Rightly ho folkies (and fridge and Beaumont)

Megasquirt / MegaJolt

I have been doing some reading...and also looking at megasquirt / Jolt ...and I have been considering this as a route PURELY at the mo for ignition Via a Dizzyless V8....


Most of the mods see the 36:1 wheel in the pulley at the bottom of the engine..

If you look at mine it has a "selection" of "loving nudges" read dents bangs thumps and scrapes off road "Gracefully souvenired" into the metal.

So, one thought is that if I went this route a good "Kiss" on the pulley arwea off road would see a end to the ignition...........

So, My thought was a wheel and VR sensor INSIDE the dizzy (now empty) sealed up etc

BUT

the dizzy turns 2x for every crank (and bottom pulley) rotation, so how can this be overcome please ?.

Is it poss and has it been done if so the more details the better but keep it in "simple muppet speak" please

Nige

Spooky......

Myself and DirtyDiesel were only talking about this same subject the other night, and require the same answer.

Over to you Fridge and Beaumont

I may be wrong here but i think general slack in the timing chain & gears give some inaccuracy over a crankshaft sensor.

Other option may be to mount the sensor inside the bell housing near the starter ring / flywheel.
I think the 4.6 block has something like this as stock because mine has a hole for a sensor which looks towards the flywheel (i blanked it off on mine as i run a carb)

Try asking Dave White: http://www.yorkshireoffroadclub.net/vehicl.../megasquirt.php how he did his.

With a vernier timing gear and steel gears top and bottom plus duplex chain doubt there would be much, plus any slack could be tuned / timed out, otherwise how could you get the Std dizzy to work ?

Or am I missing something ?

Nige

My thoughts exactly.

Somewhere in the distant past i have seen a rv8 in a kit car on throttle bodies and coil packs, and it had the timing sensor in the hole where the dizzy normally is, viewed from the top it was a teardrop shape that bolted on with a multiplug on top.

I carn't remember who manufactured it or marketed it, but it was in the days before megasquirt and it looked pro built so could have been part of a kit from someone.

Sounds rather posh n nice ?

Nige

Ah! New you'd see the light one day, Nige


Steering guard? Barring that, it sounds like you'd need to look at a different solution. As TomG says, later RV8s had a timing sensor on the flywheel which I'd guess Megasquirt is able to decode. EDIS couldn't, so you'd have to go for the built in wheel decoder, but this has benefits anyway, like the ability, I think, to go coil on plug and do away with the HT leads.


I don't know whether it's been done, but it seems perfectly feasible. You could compensate for the double revs by replacing the 36-1 (36 teeth with one missing) wheel with a 72-2 wheel, but I'm not sure whether the EDIS VR sensor would work reliably on a wheel that small (especially cramming that many teeth onto it), so again it's probably time to look at the built in wheel decoding which should cope quite happily with a suitably sane tooth arrangement.


Crank position sensors that replace the dizzy drive definitely exist and can readily be ordered off some mainstream american websites (sorry, don't have a link handy - pretty sure Mallory do them), but I've only seen ones for Chevy engines. Never managed to find out if they would fit an RV8. If you can find one that does, problem solved

It's well worth asking questions on the Megasquirt Forums - they're busy, so try to pick a relevant subsection (Megasquirt'n'EDIS would probably be a good bet). Lots of helpful guys on there, and there's probably at least a couple of people who've already done what you're thinking of.

In short, yes its possible, but not using EDIS. Megasuirt could probably be made to decode it however, but I personally dont like the way that to run coil on plug with megasquirt there are no positions on the PCB for the drivers. Soldering wires onto the legs of chips and bolting the drivers to the case is a horrible bodge in my opinion.

Edis can only decode 36-1 wheels. As the dissy turns at a different speed to the crank there is no other way round this.

Only other thing you could look at is fitting the toothed wheel to the flywheel and running the sensor in the bellhousing similar to a later V8.

Jon

Surely EDIS only counts the teeth - that way it should be able to count any combination of 36-1...??

Unless I've missed something.....

Cheers

Pete

I think you are worrying about something that will not be a problem.

Virtually all the Rover V8's i have seen using Megasquirt to control the ignition have either used the Original Equipment sensor onto the flywheel/flexplate or used the 36-1 wheel on the front pulley.

Dave White uses the front pulley route and has never had a problem with his Outback Challenge motor as far as i understand it (i am also led to understand he does not even carry spare for it now in the car!!!).

I have a 36-1 wheel on the front pulley too. My wheel is cut from 6mm plate steel and then machined to fit behing the damper with the timing marks on. I then fitted it in front of the damper but that another story. The teeth although pround of the damper are inside the diameter of the pully driving the Alternater and the pulley driving the power steering. Furthermore, the VR sensor is mounted above the crank line.

