200ci Degree the cam?

[63 Sprint]

Dustyford to do & check off list:
(tests and findings will be posted here for reference)

Engine Initial Timing 10-12 degrees ok

• Timing mark on flywheel damper: ok

• Engine Compression: ok

• Camshaft Degree: ok

• Fuel Pressure: 3 lbs. ok

• Distributor: run vacuum canister leak down test. ok

• Fuel: Using ethanol free. questionable

• Ignition Coil Test: ok



Do these tests in order:

1• Test Carburetor Idle Circuit:

2• Exhaust Restriction Test:
Remove Exhaust Down pipe from exhaust manifold outlet.

3• Check the vacuum at Wide Open Throttle under full load @ 3,000 rpm on the highway for 5 to 10 seconds.

To do the test:
Buy a cheap small roll of vacuum hose so you’re able to mount the vacuum gauge on the windshield with duct tape. Mount the gauge where you’re able to see it without obstructing your view.

Note:
The vacuum hose should be able to be ran between the fender and side of hood or between back of hood and near fire wall without pinching the hose totally shut.

 

[awasson]

I am introducing ported vacuum at idle if I run it over 550

Oh wow... That is a deal breaker for a higher idle then. Mine doesn't introduce ported vacuum until a little further on.

EDIT: @63 Sprint brings some excellent thoughts about that regarding the idle circuit.

 

[DON]

IMO if you are have to increase the idle screw far enough together into ported vacuum and are at 550 rpm, something is wrong. It goes back to getting a AF meter, it will tell you a lot about what is going on with the carb

 

[Frank]

IMO if you are have to increase the idle screw far enough together into ported vacuum and are at 550 rpm, something is wrong. It goes back to getting a AF meter, it will tell you a lot about what is going on with the carb

Oh wow... That is a deal breaker for a higher idle then. Mine doesn't introduce ported vacuum until a little further on.

EDIT: @63 Sprint brings some excellent thoughts about that regarding the idle circuit.

Why so much throttle for a slow idle? We've veered off onto carburetor. Maybe. Remember where this started: late valve timing, late ignition timing, significant exhaust restriction. None of which, as far as I can discern, have been sufficiently tested and checked off the potential-cause list.

SOMETHING is "holding the engine back". Carb transition circuit and ported vacuum active to = 550 rpm. . Just another symptom that aligns with all the others in this thread.

A carb idle circuit may play a role here, but will not be a factor with a lethargic engine under attempted heavy load.

 

[63 Sprint]

Frank, this is why the tests need to be preformed that is written on the to do list that is in post #161. And they need to be done properly.

Yes, an idle circuit can be malfunctioning and an engine will run once the throttle is opened enough to transition in the main circuit. But possibly, not very well.

I went through this thread many times looking and searching for a cause. A matter of fact. I spent hours. And, I’m surprised that something so simple was overlooked. Even I missed this. We will find out if it’s the problem or not once the test is done.

“Sometimes people question why a certain procedure should be done in a certain way when they should just do what they have been asked to do.”

We have some of the best heads working on the issues. It turns out that there could also be valve spring issues that is preventing the engine to rev. But I highly doubt that the springs are causing the idle issues. So it seems like it’s very likely that there are multiple issues that need to be addressed to get the engine running properly.

The reason why we’re asking for inches of manifold vacuum at wide open throttle is we want to rule out the possibility that carburetor might be too small.

Again , we won’t know until all tests are done.

 

[Dustyford]

Frank, this is why the tests need to be preformed that is written on the to do list that is in post #161. And they need to be done properly.

Yes, an idle circuit can be malfunctioning and an engine will run once the throttle is opened enough to transition in the main circuit. But possibly, not very well.

I went through this thread many times looking and searching for a cause. A matter of fact. I spent hours. And, I’m surprised that something so simple was overlooked. Even I missed this. We will find out if it’s the problem or not once the test is done.

“Sometimes people question why a certain procedure should be done in a certain way. When they should just do what they have been asked to do.”

We have some of the best heads working on the issues. It turns out that there could also be valve spring issues that is preventing the engine to rev. But I highly doubt that the springs are causing the idle issues. So it seems like it’s very likely that there are multiple issues that need to be addressed to get the engine running properly.

The reason why we’re asking for inches of manifold vacuum at wide open throttle is the carburetor could be too small.

