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Old 03-08-2010, 02:02 PM   #121
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CAR RUNS!!!!
Awesome.

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I thought that maybe the old CAS started "floating" around the timing at high rpms, but the new one does the exact same, and it's load related, not rpm related.
They all exhibit spark scatter to some degree or another. It's caused by deflection / stretching / etc of the timing belt itself, and is one reason why I went with a crank trigger.

Oh, in Megatune, look under Advanced -> Advanced Code Options. At the bottom is a setting for Hardware Latency. This is a compensation for fixed delay through the trigger circuit, but if it is set higher than necessary, then it will cause the ignition timing to progressively advance as RPM increases.

Verify by locking ignition timing 10, and then slowly running the engine from idle to 6,000 RPM while observing with a timing gun. If the spark tends to retard as RPM goes up, you need to add latency correction. If the spark tends to advance as RPM goes up, you need to reduce latency correction.


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This afternoon I am going to take the crank pulley off, and install my old one from the other motor.
Might be worth pulling the #1 plug and dropping the dipstick down the hole to verify that when the pulley says you are at TDC, you are in fact at TDC.
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Old 03-08-2010, 02:04 PM   #122
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You might be right there. I dont think it is the tune. This knock you get now occurs in areas where it did not before the shut-down right? As in, it happens in situations below max boost with moderate/high load where this particular engine did not knock at that load state previously?

So to me, I think: "What changed?"

And that leads to:

How confident are you in this 'new' CAS?
How sure are you on the cams and thier being just right?

Also, if i am misunderstanding and the knock you have now is just like before the unexpected shutdown, then I would look around the engine bay too. How are your motor mounts looking? Weird I know, but worth checking.


Screw it. What Joe said/says.

Last edited by Sparetire; 03-08-2010 at 02:05 PM. Reason: Screw it....
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Old 03-08-2010, 02:05 PM   #123
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you have a 92....is your oil pressure gauge going crazy when you hear this knock?
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Old 03-08-2010, 02:08 PM   #124
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Oh, in Megatune, look under Advanced -> Advanced Code Options. At the bottom is a setting for Hardware Latency. This is a compensation for fixed delay through the trigger circuit, but if it is set higher than necessary, then it will cause the ignition timing to progressively advance as RPM increases.

Verify by locking ignition timing 10, and then slowly running the engine from idle to 6,000 RPM while observing with a timing gun. If the spark tends to retard as RPM goes up, you need to add latency correction. If the spark tends to advance as RPM goes up, you need to reduce latency correction.



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Might be worth pulling the #1 plug and dropping the dipstick down the hole to verify that when the pulley says you are at TDC, you are in fact at TDC.
Was going to try this...considered writing at end of last post, but figured it's easy enough before unbolting everything.

I was actually halfway considering putting #1 at TDC using a plate across the valve cover, a bar in the cylinder, and a caliper held upright measuring the distance from plate to rod. I'm not sure if this would be good enough to make my own timing mark that would be easier to find in the future.

My understanding of internal combustion motors tells me I'd put this mark at the "0" at the far right of the plastic cover...but PLEASE correct me if I'm wrong.

Thanks.
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Old 03-08-2010, 02:09 PM   #125
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you have a 92....is your oil pressure gauge going crazy when you hear this knock?
Yes...it wigs out like Christopher Walken and Steve Buscemi's lovechild.
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Old 03-08-2010, 02:13 PM   #126
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You might be right there. I dont think it is the tune. This knock you get now occurs in areas where it did not before the shut-down right? As in, it happens in situations below max boost with moderate/high load where this particular engine did not knock at that load state previously?

So to me, I think: "What changed?"

And that leads to:

How confident are you in this 'new' CAS?
How sure are you on the cams and thier being just right?

Also, if i am misunderstanding and the knock you have now is just like before the unexpected shutdown, then I would look around the engine bay too. How are your motor mounts looking? Weird I know, but worth checking.


Screw it. What Joe said/says.


It seems to have gotten worse, which is pointing back to base timing since this has to be set when you install or move a CAS.

How confident...more so than the last one considering this one actually gives MS a second trigger input.

Pretty damn sure on cams. Have done that job about 5 times just on this car. Found the problem (f u Brainy) and fixed it.


Why do you mention motor mounts?

I had to reuse my DIY urethane ones since my new MMR/MC combo didn't show up until the Monday after the motor swap weekend. The motor pull/install could not have been easy on them, quite a bit of wiggling and pushing.

I have checked the ground strap, and I have another one on passenger side I added for good measure that runs from my rear of head ground block to the chassis.
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Old 03-08-2010, 02:18 PM   #127
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I was actually halfway considering putting #1 at TDC using a plate across the valve cover, a bar in the cylinder, and a caliper held upright measuring the distance from plate to rod.
(...)
My understanding of internal combustion motors tells me I'd put this mark at the "0" at the far right of the plastic cover...but PLEASE correct me if I'm wrong.
Assuming you can keep the bar relatively straight, this is a more-or-less ideal thing to do. I do a very similar thing, using a dial indicator on a base, set atop the machined surface of the head itself (with the VC removed) and a dowel dropped into the plug hole. You wind up with a tiny range of crank movement during which there is no observable dowel movement, and true TDC is in the middle of this range.

