1972 international scout2 258 six cyl.

[Trubled1]

I am having problems going uphill. Loss of power under load.  Does fine on level ground. This truck used to have more power.  It has all new fuel lines and gas tank. New tune up parts. Plugs are gapped at .035. It has the hei distributor upgrade. Checked timing a few times. Runs and sounds strong. Air filter is clean. No air leaks, all new. What should I check next?

Edited February 20 by Trubled1 (see edit history)

[plymouthcranbrook]

Is the distributor advance system working correctly?  Vacuum and/or mechanical.

[Bloo]

It is common for HEI that hasn't been well maintained in the past to have the pins the weights pivot on nearly cut off. The mechanism can still move, but due to all the extra slop it doesn't advance much. I'd have a look at that.

 

I'd run the plugs at .045 on HEI also, but that wont make any difference in solving your problem.

[Oldtech]

Partially plugged Muffler?  What Bloo says?  Or is it starving for fuel? does it ever backfire in the carb under load? 

If you have a good timing light, test it at varying speeds and see that the advance runs off the scale at 2000. ( it should)

[Trubled1]

42 minutes ago, plymouthcranbrook said:

Is the distributor advance system working correctly?  Vacuum and/or mechanical.

I’m not positive on that. The air filter is an open style, so the hoses for air aren’t there?  The valve cover has two holes on top. One at the top by the radiator has what looks like an ekg valve in it.  The other hole is at the opposite end on top by the firewall. 
In all of the pictures that I’ve seen of other engines, that hole has a hose going to the air filter housing.  When I plug that hole while running, it causes the engine to stall out. I’ve been driving it with that hole open the whole time. But I know it’s not right. Maybe something with that?

[Trubled1]

28 minutes ago, Oldtech said:

Partially plugged Muffler?  What Bloo says?  Or is it starving for fuel? does it ever backfire in the carb under load? 

If you have a good timing light, test it at varying speeds and see that the advance runs off the scale at 2000. ( it should)

It backfired like two times. That’s all. A friend timed it by ear last. But I think it may be air hoses either missing, or wrong hook up. Thanks 

[Trubled1]

39 minutes ago, Bloo said:

It is common for HEI that hasn't been well maintained in the past to have the pins the weights pivot on nearly cut off. The mechanism can still move, but due to all the extra slop it doesn't advance much. I'd have a look at that.

 

I'd run the plugs at .045 on HEI also, but that wont make any difference in solving your problem.

Yes, thank you, I did see that in another forum that the plugs should be at .045 That could make a big difference. And would be an honest mistake. I will change those as soon as the snow melts. A couple of days.

[joe_padavano]

Just to confirm, is this an aftermarket GM-style HEI with coil-in-cap, or is this an electronic points conversion in the stock distributor (which is not "HEI", despite what people call it)?

Edited February 7 by joe_padavano (see edit history)

[Trubled1]

11 hours ago, joe_padavano said:

Just to confirm, is this an aftermarket GM-style HEI with coil-in-cap, or is this an electronic points conversion in the stock distributor (which is not "HEI", despite what people call it)?

Hei with coil in cap. Not stock.

[Trubled1]

12 hours ago, joe_padavano said:

Just to confirm, is this an aftermarket GM-style HEI with coil-in-cap, or is this an electronic points conversion in the stock distributor (which is not "HEI", despite what people call it)?

Hei with coil in cap. Not stock.

[rocketraider]

I see a couple of things that may or may not contribute to your lack of power. 

 

Your PCV system has no fresh air intake. The two two PCV valves tied together are keeping the crankcase under full manifold vacuum with no way to vent and allow fresh air for proper scavenging.

 

Here's a picture of the AMC-sourced 258 in a Gremlin. Notice the PCV valve and hose at the rear of the rocker cover and the crankcase fresh air intake running from the airfilter housing to the front of the rocker cover.

[Trubled1]

38 minutes ago, rocketraider said:

I see a couple of things that may or may not contribute to your lack of power. 

 

Your PCV system has no fresh air intake. The two two PCV valves tied together are keeping the crankcase under full manifold vacuum with no way to vent and allow fresh air for proper scavenging.

