TBucket Engine Project (Dart SHP)

If you will remember I changed to some slightly used plugs that still looked pretty
good. I have put 739 miles on them just before I cleaned them by running the following
mixture thru the carburetor at about 2500 RPM.

http://garage.grumpysperformance.co...-carbon-and-fuel-additive-ash-build-up.12475/
33% Distilled Water
33% Denatured Alcohol
33% SeaFoam Motor Treatment

After running the cleaning mixture thru the engine I pulled the plug, but they were still
completely dark and would be hard to compare the before and after photos. I decided to
reinstall the plugs and drive it another 20 miles(759 Total Miles) to recolor the plugs.

Frankly I can't tell much difference in the buildup on the plugs, but it did seem to run
without knocking as much . It's still knocking under some conditions. I would quantify
the improvement at 60%, but it's not perfect. I still have a slight amount of 110 octane
left in the tank, but it's so diluted I can't see it making much difference. But still, I'm
going to go thru another tank full before calling the above observation true and correct.

CleaningMixture-Before_6346.jpg CleaningMixture-After_6351.jpg

My next move will be to change the springs in the distributor back to the slower curve
that I was using previously. That way I can keep the 35° of total advance and not hurt
maximum output of the engine. That is unless I still have detonation, then I will have
to make another adjustment and test again.
 
obviously I don,t know how much, of that listed solution mixure , was used,
or under what conditions or for how long,
I generally dribble about a quart of the mixture slowly through the engine once its up to operational temperature,
but I will say I generally see a much more noticeable result, so I'm a bit surprised the plugs don,t look cleaner.
 
The total amount of mixture was roughly 30 oz in a spray bottle like you showed in
the link above, which used most of the bottle of SeaFoam. The engine was running
around 210°F while idling at about 2500 RPM. It did smoke some, but nearly like I
thought it would. I thought the neighborhood would be outside to see what was
burning! hehehe!!!

It's just me, that's why it does not work as good. That's the way life treats me!:(:confused:
 
Seafoam sucks Rick.
I use Marvel Mystery Oil.
Its OK to add a 1 quart bottle to 5 gallons of gasoline.

It really cleans the spark plugs off & the combustion chambers out.
 
You will not get 100 % optimum piston ring seal again till you eliminate all pre ignition / detonation issues.
In my case dropping water temps down to 140-160 F did the trick.
 
I found a later timing curve than the one I posted earlier, see link for reference.
http://garage.grumpysperformance.co...ine-project-dart-shp.3814/page-104#post-64205

My real timing curve is posted below and it's already a pretty slow curve. Bob suggested
that maybe it's too slow and causing the chamber to run hotter than they should which
could be causing the detonation.

When I think back to the beginning I didn't have this detonation problem early on, so I'm
wondering if he might be right..... can the advance curve be so slow that it causes detonation?

IgnitionTimingCurve.JPG
 
Ive never heard of that, issue before but it might happen, you can obviously make a quick test and get some results too see.
 
What I am thinking tonight Rick something like the 91 RM/2 Ethanol free gasoline you used in the past has changed actual octane rating to a lower number.
Proving it is another matter.

The baseline is 110 racing gasoline or 100 LL Aviation fuel.
 
Made the change back to the blue curve and went for a test drive......No Change.

Was watching the AFR meter and it's hitting 16:1 to 17:1, so I think my next move
would be to richen up the mixture under light load. Hate to give up the good mileage
I'm getting, but it's obviously not worth destroying an engine for.

Ignition-Timing-Curve_2014-05-30.jpg
 
What is The Fuel pressure reading on the Auto Meter Pro Comp Fuel pressure guage mounted in the dash while driving 55-60-70-80-90-100 mph ?
 
WOW, running that lean I would be shocked if it did not detonate. With the current curve, when you richen up the AFR I think your detonation will go away!
 
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Some engines are Ok running lean while cruising Bob.
Example was the old Chrysler Lean Burn 318 & 360 engines. Ran AFR around 19.0 :1.
David Vizzard worked on Lean Burn engines too.

Rick said something changed.
What is it ??
Carb has not been touched in over 1 year now.
 
Yeah, while that may be true, I would not feel good running that lean. I want mine to run around 14.5 cruising. I am not saying you're wrong, I agree about certain things. Like the quality of pump gas, I have 93 octane available here in Wichita Falls in a few places. I am thinking you may be right about the gas Rick is getting. I have about accepted the fact mine will need fuel mix to keep it out of detonation. I will probably mix 3-4 gallons of Toulene with each tank.
 
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The Holley Red / Blue Fuel pump is suspect.
Need a Fuel pressure guage in plain view.
Test drive. Verify fuel pressure while driving .
 
Depends a lot how much duration a cam has & Overlap numbers.
55 degrees overlap & higher tend to want Rich side AFR numbers all the time.
 
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