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(JOY FOUND!!!!) Final engine tune - no joy yet!!


worzella
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For those of you following my posts, after 8 years of working 
on this '75, I have it at my brothers in Charlotte for final 
tune and maiden voyage. We conquered brake bleed woes and 
think a new alternator will solve charging "L" light mystery, 
but this past weeks visit (I live in Raleigh) was to get the 
newly rebuilt motor "purring". That is the word I am shooting 
for, since other posts say that is how they run when the 
stars align.

But after 2 days of work, it is far from purring... more like 
puking!

1) Hot Spark wired correctly and plug wires right. No dwell 
to set.

2) Timing next. I unpacked my shiny new Innova and after getting 
the RPM to settle as close to 1400 as possible, I was thrilled 
to see the BB in the flywheel viewing window and the pulley mark 
fairly close to the pointer. After some small rotation of the 
dizzy, the BB slid over to the edge and the pointer pulley 
mark was almost dead on. My brother and I agreed we now had 
it timed pretty solid.

3) Valves... I set them to .007" and felt they were good.... 
but more on this later.

4) Distributor - Reman Cardone from Rock Auto. Yes I know the 
quality and curve numbers are a crap shoot, but I decided to 
take a chance since other reputable post'ers said they run 
with one just fine. I tested the plate movement when I got 
it in the mail, and a good suck moved it fine. After the 
initial basic 1400 BB/timing I hooked up the advance hose 
to the carb vacuum port down at the base.

5) Finally, as everyone says, now is time for carb adjusting. 
This is a brand new Carbs Unlimited official Spanish 32/36, 
not a China knockoff. I paid extra to jet to CD's recipe 
and I can only assume it was done. More on that later too. 
I followed the instructions that came with the carb from 
Weber and they were VERY, VERY adamant (bold text and 
exclamation points) and set up the initial idle/mix settings.

Check, double check and fire in the hole. My heart hoped for 
a purr or close to it, but instead it ran like a pig, 
faltering, unable to take a rev without constant backfire 
through the carb. Hope for joy sank into deep depression. 
I am a person with happy brain chemistry, but man this 
car really sends my joy spiraling downwards at times like 
these.

So on to the possible issues..

1) The biggest clue/issue seems to be the backfire out 
of the carb. The primary barrel and plugs are full 
of dry, back soot. FAQ posts say this is a RICH condition 
but CD and other posts say backfire from intake 
is a LEAN condition. My brain tells me explosions out 
of the carb mean one of two things. Timing way off 
or intake valves not closed during ignition

2) Timing
   But having the BB and pulley pointer line up almost 
textbook makes me feel OK about timing. But later that 
night at my brothers favorite bar (trying to re-align 
my brain chemistry from sadness to joy), I was talking 
to many of his motor head friends and one suggested we 
have to consider the POSSIBILITY that we have the 
timing chain one tooth off. WTF!!! I can't even comprehend 
right now what that means but am thinking it through.

3) Valves
   I set the valves to .007" on the bench when i got 
the head back from the shop. I have set clearance 
before, so have some experience, but totally possible 
one/more intakes are way out of spec. My brother 
is going to crack the cover and check my homework.

4) Dizzy
   Another guy at the bar said we have to test vacuum 
levels since low values point to the valve problem 
and would lead to poor advance.  

5) The overly complicated, fuel leaking device - AKA the carb
   I may have to crack open the top and verify the CD 
jets were built and the float is correct. Some 
posts say too much fuel being dumped could be an issue. 
But another thing that really bothers me is 
that with the Weber prescribed initial settings of idle/mix, 
the car would hardly start, let alone idle. 
We had to actually clip the idle screw spring in half to 
get enough forward movement of the screw to 
find an idle that seemed OK. We finnaly found idle/mix 
that seemed to be the sweet spot. But the Weber 
docs had another BOLD note saying that if you have to 
adjust in the idle screw more than xxx turns, the 
jetting is wrong and should be addressed.

But regardless, it ran lumpy and like shit with lots 
of shake and any rev causing a carb backfire. I 
will not get back to car till Jan probably what with 
holidays coming up, but any thoughts (and prayers!) 
will be greatly appreciated.

Randy 
Edited by worzella
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Couple of thoughts....

 

- confirm distributor is rotating in the correct direction = clockwise

    (rebuilder could have installed the incorrect distributor gear)

- with engine at TDC, confirm #1 plug wire goes to cap location where rotor is pointing (or close)

- confirm 1-3-4-2 firing order

- next time it’s running, loosen the distributor a bit and try rotating it a few degrees each way and see if it smooths out

 (you know I’m not keen on using the ball method for timing, for more reasons than space/time here to explain).

