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9,814 Posts
What fuel and what are the IAB's and IFR's?
Spark plugs black
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9,814 Posts
Ball park anyway.
Usually I see them in the 70-30 range but that makes it richer....you're needing more air, not less.
I don't see anything abnormal in the pictures.
Is the ignition in good health? juat kinda wondering if the ignition is failing to start the fire and what your smelling is unburnt fuel going out the exhaust.
Usually I see them in the 70-30 range but that makes it richer....you're needing more air, not less.
I don't see anything abnormal in the pictures.
Is the ignition in good health? juat kinda wondering if the ignition is failing to start the fire and what your smelling is unburnt fuel going out the exhaust.
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236 Posts
Ignition is all new. 6AL with blaster 3 coil. Performance distributor livewires. New autolites that got blackened in just a few minutes.
I called AED as suggested buy you guys. They are sending 75 jets. They said 77 are too big. They are also sending larger IAB to start with and smaller IFR’s.
I called AED as suggested buy you guys. They are sending 75 jets. They said 77 are too big. They are also sending larger IAB to start with and smaller IFR’s.
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9,814 Posts
As a test, if you have a different coil. I'd try it. I don't like those oil can types. I can't seem to get along with em.
If you don't have one, yours is probably fine.
If you don't have one, yours is probably fine.
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236 Posts
Ok guys. I put it all back together. I have the total IDLE timing at 36 degrees. 36 degrees all in at 3000 rpm and 10 degrees vacuum advance excluding timing. Idle is fixed at 36 degrees.
Bowls set to the bottom of sight window.
No dripping out of boosters.
Still idles a little rich but not that white smokey raw fuel smell.
Primary transition at about .030. Secondaries at 1/2 turn.
The mixture screws want 1 turn at the rears and 1-14 at the front.
950 rpm at idle.
it’s running better but smokey. Like oil maybe. I tried running it without the PCV hooked up and it’s just as smokey. I noticed some good blow by puffing out of the PCV port when I tried this.
mom also getting a hesitation or sputter when I rev it up with the primaries only. If I hit the throttle hard to use both pumps it fine, but it I rev it up with the primaries only, it does like a blip blip. Like a double rev. Rev rev. I can’t explain it. My primary pump shot seems weak. Not as strong as the front. I may have ripped the diaphragm. It feels like it has a miss. I think it’s these fouled plugs.
Bowls set to the bottom of sight window.
No dripping out of boosters.
Still idles a little rich but not that white smokey raw fuel smell.
Primary transition at about .030. Secondaries at 1/2 turn.
The mixture screws want 1 turn at the rears and 1-14 at the front.
950 rpm at idle.
it’s running better but smokey. Like oil maybe. I tried running it without the PCV hooked up and it’s just as smokey. I noticed some good blow by puffing out of the PCV port when I tried this.
mom also getting a hesitation or sputter when I rev it up with the primaries only. If I hit the throttle hard to use both pumps it fine, but it I rev it up with the primaries only, it does like a blip blip. Like a double rev. Rev rev. I can’t explain it. My primary pump shot seems weak. Not as strong as the front. I may have ripped the diaphragm. It feels like it has a miss. I think it’s these fouled plugs.
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22,051 Posts
Once plugs get gas fouled or oil fouled, it is very hard to bring them back to good. Especially if you are still chasing the tune.
Once it is running well, you may be able to swap fouled plugs in and get them to clean.
Right now your only choice is replace them.
On the accelerator pump, if you rip the diaphragm it gives an instant leak out of the pump housing. Leaks all over the manifold, you'll know if its ripped just as soon as fuel is in the float bowl.
A hesitation rev like you described is typically lack of enough pump shot....if the pump shot seems weak, examine the pump check valve.
Pump check valve is either a suspended ball in the pump cavity, or it will be an umbrella check valve in the pump cavity....check to make sure the ball moves free/or the rubber check umbrella fits flat to the inside of the pump cavity on the bowl.
There is also another pump shot check valve, a needle check valve, just below each squirter....make sure they are there.
What color pump cams are on it??
What hole are they set in??
Absolutely zero slack in the accelerator pump linkage at idle?
Ring break-in will be longer if the block wasn't honed with a torque plate bolted on it....and ring break-in really needs to have a load put on them to get it done.
EDIT:
Idle feed restriction seems big to me if it is 35.....streetable 750 carbs will typically be in the range of .028-.031"
Once it is running well, you may be able to swap fouled plugs in and get them to clean.
Right now your only choice is replace them.
