Explorer EFI 5.0 Poor Throttle Response

[betzgb]

And let’s get some thing clarified here. Are your tires 33‘s, or are they 33’s?
The difference being are they flotation sizes that have a rating of 33 inches, or are they metric that you’re calling 33?
For example, if they are 33x12.50x15 then they are probably between 31 and 32 inches.
But if they are metric, they’re probably bigger and heavier than those other 33‘s.

And great point DirtDonk - truly are 33" as they are LT305/70R/16

 

[betzgb]

With some more miles on the build what sounds like an exhaust leak to me is getting louder and particularly loud when you goose the throttle. I am used to finding the exhaust leak by looking for black soot but these EFIs run so much cleaner the obvious signs aren't there! Looking further the header flange to head is my leak area based on some black silicone i see hanging loose. Against my better judgement, I followed the Sanderson directions below. I didn't love the idea of black RTV as the gasket. First time I have ever done that. Maybe I had a thin line that blew through or a head surface not perfectly clean? You can see the RTV hanging down to the right of the red spark plug boot. Well this leak is certainly before the O2 sensor and needs to be fixed before going further on my sluggishness concerns. Never a dull moment...

What is your favorite header install and forget about it process?

 

[lars]

No gasket and RTV seems insane to me. But maybe someone knows something I don't. I have been using Remflex gaskets recently. There are lots of other good choices no doubt. But all are gaskets, not RTV. In any case, the gaskets I'm using now and the no-longer-available Earls Pressure Master gaskets have always been no-leaks and served me well.

 

[bigmuddy]

No gasket and RTV seems insane to me. But maybe someone knows something I don't. I have been using Remflex gaskets recently. There are lots of other good choices no doubt. But all are gaskets, not RTV. In any case, the gaskets I'm using now and the no-longer-available Earls Pressure Master gaskets have always been no-leaks and served me well.

My favorites are the dead soft aluminum header gaskets, they don't leak and they are reusable. Several manufacturers of these to, I order them through Summit racing.com

 

[DirtDonk]

Since most of our engines didn’t come with gaskets from the factory, it wasn’t much of a stretch for me to see header manufacturers doing it.
As long as they were using really robust heavy duty flanges with perfectly flat surfaces that is.

Sounds like that’s not necessarily the case here. I was surprised earlier, when regular ultra Black was mentioned as a recommended sealant.
After all, if it doesn’t need a gasket, why would it need a standard low temperature sealer?

 

[betzgb]

Since most of our engines didn’t come with gaskets from the factory, it wasn’t much of a stretch for me to see header manufacturers doing it.
As long as they were using really robust heavy duty flanges with perfectly flat surfaces that is.

Sounds like that’s not necessarily the case here. I was surprised earlier, when regular ultra Black was mentioned as a recommended sealant.
After all, if it doesn’t need a gasket, why would it need a standard low temperature sealer?

I called Sanderson Headers today to get their point of view on why this started leaking. They suggested I re-seal using black rtv again but this time put a thinner film on the flange - thickness of a dime this time vs. the 1/8" bead the instructions recommended. They stated the instructions should probably be updated because the purpose of the rtv is just to ensure any grinding scratches on the flange are sealed up completely. They insisted this was the best way to ensure long leak free operation for their design and if it weren't for the slightest imperfections in the finishing process you wouldn't even need a gasket with their headers. So... I guess I am going to give it a shot again with the RTV and go thin this time.

 

[DirtDonk]

I know it’s extra hassle to do something over again. And especially to worry about whether the second try is going to work either!
But I’m glad you’re going through this (and not me!) and documenting it, because this is been a big bone of contention for a while now.
If you can get it to seal with their method, then we know it’s possible. And you won’t have to worry about a gasket leaking down the road.
Although, as gaskets go, the previous recommendations of super thin copper, or the crushable aluminum versions, are probably a good fallback even for this type of header. I imagine they would work with just about anything.

These headers are fabricated steel, and not one of their cast models. Correct?
And are you running cast-iron heads, or aluminum?

 

[betzgb]

I know it’s extra hassle to do something over again. And especially to worry about whether the second try is going to work either!
But I’m glad you’re going through this (and not me!) and documenting it, because this is been a big bone of contention for a while now.
If you can get it to seal with their method, then we know it’s possible. And you won’t have to worry about a gasket leaking down the road.
Although, as gaskets go, the previous recommendations of super thin copper, or the crushable aluminum versions, are probably a good fallback even for this type of header. I imagine they would work with just about anything.

These headers are fabricated steel, and not one of their cast models. Correct?
And are you running cast-iron heads, or aluminum?

GT40 iron heads and the headers are steel. Here is the model specifically: https://sandersonheaders.com/product/ff758-small-block-ford-bronco-header-set/

 

[DirtDonk]

Thanks. Damn fine lookin’ set of tubes you got right there!

 

[Speedrdr]

Being what looks like are ‘shorty’ headers, would it be possible (or maybe workable is the better word) to turn the exhaust into the wheel wells? The power is off in a large area of the county and I can’t sleeping so I’m running through odd ideas in my mind.

Randy

 

[betzgb]

Well I pulled off the header and it was clear that the black RTV had blown out on the front tube flange. I recoated much thinner this time and letting it dry overnight per the instructions. The bolts were fairly loose when I went to remove this passenger side header. My theory is I put on too much RTV the first round and it compressed quite a bit over time. I had not gone back to retighten the header bolts and I think they were too loose and blew through the RTV. I did re-torque the driver side which was also fairly loose, but has no evidence of leaking at this point. I will get things bolted back tomorrow and heat cycle several times then re-torque. I will end with a small prayer to the Bronco Gods that I don't have to do this again, such a pain to get to all the header bolts and collector bolts!

 

[badandy73]

Well I pulled off the header and it was clear that the black RTV had blown out on the front tube flange. I recoated much thinner this time and letting it dry overnight per the instructions. The bolts were fairly loose when I went to remove this passenger side header. My theory is I put on too much RTV the first round and it compressed quite a bit over time. I had not gone back to retighten the header bolts and I think they were too loose and blew through the RTV. I did re-torque the driver side which was also fairly loose, but has no evidence of leaking at this point. I will get things bolted back tomorrow and heat cycle several times then re-torque. I will end with a small prayer to the Bronco Gods that I don't have to do this again, such a pain to get to all the header bolts and collector bolts!
View attachment 909877

Remflex gaskets and stage 8 locking bolts and you won't ever have to touch them again..

 

[73azbronco]

Yuck, seriously. buy yourself some aluminum header gaskets now.

 

[JKH67302]

Another vote for Remflex gaskets and stage 8s. Never touch it again. I have the same headers and exhaust. I feel your pain on those collectors.

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