Again , we won’t know until all tests are done.

Working on it guys. I hope to get the car running today. I appreciate everyone’s help. I have been bombarded with advice and my brain is twisted up in the game.

 

[63 Sprint]

One step at a time. Rule out issues by process of elimination.

 

[Dustyford]

Dustyford to do & check off list:
(tests and findings will be posted here for reference)

Engine Initial Timing 10-12 degrees ok

• Timing mark on flywheel damper: ok

• Engine Compression: ok

• Camshaft Degree: ok

• Fuel Pressure: 3 lbs. ok

• Distributor: run vacuum canister leak down test. ok

• Fuel: Using ethanol free. questionable

• Ignition Coil Test: ok



Do these tests in order:

1• Test Carburetor Idle Circuit:

2• Exhaust Restriction Test:
Remove Exhaust Down pipe from exhaust manifold outlet.

3• Check the vacuum at Wide Open Throttle under full load @ 3,000 rpm on the highway for 5 to 10 seconds.

To do the test:
Buy a cheap small roll of vacuum hose so you’re able to mount the vacuum gauge on the windshield with duct tape. Mount the gauge where you’re able to see it without obstructing your view.

Note:
The vacuum hose should be able to be ran between the fender and side of hood or between back of hood and near fire wall without pinching the hose totally shut.

I got her running. I raised timing to 13.5* to get idle to 650. I have fluttering 14” at idle. I played with the idle mixture. I started at 1 1/2 turns out. I went 1/2 turn in and it stalled. I went out to 1 3/4 where I got best lean idle and vacuum reading. I went a total of 3 1/2 turns out with no change in rpm or vacuum. Next will be the exhaust restriction test. Another day

 

[63 Sprint]

I got her running. I raised timing to 13.5* to get idle to 650. I have fluttering 14” at idle.

Ok, advancing the initial timing helped.

I played with the idle mixture. I started at 1 1/2 turns out. I went 1/2 turn in and it stalled.

Ok, good.

I went out to 1 3/4 where I got best lean idle and vacuum reading. I went a total of 3 1/2 turns out with no change in rpm or vacuum.

Ok, the Carburetor idle circuit seems like it’s too lean we won’t know until an AFR meter is installed. An AFR reading over 13.5 is normally too lean. Some engines like the AFR near 12.5.

Question:
The carburetor you’re using. Is it re-manufactured, or new Chinese copy? Where did you buy it? What brand is it?

I went back and re-read some posts and you mentioned that it’s a carburetor for an automatic transmission equipped vehicle. Vehicles equipped with automatic transmissions suffer much greater parasitic loss and the engine must work harder to achieve proper idle.

You written that the throttle plate has a hole in it. This is where I need help from others, does a 1968 carburetor spec’d for a 200 six equipped with a standard transmission have a hole drilled in the throttle plate? What we need to figure out, is the carburetor matched for the engine?

Another important question:
Is the carburetors ported vacuum line still pulling vacuum on idle at 650 rpm’s?

Next will be the exhaust restriction test. Another day

Great!

 

[Dustyford]

Ok, advancing the initial timing helped.


Ok, good.


Ok, the Carburetor idle circuit seems like it’s too lean we won’t know until an AFR meter is installed. An AFR reading over 13.5 is normally too lean. Some engines like the AFR near 12.5.

Question:
The carburetor you’re using. Is it re-manufactured, or new Chinese copy? Where did you buy it? What brand is it?

I went back and re-read some posts and you mentioned that it’s a carburetor for an automatic transmission equipped vehicle. Vehicles equipped with automatic transmissions suffer much greater parasitic loss and the engine must work harder to achieve proper idle.

You written that the throttle plate has a hole in it. This is where I need help from others, does a 1968 carburetor spec’d for a 200 six equipped with a standard transmission have a hole drilled in the throttle plate? What we need to figure out, is the carburetor matched for the engine?

Another important question:
Is the carburetors ported vacuum line still pulling vacuum on idle at 650 rpm’s?

Great!

Carburetor is original ‘68 Autolite 1100. I bought it from a man on eBay. I rebuilt it with the dashpot blocked off.

Yes the throttle plate has a factory hole in it. I posted this before asking about the hole and nobody responded. I could put a screw in it but I read it actually helps idle. I read people prefer original AT carbs because they have less throttle shaft wear.

