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The Brunhilde Tuning Thread


2002Scoob
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Hi all!

 

So it's been a long time since I first posted about trying to self-tune my setup. 

 

For those who might not remember (or are new to my debacle, haha) this is what I'm working with-

 

Factory Bottom End- No evidence of a lower-end rebuild, very likely has some oil blow-by on the piston rings, but that's ok for now. I'm working with what i've got both car and budget wise. A higher compression rebuild is likely in the future.

 

Rebuild Cylinder head

-Schrick 292 Camshaft

-Schrick HD Springs (singles)

-IE HD Rocker Arms

-IE Rocker Locks

 

Rebuilt Italian Weber 40DCOE32's

-Not a true 'matched' pair, but both Italian, and both DCOE32's.

-32mm Chokes

-F16 Emulsion Tubes

-50F9 Idle Jets

-2.00 Needle Valves

-Cold Start Elimination Kit

- 132 Mains

-195 Air correctors

- 25mm Trumpets

- Home-Made Air-Filter

 

Ireland Engineering Shorty Manifold

 

Ireland Engineering sourced Low-Pressure Electric Fuel Pump (trunk-mounted)

 

Ireland Engineering Distributor

 

Pertronix Flamethrower Ignition Coil

 

After installation of the Cylinder head and re-assembly, I torqued everything down and set valve clearance appropriately.  

 

So, here's the first time Brunhilde ran after a 1 year hiatus! First thing I notice was that even though the timing was just hand-adjusted at this point, the idle is relatively smooth and the engine has no shakes.

 

 

MIXTURE SCREWS WITH 50F9 IDLE JETS- ~2.5 turns out

After that, I've since settled on an even 16 degree's advance at 1000 RPM, and it seems pretty happy with that. However, it required backing out the mixture screws 2.5+ for the happiest idle. This leads me to believe I need to go leaner on the Idle mixture jets.

 

*I have not set total advance, but will look to once I get everything else closer to the ballpark, and feel more confident rev-ing her up. Ireland Engineering's directions suggest setting 34-36 degree's total advance, and that should lead to an idle advance between 14-16, and around 16 she seems to run best. 

 

FLOW RATES AT IDLE (1000 RPM)

Cylinder 1- 3.5 kg/h

Cylinder 2- 5.0 kg/h

Cylinder 3- 5.0 kg/h

Cylinder 4- 3.25 kg/h

 

I've also since installed a Fuel Pressure Gauge after the Filter-King regulator, ahead of the carbs

 

FUEL PRESSURE

2-2.25 PSI (doesn't seem to make a damn difference if I turn the adjustment screw all the way in, which should equal more pressure, so I'm guessing 2 is as high as the fuel pump delivers) 

 

 

AFR RATIOS 

Unfortunately I've been having power/ground issues with my gauge, so I need to get that fixed soon. But at Idle I was able to have the car sit happily at 12.5-13.5, but the numbers would jump around. I'll update once I get it back up and running.

 

 

Since this setup, I've driven appx. 1.5 hours, and had her running stationary another 2 or 3 total. no hard driving/ hard acceleration under load. Below is a video I took yesterday of her running after I had a situation where she died at a gas-station for a while. 

 

What happened was I started/warmed her up at home in my garage, drove around for maybe 15-20 minutes, shut her down at a gas-station, filled up, and when I went to restart she refused. You could smell fuel, and I was getting spark but she wouldn't cough to life. 

 

Unfortunately I didn't have my spark-plug tool on me, so I had to wait about an hour, and then was able to get her re-started by going WOT and cranking a bunch. I'm leaning towards flooding of the cylinders. 

 

Here's the vid-

 

 

WHAT I NOTICE

 

1. When comparing the vids from first startup till now the idle is not as smooth.

 

2. She's started coughing a bit through the rev range. 

 

3. When I have tried leaning into the throttle around town, the response is quite sluggish, and not snappy or aggressive, leaving me thinking that the jetting is not ideal. Perhaps too rich? (need to confirm with AFR gauge)

 

4. With zero load, she seems to rev-up fine, but like I said before, under load, the motor feels a bit pig-ish.

 

5. At higher RPM's, I'm getting a bit of smoke from the exhaust... Likely Oil. Likely cylinder rings. 

 

6. Theres very light puffing of smoke from the valve breather. also guessing ring blow-by. But there isn't an excessive amount of air-pressure. This wasn't an issue when I pulled the original head, but it had pretty bad valve-guide blow-by originally, so I'm going to bet the tighter top-end is exposing weaknesses in the bottom-end.

