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Fuel/Heat Distribution Problem
https://slantsix.org/forum/viewtopic.php?t=36398		 Page 2 of 2
Author:  SV162 [ Thu Aug 13, 2009 8:31 pm ]
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Back to the drawing board.
Gave the car a good run a couple of nights ago, which included some hard launches and high rpm stuff and I could hear the dreaded sound of detonation(pinging/pinking/knocking - call it what you like) at around 4500 rpm in both 1st and 2nd gear. Pulled the plugs, number one which is one of the plugs I switched for a hotter heat range was white with little black spots on the porcelain. I've since found out this is a sign of detonation caused by the plug getting too hot. :roll:
So I'm back to running all my plugs at the same heat range. The car doesn't run any worse so I'll just have to live with dirty plugs in 1 and 6 unless I go for a long drive. And as I said before, I'll look into a way of heating the intake.

On a good note I finally got to give the car a workout with the new head, unfortunately I now have a new problem.............lack of traction.:twisted:
Author:  Aggressive Ted [ Sat Aug 15, 2009 12:46 pm ]
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SV162,

I would do some of the other changes I listed earlier and just use the same plug in all the cylinders so you don't get the detonation problem racing. You could always run a 195 degree stat......
The heat deflector under the carb really helps too and the electric fan. In your climate situation the fan may never kick on. I know mine doesn't very often, only on 80+ degree days.
Author:  Wesola78 [ Sun Oct 11, 2009 8:23 am ]
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Quote:
SV162,

Two more cents...

A few photos of my carburetor ice prone Clifford Intake that caused all kinds of drivability & poor fuel economy problems before I made a Rasco knock-off hydronic hot spot. The car was un drivable under 35 degrees last fall suffering from carburetor icing, and was getting about nine miles per gallon.

I just pulled a few spark plugs as this thread has captured my interest to see how my old crate is combusting with the hot spot rigged up. I have driven about 1500 miles on these new plugs. Plug #1 & 6 are hotter than the other four: #1- slight reddish tan with a bit more build up; #2- light tan; #5 light tan; #6- slightly darker light tan. In all cases the white porcelain can be detected under the tan deposits. My Holley 390 primaries are mounted forward of the manifold center line.

Image
Here a home made hot from two strata of 1/2" aluminum stock, and two brass fittings I got at a hardware store.

Image
Heater hose connected to brass fittings.

Image
Installed on engine, spliced into the heater loop, sorry dosn't show much.
I really like the "Hot Spot" that you fabbed up. What is on the inside, where it mounts to the bottom of the intake? Or, what is on the other side of the brass fittings? In other words, is it the antifreeze/coolant that is heating the bottom of the intake?
I would like to try and fab up something similar for my Offy intake.
Looks nice! 8)
Author:  wjajr [ Sun Oct 11, 2009 9:49 am ]
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Wesola78:
I really like the "Hot Spot" that you fabbed up. What is on the inside, where it mounts to the bottom of the intake? Or, what is on the other side of the brass fittings? In other words, is it the antifreeze/coolant that is heating the bottom of the intake.

Just good old coolant from the heater core loop heats the “under-sideâ€￾ of the intake manifold.

[img]http://i294.photobucket.com/albums/mm87/wjajr/100_1093.jpg[/img]
Heater hose routing showing hot-spot loop


[img]http://i294.photobucket.com/albums/mm87/wjajr/100_1091.jpg[/img]
Hot spot under manifold feed by heater hose loop.

All I did was make up a water pocket out of two chunks of ½â€￾ aluminum plate one of which was cut out in the shape of the letter “Dâ€￾ sandwiched between the manifold & the other ½â€￾ plate containing two 3/8th brass PEX adapting male nipples.
Author:  Wesola78 [ Sun Oct 11, 2009 10:36 am ]
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wjajr,
So the warm coolant is "washing" the bottom of the intake underneath the carb?
Thanks for the response!
Author:  Wizard [ Mon Oct 12, 2009 11:49 am ]
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Yes that what this does. Much better and saves the aluminum intakes from cracking any futher if subjected to exhaust gases.

Cheers, Wizard
Author:  Wesola78 [ Tue Oct 13, 2009 9:56 pm ]
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Okay, thanks!
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