- re-check your valve clearance

- when you rotate engine back to #1 (where the ‘line’ on the camshaft flange is directly under the center of the spray bar) look for the “OT” line through the bellhousing. If you see it, you have not likely skipped a timing gear tooth).

 

Finally: clipping screw on idle mixture volume screw indicates an issue - never had a need to do that.

 

Good luck. And Happy Holidays. -KB

 

 

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12 minutes ago, kbmb02 said:

- confirm distributor is rotating in the correct direction = clockwise

    (rebuilder could have installed the incorrect distributor gear)

 

 

you cannot just change the distributor gear and still have it mesh with the camshaft, can you?

 

if the distributor is spinning counter clockwise, it must have the wrong gear as well as the wrong camshaft.

 

no?

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42 minutes ago, '76mintgrun'02 said:

if the distributor is spinning counter clockwise, it must have the wrong gear as well as the wrong camshaft

And if the dizzy is made to rotate counter-clockwise and it is now rotating clockwise, when the mechanical weights swing out, the rotor won't advance, it will RETARD?  The "Master Dizzy Tinkerer" can confirm this

Edited by jimk
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If your timing is outa wack, the carb's idle speed screw setting will be 'misleading'.

 

Float height is worth rechecking.  Remember there are different settings for plastic/brass floats.

 

Since you have a timing light with the variable advance feature ((:))), you might as well see what you can learn about that Cardone distributor.

 

Setting the BB at 1400 is not correct across the board.  

 

With the BB set there, you can then check to see what the all-in advance is, as well as the advance at idle.

 

Another way to go about it is to set the all-in advance where you want it and then hunt for the BB, to find the rpm that gives 25 degrees (for future timing setting ease) and also check the idle advance at that setting, to make sure it is in the ballpark.

 

As for the vacuum affecting timing and making it run poorly, the vacuum advance pod should be disconnected during timing tuning procedures; so, it is not the problem here (unless it was still connected).

 

I'd plot the curve for that new distributor, if it was me.  Start with the high rpms and work down.  It makes for a less stressful finish.  Set the light for the advance you want to plot and then find the rpm that gives it; rather than holding an rpm and hunting for the advance reading.  It is much quieter that way.

 

 

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I am absolutely no expert and Ken is the first person I’d call if I had this problem but the first thing I would do is ABSOLUTELY loosen the distributor and move it one way or another and see if it runs smooth. The backfire thing sounds like timing to me. I know you are trying to tune it “by the numbers” but with a variance of parts and suppliers sometimes the numbers don’t work as well as good old fashioned how does it sound and feel. At least to get you In The ball park.  

Edited by jrhone
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5 hours ago, '76mintgrun'02 said:

 

 

you cannot just change the distributor gear and still have it mesh with the camshaft, can you?

 

if the distributor is spinning counter clockwise, it must have the wrong gear as well as the wrong camshaft.

 

no?

 

Yep, you’re correct - I only half-thought that one out. (The one time I had a CCW/‘backwards’ set-up in the car, I almost set the plug wires up the wrong way.) -KB

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+1 Verify plug wires have correct firing order. Reversing 2+3 wires will do that.   +1 on moving the distributor while running.   +1 on vacuum leak. Put a vacuum gauge on something and check vacuum. Is booster connected properly or is the hose cracked? Pinch booster hose off and try again.   Pull plug wires one at a time while running and check idle drop. Something basic is off and it's probably not the carb. Don't diddle the carb too much and get lost as to where it was when you started.

 

You didn't drop a spark plug when installing and close the electrode, did you?

 

It'll be fine. It's something stupid.

 

 

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  • 1 month later...

Hello all - 

 

I have not posted in recent weeks due to my depression about the state of my rebuild and the final steps. But Santa came early and gave me the gift of “Here’s what the hell was wrong!”.

 

For those following some of my issues (see top of post), my brother and I could just not get my rebuilt motor to purr. We ran out of time in my last visit and we put the car cover on it and walked away in disgust. As many of you probably have felt, I have had this gnawing disappointment after such a long run to get my car restored. 

 

Well, I got some great advice from many of the gurus on the FAQ and I have learned an important lesson in “Listen to your elders!” :) I say this since the answer was in the words of the posts. And Andy Leonard gave the most sage advice:

 

    “It'll be fine. It's something stupid.”

 

And indeed it was! The other guys who advised had comments like these:

 

Ken

    - confirm 1-3-4-2 firing order

    Clipping screw on idle screw indicates an issue - never had a need to do that.