 

7. Something definitely sounds off to me, as if the motor is missing a beat. (there is a slight exhaust leak at the doughnut gasket I'll fix that, so listen past it) But all 4 cylinders are getting spark. I'm going to maybe guess due to fowling of plugs?? 

 

Speaking of...

 

 

PLUG CONDITION AFTER INITIAL SETUP/RUN-IN

 

Here's where deeper issues start to show themselves...

58ea12b9a745f_SparkPlugsRound1.thumb.jpg.9fd791db5f9d073198d8c931b97f0fd4.jpg

 

To me it's obvious that the forward carb is running much richer than the back carb... which is concerning. and the back 2 cylinders look pretty good. 

 

1 and 2 are heavily fouled, but the residue wasn't apparently oily.

 

QUESTIONS

 

Do you think the rich-ness fouling on the forward carburetor has more to do with the Idle circuit, the actual jetting, or the carb itself?

 

What would cause two carburetors with the same prescriptions to be so much different in rich-ness, and what could possible problems leading to it be and their fixes?

 

As for Jetting, do you guys still think I'm in the ballpark? Looking at #3 and #4 I'd lean towards yes, but the fronts... no.

 

Hesitation starting and Hot-starting issues- I'm leaning towards the front carb having the flooding issue, looking at the #1 and #2 plugs... It was recommended in my other thread to pull the floats and see if they're leaking. Any other possibilities, remedies, or places to look?

 

Toby and other often bring up the possibility of twisted throttle shafts... Could this be what's leading to the different flow rates between 1&2, and 3&4? How far off is too off? What's the remedy (I'm guessing it's removing the carbs and doing some twisty-pully action)

 

Thanks again 02FAQ community! Me and Brunhilde appreciate your efforts :)

 

-Jeff+Brunhilde

IMG_4283.thumb.JPG.2dc1a1dfb557d8fd99a0ab8d2414af4d.JPG

 

 

 

 

 

Edited by 2002Scoob
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The difference in flow between chokes on the same carb is disturbing. This definitely needs looking at. Where are the edges of the throttle plates compared to the transition holes? I assume those carbs don't have idle air bypass screws?
 
 

Nope, no bypass screws on the old webers.

Transition holes look pretty darn even. You can refer to my 'no money to tune' thread where I showed the mechanicically syncing of the two comparatively.

I'll revisit and shine some light in the progression holes when I'm next in the shop and take some photos.


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Second the flow difference and those plugs are what I see as the main concerns.  #4 also looks *too* clean, like not much is happening back there, but maybe that's just the picture.  Here's my two cents for both the carbs and ignition items:

Ignition - put you light on each HT wire individually and make sure you're getting consistent steady flashes for each cylinder.  If so, then put in fresh plugs. If not, look deeper into the distributor.

Carbs - I know you've checked the float levels, but how old are the needles? Might be one needle isn't sealing at the same height as the other.  My other thought is the acceleration pump circuit. Is yours the piston or diaphragm type? I forget how they adjust, but you can at least visually check for similar amounts of 'fuel squirtage' when you pump the linkage and then look into any adjustment if something looks off.  I can't think of how one might leak extra fuel at idle, but should be possible.

P.S. Wie geht's das Wetter in DE diese Fruehling? 

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The difference in flow between chokes on the same carb is disturbing. This definitely needs looking at. Where are the edges of the throttle plates compared to the transition holes? I assume those carbs don't have idle air bypass screws?
 
 

Nope, no bypass screws on the old webers.

Transition holes look pretty darn even. You can refer to my 'no money to tune' thread where I showed the mechanicically syncing of the two comparatively.

I'll revisit and shine some light in the progression holes when I'm next in the shop and take some photos.


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Second the flow difference and those plugs are what I see as the main concerns.  #4 also looks *too* clean, like not much is happening back there, but maybe that's just the picture.  Here's my two cents for both the carbs and ignition items:
Ignition - put you light on each HT wire individually and make sure you're getting consistent steady flashes for each cylinder.  If so, then put in fresh plugs. If not, look deeper into the distributor.
Carbs - I know you've checked the float levels, but how old are the needles? Might be one needle isn't sealing at the same height as the other.  My other thought is the acceleration pump circuit. Is yours the piston or diaphragm type? I forget how they adjust, but you can at least visually check for similar amounts of 'fuel squirtage' when you pump the linkage and then look into any adjustment if something looks off.  I can't think of how one might leak extra fuel at idle, but should be possible.
P.S. Wie geht's das Wetter in DE diese Fruehling? 


