I'll start this with, I'm still not sure I want to delete EGR, mostly because after I rebuild my engine from a cylinder 6 head gasket failure, I have to pass emissions ONE MORE time in Georgia before the truck is 25 years old and no longer requires emissions. I just don't want the extra headache to get it back on the road and driving. I'll also state that I'm not convinced EGR has anything at all to do with head gasket failures. But I'm not convinced it doesn't either!
I think there is a lot of misinformation about EGR and what the actual components look like, where they are located on the engine, where the EGR gas comes from and where it goes. At least I didn't have a good idea until I took the motor apart. So, if all my jibber jabber isn't useful, at least hopefully the pictures will help someone a little.
Here's my cylinder 6 head gasket failure. The #6 piston top got steam cleaned from coolant. You can see in the close-up picture where the gasket deformed.
EGR pictures.
I'm not going to talk about how or why EGR works or why you should or shouldn't delete it. I hope this doesn't turn into that. That info is out there already. So I'll get to my main point:
If I agree EGR causes a cylinder 6 head gasket failure, I do not think it is because EGR gas is getting pumped into the intake manifold; I think it is because hot exhaust gas passes through the back of the head right behind cylinder 6. Explanation below.
A lot of people say that EGR gas dumps right into cylinder 6 in the intake manifold. I took this at face value until I actually had the manifold off the engine. This is just simply not accurate. Look at the picture of the intake manifold. EGR gas dumps straight into the middle of the intake manifold, not "directly into cylinder 6". Any EGR gas that gets injected here will get distributed evenly to all cylinders. Now, the internal plumbing for the EGR gas gets routed along the cylinder 6 intake manifold runner, I'll give you that. Maybe this heats up the air going to cylinder 6 by a few degrees, MAYBE! But no more actual hot exhaust gas goes into cylinder 6 than any other cylinder. And maybe this is what people have been saying all along and I misunderstood it, but the language people use doesn't seem to make that clear.
So let's say we want to stop exhaust gas from going this far to keep the intake passages clean and keep the cylinder 6 intake runner cooler. We all know about the resistor mod. It prevents hot EGR gas from going into the intake manifold as well as running along the runner for intake 6. Great, that solves part of the EGR issue, but not all of it.
The next issue is that even with the resistor mod, the hot exhaust gas still makes its way through the bottom end of the EGR pipe and makes the wiring harness vulnerable to melting and chafing. I have had issues with that in the past, solved temporarily with extra wraps of heat tape. The only way to fix this completely is by using block off plates to remove the hot EGR pipe. A block off plate on the back of the head, and a block off plate on the intake manifold will allow you to do this. So, if you do that, you've prevented the EGR gas from coming through the pipe and damaging your harness and you have completely removed EGR and you can forget about it, right?!
I don't think so. Hot exhaust gas is still being scavenged from cylinder 6 and just sitting there all hot and toasty, right in the back of the head, wait for it, right next to cylinder 6! I'll repeat for emphasis: even if you delete the EGR hardware with block off plates, millimeters away from the back side of cylinder 6, inside the head, is a pocket of hot exhaust gas just sitting there! Now take a look at where my gasket failed. It deformed on the back side near where the hot exhaust gasses are sitting in the head. Now again, I'm not saying I am 100% convinced, but if I was going to allow myself to believe EGR had anything to do with my head gasket failure, it wouldn't be from exhaust getting "dumped into cylinder 6 intake manifold" it would be that the hot exhaust is going in the head right behind to cylinder 6. And if I wanted to remove EGR for this other reason, not a single popular method of "completely deleting the EGR" addresses this issue.
That brings me to the next part, how can I completely get rid of EGR to fix this other issue of hot exhaust still getting pumped into the back of the head? The little extra runner on the cylinder 6 exhaust manifold needs to be eliminated and sealed off. I tried to find a non-US, non EGR exhaust manifold and gasket but I came up empty. I have seen aftermarket headers that might work, but the easiest cheapest way I could think of is to weld up that runner on the exhaust manifold and have it machined back flat. I know, cast iron has to be welded a certain way, you wouldn't want the weld from your Harbor Freight flux core coming loose in there. Then that leaves the exhaust manifold gasket. The stock gasket accommodates that runner and would not seal off that hole in the back of the head from the exhaust. Well, it turns out you can use the front exhaust manifold turned upside down, just one of the holes doesn't quite line up. You could drill it larger a bit and make it work without issue, I think.
What do you guys think? Has someone already figured this out or come up with a reason it is a waste of time? I certainly couldn't find anyone talking about this.
