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Way glad to hear it's just a welsh plug. Phew! You got some plugged up exhaust system somewhere which them pushed the plug out?
Now that you mention it, last winter I replaced my existing 3" dual exhaust with a new 2.5" dual exhaust. I assumed the 2.5" would still flow well enough for 400ish HP? Perhaps not
Now that you mention it, last winter I replaced my existing 3" dual exhaust with a new 2.5" dual exhaust. I assumed the 2.5" would still flow well enough for 400ish HP? Perhaps not
I would have thought so also but a 460 is a heck of an air pump! Are all of the pipes mandrel bent?
I would have thought so also but a 460 is a heck of an air pump! Are all of the pipes mandrel bent?
The pipes are all mandrel bent, I had to cut/ weld all the curves myself. I was able to get a better look at the plug itself today. It developed a small rust spot in the middle that finally blew out I guess. The plugs are just mild steel, and I guess the exhaust gasses are not healthy for them. I ordered two more (just in case the other side lets go).
The pipes are all mandrel bent, I had to cut/ weld all the curves myself. I was able to get a better look at the plug itself today. It developed a small rust spot in the middle that finally blew out I guess. The plugs are just mild steel, and I guess the exhaust gasses are not healthy for them. I ordered two more (just in case the other side lets go).
Smart move. Sounds like something I would have done. Are your plugs reading lean by chance? I know you know this Merc but for the googlers out there , a lean mixture creates hotter exhaust.
Smart move. Sounds like something I would have done. Are your plugs reading lean by chance? I know you know this Merc but for the googlers out there , a lean mixture creates hotter exhaust.
They are a very light tan..... which indicates a leaner mixture. Yet when it's idling, it'll make your eyes water cuz it's so rich....
Holley 770CFM Street Avenger.
I bolted it on right out of the box, and it has always worked well. It idles rich when cold even with the choke off, and runs a little lean on the top end. I've though about changing jets, but it's something I've never done before.....not that has ever stopped me with this truck before.
If you don't have any pre-ignition like pinging or other problems then should be okay and your timing is not to far advanced other wise pinging may occur.
They are a very light tan..... which indicates a leaner mixture. Yet when it's idling, it'll make your eyes water cuz it's so rich....
Making your eyes water is more likely lean. That is unburned hydrocarbons that burns your eyes, a product of incomplete combustion due to lean mixture. Take it to a shop with a good 4 gas analyzer (and someone who knows how to run it) and you can find out more in 10 minutes than hours of trial and error tuning.
I have also fixed those burned out plugs a different way. Since that is the provision for air injection, there is a bolt hole right by the welsh plug where the rail was bolted down. I have made a heavy strap and sealed it with high temp silicon to bolt into the bolt hole and cover the welsh plug hole. But only when the space was too confined to have access to the welch plug.
^ never would have guessed that......goes to show you can't always go by instinct. I have the same issue with mine, figured it was idling rich and running a little lean.
Making your eyes water is more likely lean. That is unburned hydrocarbons that burns your eyes, a product of incomplete combustion due to lean mixture. Take it to a shop with a good 4 gas analyzer (and someone who knows how to run it) and you can find out more in 10 minutes than hours of trial and error tuning.
I have also fixed those burned out plugs a different way. Since that is the provision for air injection, there is a bolt hole right by the welsh plug where the rail was bolted down. I have made a heavy strap and sealed it with high temp silicon to bolt into the bolt hole and cover the welsh plug hole. But only when the space was too confined to have access to the welch plug.
Really?! I always thought it was from being too rich.
That's got me thinking....
The truck always runs awesome in the warm/ hot weather of summer. When the weather cools off in the fall, the truck doesn't seem to have the "punch" that it does in the summer. It doesn't run poorly, it just doesn't feel the same. I've had two different Holley Street Avengers on this truck and they both performed the same. Up here, (Northern Ontario), anything with a carb always ran better in the fall, with the cooler/ denser air. With my Holley, I figured it was jetted to run better in the hotter Southern USA, not the frozen North? I always put the truck away in October anyway, so driving it in the cooler weather was never much of a big deal. When I get the truck back together, again, I'll do some reading up on carb jetting.
And thanks for the tip about those plates you made. Between you and Orich, I have a few different ideas to permanently fix this exhaust leak issue.