 

Here's a picture of the AMC-sourced 258 in a Gremlin. Notice the PCV valve and hose at the rear of the rocker cover and the crankcase fresh air intake running from the airfilter housing to the front of the rocker cover.

Much cleaner than mine. I’m embarrassed..  the battery was dead when I went to start him.  So charging right now. Prolly tomorrow when he starts again.

[Trubled1]

On 2/6/2024 at 8:00 PM, Trubled1 said:

I am having problems going uphill. Loss of power under load.  Does fine on level ground. This truck used to have more power.  It has all new fuel lines and gas tank. New tune up parts. Plugs are gapped at .035. It has the hei distributor upgrade. Checked timing a few times. Runs and sounds strong. Air filter is clean. No air leaks, all new. What should I check next?

Here is a pic of the hole that I was referring to. Why is it just open?  I will start with cleaning the emissions canister, and gapping the plugs to .045.  I believe that all of the top end hoses are new, by 6 years. Do they need to be replaced again? I see no cracks or splits.

[Trubled1]

1 hour ago, Trubled1 said:

Here is a pic of the hole that I was referring to. Why is it just open?  I will start with cleaning the emissions canister, and gapping the plugs to .045.  I believe that all of the top end hoses are new, by 6 years. Do they need to be replaced again? I see no cracks or splits.

To add I have found that the gas cap vent is not working.  It’s friggin cold outside.  Hate working on him in the cold.  But, the two things that are not new in the fuel system are the cap, and the canister.  I’ll get back to you later.

[Bloo]

On 2/7/2024 at 11:52 AM, rocketraider said:

Your PCV system has no fresh air intake. The two two PCV valves tied together are keeping the crankcase under full manifold vacuum with no way to vent and allow fresh air for proper scavenging.

This^^

 

The engine should have only one PCV valve. In addition to the problem @rocketraider mentioned, two PCV valves will let too much air into the PCV port. Not good if you want the engine to run right. Connect the back one only. For the fresh air intake @rocketraider mentioned, there needs to be a filter or the engine will suck dirt. If you intend to keep the aftermarket air filter, one possibility would be to get an aftermarket breather cap that fits in the oil cap hole, and just plug the second PCV hole.

 

2 hours ago, Trubled1 said:

Here is a pic of the hole that I was referring to. Why is it just open?

I don't know. It may have been plumbed into the charcoal canister system at some time. It is unusual to see. For now, plug it. Your engine will suck dirt in through the hole if you don't.

2 hours ago, Trubled1 said:

I believe that all of the top end hoses are new, by 6 years. Do they need to be replaced again? I see no cracks or splits.

If you mean vacuum hoses, their age doesn't matter. Anything with vacuum cannot be allowed to leak at all if you want the engine to run decent. They must fit tight around the nipples. If they don't, get new ones. This goes for PCV, power brake, carburetor connections, and anything that might have vacuum behind it. Hoses that do not, like most of the charcoal canister hoses, should also seal, but will have little if any discernible effect, except for the control hose, usually the smallest one. That has vacuum in it.

 

You may be able to find a vacuum diagram under the hood on a sticker. Not all cars of the era have it but some do. It will probably include the charcoal canister system.

 

Take the air cleaner off and look at the top of your carburetor. Look on the box-like structure just forward of the air intake hole and choke plate. Is there a huge hose nipple there? Some carburetors like yours have it, some don't. You might just have a blank plate up there with a couple of screws and no hose connection. If you have that hose connection way up on top of the carburetor, it is a bowl vent that was once connected to the charcoal canister system. it should not be plugged. Any other unused hose connections on the carburetor should be plugged.

 

Edited February 11 by Bloo (see edit history)

[Trubled1]

1 hour ago, Bloo said:

This^^

 

The engine should have only one PCV valve. In addition to the problem @rocketraider mentioned, two PCV valves will let too much air into the PCV port. Not good if you want the engine to run right. Connect the back one only. For the fresh air intake @rocketraider mentioned, there needs to be a filter or the engine will suck dirt. If you intend to keep the aftermarket air filter, one possibility would be to get an aftermarket breather cap that fits in the oil cap hole, and just plug the second PCV hole.

 

I don't know. It may have been plumbed into the charcoal canister system at some time. It is unusual to see. For now, plug it. Your engine will suck dirt in through the hole if you don't.