And yeah, assuming that the plastic timing scale on the TB cover is intact, then the mark you make on the pulley would go at "0" on the scale. That mark will then serve as your timing mark.
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Old 03-08-2010, 02:20 PM   #128
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A battered mount can rattle under a decent TQ load sometimes as the metal shealth through the middle is not really getting good isolation from the vibrations of the engine itself. On a lot of I-4s you will have a knock sensor screwed into the block pretty near a mount, and in rare cases this can trick a sensor into knock with all the noise it creates. That does not really compute in this case though. Hence the 'Screw it' edit. I am thinking out load so to speak.

The oil pressure is not affected by this possibility, so its not the problem. But I will say that going with quality poly bushings was one of the best things I ever did for my Laser.
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Old 03-08-2010, 02:28 PM   #129
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Joe:

Yeah, going for a DIY base-less dial indicator feel. Thanks for the clarification...

In the words of Jacobo: "I swear on my dead relatives - and even on the ones who are not feeling too good - I am your man forever!"


Sparedildo:

I am definitely looking forward to these hybrid mounts. My DIY ones made a big difference, but for the price I would rather have something proven, and somewhat stiffer.
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Old 03-08-2010, 03:24 PM   #130
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Assuming you can keep the bar relatively straight, this is a more-or-less ideal thing to do. I do a very similar thing, using a dial indicator on a base, set atop the machined surface of the head itself (with the VC removed) and a dowel dropped into the plug hole. You wind up with a tiny range of crank movement during which there is no observable dowel movement, and true TDC is in the middle of this range.

And yeah, assuming that the plastic timing scale on the TB cover is intact, then the mark you make on the pulley would go at "0" on the scale. That mark will then serve as your timing mark.
Joe,

You wouldn't have a video of this would you? I so enjoyed the thermostat one. I really did!
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Old 03-09-2010, 01:11 PM   #131
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Sparedildo:

I am definitely looking forward to these hybrid mounts. My DIY ones made a big difference, but for the price I would rather have something proven, and somewhat stiffer.
Yep. Sparedildo recomends a good stiff mount.
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Old 03-11-2010, 07:49 PM   #132
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You wouldn't have a video of this would you? I so enjoyed the thermostat one. I really did!
No, there are some things that I can figure out how to make funny, and others that just aren't.


Now, as for GoSpeed:

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Old 03-11-2010, 09:05 PM   #133
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I only drive the car every other day.

I set the base timing as well as I could yesterday.

Tomorrow morning another trip with the electronic det cans will tell if I have deeper rooted problems.
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Old 03-11-2010, 11:50 PM   #134
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I found out my spark timing is advancing with rpm...up to 5-6* halfway up the rev range!!!

Hardware latency is currently set to zero....I'm guessing it's not compensating at all, so any positive value I add will start to retard it, or keep it closer to 10* up the rev range.

Or is that backwards, and I can put negative values? Seems like latency would cause it to retard, not advance.
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Old 03-12-2010, 09:48 AM   #135
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it's doing this with the timing locked at 10?
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Old 03-12-2010, 10:09 AM   #136
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it's doing this with the timing locked at 10?
yes
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Old 03-12-2010, 10:12 AM   #137
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hmm is this through MS or your timming light?
if its via timming light i suspect your pulley is shot. and that would cause your base timming setting to be off as well. hence the nock. he damn rubber on those things dont last forever
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Old 03-12-2010, 10:34 AM   #138
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hmm is this through MS or your timming light?
if its via timming light i suspect your pulley is shot. and that would cause your base timming setting to be off as well. hence the nock. he damn rubber on those things dont last forever
wut?

This is with a timing mark I put on the pulley myself by putting #1 at TDC, and then set base timing using a decent light and making trigger angle adjustments in MS after setting the CAS back to the middle of adjustment range (allows for emergency retardation if knock ever surfaces on the road with only a 12mm wrench).

What we're trying to determine here is why base timing floats, as Joe mentioned in the other post up there. This wouldn't be a physical problem with the pulley. Joe has said it's a software latency issue, I'm just not sure how to go about adjusting it since there's a "0" there and not a number I can do step adjustments on. I don't want to mess anything up.
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Old 03-12-2010, 12:57 PM   #139
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It's advancing with RPM?

IOW, the timing notch is moving counter-clockwise (to the left) as you rev the engine?

With Hardware Latency set at 0?

That's impossible.

Or at least, not something which is explainable by me.
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Old 03-12-2010, 04:15 PM   #140
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It's advancing with RPM?

IOW, the timing notch is moving counter-clockwise (to the left) as you rev the engine?

With Hardware Latency set at 0?

That's impossible.

Or at least, not something which is explainable by me.
Yes. It looks just like a normal old vacuum advance distributor.

Yes, I have it set at positive ten when I checked, with latency set at 0. I know it's not normal advance because it doesn't match my spark table.

I will check again if I ever make it home today.
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