The Force Awakens...

from the appearance of the plugs ID suggest gaping them at .045, verify your ignition wire ohms is less than 150 ohms per foot,
and it looks like your running a bit lean and a bit too much upper rpm ignition advance in the 3500 rpm and up power band,
and a bit rich or retarded on the advance curve, at idle
Id suggest kicking the primary jet size up two steps, and adding 2 degrees initial (off idle) ignition advance,
and backing off 2 degrees on total advance,
and verify you have consistent fuel pressure about 5 psi at the carb inlet port ,
verify the float levels are set correctly the fuel filter is not restrictive,or partly clogged,
once those changes and checks are done please re-post the pictures of the new plugs after a 1/2 hour drive time.
I'm fairly sure we can get some improved results

http://garage.grumpysperformance.com/index.php?threads/spark-plug-info.202/

http://garage.grumpysperformance.com/index.php?threads/reading-spark-plugs.3949/#post-25481

http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.co...u-need-to-know-setting-float-levels-etc.1115/

http://garage.grumpysperformance.com/index.php?threads/holley-carb-power-valves.1639/

http://garage.grumpysperformance.co...olley-accelerator-pumps-cams.1790/#post-31534
 
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Ok for now.
Going to be real hard or impossible to tune correct with pump gas boiling in the Edelbrock Carb float bowls in summer heat with engine coolant temps at 230-250 F like you have now.
Only possible to tune under such extreme heat with Port Fuel injection EFI.

NEED THAT NEW RADIATOR.
$750-1000 Investment The Best.
 
heatcrossg.jpg

http://garage.grumpysperformance.co...el-percolation-cause-and-cure.3172/#post-8722

5230545.jpg

about 1.65" in diam that look like plated thin tin sheet steel that you can use ) yes they can occasionally burn through over thousands of miles of use but they cost next to nothing but a few cents to replace if that happens, the discs are use in roof repairs that can easily be modified with tin snips to function correctly for a few cents
most bbc intake gasket sets come with exhaust block plate inserts
 
If you can find Stainless steel or Copper sheets they will not burn through Grumpy.

Made copper block off plates for the TA Ponch engine.
Works.
 
Gents,

THANKS for all this great feedback.

I haven't made any tweaks yet. However, I had set my gaps at .045 when I put in the news plugs.

I drove to work today. I left really early hoping to avoid traffic but nonetheless got stuck in it. Outside temp was 60 degrees. Nonetheless, I never quite reached 210 even in (unexpected) bumper to bumper traffic. Granted, 60 is a rather cool morning. The drive back should be around 80. I could detect small misses at idle. Possibly popping in the mufflers.

Grumpy, I will go through the suggestions and report back. It is just good to see that there is some temp control going on.

When you say:
Grumpy said:
adding 2 degrees initial (off idle) ignition advance,
and backing off 2 degrees on total advance,
Click to expand...
You do not mean via the vacuum advance, do you?
Do you mean rotating the distributor clockwise 2 crankshaft degrees to take two out of the total and then adding back in 2 degrees of vacuum advance?

Grumpy said:
Id suggest kicking the primary jet size up two steps,
Click to expand...
This is because I am a bit lean at mid-cruise and upper RPM?

Grumpy said:
a bit rich or retarded on the advance curve, at idle
Click to expand...
I tried leaning out the Idle Mixture Screws some days ago, but it seemed to me that idle quality degraded slightly.

Grumpy said:
verify the float levels are set correctly
Click to expand...
Yes, I had set those very carefully when I did the carb rebuild.

Maniacmechanic1 said:
NEED THAT NEW RADIATOR.
$750-1000 Investment The Best.
Click to expand...
Yes, I think there is very little doubt there.

I wish I had thought of blocking off that crossover before I installed the intake manifold. Now that you mention it, it is true that I haven't had an intake manifold with a crossover in years.
 
DorianL said:
Gents,

THANKS for all this great feedback.

I haven't made any tweaks yet. However, I had set my gaps at .045 when I put in the news plugs.

I drove to work today. I left really early hoping to avoid traffic but nonetheless got stuck in it. Outside temp was 60 degrees. Nonetheless, I never quite reached 210 even in (unexpected) bumper to bumper traffic. Granted, 60 is a rather cool morning. The drive back should be around 80. I could detect small misses at idle. Possibly popping in the mufflers.

Grumpy, I will go through the suggestions and report back. It is just good to see that there is some temp control going on.

When you say:

You do not mean via the vacuum advance, do you?
Do you mean rotating the distributor clockwise 2 crankshaft degrees to take two out of the total and then adding back in 2 degrees of vacuum advance?


