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Rusted on Exhaust Manifold and Riser Problem

knuckle47

knuckle47

Advanced Contributor
"I am having to do a top end j

"I am having to do a top end job on the port 454 engine and I have it ALMOST fully disassembled. Here is my dilema...I had to cut the heads off of 5 of the 8 bolts that secure the manifold to the head. This means there are 2 long "studs" and 3 short ones STILL holding the manifold onto the head. It seems like the 2 inches of long stud passing thru the hole of the manifold and into the head are SO CORRODED they have "rust welded" the thing together. Without removing the manifold I cant remove the head or valve cover. I have SOAKED and SOAKED the area with penetrating oil BUT I believe I may need more drastic measures. Anyone venture a plan like drilling the studs out or cutting the tabs on the manifold....I sure hope there might be an easier way....
"
 
"Ayuh,......

I'd think

"Ayuh,......

I'd think a few select Whacks with a BFH should do the Trick..........

A Blue-Tipped Wrench might blow enough of the old bolts out,.....
But,....
The bilge of a boat was Never a place I like throwing molten metal around......"
 
Bondo is right. If the hardwa

Bondo is right. If the hardware is that rusted the manifolds are probably junk anyway. Have at it!!
 
"Funny, my brother and I felt

"Funny, my brother and I felt the same way. I am replacing the manifolds as part of my plan anyway.BUT ( you're going to love this) AS MUCH as we whacked that one manifold and riser, lubed it, and sliced out the block off plate on the elbow to get more juice into the groove...THEY STILL WON'T BUDGE !... We had the same thoughts about the torch so that is out...Today (Monday 12-31) I am going to try to drill out the bolt holes to loosen it further. Eventually, there will be a point at which the PERSUADER should do it...Does anti-sieze help prevent this problem or does the exposure to heat for years eventually void the effect of the lube?

By the way...my Ford F-150 must have the same wheels that these bolts are made out of..A dealer told me they loosen the studs and drive over curbs to break them free from the hub !"
 
"[b]"THEY STILL WON'T

""THEY STILL WON'T BUDGE !... "

Ayuh,.......

When that happens,.....
Try Destroying the Manifolds,.... Take them out in Pieces.......
A Chisel shaped Bar,+ a Bigger BFH might be what it takes.......

Never-Sieze is Always a Plus,......"
 
"Got out there this afternoon

"Got out there this afternoon and I made some progress...NOT A LOT...but I was able to remove the elbow (big deal) and I THINK I got a slight movement from the 8th cylinder point forward...I soaked it in oil again and started to dent the manifold a tiny bit. The BFH is my next step. I feel IF I was able to gain any movement from it....I get probably get it off the next visit. I have about 12 hours into just removing the 2 mainfolds....phew!

While discouraging (VERY) I feel I am no longer looking up at the top of a mountain but have reached within 50 feet of the top....Of course, when I get to look over the top, you know there will be just another mountain range there.


Here is another question... I am running 454's with 3 inch elbows into 3" hose into 3" mufflers and 3" outlets. I read in the manual, the minimum size for 454 should be 4"...Is it necessary to switch to the 4 or even 5" system? What other than less back pressure is the gain and what harm is done by using the 3" ports."
 
"That's 3 inch PER side, o

"That's 3 inch PER side, or 4 inch together.

I'd try wedging them off with wooden wedges.

Jeff"
 
"Al,
Back in the day, 3"

"Al,
Back in the day, 3" was standard. At minimum. I would use the new 4" discharge elbows and if you don't care to replace the mufflers use a 4x3 reducer, installed as close to the muffler as possible. One of the key issues is getting that cooling water away from the elbow as quickly as possible and 4" discharge and hose will help in that area.

If you do decide to change the mufflers, that's even better but you still have the 3" exhaust port to deal with at the transom. If the wife is not watching, you can do the whole thing in 4".

Rick"
 
"THANK Goodness I don't de

"THANK Goodness I don't deal with that issue too much. Just got a 6 person offshore life raft for Christmas...so either she is enjoying the ride or trying to tell me something...

My concern is what is best for the longevity of the engine and performance. It looks like we are currently throwing water from those 3" ports about 15 feet or so from the boat at 3200rpm. I would happily change the entire system for the benefits to the engine. The old 3" exhaust tips have a 90 degree outer ring screw placement so ENLARGING the hole for the 4" tips will likely just encompass the old holes. Should I go with 5" or is this overkill?

Regarding the stuck manifold. I have a 5-lb sledge hammer (instead of my 16 oz. )and a larger chisel. I will give it one more shot after work this week and I do believe that this 100% effort will work.

Thirty years ago while fishing on Island Beach State Park in NJ, I saw a guy with a 4x4 stuck in the sand. I had always used this first try best try theory and never personally had a problem like that. Using this plan was out in about 15 minutes compared to trying all of these little things that were useless...

Do it right the first time...I am trying to maintain this theory as I age "gracefully"
Having put 12 hours in the removal of 2 heads proves I am not following the plan to well.

