TBI rebuild

[tsr2185]

The timing is not at "0" degrees, if the pointy things don't line up at TDC.

Hb is at 0, and the best I could get to TDC with wrench and straw.

So what does that mean?
Timing chain off?
Dizzy skipped a gear?
My harbor freight gun is junk?
Do I need to manually orient dizzy to make the pointy things align?
Is this obviously my issue?

Need to know my path forward. Thanks for all the jnput!!!

 

[Schurkey]

Hb is at 0, and the best I could get to TDC with wrench and straw.

So what does that mean?
Timing chain off?
Dizzy skipped a gear?
My harbor freight gun is junk?
Do I need to manually orient dizzy to make the pointy things align?
Is this obviously my issue?

Need to know my path forward. Thanks for all the jnput!!!

Timing chain could be worn--or not. If the timing chain is worn, the cam timing could be off a little. This doesn't affect ignition timing, 'cause you'd just turn the distributor to compensate. The same goes for minor wear to the cam and distributor gear mesh--until it's so bad that the gear has terrible wear, you'd just turn the distributor to compensate.

Dizzy "skipped a gear" doesn't matter for ignition timing--you just turn the housing to compensate. If the housing has to be turned far enough, you'd move all the plug wires one post over, forward or backward depending on which distributor gear tooth is meshing with the distributor drive gear on the cam .

Hazzard-Fraught gun is junk? Possible. Worth inspecting. I'd expect a faulty gun to show overly-retarded timing; If I'm seeing the orientation of the teeth properly--and if I'm thinking straight--your timing is actually advanced. So that's the error I'd expect to see. Your advanced timing is showing as retarded.

You don't need to deliberately orient the pointy things, you need to verify your ignition timing with a known-good timing light.

No, I don't think this is an obvious cause for your driveability problem. Having a couple extra degrees of advance might (or might not) actually be beneficial. But probably not harmful especially if the knock sensor is happy.

 

[thinger2]

Mo better pictures. Seems like the pointy things dont line up? Also the rotor just snaps on??? I would think that's just a bad connection waiting to happen...

If you are truly at TDC I think you are off one tooth.
Happens all the time.
Yep, the rotor just pushes on. Make sure the shaft isnt all rusted up.

 

[thinger2]

Step one of engine diagnosis.
Determine the basic mechanical function of the moving parts.
The geometry and correct aligment and continual and consistant alignment of that geometry through rotations of the assembly.
That is just so basic.
Why in the flaming hell would you try for live data if you havent figured out if youre off a tooth, or timing chain skipped, or balancer is bad?
Make sure the mechanical parts all line up properly before you go chase something else.
It really does not help anyone even a little ******* bit if you tell them they need live data when you have skipped the very basics of engine timing.
And that phoney egalitarian self serving preening ego stroke is exactly how you chase people away.
How about helping the guy?

 

[tsr2185]

Step one of engine diagnosis.
Determine the basic mechanical function of the moving parts.
The geometry and correct aligment and continual and consistant alignment of that geometry through rotations of the assembly.
That is just so basic.
Why in the flaming hell would you try for live data if you havent figured out if youre off a tooth, or timing chain skipped, or balancer is bad?
Make sure the mechanical parts all line up properly before you go chase something else.
It really does not help anyone even a little ******* bit if you tell them they need live data when you have skipped the very basics of engine timing.
And that phoney egalitarian self serving preening ego stroke is exactly how you chase people away.
How about helping the guy?

In the AM I will pull the driver valve cover off and verify with the rockers tdc on cyl 1. it's pretty difficult ( for me) to 100% say its 100% tdc with the straw. I may also remove clutch fan to make it easier to access for me to manually turn over engine (which I only did with just cyl 1 spark plug out) and go grab there. I do believe the dizzy is too far clockwise compared to oem installation, I may remove and turn it a little once TDC is confirmed.

I appreciate all u guys input. I literally can spend more time on my phone than under the hood with the kids. Eldest starts school tomorrow and will have more time.

 

[thinger2]

In the AM I will pull the driver valve cover off and verify with the rockers tdc on cyl 1. it's pretty difficult ( for me) to 100% say its 100% tdc with the straw. I may also remove clutch fan to make it easier to access for me to manually turn over engine (which I only did with just cyl 1 spark plug out) and go grab there. I do believe the dizzy is too far clockwise compared to oem installation, I may remove and turn it a little once TDC is confirmed.

I appreciate all u guys input. I literally can spend more time on my phone than under the hood with the kids. Eldest starts school tomorrow and will have more time.

Just keep in mind that when you watch vids or look at websites.
A lot of that info dates back to way before TBI.
The basics of static timing a small block chevy really havent changed but the TBI system is a little bit different.
You cant just guess at the distributor placement.
You really do need to start with everything aligned properly.
This isnt an old HEI or points system.
You cant just aim it towards number 1 and expect it to work.
That is not how a TBI functions.
Just check the mechanical timing of the engine first.
Then you have some reset procedures to go through.
If it is mechanically correct.
Everything rotating the way it should valves opening and closing etc....
Then you start with the "bolt on" parts.
Does the egr work, is the throttle body leaking, are the injectors spraying correctly.
Etc...
Do a compression test and a leakdown test just for the **** of it.
In other words, before you get all neck deep into an engine.
Do the cheap and easy tests on it to see whether its worth it or not.
Thats just backwoods basic farmer ****
Make sure its worth it first bud.

