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454xLi exhaust system replacement

K

kimosammy

Contributing Member
I have a couple 454xLi's with internal cooling.
I'm getting prep'ed to change the exhaust system on the Starboard motor.
The exhaust riser has raw water going to it and then out the exhaust.
I noticed the manifold has anti-freeze going in to it.
If the manifold is cooled by anti-freeze, why not just replace the exhaust riser and leave the manifold?
 
Replacement depends on condition. Te anti-freeze cooled manifolds last far long (especially in salt water), but they too eventually will need replacement. The elbows ands risers are no where near as long lasting, being raw watr cooled.

It all depends on their condition.

Jeff
 
From my own experience, we had a major failure 5-6 years ago and needed to replace it all. During that time my manifolds were about 13 years old. It made sense after realizing the scope of MY work needed at the time and the assumption that 20 years useable life might be considered as a good run. Not an inexpensive proposition but glad we did it. As Jeff said, it all depends on their condition. You could see that mine had a hard life just from the corrosion. Some of that was due to the water ingestion as well and we needed to pull the heads so they had to come off one way or the other....it was the other that worked
 
Sometimes you do not have a choice but to change everything. On more than one occasion I have not been able to separate the manifolds from the risers with out doing damage. I mean the corrosion around the studs holding the risers to the manifolds was extensive.
 
Good points...I'll replace them....it a 98, 14 years would be a good run and separation without damage would be tough....
 
Speaking of corrosion: I have said this before but our 9/16 bolt heads were corroded down to 13mm. We spent 3 weekends trying to remove the manifolds to get the heads off. We used mirrors and cut-off wheels, modified tools, wrenches, and having limited space on outboard sides made hanging upside down equally important. The sinking feeling of a wrench slipping around the bolt heads is very upsetting by the third weekend

It was when the big hammer suggestion came out that I assumed we may have some level of success. I didn't think I would ever have the need for the 12 lb sledge hammer sitting in the shed. After smashing the pieces apart, we were able to remove the heads and move on
 
knuckle47 said:
Speaking of corrosion: I have said this before but our 9/16 bolt heads were corroded down to 13mm. We spent 3 weekends trying to remove the manifolds to get the heads off. We used mirrors and cut-off wheels, modified tools, wrenches, and having limited space on outboard sides made hanging upside down equally important. The sinking feeling of a wrench slipping around the bolt heads is very upsetting by the third weekend

It was when the big hammer suggestion came out that I assumed we may have some level of success. I didn't think I would ever have the need for the 12 lb sledge hammer sitting in the shed. After smashing the pieces apart, we were able to remove the heads and move on
Click to expand...


When I have rotted manifold attaching bolts on a 7.4, I use an angle die grinder with a ball bit. Takes whats left of the bolt heads right off so you can slip the manifolds right off.
 
Docksidemarineservices said:
When I have rotted manifold attaching bolts on a 7.4, I use an angle die grinder with a ball bit. Takes whats left of the bolt heads right off so you can slip the manifolds right off.
Click to expand...

This may seem like a stupid question, but here goes. How do you get the frozen bolts with no heads out of the block?

Erich
 
No stupid questions, just dumb answers!

If the head of the bolt is gone (drilled or burnt off--or just gone) this is good. Using wooden wedges, pry the manifold off the remains of the bolts. The bolts can then be grabbed by a small pipe wrench or Vise Grips and CAREFULLY wiggled out. The trick here is to be patient! The bolt's remains will loosen up if you work it back and forth. Heat helps here, but be damn careful if you're in the bilge.

Jeff

PS: If a few bolt heads remain, and they don't want to unscrew, DRILL the heads off. What ever you do, DON'T try to unscrew the bolts that don't want to come out! That only snaps them off in the head which makes a damn mess.
 
" The bolts can then be grabbed by a small pipe wrench or Vise Grips and CAREFULLY wiggled out."

Thanks for the "not dumb" answer. I forgot that after removing the manifold there would be a few inches of bolt remaining to grab.

Erich
 
That was one reason years ago, that we used the die grinder and cut-off tools. Were were hoping to have SOME length of stud to extract. We did get lucky in that all of them were eventually removeable. After smashing enough manifold off to remove the heads, the rest was easy since it eliminated the need to be screwed into positions the human body was never intended for, especially with some iron housing poking into your most sore places.

I used to think that some of the older cars were tough to change spark plugs on, ha ha ha. My thinking has since changed
 
Al: No reason to keep those other two plugs out of the Triton...if we get a warm day, I could take a road trip if you need a hand.
 
Two plug changing nightmares: The old 1980s Monza V-8s (you had to remove the motor mounts), and Chrysler PT Cruisers (the intake has to come off. Thanks a lot!)

Hey, Knucklehead, thanks for the best laugh of the year to date! From what I hear the Triton V-8's weird plugs have a nasty habit of snapping off. Hope that's not your difficulty....

Jeff
 
Wow: 1980s Monza V-8s, a bit if history!

The most difficult I have had is now, getting around those engines is a task, have to be snake. I now will wait until other work to be done and
remove the engine hatch, this way I can stand up when doing the work. Next boat will have a decent engine room, I never thought about this
until I had to work on the boat.
 
If I remember right, its the two aftmost plugs on the driver's side. The four on the passenger's side were a piece of cake. I've only had to do the triton three times and never had a thread issue. Design is poor from a maintenance point of view.

Worst one i had was an old (late 70's - early 80's chevy van.....until about the sixth plug. The resident 'greybeard' came back from lunch and showed the youngster how to access them from the wheel wells. another 'priceless' moment.
 
If you can get those plugs out of that Triton--no matter how hard--you need to, for if they seize in the head you'll have massive problems. Once they're out, and you coat the new ones with anti-seize, you should be set for the life of the truck. But don't just leave those two in there! You've been warned.

Jeff
 
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