This is because I am a bit lean at mid-cruise and upper RPM?


I tried leaning out the Idle Mixture Screws some days ago, but it seemed to me that idle quality degraded slightly.


Yes, I had set those very carefully when I did the carb rebuild.


Yes, I think there is very little doubt there.

I wish I had thought of blocking off that crossover before I installed the intake manifold. Now that you mention it, it is true that I haven't had an intake manifold with a crossover in years.
Click to expand...
I really helps on the street having a functional heat crossover non blocked off year round driving.
Fuel distribution is more even to each cylinder.
Spark plugs foul out less often.
The time to block them off is WOT DRAG RACING.
To me thats a full drag cammed off the Grumpy charts safe.
High compression 12.0 - 13.0 :1.
Run Race gas only.

The biggest problem is high engine coolant temps.
Vintage Carburated Chevrolet, Pontiac, & Olds V8 do not like at all.
160-180 F is best I have found.

Light miss at idle may be due to the ignition wires you have.
Carbon core wires are not dependable.
Use Taylor, Accel 8.8, Or Moroso Race ignition Wire sets.
 
My favorite Ignition wire seperators are the Moroso ones.
All fiberglass reinforced plastic that withstands ultra high engine heat.
Devolped by Smokey Yunick himself.
Many of Moroso parts were personality developed by Smokey Yunick himself in the 1970's.
Dick Moroso put Smokeys items into production.
I never ever had a bad Moroso part.
Top notch all.
 
What happens at High Coolant temps your seeing Dorien is hidden steam pockets are forming in the cylinder heads.
One way to combat is use a high pressure radiator cap.
19-21 psi cap.
But if the head gaskets are marginal or radiator....bam they let go.
Risk and try I have done it on the street.
Works for a while.

Best thing I have found is a HUGE MASSIVE THICK GRIFFIN RADIATOR.
Found a few for You.
Just that Corvette Tax....
But I know its Excellent.
 
don,t try to lean out the carb with the idle screws
add new slightly larger jets

this is the ignition advance I generally you suggest you start with



chart3e1.jpg

youll want too adjust your ignition curve to closer too the black line
chart3e2.jpg
 
Grumpy said:
don,t try to lean out the carb with the idle screws
add new slightly larger jets
Click to expand...

Confused here. Slightly “larger” jets ? (This is an edelbrock Performer carb 750cfm). Won’t larger jets (same rods and springs) make everything but the idle richer ?
 
So new plug wires are definitely in order.

Grumpy, you are recommending 36 mechanical and 10 initial, correct ?

My centrifugal advance is 20 degrees by about 3000.

I had set it to 16 degrees initial to give me (+20 centrifugal) 36 degrees of mechanical.

Your recurve plot is 10 degrees initial, plus 26 degrees centrifugal to give 36 mechanical.

I don’t think I can do that with a distributor that’s 20 degrees of centrifugal.

My vacuum advance starts at 6in/Hg and gives me 14-16 degrees at 16in/Hg.
 
yes your PLUGS INDICATE YOUR a bit rich AT IDLE NOW but the electrode on the plug indicates too much total advance and porcelain insulator and plug color ,
show your running too lean under power, adding a bit of initial off idle ignition advance will heat the combustion off idle ,
generally cleaning up the off idle richness reading, richening up the jets or using smaller rod diameters will tend to richer the mix at higher rpms where your running lean
you can,t get everything perfect with that change but it should be close, and personally ,its isolate and test,
see results and make changes through seeing verified e results, if things get better, fine, if they get worse, step back and change as required.
your object here is to add minimal more initial ignition advance,
a bit less total ignition advance and a smidgen more fuel over the whole power band..
you have options on how to go about that,
but its what the plugs indicate should help.
 
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Sorry. I’m still trying to wrap my mind around what you’re telling me to do.

My initial right now is 16 degrees.

When idling my vacuum advance kicks in and adds another 14 degrees. So effectively at idle, my timing is 30 degrees of advance. I presume you mean that I should not mess with the vacuum advance.

From what I could measure centrifugal gives me 20 degrees. So I’m getting 36 degrees of advance at 3,000 rpm. (Not counting vacuum advance.)

When you say “add minimal more initial and a little less total” that would mean go from 16 initial to 18 and come down from 36 to 34 ? (Ignoring vacuum advance in all this tweaking?)
 
do what you can to induce a minor richer fuel/air mix as a first step,
 
Dorien needs an Edelbrock Carb Jet and metering rod kit with power piston springs.
Its a 2 seperate pack kit for all.
Be around $120-150 for all the Goodies.
I am sure its hard to come by in Belgium.
 
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