 

[Erik the Awful]

"Waste spark" uses a single ignition coil with twin output terminals, to fire spark plugs in two cylinders at the same time--one on the exhaust ******.
...
You're describing a rotary engine system using parallelled components. Not exactly the same thing, since the rotary engine geometry never has a spark plug in the exhaust position.

Are the coils run as coil-near-plug? Because I still fail to see how you're getting your spark back through the distributor. I'm legitimately asking because I never heard that they ran that way.

EDIT: Google to the rescue! https://ngksparkplugs.com/en/resources/waste-spark-ignitions To be honest, I think wasted spark refers to firing on the exhaust stroke, and it doesn't necessarily mean two plugs are firing in alternate polarity, but that's what most people are familiar with.

 

[Schurkey]

Are the coils run as coil-near-plug?

No, because you need enough coil wire to reach from the coil output terminals, to two spark plugs. Well, I guess it depends on how "near" the coil is to those two plugs.

Because I still fail to see how you're getting your spark back through the distributor.

In a waste-spark system, there isn't a distributor.

In a distributor system, one end of the coil secondary winding is connected to the output terminal, and therefore to the distributor cap, rotor, and the plug wires. The other end of the secondary winding can be wired one of two ways--either it's grounded directly--to the distributor body, in the case of most HEI coil-in-cap distributors--or it's spliced into the primary winding, which makes the spark return path more complex because the spark current has to ride on the vehicle electrical system as "noise" on it's way back to the other end of the coil secondary windings. This is common, but the directly-grounded way is a bit more elegant.

EDIT: Google to the rescue! https://ngksparkplugs.com/en/resources/waste-spark-ignitions To be honest, I think wasted spark refers to firing on the exhaust stroke, and it doesn't necessarily mean two plugs are firing in alternate polarity, but that's what most people are familiar with.

Is there a factory-engineered system where a plug fires on the exhaust stroke, that ISN'T done by pairing spark plugs on a common coil, using a + output post and a - output post? Motorcycles have been doing that since Fido was a pup--the typical 4-cylinder in-line motorcycle engine uses two coils, one for 1 and 4, one for 2 and 3. They were waste-spark since at least Honda's original SOHC 750 in...1968 (?); and probably before that on some (not all) twins.

Your rotary didnt' fire on the exhaust stroke, because the spark plugs aren't positioned where a rotary has it's "exhaust stroke".

Or am I missing something?

 

[Erik the Awful]

Your rotary didnt' fire on the exhaust stroke, because the spark plugs aren't positioned where a rotary has it's "exhaust stroke".

Or am I missing something?

It'll help if you look up a diagram of a rotary engine while you read this. The leading ignition on a rotary is the lower set of plugs on the rotor housing, and the trailing is the higher set of plugs. The rotor face (the side of the triangle) sweeps upward from the intake, drawing in the mixture and slowing, then rapidly closes with the spark plug side of the housing. The lower plug fires first, optimally about 16 degrees BTDC if I remember right, and the higher plug fires 4 degrees later, about 12 degrees before the rotor face is flat to the plug side of the pertrochoid (fancy name for the rotor housing shape). As the combustion gases push the rotor on down, the rotor apex at the head of the flame front opens to the exhaust port right about the time the opposing rotor is firing. Thus, if you have the plugs both running on once coil, you're sparking during the exhaust cycle. It'll probably take most people several read-throughs along with a diagram to understand this, and I probably ought to make a video on it. It blew my mind when I first heard of running wasted spark, but with a 2nd gen RX-7 coil and an MSD-6A it made a significant difference in my engine performance. Rotaries lack torque? Not with the right ignition setup.

 

[tsr2185]

If you are truly at TDC I think you are off one tooth.
Happens all the time.
Yep, the rotor just pushes on. Make sure the shaft isnt all rusted up.

I was in fact off a tooth. I made marks when I installed the dizzy the first time and got it lined up now.

Confirmed TDC and HB we on with a wooden dowel on cyl 1 spark plug hole. Lined up good with the HB. Got it all back together and fired up and ran the same. Manually adjusted dizzy by ear and it sounded best at 12 deg adv. When I reved it it smelled almost like burnt oil so I put it to 2-1deg adv. I will take it to oreileys and use their gun to confirm mine.

Also, the cough is still present at the passenger side tail pipe. I put my hand over the drivers side hard and it blew ot off. I put my hand on the passenger side and push/pulled and when I pressed hard the truck stumbled. I set preload on all my valves, and the passenger side still has a cough/miss. Is this pretty much indication of a burnt valve? The radiator looks pretty new, and who knows probably was overheated prior to the new radiator.

Thoughts?

Anyway to confirm burnt valve without tearing engine apart?