Pull the head before FWC install??

[Solana]

I haven't seen an answer to this so here goes...
I'm preparing to install FWC. I've done the acid wash and rinse and pulled the cooling cover. I'm amazed at how much junk was left after the acid and rinse- cleaned all that I could get at. At this point I'm debating whether I should pull the head and clean out the water jacket from above. I know this isn't trivial, but I don't mind if it is worth while. If there is no real benefit I'll just leave it alone. Thoughts? Thanks in advance. BTW- this is in a 1978 Catalina 30- great boat.

[joe_db]

I did not do this. I am not sure how much access you have from above anyway, if memory serves the passages are pretty small. You always could hot tank the head itself if you think it might be clogged.
And yes, I too was surprised at the "stuff" I cleaned out of my engine. I gave it two cleanings and then ended up taking the HX back off and giving THAT a cleaning too. I didn't do it, but if I was starting again I would do the filter idea for awhile.

[ndutton]

Pulling the head will give you a better clean up prior to FWC and is pretty easy on a Catalina 30. You could also make the conversion without pulling the head and see how the temperature behaves, pull the head if it's higher than expected. Again, easier on a Catalina 30 than most others and all you risk is a gallon of anti freeze.

I did the same as you so far, pulled the side plate, physically excavated the water jacket, reassembled and acid flushed. My target temp was 180° and that's what she ran although I admit it was without a thermostat.

Are you planning on using an electric coolant pump? If so, have you considered enlarging the sideplate Tee and diverter cap? Bypass valve installed? Modified hose routing aka Thatch mod? Following an acid flush it is good practice to replace the plumbing elbows in and out of the manifold for better flow and assured elimination of rusticles that may be lodged inside.

[Marian Claire]

"You could also make the conversion without pulling the head and see how the temperature behaves, pull the head if it's higher than expected."

That's what I was thinking.
I thoroughly cleaned the passage ways in the head when I rebuilt my A-4. I then ran RWC for several hundred hours. I flushed the engine before converting to FWC but did not remove the water side plate or head. Over time the coolant got darker and darker. Last month I drained the coolant and flushed the coolant side with fresh water. It took several gallons before it ran clear. Will be interesting to see if it darkens up again.
The point is that even when the coolant was darn near black it had no effect on my operating temp as far as I could tell. So I do not think you will do any harm leaving the head on and seeing what happens.
Dan S/V Marian Claire

Welcome to the forum.

[alcodiesel]

No comment on the head pulling idea except being lazy I'd rather not do it, but I have been thinking of FWC conversion. Are you going electric pump or off the engine? I like the electric pump (Indigo) idea.

[romantic comedy]

Pulling the head can be a breeze or it can turn into a nightmare.

I converted to FWC 20 years ago. I did an acid flush and that was it. I run a thermostat and it runs at 180 all day. Happi engine!

[Solana]

Thanks for the useful advice. I think I'll leave the head alone. I'm planning on installing an electric pump (redundant) from Indigo and using the existing mechanical pump for the raw water. My whole motivation for this project is to make my wife happy (adding hot water to the boat!).
You might be interested that I did the acid flush a little differently. I plumbed the three drains together (including the one in the manifold) and actively circulated the acid through the block using an electric transfer pump into the drains and out of the thermostat housing. Discharge went to a 5 gal pail, which collected a lot of nasty stuff. I let it run for a half hour or so. In hind sight, maybe a little risky. If one of the hoses, clamps, etc. let loose it would have been interesting with the acid flying around. I did run it with water first to look at the robustness of the setup.
Access on the Catalina 30 is really very good. Three or four screws and disconnecting some plumbing allows removal of the cabinet which is over the engine.

[ndutton]

Solana, I have hot water on my boat (11 gallon) and after a 4 hour channel crossing under power to Catalina I still have water too hot to touch the following morning. I use it for hands and dishes only, showers are by 5 gallon solar bag hoisted in the rig.

[indigo]

My own personal experience with head removal on an A4 that had 20 years of RWC salt water service was that removal of the head is absolutely advisable in order to insure that the 6 oblong cooling passages (in the picture they are on the manifold side of the block, behind the studs, between the intake and exhaust ports) are open. This area of the block is the hottest due to the exhaust ports and for that reason, these large openings tend to become completely plugged. In my case, no amount of flushing would have ever cleaned them out. It literally required physically drilling them out.

And by all means, enlarge the hole in the diverter cap on the side cleanout plate to at least 1/2" as this is the point of greatest flow restriction in the cooling loop and thus has the greatest impact on flow regardless of what kind of pump is used to circulate the antifreeze.