7 port ignition mapping issue.
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dare I ask... why did Mr swift point you in that direction.. ??

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

Is that at the pushrod or the rocker tip? There will be a difference. Have you checked lift on all 4 exhausts to compare?

I seriously doubt it!

Edited by alaskanow0 on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

Edited by alaskanow0 on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

Could it be worth running it up with the 5 port again just to pin point the 7 port head as the problem?

I seriously doubt it!

Just thinking out loud ( i like puzzles

would'nt it just prove that the bottom end is ok though as you can't use the ECU ?

You should be able to check the bottom end by measurement.

if tdc is ok, cam timing is okey and the compression and leakdown is okey cam&crank not binding , what more can there be wrong ? (it's a proper question, not trying to be a smart arse here).

I'd say the cam sensor is either feeding you bs (offset of the camwheel missing tooth wierd of something) and advance is actually normal-isch just reading high. Sensor wires inversed ( should be visible on the DTA scope mode while cranking). You not by any chance using a distributor based crank sensor right ? with wasted spark you have to divide by four not two as the dizzy is driven at half speed ??

or it is not (duh) and then something is
off that causes very slow burn.

I can imagine that a aluminium head requires a bit more advance (more heat loss in the head or something) but that would be something like 3 degrees not ten ).

could it not be that the voltage/current to the coils is sagging on higher rpm leading to a weaker spark as you rev higher requiring more advance?

Edited by Sir Yun on 5th Sep, 2012.

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

how about this?

http://www.myaustinhealey.com/aec960-heale...inder-head.html

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

Edited by alaskanow0 on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

I have already modified the chambers to expose the sparks, before they were more or less consealed.

Edited by alaskanow0 on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

Im using a MED 36-1 Trigger wheel, Sensor is 100degrees from missing tooth. DTA set to 100degress. I checked this serveral times and it matches timing at low revs (double on gun, due to wasted spark) I havnt checked high revs yet, have been assuming it should be correct.

Ive always seen 90degress with this setup, but with the new DSN cover and sensor bracket is 100. TDC is dead centre of missing tooth.

Class C 3rd Place Avon 2011 14.18 @101mph

well the fuel is roughly the same and the chamber shape as well, so the 46 degree advance strikes me as being significant. you basicly have a plug this deep and it causes the ingnition to requite a load more advance. add a bit more due to the al-alloy head subtract a bit due to more squish (your increased CR) of some other form of turbulence inducer (mixes the fuel more so burns faster).

could be ..

if not "

the voltage needed to spark is also dependent on the AF so if the ECU/
coils have a juice problem ( did you check ? while runing). it all affects each other . but for now i would suspect the plug position could be the starting point

if that does not do anything ->

i'll just copy past something i have read with regards to a big 16 liter v12 having somewhat similar issues.


Re: What fuel would increase burnrate

Postby David Redszus » Mon Aug 27, 2012 4:21 pm
One of the most important (and often forgotten) tuning techniques is the use of an oscillioscope while the engine is on the dyno. Its use can determine spark duration, required firing voltage under load, spark indexing, misfires, spark scatter and firing point jitter.

In my view, a scope is every bit as important as an O2 sensor when tuning or evaluating an engine.

And, if the engine is injected, then the scope becomes critically important in the troubleshooting of necessary sensors.

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

also yunmiester ,nobody seems to talk about using a scope to spot detonation ..

matt , is there any possible way you could get the plugs to go a fair bit further into the chamber ? eg longer plugs or machine down the seat ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

don't you just hate when that happens

Edited by Sprocket on 5th Sep, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Let me just add, that The trace I was looking at was done in an engine testing center by professionals, and their equipment might be a little more sophisticated than a 25 year old motorscope, but it was a primary and secondary trace that coresponded to the cylinder pressure trace during knock.


One real way to find out of your sun motorscope will indicate knock is to try it with and without knock

Edited by Sprocket on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Edited by alaskanow0 on 5th Sep, 2012.

Class C 3rd Place Avon 2011 14.18 @101mph

Hi,

that burn pattern you have in the chamber : do you have a pic of the pistons as well?

well I quote again.. just to show I did not make this up myself.

''I was one that used to think that the clean areas where" fuel wash" when in fact, wet flow testing proved that the clean areas are dead lean. That was the first thing I learned on the wet flow bench. Where you have carbon, you have fuel. The biggest areas of carbon build up are usually vortex generation (large areas of fuel fall out that burn to latent to be useable cylinder pressure).



__________________
Darin Morgan

(Chief R&D head guy for Reher-Morrison)

So the plug is in an area that is quite lean by the looks of it . So I can sort of imagine that this plug has a hard time igniting the mixture. But it does not show WHEN the mix is lean or rich or the point you want to set fire to it. or if some point later ( when the piston is closer the plug) does not get washed with fuel so is hard to light at all. .


ps.
apparently you can use an accelerometer and a scope to ''listen'' for knock

Edited by Sir Yun on 5th Sep, 2012.

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

Have you seen what Joe C did with his plugs?

In the 13's at last!.. Just