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Exhaust manifold replacement FWC 454bs

bobct

Advanced Contributor
"I'm sure this topic has b

"I'm sure this topic has been beaten to death, let me give it one more shot.

I have an '88 Trojan with about 700 hours. I think the exhaust manifolds are original on both engines. I'm planning on doing the risers/elbows on both sides, on the fence about the exhaust manifolds.

Both engines run about 180 degrees now although the port engine heats up a lot faster and gets a little hotter if I push it. Elbows/risers might be original on this side. I'm going to change Raw water pumps and thermostats as well.

What's the verdict on doing the ex manifolds pro-actively? Am I down to minutes or should I leave them alone? When they fail, is catastrophic or will I get some warning?

I'm also planning on changing the hoses at the same time, a lot of them are original. My other question is.....how do I "test" all of this work, the boat is coming out of the water this weekend.

I really don't want to wait until the spring launch if I can help it. Is this any sort of attachment I can get to run the RWC side in a loop so I can check for leaks as I move along?

thanks,
Bob"
 
forgot to add:

1) what


forgot to add:

1) what socket do I need for the riser/elbow bolts. Is that a 12 point external torx? Not sure what size I need. Can I replace those with a hex bolt instead?

2) Do I have any chance of getting these out w/o breaking? I'm going to start soaking them with PB plaster now.
 
"Bob:

Board Member Al has e


"Bob:

Board Member Al has extensive experience with your area. i'd suggest you search for his posts in the Crusader archives.

The manifolds should be serviceable if they are in the coolant side. The risers and elbows are overdue if they are original. When the risers finally come off, you should be able to assess the state of the manifolds.

You can use a standard radiator tester to pressure check the coolant side of the system.

Positive testing of the raw water side (elbows and risers) is a bit tougher due to the elbow's construction.

My original '86's had hex nuts, can't remember exactly but think they were 3/8" threads so 5/8" wrench needed. If they are twelve points, the customary box end wrench usually works fine. BTW, external torx fasteners are 6 points, not 12."
 
"thanks, will do a search. Can

"thanks, will do a search. Can't believe I didn't think of a 12 point socket or wrench. I assumed that there was a "specific" tool but I all already own those!

Bo"
 
"Bob- The reason my manifolds

"Bob- The reason my manifolds were replaced is two fold. MAIN reason was that the cylinder head valves were the big issue and corrosion in the manifolds was significant. Had they been at a point where a good cleaning rendered them usable...done ! Corrosion was so bad on the 9/16 bolt heads they were literally erroded to 13mm sockets and that just slipped and stripped. As you will probably read, the only solution was the "BFH". Once reduced to hand sized pieces by beating the "S" out of them , we basically started from scratch having the heads re-done and used new manifolds. It had taken many weekends of frustration before learning of that fabulous new tool... FYI: the "BFH" is not a Snap-On item...more like "Stanley or Craftsman"

One other thing, IF IT COMES TO THAT...I did not know at the time that their newer style manifolds could replace the log style... I would have changed to that center riser style. I could have used a different exhaust system that Rick had and quieted down the roar somewhat."
 




Hello all, I know I'm coming into his thread rather late but it's the closest one to problem.

I started by trying to replace the risers on my 454 Crusader starboard engine. The starboard riser on this engine is running at 220F and must be totally blocked with rust, and the engine slowly overheats. I had thought about pouring some acid through the raw water outflow to disolve the rust blockage in case I can’t get the risers off.

Anyhow, I have 8" aft risers with an upper and lower elbow system. They look like the originals (25yrs). I have tried hammering chisels, wedges, blades etc between the manifold and riser joint but no action. I used my 30lb bfh on the riser but it looked like the engine itself might move.

So, I've resorted to trying to take the manifold/riser/elbow off as one piece and replace the whole lot. It might be the easiest and best but expensive way forward.

W
hen I took the 4 bolts out of the port manifold, the bolt farthest aft had black engine oil on it and in the hole. The other 3 bolts were dry and rusty. Sounds like more fun but this development may confirm my approach as it would appear there is a problem with the manifold gasket, or maybe worse.