If you mean vacuum hoses, their age doesn't matter. Anything with vacuum cannot be allowed to leak at all if you want the engine to run decent. They must fit tight around the nipples. If they don't, get new ones. This goes for PCV, power brake, carburetor connections, and anything that might have vacuum behind it. Hoses that do not, like most of the charcoal canister hoses, should also seal, but will have little if any discernible effect, except for the control hose, usually the smallest one. That has vacuum in it.

 

You may be able to find a vacuum diagram under the hood on a sticker. Not all cars of the era have it but some do. It will probably include the charcoal canister system.

 

Take the air cleaner off and look at the top of your carburetor. Look on the box-like structure just forward of the air intake hole and choke plate. Is there a huge hose nipple there? Some carburetors like yours have it, some don't. You might just have a blank plate up there with a couple of screws and no hose connection. If you have that hose connection way up on top of the carburetor, it is a bowl vent that was once connected to the charcoal canister system. it should not be plugged. Any other unused hose connections on the carburetor should be plugged.

 

The hole cannot be plugged/covered, it stalls the engine.  There is no air cleaner housing. So it was modified. I think that the vacuum system is compromised. Bad gas cap to start.

[Bloo]

I'm not sure what the gas cap has to do with it, but a vented one for now couldn't hurt.

 

[Trubled1]

6 hours ago, Trubled1 said:

The hole cannot be plugged/covered, it stalls the engine.  There is no air cleaner housing. So it was modified. I think that the vacuum system is compromised. Bad gas cap to start.

It’s a one barrel.  I will look tomorrow.

[Trubled1]

20 hours ago, Bloo said:

This^^

 

The engine should have only one PCV valve. In addition to the problem @rocketraider mentioned, two PCV valves will let too much air into the PCV port. Not good if you want the engine to run right. Connect the back one only. For the fresh air intake @rocketraider mentioned, there needs to be a filter or the engine will suck dirt. If you intend to keep the aftermarket air filter, one possibility would be to get an aftermarket breather cap that fits in the oil cap hole, and just plug the second PCV hole.

 

I don't know. It may have been plumbed into the charcoal canister system at some time. It is unusual to see. For now, plug it. Your engine will suck dirt in through the hole if you don't.

If you mean vacuum hoses, their age doesn't matter. Anything with vacuum cannot be allowed to leak at all if you want the engine to run decent. They must fit tight around the nipples. If they don't, get new ones. This goes for PCV, power brake, carburetor connections, and anything that might have vacuum behind it. Hoses that do not, like most of the charcoal canister hoses, should also seal, but will have little if any discernible effect, except for the control hose, usually the smallest one. That has vacuum in it.

 

You may be able to find a vacuum diagram under the hood on a sticker. Not all cars of the era have it but some do. It will probably include the charcoal canister system.

 

Take the air cleaner off and look at the top of your carburetor. Look on the box-like structure just forward of the air intake hole and choke plate. Is there a huge hose nipple there? Some carburetors like yours have it, some don't. You might just have a blank plate up there with a couple of screws and no hose connection. If you have that hose connection way up on top of the carburetor, it is a bowl vent that was once connected to the charcoal canister system. it should not be plugged. Any other unused hose connections on the carburetor should be plugged.

 

Thank you for the detailed explanation.  I have found one port that is plugged with what i describe as looking like a piece of chewing gum.  I do have the international book. But, it’s very hard to follow. The page numbers are confusing.  Here is a pic of the port. If it blows, I should connect it to the front pcv  valve hole by the fan right? For the fresh air intake to the valve cover?  I was told that the gas cap is significant to the vacuum system for venting the gas tank.  I replaced all hoses and clamps, when I replaced the gas tank. But, I can’t get the gas guage to come online. When filling the tank it will overflow at the top. That says that I may have to take it out again, and fix.  It’s a polymar tank. I tried to ground it properly. Would you agree? Thanks.

[Bloo]

No. Any unused ports on the carburetor need to be plugged, except for a big one, up on top of the box structure ahead of the intake, hidden by the air cleaner. It probably isn't there at all, but if it is there, it needs to be left open (or connected to the charcoal canister system if that's how it was originally).