My engine is also lower by 6" than a standard Range Rover position and i still consider that the wheel and sensor are protected enough, to knock the toothed wheel then the other pullies will have been damaged beyond use allready.

True, there is a very slight risk of the wheel filling up with mud at very low speeds and then damaging the sensor but a quick search of the MS forums has never shown this to be a problen so i think i am maybe being over sensitive.

Just do it as it will be the best mod you will ever do. Reliability will be improved as will control and driveability.

If in doubt come and see mine at Sidbury (Tidworth) on the 19th March.

Cheers

Nev

Any chance of a piccy of your toothed wheel / VR sensor install?

Cheers
Jon

Yes but no - i do not have a digital camara (i know but digital is a pain where we went when we needed a camara).

However, you more than welcome to come round and see it and take photo's your self!!

Cheers

Nev

Nev

Dave is going to sort yours then mine is next if I get my chassis sorted he is using your idea's and seeing how the challenge truck drives with it.

I was chatting to Dave about doing a Mag article on the change over.

Julian,

I have been taking photo's and they are all on cd for just that eventuality.

Starting up this Saturday..................................................

The LSx ones are mounted on the crank in the sump, not able to look at one right now to see if that might be possible on the Rover.

I have a Mazda SLT that came with a sensor kit to provide Tach signal that picked up off the starter, never fitted it as the 78 motor didn't have a tach so never figured it out.

There should be space to get a trigger wheel on the forward side of a flywheel of flax plate and mount the pickup on the bellhousing cover plate, not much would get to it there.

Agree with Nev though, if you are worried about it up behind the damper then I think you will have bigger concerns

I'd be more worried about the VR sensor than the actual trigger wheel - if I damage my trigger wheel I'll probably wreck my pulley assembly and put myself out of action anyway. In fact, the trigger wheel would probably be the easiest bit to fix - just a bit of hammer work (mine's 1mm steel with the teeth bent over).

The VR sensor is mounted fairly well up on the left hand side. I guess it could get hit by debris thrown up off the road (more likely than off road), but there's no sign of things having hit up there in the past. Off road I was concerned that mud and gravel could get thrown round into the VR sensor by the the trigger wheel, but judging by the experiences of others so far this isn't an issue.

So far mine is still largely theoretical - the only bit that's on is the trigger wheel and that's been just fine. Hasn't been anywhere particularly demanding though.

err, I don't think so. I'm pretty sure that the crank rotates twice for every camshaft rotation; dizzy rotates in unison with the cam. (it is 4 stroke)

In other words dizzy turns 1/2 for every crank (& bot. pul.) rotation.

This is the V8 timing gear (in fact the pulleys will be in the same diameter on all 4 stroke engines).



... now that has got me thinking - if the sensor is on the crank, how does the electronic brain know TDC is on the compression stoke and not exhaust stroke? ( use wasted spark ignition?)


oh, to answer your question. You would need to lock the dizy plate so there is no mechanical nor vacuum advance. Then I use an optical sensor. It should be easy to print onto clear plastic sheet a notched wheel and then glue it on to perspex; just a matter of having a narrow beam using a couple of slot?

Or maybe a small gear wheel with the right number of teeth; file one off and then similar type of sensor.

Or thje other side of the engine i.e. the flywheel - already should have the little pointy bits except there is no reference.

Yep 1/2 turn, too much beer at the time of typing maybe !

But still thinking as to how I can get kit inside dizzy rather than pulley area...
Nige

Since the dizzy is superfluous, once you take its innards out, there is plenty of room for a disc and sensor. And if that is not enough, chod of the dizzy body except the base and stick on a biscuit tin. (think outside the dizzy box).

I am guesing the bigger problem will be the accuracy to which you can set the disc relative to the crank - you have 1/2 the resolution due to the rotation plus sloppy chain and drive gears.

Nige - the latest MegaSquirts with built-in wheel decoding can decode almost anything, and from most common types of sensor. I would suggest magnetic / hall effect rather than optical as it's not affected by mud. Go look in a few modern cars with dizzies - the Primera has a cap & rotor and then underneath there's a very finely slotted wheel & sensor so the bits are out there.

Failing that, I'm sure someone can laser cut you a trigger wheel.

I would suggest reading the MSEFI.com forums and see what people have done, and http://megasquirt.sourceforge.net/extra/setup-wheel.html which gives some ideas of what the code can do and where they're taking it. The rate things develop you might find what you want will appear in a month's time. In fact if you ask James (who develops the software) he might be able to put something in for you!

Nige - seems like an awful lot of hassle to go distributorless... why not just buy a 4.0 or 4.6 GEMS engine?

Also, I thought you'd just bought that nice waterproof Military dizzy off Ripley?

Also, I thought you'd just bought that nice waterproof Military dizzy off Ripley?
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if i had one, i definately wouldnt of sold it!!
but if you want to sell it nige

Oh - must have been someone else.... (too much wine last night!)