All Spark and No Bark

[ThreePointFive]

It starts! Put fuel in, took the pin out of the fire extinguisher, pressurised the system, had a leak around the cannister on the fuel filter (bad O ring), binned it, fitted an in-line filter, bought another (bigger) fire extinguisher, checked the whole system, pressurised it, no leaks. Fired right up, ran like a pig at first and then settled into a rough idle around 1200 RPM. Tacho says it's doing >6000 RPM but MS and my ears say otherwise so have to look at that.

It is smoking a fair bit of blue smoke and smells like burning oil but it's been sat for 8 years so I'm going to get it properly hot before I get too worried. There's a lot of smoke from everywhere while the diverse range of schmoo burns off.

I'm getting a very odd hesitation when applying throttle, it's almost carb-like in the initial stall then revving. 

I've not touched the stepper motor so do I need to if it's running?

[FridgeFreezer]

Congratulations!

It will be rough as hell when you first start it as everything will be "near enough" but nowhere near right.

You just need to go through the various bits and bobs in order of priority - 1st thing is to get the timing right (value in MS equals value shown by timing light), until that's bob on nothing else is worth fidddling with.

Then get it idling about right, which gives you a basic idea that you've got the bottom corner of the fuel map about right, then worry about other stuff from there.

[elbekko]

Good to hear!

[ThreePointFive]

4 hours ago, FridgeFreezer said:

Congratulations!

It will be rough as hell when you first start it as everything will be "near enough" but nowhere near right.

You just need to go through the various bits and bobs in order of priority - 1st thing is to get the timing right (value in MS equals value shown by timing light), until that's bob on nothing else is worth fidddling with.

Then get it idling about right, which gives you a basic idea that you've got the bottom corner of the fuel map about right, then worry about other stuff from there.

Looks like I need to buy a timing light, I don't have one!

[FridgeFreezer]

Worse than  that, the 4.0 doesn't have a timing mark on the pulley

I actually timed mine by putting a spare V-belt pulley on, setting up a timing pointer to match TDC and the replacing the proper pulley and marking it.

Sure there must be a better/nicer way perhaps using the cam position sensor hole and wheel as an accurate marker to set it all up?

[ThreePointFive]

So as well as learning how to bleed brakes and clutch, I'm going to have to learn about timing. I do quite like this stuff.

I'd assumed I could find TDC the same way I did for fixing the MS trigger wheel and just mark the crank pulley but I'm going to assume if that was the way, you'd have suggested it.

I don't even know which is the can sensor hole! Timing light is ordered, this is going to be a steep curve but looking forward to it.

 

[elbekko]

10 hours ago, FridgeFreezer said:

Worse than  that, the 4.0 doesn't have a timing mark on the pulley

I actually timed mine by putting a spare V-belt pulley on, setting up a timing pointer to match TDC and the replacing the proper pulley and marking it.

Sure there must be a better/nicer way perhaps using the cam position sensor hole and wheel as an accurate marker to set it all up?

IIRC the woodruff key is at TDC. So fairly easy to mark.

[FridgeFreezer]

1 hour ago, elbekko said:

IIRC the woodruff key is at TDC. So fairly easy to mark.

I could never find info on it, if you've got something official that'd be very useful to know!

[elbekko]

Figured it out years ago while looking at a crank, but my memory is fuzzy as always. I'll try to remember to verify when I have my crank in my hands in a few weeks.

[FridgeFreezer]

I thought I'd seen somewhere the keyway points at cylinder #1 when the engine's at TDC but can't recall where.

[ThreePointFive]

Page 18 of the MS manual.

[FridgeFreezer]

2 hours ago, ThreePointFive said:

Page 18 of the MS manual.

Which one - the megasquirt.info site, Nige's instructions, or a thread on here, or somewhere else?

[ThreePointFive]

Nige's manual - I should have been clearer.

Edited July 1, 2020 by ThreePointFive

[FridgeFreezer]

Fair enough - that didn't exist when I did mine so I've not read it!

[ThreePointFive]

I know I'm going to ask one of those questions everyone hates but after searching, all of the advice I can find is about timing chains or distributors.

