I have 2 1990 454 mags from a salt water 14 yr old boat. I have replaced with homemade MK VI 7.4's and the boat is runnin' great, right at 80mph. I spun bearings on both motors but they where not leaking water at that time. My question is , can I clean/coat with rust treatment, etc? Will these treatments hurt the heat transfer enough to matter? I'm a frugal Bast-rd and hate to throw anything away I can use or sell. Should I toss the block,keep the heads,sell the heads, both and use the rods and crank? I was thinking about building one or both for spares but could build a 540/572? for how much more? I'm thinking with cleaning and a thin or even no coating they could run for yrs with anti-freeze?? Hate to toss a 454 mag with forged goodies. What would you guys do??

I'm not sure what you're asking.

1) No such things as Mk VI's. I assume it was a typo and they are Mk IV's? I don't guess it matters as far as what you're asking...

2) Are you wanting to treat the 1990 454 mags? Or the homemade 80mph motors?

3) Are you asking if you should do something with the motors to "clean out" the water jackets? And then coat them with something?

I'm trying to understnd

here ya go

http://www.earlstation.com/chemprime.html

i use this to treat and have been very satisfied with it's performance

You're trying a little to hard MC> The 1990 mags are the motors(engines not to confuse again) in question. By expressing concern for the heat transfer I inferred the jackets as this is not an air cooled system. My new homemade motors are Gen 6 , not mk 6 , got me there.
Yes to # 3. I want to clean out the jackets and possibly treat them to prevent more erosion but don't know if this is worthwhile. And thanks, OPEN72, for understanding.

it's great sh!t !! now if my lady could only understand me

Open72:
Does that stuff affect the 'blue paint' that some of us have?

From the website, that stuff is nasty! It removes everything else...
Kent

this is how i do it - , get some decent thinner , wipe clean till the part is free of oil and grease. take the chemprime and a cotton rag , and blot it on wet , and let it dry. it's that simple. if you are going to paint , wipe down with a good reducer after a day , epoxy seal and paint it's done.

are you asking if it affects paint ?? ( removes ) no. it will leave a white residue that can be cleaned with the reducer.

The usual "hot tank" acid bath will boil out the innards as well as anything. It's rare for an engine block to rot thru, but it CAN happen, especially if the boat was run often in salt, and stored on a lift or rack without flushing. Exhaust manifolds, intake manifolds, and then heads are the normal order of rot victims. This is because that's where the air pockets are (which feed the rusting process).

Normal old radiator flush will also assist you in cleaning the nast out of your motor. You can plumb it up with no stat and an automotive water neck. Just loop the hose back to the circ pump and spin the pulley with a motor. Hot water works best with the flush solution. Run it for a half day. Drain. Repeat.

That's all I know that you can do while assembled.
The hot tank works better..

When it's done you can determine whether there are any "dangerously thin" spots. If not, it can be resurrected as a freshwater motor or a closed-cooled motor and live out a happy life.

Cool, my exhaust was leaking a little and original so maybe the heads are salvagable as well as the block. Thanks , that's what I needed to know.