In order to remove the manifold, the manual says to insert 7” studs in the 4 manifold screw holes to facilitate removal. Do I really need to do that if I am going to replace the manifolds? Will the studs help? These guys are really on there. Can anyone tell me what’s the best/easiest way to get these manifolds off?

Many thanks.
 
Anyhow, I have 8" aft risers with an upper and lower elbow system. They look like the originals (25yrs). I have tried hammering chisels, wedges, blades etc between the manifold and riser joint but no action. I used my 30lb bfh on the riser but it looked like the engine itself might move.

If at all possible, take the entire manifold/riser assembly off and save the engine trauma. Of course, your back will now take some stress!

hen I took the 4 bolts out of the port manifold, the bolt farthest aft had black engine oil on it and in the hole. The other 3 bolts were dry and rusty. Sounds like more fun but this development may confirm my approach as it would appear there is a problem with the manifold gasket, or maybe wors.

There are 8 bolts. I don't think any should be threaded into the oil passageways, but after 25 years, expect some gasket seepage. I can't explain lots of engine oil in the exhaust tapped holes of the head.



In order to remove the manifold, the manual says to insert 7” studs in the 4 manifold screw holes to facilitate removal. Do I really need to do that if I am going to replace the manifolds? Will the studs help?

I use a couple of studs, both maybe 3" long, one each on the forward and aft most cylinders. They help hold the gasket in place as you replant the manifold.
 
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that's what I did, I cut the heads off a couple of the old bolts. That'll help hold the weight and keep it from crashing straight down. If you can get an extra hand on the end to help remove it that's a big help as well.
 
Same thing when my brother and I did it but since we did beat the SHIP out of them, the smaller pieces were a tad lighter. In reality, the BFH did break a few holes here and there in the logs but their big help was in breaking the seal between the heads and the manifolds. IT WAS STILL A MAJOR NIGHTMARE and took several tiring trips to the boat to get the job done as we would be fully spent bending, lifting, swinging, pulling, twisting....you get the idea.

Regardless, they are a very heavy assembly.........

By the way....if you find a topic that fits your needs, go for it. I just realized I 'd responded to Bob 8 months ago...my reply is essentially the same. We used a cutoff tool and a chisel to get the headbolts cut and that was cutting a bit into the manifold but we were replacing it anyway. Thinking about the process makes me want to go spray corrosion stuff on the heads RIGHT NOW. I almost think that removing the engine is an easier approach...really..maybe overkill but, the drive damper last year was really much less labor intensive and NOT having to bend and twist in that little space makes it all seem worthwhile.......good luck
 
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Thank you gentlemen for the advice.

I am trying to get the entire assembly off as there is no way the risers are coming off on their own without some major crashing going on Are there 8 bolts for both manifolds or 8 bolts per manifold? I can’t clearly see the other 4 if there are. Are they in under the rocker covers or something? I think the oil mystery will show itself once I get the manifolds off. I have a pulley over the manifold and tied it off to hold the weight. I was thinking of using the studs to put the new manifold back on, not for taking it off. Is this okay to do that? Isn't it only the head gasket between the head and the exhaust manifold that's holding them together, apart from the bolts of course? Oh, did I tell you I have an aft cabin (425 Uniflight/ChrisCraft with FWC 454s)? So the engines are in my living room/salon. There is a rear glass window that could be removed to get the engines out but it’s 4 feet above the floor level and I’d need to pop the seals etc. fun eh! Anyhow, any advice on how to separate the exhaust manifolds from the heads would be much appreciated. Many thanks.

Anyhow,
 
Anyhow, any advice on how to separate the exhaust manifolds from the heads would be much appreciated. Many thanks.

I think the best advise is to get those other 4 bolts out! THere are 4 short, and 4 long bolts (or studs/nuts). That gasket will fall apart, no worries there!
 
Got it, thanks Dave.

Any advise on the best place to get the new manifolds,risers,elbows and gasket kit parts for my 1984 454 FWC big block V8s?
 
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