sensor, tooth size etc, not the system

Sensor only functions on the face and often over a small area of the face. The pulley beside it should not matter, you look miles away from it

SuperV8 · Post by **SuperV8** » Thu Mar 24, 2016 1:13 pm

You can see that my trigger wheel is quite a bit smaller than my pulley and this works great.
If it was me I would either turn the wheel down so it doesn't foul the water pump or machine the pullet a little more so it will pull the trigger wheel away from the pump.
If you grind the pump to make it fit, then if ever there is a new pump fitted in the future that will need to me modified as well.

As for gap, 0.5 - 1.0mm should be ok, just ensure your sensor is adjustable to you can accurately set up the gap and tweak if necessary.

When you say Edis 8, are you actually running the Edis 8 module, or are you just using the Edis VR crank sensor and coil pack? I have a feeling the Edis 8 module needs to be accurately set up so the correct tooth points to the sensor, much easier to wire the sensor directly to megasquirt and use an external coil module to trigger your coil packs, then all you do is tell MS which tooth is at the sensor at TDC.

Tom.

garrycol · Post by **garrycol** » Thu Mar 24, 2016 1:24 pm

stevieturbo wrote:Sensor only functions on the face and often over a small area of the face. The pulley beside it should not matter, you look miles away from it

I am not sure I follow - the teeth of the trigger are currently only 5mm from the pulley - as per the pic. The sensor is 8mm wide so when centred on the trigger, the edge of the sensor is already only 1mm away from the pulley. If I take say another 2mm off the pulley, the edge of the sensor will be over the pulley as little when centered on the trigger - i am not sure whether this will cause an issue or not.

Cheers

garrycol · Post by **garrycol** » Thu Mar 24, 2016 1:28 pm

SuperV8 wrote:When you say Edis 8, are you actually running the Edis 8 module, or are you just using the Edis VR crank sensor and coil pack? I have a feeling the Edis 8 module needs to be accurately set up so the correct tooth points to the sensor, much easier to wire the sensor directly to megasquirt and use an external coil module to trigger your coil packs, then all you do is tell MS which tooth is at the sensor at TDC.

Tom.

Yes it is an EDIS 8 system running an Edis 8 module and coil packs - feeding to a MS3 ECU.

garry

DaveEFI · Post by **DaveEFI** » Thu Mar 24, 2016 2:19 pm

EDIS defaults to 10 degrees BTDC if SAW is lost. So you obviously need the relationship between the trigger, missing tooth and TDC to be correct for this.

What I'm not sure is just how soon MS takes over the timing when cranking.

I've not found the air gap to be critical with EDIS, so just set it at 1mm.

On my SD1, the trigger wheel is near identical in diameter to the V pulley it is next to, and about 3mm clear of it. Never had any sync problems with MS.

DEVONMAN · Post by **DEVONMAN** » Thu Mar 24, 2016 7:32 pm

garrycol.
My arrangement is identical to yours and all works fine with EDIS 8.

The machining of the pulley is the same, the space between the pulley and trigger wheel is the same. I suspect my trigger wheel is a snifter smaller in diameter as it just clears the water pump, or my water pump has a less bulky casting. Different makes of water pump are likely to have small variations in the casting. If there is say 5mm of thicknesss at this point in the pump wall I would just remove a couple of mm to get the running clearance. It's a 1 minute job with a grinder but Reducing the trigger wheel diameter is a better engineering option.

The VR sensor may be 8mm wide but the effective magnetic bit is much less and I have had no problems running with the trigger wheel 5mm from the pulley.

garrycol · Post by **garrycol** » Fri Mar 25, 2016 12:22 am

Thanks for those comments - have satisfied my concerns.

I will take the trigger wheel down a little and see how I go.

Cheers

Garry

unstable load · Post by **unstable load** » Fri Mar 25, 2016 5:56 am

Why not chamfer the back of the trigger wheel a little to give you clearance?

garrycol · Post by **garrycol** » Fri Mar 25, 2016 10:18 am

I have now managed to get about 1mm clearance on the water pump.

John - I did chamfer the inner edge of the trigger teeth - about 1/2mm in and 1mm down bit still did not quite give me the required clearance. I then just ground the rough casting on the water pump and that was enough.

Thanks for all the input - Garry.

stevieturbo · Post by **stevieturbo** » Fri Mar 25, 2016 10:26 am

Even with 1mm static, there's little doubt it will still hit when the engine is running

grind a little off the pump