Super tuning car runs good shooting for great
- Thread starter skep419
- Start date
-
skep419
No show, all go!
skep419
No show, all go!
skep419
No show, all go!
Had pinging under wot. unhooked vacuum advance and set timing at 15-32. No more ping.
I am now trying out a 600 mechanical secondary holley that I had laying around. Going to get cold soon and this carb has a choke.
First issue I had is the secondary float filled with fuel. Got it replaced and the floats reset.
New issue is the manifold vacuum port now has fuel in the rubber plug
What are some possible causes?
Probably going to have to take the distributor apart and limit the mechanical advance. The idle speed screw is now open too far. (too much transfer slot exposed)
Hoping to get some timing numbers on my lunch break.
-what rpm is the mechanical advance all in
-how much vacuum advance is being added between 16-18"
I am now trying out a 600 mechanical secondary holley that I had laying around. Going to get cold soon and this carb has a choke.
First issue I had is the secondary float filled with fuel. Got it replaced and the floats reset.
New issue is the manifold vacuum port now has fuel in the rubber plug
What are some possible causes?
Probably going to have to take the distributor apart and limit the mechanical advance. The idle speed screw is now open too far. (too much transfer slot exposed)
Hoping to get some timing numbers on my lunch break.
-what rpm is the mechanical advance all in
-how much vacuum advance is being added between 16-18"
skep419
No show, all go!
So the mechanical is all on by 2200.
Checked the vacuum advance. The can has 18 degrees. It's all in at 30 (50 deg)
25 (44)
20 (38)
Adjusted the can so it pulls 40 at 17". No pinging on the ride home.
The tuning mode is engaged.
Checked the vacuum advance. The can has 18 degrees. It's all in at 30 (50 deg)
25 (44)
20 (38)
Adjusted the can so it pulls 40 at 17". No pinging on the ride home.
The tuning mode is engaged.
seabee
Well-Known Member
Glad to see it is getting close. I have been in the same boat trying to get it perfect.
skep419
No show, all go!
Had a slight bog at wot. Upped the front squirted from a 25 to a 28. Adjusted the secondary accelerator pump 1/8 turn. Bog is gone.
Squirted didn't do anything so I could probably put it back but with the choke it's nerve racking trying to get it out and in without dropping parts down the carb.
The 600 doesn't have as much top end power but it sure runs slot smoother than my 750 street hp.
Wouldn't mind finding a 750 double pumper just like it.
Squirted didn't do anything so I could probably put it back but with the choke it's nerve racking trying to get it out and in without dropping parts down the carb.
The 600 doesn't have as much top end power but it sure runs slot smoother than my 750 street hp.
Wouldn't mind finding a 750 double pumper just like it.
skep419
No show, all go!
leaning out the idle mixture screws to see what kind of mpg I can get.
I have an innovate lc1 wide band reader that I'm going to hopefully be using soon. Plan to install the O2 sensor in the cap of my exhaust cutouts. Mount the gauge in a box so it's portable.
skep419
No show, all go!
So the rod bearings last around 500 miles before a slight knocking is heard. The last set I drove a lot longer before pulling the engine apart. (Jackhammer/Down to copper). Should have done some more testing before throwing a new set of bearings in it but I didn’t. Threw it back together and I was driving again.
So the Engine is on the stand. Pulled all the bearings one at a time. They aren’t down to copper but they don’t look good.
Bought a fresh set of bearings and plasta gauged a couple. (Pictured above)
The car isn’t going to be driven over the winter. Just looking for possible causes.
skep419
No show, all go!
skep419
No show, all go!
Bring this thread back from the dead.
Didn’t read through everything but found two rod caps swapped causing an out of round situation which caused the rod bearing failures.
Since then I have swapped out solid motor mounts. (Vibration is more or less gone/header was hitting steering box) Installed headlight relay kit. Exhaust was redone, added electric cutouts and o2 sensor bungs for the lc1 innovate wide-band. Spring perches got welded back in 3” Inboard -4 deg pinion angle. 275’s are back. Welded brackets back in for the stock console with the B&M quicksilver. New stereo,dash speaker/6x9’s.
Still have this oil leak that won’t ever go away. sitting still it won't leak. rev it all day. drive it down the road nice and it leaks.
Didn’t read through everything but found two rod caps swapped causing an out of round situation which caused the rod bearing failures.
Since then I have swapped out solid motor mounts. (Vibration is more or less gone/header was hitting steering box) Installed headlight relay kit. Exhaust was redone, added electric cutouts and o2 sensor bungs for the lc1 innovate wide-band. Spring perches got welded back in 3” Inboard -4 deg pinion angle. 275’s are back. Welded brackets back in for the stock console with the B&M quicksilver. New stereo,dash speaker/6x9’s.
Still have this oil leak that won’t ever go away. sitting still it won't leak. rev it all day. drive it down the road nice and it leaks.