On the accelerator pump, if you rip the diaphragm it gives an instant leak out of the pump housing. Leaks all over the manifold, you'll know if its ripped just as soon as fuel is in the float bowl.
A hesitation rev like you described is typically lack of enough pump shot....if the pump shot seems weak, examine the pump check valve.
Pump check valve is either a suspended ball in the pump cavity, or it will be an umbrella check valve in the pump cavity....check to make sure the ball moves free/or the rubber check umbrella fits flat to the inside of the pump cavity on the bowl.
There is also another pump shot check valve, a needle check valve, just below each squirter....make sure they are there.
What color pump cams are on it??
What hole are they set in??
Absolutely zero slack in the accelerator pump linkage at idle?
Ring break-in will be longer if the block wasn't honed with a torque plate bolted on it....and ring break-in really needs to have a load put on them to get it done.
EDIT:
Idle feed restriction seems big to me if it is 35.....streetable 750 carbs will typically be in the range of .028-.031"
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236 Posts
AED is sending smaller IFR’s, bigger IAB, and 75 jets. These 77 jets are too big.
With how rich this carb is, the accelerator pump nozzles are both 31 only. Should they be bigger. They also don’t squirt. They spray. It’s weird.
I checked the primary pump diaphragm and the spring had some kind of blue coating peeling off. It was all stick in the channel. I cleaned it out.
Yeah, these plugs are screws. Missing pretty bad. The rich idle is a little better. No more raw fuel white smoke but still a little oil burning out the exhaust. Makes me worry. Plus blow by. I’ll load this thing good when I get it back on the road.
Should I up the accelerator squirter nozzles? To 35?
With how rich this carb is, the accelerator pump nozzles are both 31 only. Should they be bigger. They also don’t squirt. They spray. It’s weird.
I checked the primary pump diaphragm and the spring had some kind of blue coating peeling off. It was all stick in the channel. I cleaned it out.
Yeah, these plugs are screws. Missing pretty bad. The rich idle is a little better. No more raw fuel white smoke but still a little oil burning out the exhaust. Makes me worry. Plus blow by. I’ll load this thing good when I get it back on the road.
Should I up the accelerator squirter nozzles? To 35?
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1,803 Posts
What do you mean by "total idle timing"?
What do you mean by 10 degrees vacuum advance excluding timing?
Do you mean you have the timing effectively locked at 36 degrees, but add up to 10 degrees on top of this with the electronic vacuum advance?
If you put a timing light on it at idle, do you read 46 degrees using the timing marks? If not, what does it read at what vacuum?
If you put a timing light on it at 3000 rpm in park, do you read 46 degrees using the timing marks?
All of this carb advice desn't apply if the timing isn't right.
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236 Posts
It’s a progression ignition distributor. You program what you want. It’s hooked to full manifold vacuum. It uses a MAP sensor. It behaves as if it’s plugged into ported. Basically vacuum signal is ignored under 1000 rpm. You program what you want it to do. I program what the engine idle is. I set Idle timing is set to 36 degrees. The “mechanical advance” is set to start at 1000 rpm then all in at 3000. All in advance is 36. Vacuum advance is 10 degrees for cruise. It does not apply at idle. I confirmed all the timing with two timing guns. I was skeptical also.
I can change my ignition on the fly from my phone. It’s pretty cool. I confirmed the timing probably 50 times.
I can change my ignition on the fly from my phone. It’s pretty cool. I confirmed the timing probably 50 times.
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9,814 Posts
Try closing up the plug gap to .025
Small I know....but it's just testing.
The only way to know if the rings are seated or going to seat at all is with a engine dyno OR leak down tester.
everything else is basically a guess at best.
My best guess, your 20w oil or washed down cylinders aren't a problem to worry about right now. To wash down a hole tales enough fuel you would nearly see it dripping from the exhaust pipes.
You haven't yet said anything about how the bores were prepped or what ring your using. Based on all you have said, I don't have anything to suggest washed down walls or oil problems. I know your reaching for a problem, but I don't think this is where to concentrate your efforts.
I suspect, you have two problems. The first is a slight over fueling problem AND a ignition problem failing to start the burn consistently, or completely, as in it may begin to burn but blows itself out leaving traces of fuel in the exhaust. That is why a new set of plugs and closing up the gaps are my suggestions. The smaller gap is easier to jump for the ignition system.
Leaving the timing at 36 locked is fine for now as its eliminates a variable, play with it later.
On a street application you want to pump to begin at throttle application and end as soon as the booster begin to come in.