I thought the #4 also looked a bit oddly clean when I pulled it as well... but I did do as you suggested- putting the timing light on each lead to check for spark and all 4. I've got 2 sets of fresh plugs I can try, so I will.

As for gap I'm running .8mm (appx .35 in) if that means anything. I had thought to close it down a bit, or switch to 5's due to burning a little oil.

The accelerator pumps are piston style, not diaphragm.

Are you referencing the float needles or mixture adjustment screws? All were replaced.

Und die Wetter ist so geil en Freiburg! sonnig und warm heute. :)


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Hmm, alright will if all 4 wires are flashing nicely and with a new set up plugs, my guess is that your ignition is in fine shape and we should really focus on the fuel.  And I meant the float needles, but it sounds like you've done your due diligence on these carbs.  Still at this point, it might be worth just pulling the lids off and the jets out and just checking everything over a second time, especially because I agree it looks like it idled better in your first video.  I just have a hard time believing that the difference in airflows really explains those plugs. . .but let me keep thinking! Viel glueck!

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So, this evening I was able to get a light back in the chokes, and I think I confirmed part of what could be contributing to the lean-rich scenario between the carbs.

 

It appears that the linkage slipped somewhere, probably at the arms to the main shaft.

 

Here you can see where the forward carburetor's first progression holes were half-covered, where as rear carb's were almost completely covered.

58eab97746317_Carb1ProgressionHoles.thumb.jpg.b4f991bdb21b0bfd0796393a9e2a3ed1.jpg

58eab98654936_Carb2ProgressionHoles.thumb.jpg.5061406df0078c7ebc889b72d2758035.jpg

 

Maybe also contributing to the flow differences between chokes on each carb, 1&3 appear to be letting slightly more light through... whatch'all think?

 

I went ahead and filed the shafts where the arms mount, and after visually matching the carbs, applied permanent loctite to secure the arms to the shaft. (I remember somebody recommending actually tack-welding them)

 

Here you can see the corrected rear-carb. 

 

58eaba9549fe5_Carb2ProgressionHolesReset.thumb.jpg.b7683ed57e629d52aaa47b9a5b1b50e8.jpg

 

I also went ahead and pulled all the jets to let them soak over-night in carb-cleaner, just for good measure.

 

My plan tomorrow is to check the needle valves for freedom of movement in the forward carb, as well as check for a possible leaky float.

 

If all is well, install some new plugs, get my AFR gauge back up and running, fire her up again, and see where those flow rates are at again. 

 

When I rebuilt the carbs, I intentionally left the throttle shafts/valves as-is other than a gentle cleaning, as they looked good so I was hoping they were fine. That coulda' been a mistake. 

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Sooooo. After the above visual synchronizing I'm back where I started, but a bit worse.

 

I pulled the float on the forward carb, didn't sound like fuel inside, and no temp change when rolling it around in my hand.

 

I went so far as to weigh it on a gram scale (26g if you're curious) submerged it in water for 5 minutes while lightly squeezing the floats. No bubbles, and no change in weight.

 

I just bolted everything back together with freshly cleaned jets, fired her up, reset idle, and messed with mixture screws so that the AFR is appx 13.5.

 

I'm registering spark on all 4 according to my timing light, no way to tell if #4 is weak, but the flash is consistent.

 

Airflow readings at 1000RPM as follows...

#1 -7

#2-5.5

#3-5.5

#4-3.25

 

What do you guys feel could be the culprit(s) ?

 

 

If it is the throttle shafts is it possible to re-torque the shafts, or is it better to just pull em and replace?

 

At what point should I just man-up and get a pro? Haha.

 

I was however googling home made flow benches... looks pretty easy [emoji14]

 

 

 

 

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First off, Jeff... GREAT pictures and video and data.  It's refreshing to see someone lay out all the evidence so nicely.

 

Puzzling that you see so much difference between throats on the same carb (#1 & #2).  Solexes use individual shafts with a balancing screw in between each throat to help with such sync issues.  USUALLY Webers don't have such a varied flow with the shared throttle shaft.  