Last edited:
MopaR&D
Nerd Member
I just got my 5.9 Magnum build running in my Duster and I've got the same damn leak. I never even touched the #5 main cap, just swapped oil pans... whatever as long as it's small I'm just going to ignore it. I have a crazy idea it might have something to do with the torque being applied to the driveline when you're accelerating, might flex the oil pan juust enough to let oil through?? Bah who knows...
You'll love the wide-band AFR readout if you haven't run with one before. It really helped me understand my carb, along with a vacuum gauge; both of those are like having lifelines on "Who Wants to Be a Millionaire?" lol
Btw I installed speakers above the rear seats and in the front doors and it sounds pretty good but could be better, how is your setup with the dash speaker?
skep419
No show, all go!
Dash speaker works great. Doesn’t need to sound perfect. Nice to be able to fade it to the front when the kids are in the back seat.
skep419
No show, all go!
First things first. Carb loading up. Tried dropping the float level on the primary side with no luck. Fuel pressure is regulated at 6pounds. Tried hopping out of the car real fast to see if it’s dripping from the boosters. Looks dry.
Last edited:
skep419
No show, all go!
opened the fast idle screw 1/8 turn. we'll see what it does on the way home.
MopaR&D
Nerd Member
What are the ambient temps? Just an idea but your carb could be getting cold or slightly icing up on your way to work, I had this issue with my car. The O2 sensor made it a bit easier to figure out, carb would go super lean and stumble. Once I got off the highway and sat in a bit of traffic it would warm up and be fine.
Big reason why I went with a non-Air-Gap manifold this time
skep419
No show, all go!
25 degrees on the way to work
nm9stheham
Well-Known Member
Unusual IMHO.... most of the time if caps get swapped, the offset is large enough to either lock the crank or at least make it hard to turn. I always spin the crank by hand after installing the mains to feel for any irregularities, or with a small wrench after each rod is installed, to try to detect anything unusual like that.
Yes, AFR's make life so much easier! There are a few tricky times, like during warm-up, where it will give false readings.
Skep, the loading up.... is that showing on the plugs? For plain low speed cruising like that, the AFR ought NOT to be at 13:1 but up in the 15:1 range for light cruising.
Last edited:
skep419
No show, all go!
all I know is that's all that was changed and its got thousands of trouble free miles on it now.
MopaR&D
Nerd Member
That's pretty chilly I definitely got carb icing in those temps... not fun when trying to catch an early-morning flight out of DIA an hour away and decided to drive the Duster because it's faster lol
The proper solution is getting warm air to the carb but to do that you'd have to rig up a system like the factory did in the '70s and '80s having the diverter valve in the air cleaner with the heat riser pipe off the exhaust manifold. I ran a setup like that with headers, just cut up an old manifold heat shield/riser thing and used stainless steel zip-ties to attach it to one of the header tubes. I never got around to it but I always wanted to run the vacuum lines into the car so I could switch the valve on command, I had it where I had to get out of the car and lift the hood to disconnect the line.
skep419
No show, all go!
Idle
Turned the secondary idle mixture screws in 1/8 turn. Got it up to 13.0.
But here is the cruise air fuel.
Turned the secondary idle mixture screws in 1/8 turn. Got it up to 13.0.
But here is the cruise air fuel.
nm9stheham
Well-Known Member
14.9 is not bad at all IMHO.... .just as long as you are not looking for 13 at light cruise.... too much fuel for most engines. Other thoughts:
- Have you looked at the plugs after a drive to/from work to see if they show rich?
- Have you worked with adjusting the secondary stop screw? Like make sure the secondaries are on the stop screw and not resting on the bores? You'll have erratic idle when that happens.
- And maybe put a voltmeter on the coil + when warmed up and idling OK, and then see if it is the same when the idle goes rough. (Sorry, I have not gone through the thread to see what your ignition is so this may or may not apply.)
- Put on a vacuum gauge and monitor the vacuum to see if there is anything odd going on. It will drop when the idle drops, so determining cause or effect may not be easy, but you might catch some clues.
skep419
No show, all go!
skep419
No show, all go!
Secondaries are cracked slightly.
The 'cruise' AFR depends entirely on the engine and gearing.
If it can run 14.9, that's great.
Same advice I just gave the guy playing with an Eddy. If you want to experiment, go as lean as it will tolerate without surging or trailer hitching at high speed steady state.
So with a Holley type carb, that's the primary main jets. When it surges, that's followed by dying, so you need a place where you got some room - not heavy rush hour traffic!
It will usually catch as you let off the throttle, and you can continue on your way, but your speed will be limited to 50 or 55 or whatever it is where the mains fully take over from the ide/transfer.
If it can run 14.9, that's great.
Same advice I just gave the guy playing with an Eddy. If you want to experiment, go as lean as it will tolerate without surging or trailer hitching at high speed steady state.
So with a Holley type carb, that's the primary main jets. When it surges, that's followed by dying, so you need a place where you got some room - not heavy rush hour traffic!
It will usually catch as you let off the throttle, and you can continue on your way, but your speed will be limited to 50 or 55 or whatever it is where the mains fully take over from the ide/transfer.
-