Your continued suggestions are EXTREMELY WELCOMED ! Thanks"
 
"You can't buy 5" exha

"You can't buy 5" exhaust elbows, but you can buy mufflers with a 5" outlet. I wouldn't go with 5" on a gas boat unless the cost and availability of the muffler dictated it."
 
"[b]"Regarding the stuck m

""Regarding the stuck manifold. I have a 5-lb sledge hammer (instead of my 16 oz. )and a larger chisel."

Ayuh,.......

That ain't no BFH,......
A 3/5lb.er is for cracking Walnuts maybe,.....

You need a 10/20lb.er..........That's a BFH.....
thumbs_up.gif
"
 
"OH....Its in perspective now!

"OH....Its in perspective now! I did'nt think of it along that size, I thought I could damage the motor mounts with that kind of force."
 
"Rick,

Along that same line

"Rick,

Along that same line regarding the 4" exhaust, is there a PREFERRED set up i.e. crossover, or ????

Currently, as I understand it, when I re-connect it all, the 4" elbows will go into 4 4" mufflers AND exhaust tips....2 for each engine?"
 
"If that is the way you are se

"If that is the way you are set up now that would be fine. Most boat manufacturers today use one muffler per engine with two inlets and a single larger discharge. This would require you patching two holes in your hull which may be getting more involved than you want to, and to no real advantage, performancewise."
 
"On the exhaust size issue...u

"On the exhaust size issue...unless you're an off-shore racer, a 3 inch exhaust system is all you need--and even for a 454! What people don't seem to appreciate about marine exhausts is the volumn reduction effect of the water injection. A huge mass of hot exhaust becomes a small volumn of cool exhaust after the risers, when the flow of water hits it.

I respect your restraint! Many would have resorted to dynamite or etc by now. The wooden wedges will work without buggering up any port gasket surfaces.

Jeff

PS: Once removed FOUR alunimim exhaust manifolds off a pair of saltwater engines. The largest piece would fit in your pocket!"
 
"Hi Guys....

YEE HA ! It i

"Hi Guys....

YEE HA ! It is off. The BFH did the trick in about 15 hits. Stopped at Lowe's to get the BFH and they had a huge selection of em'. Hard to believe how rusted on this one side was but when it came off, the 2 long thicker ears of the manifold had broken free but the short recessed studs on cylinders 6 and 8 broke off the manifold and are still stuck to the head. Now that the head is off I can take care of that problem.

Jeff, As for racing...it is a 20 year old Silverton 34 that was re-powered from the 350 cubes to 454's. My brother and I wanna do some fishing offshore and that is about it. One of these blocks had a coolant leak. The other runs and starts like a fuel injected (it is not) new chevy engine. On re-power, to minimize cost (cheap, cheap, cheap) they used the old mufflers and the old props. This is my 78th post and ALL are from the problems I started to have with this block from about August.

You guys have been a great reference source and the suggestion and information has enabled me to dig this far, into the repair. Once I get the heads back, I would believe that between a can of never sieze and new gaskets and bolts, IT SHOULD be pretty straight forward ? Anything I may need to know about re-assembly???"
 
OK...So my heads are finally o

OK...So my heads are finally off....While the NY boat show is on as we sit here I doubt I might find an engine shop amidst the purveyors of fine boating hardware..

Can someone recommend a shop to rebuild these heads in New Jersey..Central South would be great but hey...THIS IS MY BOAT...I'll get to the recommended guys no matter where I need to go...THANKS
 
"Al, I'm a little further

"Al, I'm a little further south, but there have to be a ton of guys in the Bordentown/Flemington area.

With all the dirt track racing in that area there have to be plenty of good machine shops. Find yourself a little mom and pop shop and ask who they use."
 
"Hi Rick and THANKS, I am usu

"Hi Rick and THANKS, I am usually somewhere close to these spots...I will do that this week....Heck, Before you know it, it is launch time."
 
"Sadly, the outstanding Flemin

"Sadly, the outstanding Flemington race track is now history. Dammed developers!

Congrats for getting those unco-operative monsters off! Now go have a cool one.

Jeff"
 
"Jeff, My wife and I moved to

"Jeff, My wife and I moved to Freehole 33 years ago as it was similiar to the spot we lived in northern Vermont, nice quiet and rural. (cept' the mountains)...We had enough common sense to buy a few acres in the woods....Those developers waved so much money under the noses of the farmers ...need I say more. Takes 2 hours to go 59 miles to work.

If I knew how to drop a picture in I would show you the broken pieces STILL STUCK to the head"
 
"just a thought....whenever po

"just a thought....whenever possible:I do not use the bolts provided, but keep them for at home and replace them with stainless steel ones.Ya never know what lies down the road ahead.One of the reasons stainless tip sparkplugs came about."
 
"Hi Todd,

I thought about t

"Hi Todd,

I thought about that but any experiences I have had with stainless is that it is either SOFT OR BRITTLE and I have broken or striped and rounded too many of them so unless there is a grade of stainless that can accept that kind of torque (is there?), I will use more agressive maintenance than previous owners and HOPE I don't go thru this SH#@ again
What really stinks is that I inherited this mess thru someone else's total neglect."
 
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