 

I could hear it out of sync, but I'm not sure what to tell you about solving the differences on 1 and 2.  Have you sync'd them at a higher rpm? say... 1500 revs?  Is the difference still noticeable?  Getting a good reading on #3 is difficult with the interference of the brake booster... Do you feel the gauge is getting a good seal in the stack?  

 

Are you sure you installed the brass throttle plates in the same position as where you removed them?  (#1 went back to #1 position, etc...)  Were all the throttle plates unmolested? Did they all have flat edges? or did any have the edges filed down to match the progression holes? IF the plates were filed down and they were not returned to their original position, that could cause an out-of-sync condition. (Simeon eludes to this above)

 

Spark plugs seem to run the gamut from too lean to sooty.... crazy.  Are you sure you don't have a vacuum leak somewhere?  (sprayed carb cleaner all around the carbs while the engine is running to listen for changes in idle speed?)

 

It could boil down to the unmatched carbs... maybe that's why someone was selling them?  Used carbs can be a crapshoot... but let's see if we can continue chopping away at your problem.

 

Ed

 

 

 

 

 

 

Edited by zinz
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First off, Jeff... GREAT pictures and video and data.  It's refreshing to see someone lay out all the evidence so nicely.
 
Puzzling that you see so much difference between throats on the same carb (#1 & #2).  Solexes use individual shafts with a balancing screw in between each throat to help with such sync issues.  USUALLY Webers don't have such a varied flow with the shared throttle shaft.  
 
I could hear it out of sync, but I'm not sure what to tell you about solving the differences on 1 and 2.  Have you sync'd them at a higher rpm? say... 1500 revs?  Is the difference still noticeable?  Getting a good reading on #3 is difficult with the interference of the brake booster... Do you feel the gauge is getting a good seal in the stack?  
 
Are you sure you installed the brass throttle plates in the same position as where you removed them?  (#1 went back to #1 position, etc...)  Were all the throttle plates unmolested? Did they all have flat edges? or did any have the edges filed down to match the progression holes? IF the plates were filed down and they were not returned to their original position, that could cause an out-of-sync condition. (Simeon eludes to this above)
 
Spark plugs seem to run the gamut from too lean to sooty.... crazy.  Are you sure you don't have a vacuum leak somewhere?  (sprayed carb cleaner all around the carbs while the engine is running to listen for changes in idle speed?)
 
It could boil down to the unmatched carbs... maybe that's why someone was selling them?  Used carbs can be a crapshoot... but let's see if we can continue chopping away at your problem.
 
Ed
 
 
 
 
 
 


Thanks for the reply, Ed!

I'll check the sync at higher RPM's tomorrow, I didn't have too much time to tinker this evening.

What I didn't do when I rebuild the carbs was touch the throttle plates or spindles. They spun freely and looked visually OK by my untrained eye. From what I remember all the dges all looked pretty good, and appeared to be decently centered in their bores upon light-inspection

Here's the photos from when I was visually syncing the carbs on my workbench-
1
46bb1aab1e8bab3427175fd0add0cb9b.jpeg
2
0d273055f000a9e2e8801f945d0e3212.jpeg
3
6fb5177f49b50e64626a665054f21b06.jpeg
4
0a8aa160c93a2de737f72e8fec290557.jpeg


It's hard to say how centered I was lining up the flashlight at the time, or if the light could have been aimed at the lens causing the light varied light flares, but the plates seem relatively centered in their bores.

My memory isn't good enough to recall if there was any filing to the throttle plate edges, but I don't think so. All things are pointing towards me having to pull'em for further investigation.

I was doing some reading up on a few other forums of guys with issues with different readings on different bores of the same carb.

I'll run her again tomorrow to double check the flow readings, and check for any errant vacuum leaks, but I don't think so... everything is torqued down tight, the only variable could be the line to the brake booster off the back of the manifold. Could a faulty PCV valve be contributing?

And with my shorty trumpets getting to #3 is a bit of an odd angle, but I can get a seal.

There seems to be three ways to address a torqued spindle issue.