 

Ed Zinz

    Double check your plug wires are fully seated and in correct firing order.

 

Andy Leonard

    +1 Verify plug wires have correct firing order. Reversing 2+3 wires will do that.  

 

A quick summary of the symptoms - The motor was shuttering, shaking and generally running like shit and to me, the biggest clue was the backfire (literally fire!) coming out of the carb. I posted several questions on this and read many things, and so many answers came back that it was caused by a “lean” condition. But in retrospect, I am pretty certain now that a “pop” may be caused by some density/vacuum  imbalance (like popping open a jar of something), but in my case these were not pops, but explosions. 

 

So to get to the point (sometimes hard for me :)), I ran across this video which is an interesting watch for more novice folks like me and it had my gut telling me that I had an intake valve adjusted so badly that it was open when a cylinder was firing.

  

 

 

This guys choices for backfire were bad timing, swapped plug wires and bent valve. I was pretty confident the timing was right and plugs wired correctly, so I was hell bent on the valve  idea. I also felt pretty good that I did not have a bent valve since the motor was a fresh rebuild. 

 

Back to the 2002 in the garage with the cover on. My brother went out last week, pulled the cover and sat down and went through the basics. He checked the coil/Hotspark/ignition wiring… all good.. popped the valve cover and every valve was dead on .007”, except for one tight exhaust. He then fought the “It can’t be this” feeling and checked the $@#%^&^$% plug wire order.. and sure enough…. wait for it… we had them wired in order COUNTER clockwise, not clockwise.

 

This will always remain a mystery, but he connected the wires initially and being an American muscle car guy, perhaps a ‘69 Dodge Dart dizzy spins counter. But in the end, I was tasked before we gave up to “Check the wiring order”. I did.. and apparently had drunk too many beers that day, because I did not see the problem. 

 

So when he swapped the wires and fired it up, it puuurrrrrrred like the fine German fraulein she is. No more shutter, no backfire and a beautiful sound to his ears. He called me at work and at first I thought it was a cruel joke, but you cannot believe the weight lifted off my shoulders. Truly one of the best Christmas presents I ever have received :)

 

So that night after work, I went to my favorite brew pub, Raleigh Brewing, for a few Moravian pilsners and drew myself a picture (below)… and so many symptoms make sense based on this. I think I am right in my analysis, so wanted to share my thoughts. Would love to here comments on what I surmise.

 

image.png.f8b61580ff9d12fb76286c7ac70f6202.png

 

My picture shows each cylinders bang, blow, suck, squeeze sequence for the proper 1342 clockwise ignition. I made a square around the proper sequence, with BANG being the right answer. But we had 3 and 2 plug wires swapped on the dizzy and this led to BANG, SUCK, BANG, SUCK as the ignitions sequence, marked by the circled SUCKs. In my brain, this means two of the four ignition sequences were on cylinders in SUCK phase with the intake valve wide open!!

 

I am a person who has to understand WHY, so this is my analysis that seems to explain exactly what I was seeing.

 

Shuttering – Well, hell.. it was running on 2 cylinders, so what do you expect.

 

Backfire - 2 cylinders igniting when intake open causing the huge backfires out the carb

 

Idle screw spring needing to be clipped – Not 100% sure on this one, but since it was firing on 2 cylinders, I am guessing that to get the proper RPM I was looking for, I had to supply twice as much fuel to get RPM out of half as many cylinders. As such, just to even get a simple idle or up to 1400 for basic timing, we had to clip the idle spring in half so we could turn the screw in a bunch more. My brother said as soon as he fired it up with proper plug wire sequence, the idle was racing at 2000. So he backed the screw way out !!

 

So that is my long story and I just can’t believe it was such a simple, stupid mistake. But thankful that it was not something worse. 

 

Happy holidays and have high hopes now of meeting everyone at the 2018 Vintage in person with my own 2002… so I can stop living vicariously through so many of you!!

 

Randy 

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I've never done that.

 

Not even on a V6.  

 

Nope.

 

Never.

 

heh.

 

Glad you sorted it!  Oddly, one of the skills you learn as you progress with this disease

is 'beginner's mind'- "yes, I KNOW this part is right, but I'm STILL going to do these very basic

tests to confirm it"- like rolling the engine over a half- turn at a time, and matching distributor tower

to plug wire

(that was how I 'fixed' the V6 after I 'fixed it better' the first time)

 

Also why I'm such a big fan of the leakdown test pretty early on in the troubleshooting process-

it eliminates the mechanical pump side of the equation in about 20 minutes.

 

t

 

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