 

There should be no "front PCV valve". PCV means positive crankcase ventilation, and it is all about using some vacuum air to remove nasty vapors from the engine before they have a chance to form sludge. No engine will tolerate enough PCV air in the intake to do the job perfectly, so there is a limit to how much air the PCV can flow not make the engine run horrible. It looks like you have about twice that much.

 

On 2/7/2024 at 11:52 AM, rocketraider said:

Your PCV system has no fresh air intake. The two two PCV valves tied together are keeping the crankcase under full manifold vacuum with no way to vent and allow fresh air for proper scavenging.

 

Here's a picture of the AMC-sourced 258 in a Gremlin. Notice the PCV valve and hose at the rear of the rocker cover and the crankcase fresh air intake running from the airfilter housing to the front of the rocker cover.

This^^

 

There has to be a way for clean fresh air to go in, and PCV dirty air to go out. It's a ventilation system. The way out is through the PCV valve. The way in on some cars is a breather cap (that would work) or sometimes a hose up to the air filter like in the picture. Either way it is just supplying clean air so the engine doesn't suck dirt.

 

No PCV system works 100% of the time. Under load, even a new engine can blow backwards out the breather that normally lets air in. There is always a little mess around a breather cap. As the engine ages, there is more leakage past piston rings, and the PCV system keeps up less and less of the time. The mess around the breather gets bigger. Moving the breather up into the air filter housing (like in the picture) just puts the mess inside the air filter where you don't see it. Also the engine tends to burn the vapors since they are in the air filter housing, and you might smell them less.

 

1 hour ago, Trubled1 said:

Thank you for the detailed explanation.  I have found one port that is plugged with what i describe as looking like a piece of chewing gum.  I do have the international book. But, it’s very hard to follow. The page numbers are confusing.  Here is a pic of the port.

 

 

I'm not sure. I think that one is for the hose that goes to the distributor.

 

[Trubled1]

3 hours ago, Bloo said:

No. Any unused ports on the carburetor need to be plugged, except for a big one, up on top of the box structure ahead of the intake, hidden by the air cleaner. It probably isn't there at all, but if it is there, it needs to be left open (or connected to the charcoal canister system if that's how it was originally).

 

There should be no "front PCV valve". PCV means positive crankcase ventilation, and it is all about using some vacuum air to remove nasty vapors from the engine before they have a chance to form sludge. No engine will tolerate enough PCV air in the intake to do the job perfectly, so there is a limit to how much air the PCV can flow not make the engine run horrible. It looks like you have about twice that much.

 

This^^

 

There has to be a way for clean fresh air to go in, and PCV dirty air to go out. It's a ventilation system. The way out is through the PCV valve. The way in on some cars is a breather cap (that would work) or sometimes a hose up to the air filter like in the picture. Either way it is just supplying clean air so the engine doesn't suck dirt.

 

No PCV system works 100% of the time. Under load, even a new engine can blow backwards out the breather that normally lets air in. There is always a little mess around a breather cap. As the engine ages, there is more leakage past piston rings, and the PCV system keeps up less and less of the time. The mess around the breather gets bigger. Moving the breather up into the air filter housing (like in the picture) just puts the mess inside the air filter where you don't see it. Also the engine tends to burn the vapors since they are in the air filter housing, and you might smell them less.

 

 

I'm not sure. I think that one is for the hose that goes to the distributor.

 

My carburetor. I just went to start him and the top fuel filter is leaking. So, since the tank and everything is new I won’t need that filter.  Going to eliminate it all together. Replace the line again. And try again. I also blew out/cleaned the engine compartment.

[Trubled1]

6 minutes ago, Trubled1 said:

My carburetor. I just went to start him and the top fuel filter is leaking. So, since the tank and everything is new I won’t need that filter.  Going to eliminate it all together. Replace the line again. And try again. I also blew out/cleaned the engine compartment.

So I thought the vacuum advance was the little filter looking thing on the rear firewall. One hose goes to the carb. The other hose I connected to the canister.  It has power to it. If not vac advance, then what is it?

[Bloo]

The vacuum advance would be on the HEI.

[Trubled1]

27 minutes ago, Bloo said:

The vacuum advance would be on the HEI.

But. It’s not on the distributor. That’s where the confusion comes in.

[Trubled1]

meanwhile, I replaced the leaking fuel line. But the battery went dead. So, charging again.  

