flushing engine block/head – JWAC 6bta 250hp

[Charles A. Beever III]

Howdy everyone. Just recently received my custom exhaust riser from SBMAR for my 236 Mako and it’s a doozie. All those that were afraid I didn’t have enough room were proven wrong by the team and I can’t say enough about it, but that is for a later post. ***Spoiler, it bolted right up like they had had my boat in their shop the entire build!

On to business. When draining coolant and replacing Tombstone aftercooler hoses, I became discouraged by the rust and particle buildup on the inside of the metal connector pipes, as well as the last bit of coolant to drain was dark and dirty.

So, while my HE was removed from engine for new hose fitment, I determined to flush the block/head/manifold/aftercooler the best way I could design.

With HE & return pipe still off, I made fittings that made up to:

* thermostat nipple up top

*coolant pump inlet elbow down low

Both reduced to garden hose. With this set up I can flush and also back flush engine, and run drain hose to a 5 gal bucket to monitor how clean it runs, which I did several times and then left running for 20 minutes for good measure. Water now runs clear.

One issue- flushing the normal flow path (water pressure hooked up to inlet elbow down low) produces MUCH better flow than the back flush method (water pressure hooked up to Tstat nipple).

I feel that this might be due to thermostat restricting flow and maybe the great amount of water pressure forces thermostat open when flushing normal flow bath.

Bottom line, should I go ahead and remove Tstat and flush again since I am this far in and replace Tstat? Is there anything out there people use to clean or arrest this electrolysis, or is a clean water flush and prompt replacement with 50/50 mix the way to go? Green antifreeze ok, or should I use Cummins or some other kind? Anyone know what temp Tstat I need?

Topic

[Tony Athens]

Drop Breanda a note…..

[email protected]

[David Wesner]

fitting

Where can you get the 1″ banjo fitting on the turbo if the upgrade is done? Is it a M18 banjo fitting?

D

[Tony Athens]

There are plenty of engine block cleaning systems on the market–Truck shops can recommend one.. Would I go there? No…………………Clean out the 3/4″ NPT outlet on the back on the head, do not use the bushing, plumb to the turbo w/ 1″ ID hose , go to a 160 stat, and you’ll have a major upgrade.

Tony

[Charles A. Beever III]

Tony:

Sorry to not reply timely. I have not had aftercooler water pipes off again so no pictures yet.

It was just a rough, grainy buildup inside pipes, didn’t really reduce diameter any noticeable amount or anything like that. But it was not “smooth and pristine”.

What I did do was remove thermostat and flush and back flush several more time, got some more gunk out and some REAL flow. Water flow is clear as gin now and strong both ways. When I was changing out head fitting for turbo return a while back, I did not notice any ugly stoppage or anything like that where you indicated. I was upgrading fitting to accommodate 1″ hose.

I read on here after searching that my planing hull will like a 160 degree thermostat, so that question is answered.

Really just want to know if there is any solution or product people like for treating innards of head/block while I have it this far undressed. My thinking is that there is probably no “magic bullet”, and a good extended fresh water flush is as good as it gets. Just wanting to make sure!

[Tony Athens]

Simple comeback for now.. Can you post a pic, 2 or 3 of the parts/areas that you felt were partially clogged with rust/crud?

The back of the head/feed fitting to the turbo is a guaranteed area that need “mechanical” cleaning/scraping/picking………………………….. No flushing would clean this.

Tony

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