So why are the plugs black if it's very lean at idle?...jh
So why are the plugs black if it's very lean at idle?...jh
Maybe that plug was from after a drive. The wideband O2 tool does not lie. It's definitely very lean at idle.
Patrick Brown
331 Stroker / T5 / 8" / Wilwood Disks / RRS R&P Steering / Megasquirt EFI
Gary MacDonald
ROGER's...
EX... '63 Hardtop
Had...
Scarebird front discs
200 w/ CI alum head
C4
Just out of curiosity, I called Quick Fuel Technologies. They make an replacement billet metering block that is fully tunable. Sadly, they do not have one for the 390. They did tell me that they could take the stock style cast block and modify one for changeable air bleeds, power valve circuit and IRFs for about $50. One of these would mean that we could do some idle jet adjustment without altering the original metering block.
Another option is to just alter the original metering block to get more fuel at idle.
Let me know if you want to pursue any of this.
Patrick Brown
331 Stroker / T5 / 8" / Wilwood Disks / RRS R&P Steering / Megasquirt EFI
Hmm...
You mentioned the air bleeds could be modified by replacing the bleed inserts with drilled-out set screws? Theoretically, wouldn't that allow going back to "stock" settings at a later date?
I'm curious about this, because at some later date I may want to change to a "milder" cam, and then perhaps need to go back to something closer to "standard" air bleeds.
Gary MacDonald
ROGER's...
EX... '63 Hardtop
Had...
Scarebird front discs
200 w/ CI alum head
C4
Hey Kenny, does your MSD box cause nighmares when you use a timing light like gary says his does? I have never heard of that, I don't remember timing a motor with a MSD, if I did I never found a problem....jh
Patrick Brown
331 Stroker / T5 / 8" / Wilwood Disks / RRS R&P Steering / Megasquirt EFI
Kenny Likins
Ballard, Seattle, WA
www.redfalken.com
`62 Tudor Sedan (`69 200, C4, 8-inch 4-lug 2.79 rearend, Duraspark II, MSD, Weber 32/36 DGEV)
Do you happen to know what the duration is at .050?
Adv Duration = 274/274
@.050 = 224/224
lift = .450/.450
lobe center = 112
RPM range = 2800-6700
I've been reading a lot and posted a couple of threads in the ether. I've had two people say that this cam needs more initial advance which I'm thinking is a good idea. I'd like to set it to about 20 BTDC. This will mean that the mechanical advance will need to be limited to 16-18 for a total advance of 36-38.
Another more advanced tuning site theorized that the lean condition was because of the cam overlap mixing exhaust in the cylinder at idle much like an EGR valve would. He speculated that the plugs would also look sooty as they do even though we are way lean.
Patrick Brown
331 Stroker / T5 / 8" / Wilwood Disks / RRS R&P Steering / Megasquirt EFI
Wow thats a lot of cam for a C-4 , and 2800 to 6700 , my 5.0 runs only 2600 @ 60mph, and it has a E-303 which is 220@ .050 and it's 12in vac at idle 900rpm, are you sure it don't have a bad vacume leak? my trucks 2.3 motor has a cam thats 224in 234ex @.050 and it shows 15in. vac @1000rpm....jh
I was thinking the same think earlier in this thread. We resealed the intake with Permatex so that is leak free for sure. The carbs small vacuum ports are both capped. There is only the C4 vacuum modulator and PCV valve in place right now. It would be easy to eliminate both of these just to be sure.
Patrick Brown
331 Stroker / T5 / 8" / Wilwood Disks / RRS R&P Steering / Megasquirt EFI
I'm running a Crane cam Dur. 244/252 @.050 lift is 553/572 108 lobe sep.
I am at 12deg. and 36 total. That's with a C4 and 5000 stall. I just put my car on the dyno at Maxwells performance in Marysville two weeks ago.
It is a 306. After some carb tuning (750 dbl pumper) we got 304hp and 445ft lbs torque. At first it was 300 and 408 on first pull. The better torque should help some off the line. I had it running a little to rich. It has been running 12.25 to 12.30s et. Might be time for a 363ci next year!
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