35's are too big, 31's should be plenty, you just need to get the timing correct with the pump cams. This also assumes good healthy pump shots. Ones that fire a solid stream across the throttle bore and hit the booster hard enough to break up the stream into smaller droplets is ideal.
What color pump cams and what holes? Eric already asked.....It's important.
Small I know....but it's just testing.
The only way to know if the rings are seated or going to seat at all is with a engine dyno OR leak down tester.
everything else is basically a guess at best.
My best guess, your 20w oil or washed down cylinders aren't a problem to worry about right now. To wash down a hole tales enough fuel you would nearly see it dripping from the exhaust pipes.
You haven't yet said anything about how the bores were prepped or what ring your using. Based on all you have said, I don't have anything to suggest washed down walls or oil problems. I know your reaching for a problem, but I don't think this is where to concentrate your efforts.
I suspect, you have two problems. The first is a slight over fueling problem AND a ignition problem failing to start the burn consistently, or completely, as in it may begin to burn but blows itself out leaving traces of fuel in the exhaust. That is why a new set of plugs and closing up the gaps are my suggestions. The smaller gap is easier to jump for the ignition system.
Leaving the timing at 36 locked is fine for now as its eliminates a variable, play with it later.
On a street application you want to pump to begin at throttle application and end as soon as the booster begin to come in.
35's are too big, 31's should be plenty, you just need to get the timing correct with the pump cams. This also assumes good healthy pump shots. Ones that fire a solid stream across the throttle bore and hit the booster hard enough to break up the stream into smaller droplets is ideal.
What color pump cams and what holes? Eric already asked.....It's important.
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236 Posts
Ok brother. Great info. Thank you for the time you spent helping me. New spark plugs it is. Smaller gap. 36 degrees locked.
mom now waiting on my 75 jets, IFR’s, and IAB’s to arrive from AED. This carb should have come with 75 primary jets but it had 77. Also, he suspected my .035 IFR’s are too big.
I missed the pumps and cams question. Sorry. I’m overwhelmed with this. The carb came with peach or off white looking cams. No slack. Holes number 1. My idle rpm is just over 900. It fluctuates between 900 and 950 so I’m not sure when to move it to number two hole. What cam do you recommend? What hole?
mom now waiting on my 75 jets, IFR’s, and IAB’s to arrive from AED. This carb should have come with 75 primary jets but it had 77. Also, he suspected my .035 IFR’s are too big.
I missed the pumps and cams question. Sorry. I’m overwhelmed with this. The carb came with peach or off white looking cams. No slack. Holes number 1. My idle rpm is just over 900. It fluctuates between 900 and 950 so I’m not sure when to move it to number two hole. What cam do you recommend? What hole?
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1,803 Posts
I know about your distributor.
Timing table is goofy at 700 and 960 rpm. Except for 700 rpm at 101 and 94kPa, there is actually more timing than at a higher RPM at same load (vacuum).
Idle is not fixed at 36 degrees (fix timing box is not checked).
You are 36 degrees all in at 2500 for the RPM based advance.
I would be really pi***d if I bought such a distributor that ignored the map sensor below 1000 rpm. It just doesn't make sense that it would.
IMHO you have way too much timing at idle in the table, but it should run OK once you have it above 1000 (if you have reference timing set correctly and the unit works as it is supposed to).
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236 Posts
In a nutshell, I have a pig rich idle, misfire, and what seems like a lean stumble with carb backfires.
a little background. I had Accel shorty plugs to break the engine in the first 30 min. They were black and fouled afterwards but never misfired. These Autolites 3924’s misfired as soon as I installed them. I’m swapping for FR5’s
a little background. I had Accel shorty plugs to break the engine in the first 30 min. They were black and fouled afterwards but never misfired. These Autolites 3924’s misfired as soon as I installed them. I’m swapping for FR5’s
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236 Posts
I do have it locked at 36. I just took screen shots of my other saved tune table to give you and idea of how it worked. Otherwise it would have shown all 36’s on every cell. It shows the un highlighted 36 due to that being my last tune.
You are right. I was pissed. It acts like ported. No vacuum at idle. The owner of the company told me they did that due to cams with such low vacuums.
The far far left column is what they use to prevent stall. No matter what your idle timing is, the left column is 5 degrees higher to prevent stall. All the rpm’s are adjustable.
the app is free to download and you can mess with it.
You are right. I was pissed. It acts like ported. No vacuum at idle. The owner of the company told me they did that due to cams with such low vacuums.
The far far left column is what they use to prevent stall. No matter what your idle timing is, the left column is 5 degrees higher to prevent stall. All the rpm’s are adjustable.
the app is free to download and you can mess with it.
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