The ported vacuum is not present at idle, 650 rpm. I always had the idle set so it wasn’t pulling vacuum.

 

[63 Sprint]

Oh, when you’re able, please take some detailed pictures of the carburetor. Top and all four sides. (No need to take it off the car.)

If there is a tag, please take a photo of it.

 

[Dustyford]

Ok. Tomorrow.
It has the original choke cover which means it probably never went to a carb swap shop. Yes it has a tag.
Question, how important is the accelerator pump setting? Mine is a little farther out from the factory spec. Thank you.

 

[63 Sprint]

I just got done researching some stuff.
What I have found is the 1968 Autolite 1100 carburetor is only rated to 156 CFM.

The 1965 through 1967 Autolite 1100 carburetors are rated rated slightly higher to 186 cfm. Unfortunately they are SCV and don’t have ported vacuum. But… the 1968 Autolite 1100 carburetor has been modified by some carb shops by changing the Venturi inside the 1968 carb to the larger 1967 Venturi. This should help some, but it still will be short on what your engine really needs.

Theoretically, a 200 engine with a volumetric efficiency of 80% needs a 162 cfm carburetor to operate near 3500 rpm.

Theoretically, a 200 engine with a volumetric efficiency of 80% needs a 185 cfm carburetor to operate near 4000 rpm. So, it seems that the 1965 through 1967 Autolite 1100 carburetors rated at 186 cfm were matched for the 200 engine to enable the engine to operate near 4000 rpm.

Theoretically, a 200 engine with a volumetric efficiency of 80% needs a 231 cfm carburetor to operate near 5000 rpm. I’m not sure what the average volumetric efficiency of the 200 engine is.

Theoretically, at 100% volumetric efficiency, the 200 engine needs a 289 cfm carburetor to operate near 5000 rpm.

It seems like the engine is choked. And this could be one of the reasons why the engine is struggling to reach 4000 rpm.

The wide open throttle test should give us some good information.

 

[Dustyford]

I just got done researching some stuff.
What I have found it the 1968 Autolite 1100 carburetor is only rated to 156 CFM.

The 1966 and 1967 Autolite 1100 carburetor is rated to 186 cfm.

Theoretically, a 200 engine with a volumetric efficiency of 80% needs a 162 cfm carburetor to operate up to 3500 rpm.

Theoretically, a 200 engine with a volumetric efficiency of 80% needs a 231 cfm carburetor to operate up to 5000 rpm. I’m not sure what the average volumetric efficiency of the 200 engine is.

Theoretically, at 100% volumetric efficiency. the 200 engine needs a 289 cfm carburetor to operate up to 5000 rpm.

It seems like the engine is choked. And this could be one of the reasons why the engine is struggling to reach 4000 rpm.

Yes it has a 1.1” Venturi. It revs pretty well up to 3500 but it doesn’t seem to have any punch. With a T5 and a 3.55 it should be pretty peppy. I didn’t want to venture into the land of two barrels and machined intakes.

 

[63 Sprint]

I just added more information to post #173.
I will update the post again if more accurate information becomes available.

 

[DON]

Just a reminder this is the combo that is on the car

Yes. Just to give you more info ahead of time, the engine has 200 miles on it. I have a ‘68 non SCV carb and a new replacement ‘68 dual advance distributor that was recurved to my specs by Dan Nolan.

 

[Dustyford]

Just a reminder this is the combo that is on the car

Yes. ‘68 1100 and ‘68 dual advance distributor

 

[B RON CO]

Hi, the dual advance distributor is an emissions piece. the Inner nipple will retard the ignition timing. Do you have all the other parts that work with the emission system? Many guys remove the inner vacuum hose. Good luck

 

[Dustyford]

Hi, the dual advance distributor is an emissions piece. the Inner nipple will retard the ignition timing. Do you have all the other parts that work with the emission system? Many guys remove the inner vacuum hose. Good luck

No emissions on this engine and not sure what you mean about inner nipple.

 

[Frank]

No emissions on this engine and not sure what you mean about inner nipple.

If there are two vacuum nipples on the distributor vacuum advance canister- do NOT use the inner one that faces up. Don't plug it either. Use only the outer horizonal vacuum nipple.