#6

[speedpro]

I checked the plugs after I got home. This one was looking pretty good, possibly a bit hot but it is a standard heat range plug.

[speedpro]

This plug was a bit harder to read

[F5 Dave]

Think that's rich. Try heat it under a flame to burn off extra oil and it will be fine for another 50,000.

[F5 Dave]

Back on the dyno today after fitting the rising rate fuel pressure regulator and the boost controller. Initial results were encouraging although as it was going overly rich early as boost rose, a lot of the low down power was lost. Hard on the boost it leapt up the revs. Only the ECU rev limiter and boost limit stopped it running away. Had lots of red flashing on the screen a couple of times.

Wow a bucket that does 32.3hp

For 8 rpm.

If I were a capricious man I'd make an unfavourable comparison to my 50.

But it turns out I'm not a revenge type of guy..

[speedpro]

It does new meaning to "power spike". Rebuilt it will hopefully be good for 18,000. The 3-4,000rpm should make it more useable and like I said I need to take fuel out below the peak to fatten it up which will make it less spikey

[speedpro]

Pulled the motor and took the exhaust, intake, and turbo off. Even the intake port had grit in it. The plenum chamber for the exhaust had a collection of small pieces of probably piston and there was even a small piece wedged in the exhaust port. I'm hoping the turbo is still OK but it will depend on whether anything managed to make it up and out of the plenum. I had to dismantle the turbo to get at one turbine housing bolt. I still can't move it so gave up before I get rough. Love these little turbines, such nice engineering.

[speedpro]

One good reason i went with the Link ECU was it's ability to log data when in use. An example of what can be done is in the image below. Not shown in this image is a table of desired lambda values at various rpm and manifold pressures.

The top left table is simply the fuel table. The values in each cell indicate the fuel quantity to be injected.
The top right "Mixture Map" table is a comparison of the desired lambda versus what was actually measured. Each cell has various values including the number of samples taken to arrive at the value.
On the bottom is a plot. In this case it is for a single run on the dyno. The plot has been expanded to only show the one run but in fact the whole time the motor was running values were being recorded. The cursor is at -3:20 at which time the engine is doing 11,000rpm and the manifold pressure is 120kPa and lambda is bottomed out at .7 or REALLY rich.

At this point you could simply enter a smaller value in the highlighted cell in the fuel table. Then drag the cursor to somewhere else on the time plot and repeat the process.

Or, you could look in the Mixture Map in the cell at the intersection of 11,000rpm and 120kPa. 410 samples were used to arrive at the listed values in the cell. The error is 0.09 which is the difference between the desired lambda(0.79) and the actual lambda(0.7).

Simply double clicking the Mixture Map cell will have the correction calculated and applied to the value in the associated cell in the fuel table.

It is possible to double click a blank cell in the Mixture Map and update every cell in the fuel map for which there was recorded data in the Mixture Map.

The values in the mixture map come from the data log. In this particular case the single data log was for the whole time the engine was running and was above a fairly low rpm value. What data is recorded can be configured and at what sampling rate

[speedpro]

The cell in the Mixture Map has been double clicked and is now blue indicating the values have been used to calculate a correction.
The matching cell in the fuel table now has the calculated value in it and is now orange indicating a new value.
The bottom row on the fuel table is all red. I added this row as the Y-axis didn't have a high enough value so I added a row with an extra, higher, value.(200kPa).

[speedpro]

It seems I now have a PHD in exploding engines. This one has been particularly thorough, even breaking a shim.

[F5 Dave]

That's really not very pretty. Time to start on the RHS of the original engine? Oh, you've sawed some of that in half.

[Grumph]

Ok, now I've seen the pics, I've fought my way on to comment.
The intact piston gives it away - as you'd know - the exhaust valves have been hitting the piston. This can only work for a very short time.
The reasons for it, I'd refer you back to my post much earlier about the problems with pressure spikes in the exhaust manifolds of turbo Subarus which were leading to similar results. You've said you are looking at reducing length and volume in your exhaust manifold, great, this should at least chenge the frequency of resonance - which may sort the problem.
I'd also change the xhaust cam timing - move it to a wider lobe center figure, say 111-112 degrees. Gives greater valve to piston clearance anyway.
Goes without saying you're looking for better springs....

Parts....well, I have quite a bit here. It's unlikely I'll build another cut engine and if the one already done goes pop, it'll probably be given away.
So bits are available. You arrange transpost and let me know what you need. Via grumphv2.

[F5 Dave]

Ahh Greg. Was wondering when youd get your internerd issues sorted. Glad to see you back on board

[sidecar bob]

Im trying to work out if the piston has been slapping the head, indicating a run big end, or if thats reflection off the bore.

[Grumph]

Ahh Greg. Was wondering when youd get your internerd issues sorted. Glad to see you back on board

I haven't and for most purposes, I'm not...The post this morning took 45 minutes, this so far around 30. Spark high speed fiber doesn't want to interface with Vodafone dialup so apparently sends it via the moon. Middle of next year we should be in a position to upgrade connection and equipment.
I look occasionally but I'd only log on if I have the time and it's something I'm interested in or can help. Nothing on TV atm....

Bob, have a look at the pic of the good piston and note the perfect circles where there should be carbon under the exhaust valves.

There's a problem with the sheer size of the valves too. I don't know how much spring pressure those thin stems can hold. I remember the batch of ZZR1100 kawa ex valves that pulled through the collets. I had to rebuild a speedway sidecar engine that dropped 3 valves at idle in the pits...
It might prove necessary to make up some valves with the common 5.5mm stems to get the mechanical strength.

[sidecar bob]

Yeah, the valves hitting was the first thing that I noticed, a run big end will cause that too as you are no doubt very aware, that's when I started looking harder to see if it was a PTV issue, or a bottom end problem.