Just to be clear, I have not tried this yet! I just want to hear some thoughts. I'm still putting my engine back together, possibly still complete with the EGR equipment, and then I will go about deleting it later. Maybe, probably, if I have time. Haha But I might also try my chances at passing emissions without it. (Resistor mod + relay to fool ECU into achieving readiness, but that's another conversation.)
I think there is a lot of misinformation about EGR and what the actual components look like, where they are located on the engine, where the EGR gas comes from and where it goes. At least I didn't have a good idea until I took the motor apart. So, if all my jibber jabber isn't useful, at least hopefully the pictures will help someone a little.
Here's my cylinder 6 head gasket failure. The #6 piston top got steam cleaned from coolant. You can see in the close-up picture where the gasket deformed.
EGR pictures.
I'm not going to talk about how or why EGR works or why you should or shouldn't delete it. I hope this doesn't turn into that. That info is out there already. So I'll get to my main point:
If I agree EGR causes a cylinder 6 head gasket failure, I do not think it is because EGR gas is getting pumped into the intake manifold; I think it is because hot exhaust gas passes through the back of the head right behind cylinder 6. Explanation below.
A lot of people say that EGR gas dumps right into cylinder 6 in the intake manifold. I took this at face value until I actually had the manifold off the engine. This is just simply not accurate. Look at the picture of the intake manifold. EGR gas dumps straight into the middle of the intake manifold, not "directly into cylinder 6". Any EGR gas that gets injected here will get distributed evenly to all cylinders. Now, the internal plumbing for the EGR gas gets routed along the cylinder 6 intake manifold runner, I'll give you that. Maybe this heats up the air going to cylinder 6 by a few degrees, MAYBE! But no more actual hot exhaust gas goes into cylinder 6 than any other cylinder. And maybe this is what people have been saying all along and I misunderstood it, but the language people use doesn't seem to make that clear.
So let's say we want to stop exhaust gas from going this far to keep the intake passages clean and keep the cylinder 6 intake runner cooler. We all know about the resistor mod. It prevents hot EGR gas from going into the intake manifold as well as running along the runner for intake 6. Great, that solves part of the EGR issue, but not all of it.
The next issue is that even with the resistor mod, the hot exhaust gas still makes its way through the bottom end of the EGR pipe and makes the wiring harness vulnerable to melting and chafing. I have had issues with that in the past, solved temporarily with extra wraps of heat tape. The only way to fix this completely is by using block off plates to remove the hot EGR pipe. A block off plate on the back of the head, and a block off plate on the intake manifold will allow you to do this. So, if you do that, you've prevented the EGR gas from coming through the pipe and damaging your harness and you have completely removed EGR and you can forget about it, right?!
I don't think so. Hot exhaust gas is still being scavenged from cylinder 6 and just sitting there all hot and toasty, right in the back of the head, wait for it, right next to cylinder 6! I'll repeat for emphasis: even if you delete the EGR hardware with block off plates, millimeters away from the back side of cylinder 6, inside the head, is a pocket of hot exhaust gas just sitting there! Now take a look at where my gasket failed. It deformed on the back side near where the hot exhaust gasses are sitting in the head. Now again, I'm not saying I am 100% convinced, but if I was going to allow myself to believe EGR had anything to do with my head gasket failure, it wouldn't be from exhaust getting "dumped into cylinder 6 intake manifold" it would be that the hot exhaust is going in the head right behind to cylinder 6. And if I wanted to remove EGR for this other reason, not a single popular method of "completely deleting the EGR" addresses this issue.
That brings me to the next part, how can I completely get rid of EGR to fix this other issue of hot exhaust still getting pumped into the back of the head? The little extra runner on the cylinder 6 exhaust manifold needs to be eliminated and sealed off. I tried to find a non-US, non EGR exhaust manifold and gasket but I came up empty. I have seen aftermarket headers that might work, but the easiest cheapest way I could think of is to weld up that runner on the exhaust manifold and have it machined back flat. I know, cast iron has to be welded a certain way, you wouldn't want the weld from your Harbor Freight flux core coming loose in there. Then that leaves the exhaust manifold gasket. The stock gasket accommodates that runner and would not seal off that hole in the back of the head from the exhaust. Well, it turns out you can use the front exhaust manifold turned upside down, just one of the holes doesn't quite line up. You could drill it larger a bit and make it work without issue, I think.
What do you guys think? Has someone already figured this out or come up with a reason it is a waste of time? I certainly couldn't find anyone talking about this.
Just to be clear, I have not tried this yet! I just want to hear some thoughts. I'm still putting my engine back together, possibly still complete with the EGR equipment, and then I will go about deleting it later. Maybe, probably, if I have time. Haha But I might also try my chances at passing emissions without it. (Resistor mod + relay to fool ECU into achieving readiness, but that's another conversation.)