 

Can I confirm that the best way to time this thing without existing markings is to:

1. Crack off the pulley bolt and washer to expose the woodruff key

2. Mark outside edge of pulley wheel in line with the woodruff

3. Mark the engine in line with the spark plug hole and centre of the pulley wheel so when the two marks meet, the engine is at TDC

 

Is this going to be precise enough or do I need to come at it from a different approach?

 

[Bowie69]

Use a piston stop, make a pointer, wind engine one way, mark pulley, wind other way, mark pulley, TDC is in the middle.

This sort of thing, but I made one with an old sparkplug and a bolt:

https://www.amazon.co.uk/RocwooD-Nylon-Piston-Chainsaw-Brushcutter/dp/B07CRNXQYR

 

[FridgeFreezer]

^ What Bowie said.

It's very hard to DIY up an accurate pointer, but it's far easier to make a pointer and then accurately mark the crank pulley using a DTI or piston stop.

[Dave W]

As above really, always best and safest to use a mechanical means, something down the number 1 spark plug hole to find the top of the piston as it approached TDC. I've had RV8s that are as much as 20 degrees out on their pulley markings so I never trust them. On my LS1/6 there are no timing marks or pointer so I made up a pointer and marked the pulley using the method described above.

[ThreePointFive]

Thanks All, appreciate the pointers - will get something made up and see how it goes.

[Bowie69]

2 minutes ago, ThreePointFive said:

pointers

I saw what you did there...

[ThreePointFive]

3 minutes ago, Bowie69 said:

I saw what you did there...

I didn't see what I did there!!

[elbekko]

On 7/1/2020 at 3:08 PM, FridgeFreezer said:

I thought I'd seen somewhere the keyway points at cylinder #1 when the engine's at TDC but can't recall where.

So, just to confirm:

#1 is right in line with the keyway.

Not sure if there are any usable markings on the front cover at 45° though. But that should be easy enough to put on with a protractor.

[ThreePointFive]

Had a go at timing it today after a long period of not getting much done. 

The piston stop I bought wasn't long enough to actually stop the piston and I don't have a spares spark plug to make one, so had to use various garage items as feeler gauges instead. I think I got a very loose approximation of TDC.

I used this from one of Fridge's old posts on the subject:

Changing this value, I'm now at 10 degrees and it's much smoother (but far from smooth) as it bounces from about 800-2,000 RPM in a rhythmic way and it still bogs when the throttle is applied. Changing this value is making it fire further anti-clockwise of the TDC mark, which I assume is advancing it?

Am I safe to keep advancing it until I get rid of this unstable idle or is that going to lead to detonation before I get there?

Edited July 14, 2020 by ThreePointFive

[FridgeFreezer]

2 hours ago, ThreePointFive said:

Changing this value, I'm now at 10 degrees and it's much smoother (but far from smooth) as it bounces from about 800-2,000 RPM in a rhythmic way and it still bogs when the throttle is applied. Changing this value is making it fire further anti-clockwise of the TDC mark, which I assume is advancing it?

Am I safe to keep advancing it until I get rid of this unstable idle or is that going to lead to detonation before I get there?

The unstable idle can be fuel and/or ignition map and/or PWM idle valve etc... if you've done what I suggest in whichever post I suggested it setting the whole ignition map to a fixed number and then adjusting the trim value until it comes out right, the timing value shouldn't change no matter what the revs are doing.

 

[ThreePointFive]

So I did that and it runs much better, still jumping 200rpm either side of 1300 at the moment.

Here's what I've been reading for most of the guidance:

I've got the rev gauge working now by putting the switches on the rear in the exact opposite configuration to the VDO instructions. Also fished out a reasonably bloated piece of fuel return hose that had actually fallen off the return pipe and was merrily floating around in the tank, as well as changing the pipe I used to extend the fuel pump for the in-tank type. With the tank open I could move the tank sender and work out which connector went where, so I know that works too. I suspect the temp gauge might not be working though, haven't seen it move at all.

Now I just need to be able to run the car long enough to really get to grips with the tuning and without gassing myself out of the garage, I might try to find TDC again just to make sure I've got it close, it's looking about 20 degrees advanced at the moment.

I don't have a PWM as I opted not to fit it in the end, so that won't be causing the rising/falling revs unless it's the absence of one that's the problem.

What else can I look at (or is that a huge question and I just need to keep reading on here)?