AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 25,077
- Reaction score
- 12,420
Saying that the ring-gaps are in spec is Not helpful.
My KB107s were installed with loose skirts and gaps in spec, and it still overheated and the so-called "in-spec gaps" were the sole source of my overheat.
----------------------------
The timing curve was worked out years ago for my alloy-headed 367, and is
14 initial/going to 28@2800/going to 34*@3400; with 22* in the VA. This allows me to run 87E10, full-time, @185psi cylinder pressure........ and more
Therefore TOTAL Cruise-Timing was and still is, 50*@2800, going to 56* at 3400
Furthermore;
When cruising, I throw in up to 6* more from my dash-mounted, dial-back, electronic timing module, or
the same module can retard the timing up to 9 degrees.
After the new gaps, the engine did not/has not overheated, even when retarded to as little as 5* idle-advance.
-------------------------------
I'd venture to say, that all our SBMs; at idle/no load, will want far more advance than our distributors can give, and still be able to run WOT with that same curve. By 2000/no load, most will accept more than 45*.. By 2800 cruise, mine wants 50/55*
But
At WOT/full-load, and after ~3600, they all want ~34* +/- 2*.
How I can tell the right cruise timing for my 367, at any speed/rpm, is to run the car up to the target mph, then retard the timing with my dial-back module. Then wait.
If the car loses speed, it wanted more cruise timing, so then I add back what I subtracted, then add 2*more, and wait. If the car picks up speed, I reduce the throttle, back to target speed, then add 2* more. Repeat until additional timing produces no more speed increase.
On one particular cross-country trip, when I did this, she ended up at 63*@ 65mph@ 2240 rpm. That's how I cruise the countryside, getting EFI -type mileage numbers.
Put a scanner on your EFI car, any modern-EFI car, and watch the computer looking for the ideal advance. You're gonna see numbers that you wouldn't believe are possible, never mind are actually being tried by your car's computer.
Good luck
PS
If it overheats on the run-stand, it will overheat when installed and sucking hot underhood air. If it was me, I'd leave it on the stand until you get the heat under control.
BTW
The fastest way I have found to bring the heat down, is to spray the rad with a fine mist. When the mist flashes to steam, it will suck the heat right out of the rad.
But
It will make a mess in your garage, lol.
My KB107s were installed with loose skirts and gaps in spec, and it still overheated and the so-called "in-spec gaps" were the sole source of my overheat.
----------------------------
The timing curve was worked out years ago for my alloy-headed 367, and is
14 initial/going to 28@2800/going to 34*@3400; with 22* in the VA. This allows me to run 87E10, full-time, @185psi cylinder pressure........ and more
Therefore TOTAL Cruise-Timing was and still is, 50*@2800, going to 56* at 3400
Furthermore;
When cruising, I throw in up to 6* more from my dash-mounted, dial-back, electronic timing module, or
the same module can retard the timing up to 9 degrees.
After the new gaps, the engine did not/has not overheated, even when retarded to as little as 5* idle-advance.
-------------------------------
I'd venture to say, that all our SBMs; at idle/no load, will want far more advance than our distributors can give, and still be able to run WOT with that same curve. By 2000/no load, most will accept more than 45*.. By 2800 cruise, mine wants 50/55*
But
At WOT/full-load, and after ~3600, they all want ~34* +/- 2*.
How I can tell the right cruise timing for my 367, at any speed/rpm, is to run the car up to the target mph, then retard the timing with my dial-back module. Then wait.
If the car loses speed, it wanted more cruise timing, so then I add back what I subtracted, then add 2*more, and wait. If the car picks up speed, I reduce the throttle, back to target speed, then add 2* more. Repeat until additional timing produces no more speed increase.
On one particular cross-country trip, when I did this, she ended up at 63*@ 65mph@ 2240 rpm. That's how I cruise the countryside, getting EFI -type mileage numbers.
Put a scanner on your EFI car, any modern-EFI car, and watch the computer looking for the ideal advance. You're gonna see numbers that you wouldn't believe are possible, never mind are actually being tried by your car's computer.
Good luck
PS
If it overheats on the run-stand, it will overheat when installed and sucking hot underhood air. If it was me, I'd leave it on the stand until you get the heat under control.
BTW
The fastest way I have found to bring the heat down, is to spray the rad with a fine mist. When the mist flashes to steam, it will suck the heat right out of the rad.
But
It will make a mess in your garage, lol.
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