Crusader 454 Exhaust Manifolds Replace or Not?

I am in the process of pulling the heads to be redone on my 1989 Crusader 454 and noticed the exhaust manifolds have some rust in them. How much is too much? I recently purchased the boat so I'm not sure how old they are or how many hours are on them. I have attached pictures.

yes definintely replace those and the elbows. Water has been leaking back into your cyls and if you try to reuse those you will be rebuilding the cyl heads AGAIN.
there should be no rust inside the exhaust gas passage of the manifolds and elbows. The only thing you should see is black/grey carbon in the exhaust gas passage. I bet you had rust in the exhaust ports of your cyl heads as well.

Is scale excessive? - hard to tell from pics. They do look like they took some water at some time in their life

You do not state whether you run in fresh or salt water. What do the risers look like? How about the riser gaskets? Water could have leaked down from risers to give some rusting. The boat could have take water in from hard stops too. What does the exhaust flapper look like?

Did you pressure test them? Make a rig to accept garden-hose fitting, and block other side, but allow for bleeding air out - maybe screw a small valve into this end. Then make a plate with some gasket material to block riser surface - or use riser with a full gasket. Hook your city water garden hose, that supplies about 55 psi, out of the faucet to manifold. Let is sit there for a while, and carefully look for leaks. You might use a flashlight to see in the exhaust ports. With water pressure on manifold, also lightly tap with hammer around on casting to see if you loosen up some scale to cause leaking.

If they hold water back, I'd clean them up, scrape gasket surfaces, then make determination. If they don't hold water, scrap them.

Is your Crusader engine Fresh water cooled?

Thanks for all of the replies!

The boat is a saltwater boat 24/7 in Southern California. It has a fresh water system for the manifolds and the block the risers and elbows are raw water. The rear flaps look good. I think the main culprit is that the boat has been sitting in the water for 3+ years and the salty air just creeped its way up.

The Manifolds don't have a ton of scale but a decant amount of surface rust there is some surface rust in the head as well. I pulled the elbows off to find a reasonable amount of scale. I added pictures of the riser and elbow.

I think I am going to just replace it all and start fresh and have piece of mind. Do you recommend a certain brand?
I found this Barr Kit on Amazon for $1400 for everything. https://amzn.to/3oPzkoA Are these junk?

Thanks,



Bill.

Your elbows actually don’t look bad. Was it leaking on the outside around the gasket? Barr has a good rep actually I’ve used them myself. You might be able to salvage those on second though.

The manifolds are probably still good.... But what is "piece of mind" worth?

Billigan said:

It has a fresh water system for the manifolds and the block the risers and elbows are raw water. The rear flaps look good. I think the main culprit is that the boat has been sitting in the water for 3+ years and the salty air just creeped its way up.

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It must be nice to not have to worry about cracking manifolds from freezing, like here in New England, only just wearing them out

You may want to consider installing a flushing valve for each engine. I use this on my boat, with great results. PERKO Inc. - Catalog - Underwater Hardware - Flush Pro™ [0456, 0457]

When you return from a boat trip and you're cleaning up, you can run fresh garden hose water from the dock to help clean out residual salt water. This won't help clearing rust at exhaust port, but running some fogging oil in carb once in a while could give a bit of oil coat there.

You can test the manifolds for leaks by propping them up level and filling with acetone (careful flammable), acetone will find leaks that water won't when they are very small. Then you have to make sure that the sealing surfaces are not pitted and flat and level (check with a straightedge and feeler gauges).

Thanks for all of the helpful responses!
I took Chris's advice and bought all new risers, elbows and manifolds from Barr. I was pleasantly surprised to see they were made in the USA!

I have cleaned all of the paint off the mating surfaces and they are ready to be installed.
My question now is do I need to put anything on the gaskets or do they go together dry?
I have read conflicting ideas online, and I cannot seem to find any offical instructions from Barr.

Also on the old parts I noticed that some kind of thread sealant was used for npt fresh and raw water inlets and even on the studs from the manifold to the riser.
What is recommended?

Lastly what are the torques specs for the head, riser studs / nuts and elbow bolts.

Thanks,

Bill.

I prefer permatex #3 for the gaskets...

Use PST (locktite's pipe sealant with teflon) on the NPT fittings. it usually works well for the fasteners....

25 ft*lbs for risers and elbows....35 Ft*lbs for the manifold-head bolts...

When I did mine I contacted Barr tech support and the guy I spoke to recommended Permatex Aviation for the manifold to elbow gaskets so that’s what I used….don’t need anything on the manifold to cyl head gaskets. Don’t forget to recheck torque after running it for a while you often have to tighten then just a bit more….

Thanks for all the replies!

I now have everything back together and I am ready to add coolant.

Is there a process to "prime" the freshwater system? Or just add coolant to the reservoir, crank then add as needed...

What kind of coolant is recommended? Can I use 50/50 premix from AutoZone or do I need something specific?
BTW it doesn't get below freezing here.

Thanks,

Bill.

if it won't freeze where you are, then you can use water (I prefer distilled) with a rust inhibitor - qty determined by reading the label.

empty, the closed side calls for 33 Qts.

If you opt for the antifreeze, you want the old 'green' type of ethylene gylcol based coolant. I prefer the full strength jugs so I can dilute it as needed...

I trust you know about the tabs on the gaskets...???

As far as purging the closed side, there should be a vent plug in the t-stat cover....I have found it helps but doesn't purge all of the air. What we do is run the engine until the t-stat opens and then shut it off and let it cool down and then recheck the tank...they only want it filled to within an inch of the filler neck's bottom. Usually two or three cycles will get rid of all of the air..

Thanks Mark!

I am not aware of the tabs on the gaskets...
Should I be Scared?

I just ran the tabs up. Is that correct?

Thanks,

Ethylene Glycol also raises the solution's boiling point so running just plain water isn't the best option.

Its a pressurized system that operates below 212 deg F and the EG lowers the specific heat....so the choice is what he wants to optimize to...

on the tabs, yes, for the most part, "UP" is the desired state. depending on the gasket (3 or 1 hole) the tab(s) will be either at '12 o'clock' or nominally at 11 & 1 (or 10 & 2)...the other thing is making sure you use the correct number of holes at the correct location....OSCO used to have a PDF showing the appropriate selections...the Crusader parts diagrams show the correct gasket locations as well.