[Bloo]

There should be a vacuum advance can on the HEI. Is it possible that you could post a picture of the distributor with the cap and rotor removed?

 

It is possible to run without vacuum advance but it is not ideal. Some cars do it, but cars that do have a centrifugal advance mechanism. The only HEI I remember that had no vacuum advance from the factory was used with computer control of all timing advance, and so it had no centrifugal advance at all. If that is what you have, it won't advance at all without a computer. That would explain a lot.

 

 

[Trubled1]

47 minutes ago, Bloo said:

There should be a vacuum advance can on the HEI. Is it possible that you could post a picture of the distributor with the cap and rotor removed?

 

It is possible to run without vacuum advance but it is not ideal. Some cars do it, but cars that do have a centrifugal advance mechanism. The only HEI I remember that had no vacuum advance from the factory was used with computer control of all timing advance, and so it had no centrifugal advance at all. If that is what you have, it won't advance at all without a computer. That would explain a lot.

 

 

[TerryB]

Is the filter looking thing on the firewall an electrically controlled valve to purge the contents of the evap canister into the carb at cold start up?

[Trubled1]

1 hour ago, Bloo said:

There should be a vacuum advance can on the HEI. Is it possible that you could post a picture of the distributor with the cap and rotor removed?

 

It is possible to run without vacuum advance but it is not ideal. Some cars do it, but cars that do have a centrifugal advance mechanism. The only HEI I remember that had no vacuum advance from the factory was used with computer control of all timing advance, and so it had no centrifugal advance at all. If that is what you have, it won't advance at all without a computer. That would explain a lot.

 

 

Tomorrow.    Here is a pic of another hei like mine, but with the VA is on the lower left side.

[Trubled1]

5 minutes ago, TerryB said:

Is the filter looking thing on the firewall an electrically controlled valve to purge the contents of the evap canister into the carb at cold start up?

Maybe, I want to say yes.  Tomorrow I will send pics of the canister system from the book.

[Trubled1]

4 hours ago, Trubled1 said:

Maybe, I want to say yes.  Tomorrow I will send pics of the canister system from the book.

It is called a vacuum valve solenoid.

[Trubled1]

13 minutes ago, Trubled1 said:

It is called a vacuum valve solenoid.

Fuel system

[TerryB]

Thanks for posting the book information.  Looks like your system has been re-plumbed to do something different than it’s original setup to control the fast idle speed.  It’s always “fun” trying to decipher what the previous owner had in mind.

[Oldtech]

I don't see much stock on here. It looks like the carb has been converted to manual choke. The fast idle setup is for an automatic choke so you must step on the accelerator before pulling the knob.  I m not knowledgeable on this engine in an International, but you should have a vacuum advance on the distributor. I take it this is an "upgrade" distributor, common on AMCs. , or did IH use the HEI?  You also need to loose that front PCV connection and, if there is no large port on the air filter plate, just make a vent filter setup.  

[Trubled1]

26 minutes ago, Oldtech said:

I don't see much stock on here. It looks like the carb has been converted to manual choke. The fast idle setup is for an automatic choke so you must step on the accelerator before pulling the knob.  I m not knowledgeable on this engine in an International, but you should have a vacuum advance on the distributor. I take it this is an "upgrade" distributor, common on AMCs. , or did IH use the HEI?  You also need to loose that front PCV connection and, if there is no large port on the air filter plate, just make a vent filter setup.  

Yes. It is a manual choke. I took that front pcv off. Now I have to find a plug. The battery is bad. So, more setbacks, lol. I could do that certainly. 
Thanx.

[Trubled1]

9 hours ago, TerryB said:

Thanks for posting the book information.  Looks like your system has been re-plumbed to do something different than it’s original setup to control the fast idle speed.  It’s always “fun” trying to decipher what the previous owner had in mind.

Yes I bought it that way. But, I’m learning a lot about the engine.  It’s a good one.

[Trubled1]

My hoses.

Edited February 15 by Trubled1 (see edit history)

[Trubled1]

Upon further investigation, I discovered that the vacuum hoses are old and cracked.  Which is why it got worse over time.  Replacing all.

[Trubled1]

Update. Got a new battery. And he’s alive!  New hoses and clamps.