1. Drill some tiny strategically sized and placed black-magic knowledge inspired holes in the offending throttle plates.

2. Somehow counter torque the spindles to obtain similar readings and hope they stay torqued...

3. Rebuild with new shafts/plates.




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Balancing- pick the highest flowing barrel. You must twist( tweak) the shaft by holding both ends with the plates slightly open to not jam the plates. ( Old Porsche trick)

 

But before you do all that, put a piece of cardboard  to block the fan's turbulence before reading airflow otherwise it's likely to be rich. Close the front carb's throttle  a bit and open the rear a bit.

 

Plumb your fuel gauge  so you can pinch off the fuel supply to each carb to check to see if the front carb's inlet needle is holding. Confirm that  each holds pressure for say at least two minutes. No guage- pull the fuel line and something should indicate pressure. The seat could be loose. It's possible for the fuel to siphon either way if the inlet needs are leaking.

 

Next is the fuel pump- supposed to be a check valve device to prevent this. In keeping with your no money for tuning- just position the fuel line slightly higher that the fittings- a hump. Not even or below in your picture.

 

Next, adjust your floats, lower the front. Then raise the rear. You've got too much fuel on the front and not enough on the rear.

 

But you've got multiple problems- pick one carb or problem and work it.  I suggest fix the lack of fuel problem on the back carb  first.

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Quote

 I know you've checked the float levels,

 

is where I'm at with the plugs.  All else being equal, #1 float level's higher.  By a bit.

Or the floats in #1 carbie are sinkier.  Take a look at the fuel levels- and if you can do a 'plug chop', so much the better.

 

Then start dicking with the idle jets.  See how much (or how little) you can influence the airflow in one barrel by

leaning it out/fattening it up.  You may be surprised...................

......................

......................

......................

at what happens.

 

Or not.  Maybe a PO ran a needle or 2 down hard, and changed the taper in the body.  It happens.

 

But I agree- you've done truly due diligence at diagnosing this, and I do love your pictures.

I don't see anything obviously off with your flappers- the progressions look like they're all in the right places,

about.

Do the throttle plates all look the same?  Nothing odd physically, like cuts, grooves, gouges, bends, soldered- on bits?  (of course they do)

 

Hey, are you sure the warm- up circuits are truly closed?  They mess everything up if they stick/bind/leak/are missing their pistons.

 

DO drive it hard.  After it thoroughly warms up, that's the best thing you can do for it.

It's not going to buff in its bearings, but it MIGHT finish seating in its rings!

 

Then check for leaky isolation gaskets.  Those suckers can leak a lot of air as the carbs flop up and down with vibration at speed...

 

 

...and stick a timing light on it at 5000- just for due diligence.  36 is good.

 

all I got, hope it helps...

t

 

 

Edited by TobyB
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1 hour ago, zinz said:

of course... fuel levels.

 

1 hour ago, zinz said:

e easiest route to try at the moment.  Tweak the fuel levels first

 

11 hours ago, TobyB said:

 All else being equal, #1 float level's higher.  By a bit.

Or the floats in #1 carbie are sinkier.  Take a look at the fuel levels- and if you can do a 'plug chop', so much the better.

 

16 hours ago, 72koop said:

Next, adjust your floats, lower the front. Then raise the rear. You've got too much fuel on the front and not enough on the rear.

 

 

This is sounding like the most important thing to check at the moment before I go tweaking/twisting/pulling stuff apart. 

 

I'm going to triple check my float measurements, and do as 72koop mentioned and lower/raise the floats of the two carbs accordingly. 

 

Question- Just how sensitive is float height? Should I be looking at accuracy to a half mm, or as tight as .1 or more? (I have the power, haha)

 

11 hours ago, TobyB said:

Do the throttle plates all look the same?  Nothing odd physically, like cuts, grooves, gouges, bends, soldered- on bits?  (of course they do)

 

If it comes to pulling the carbs off, i'll double check, but I don't remember anything standing out that seemed sketch. Otherwise I definitely would have pulled them for a refresher. 

 

From what I do remember, they all looked nicely beveled, relatively flat, and seemed to have even gaps, no old drillings that were soldered in. (speaking of, I soldered in my Wideband AFR gauge. No more fritzing out!)

 

But we'll see....

 

 

 

More progress/details to come. I'm going to look to order some new 45F8 idle jets, it was suggested to me that they should be pretty spot on, do others agree? They're not expensive, but I'd like to avoid ordering a whole slew of stuff if possible. 

 

 

But for right now.... It's beirgarten weather. 

 

And I want a Pretzel.

 

 

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