Engine and exh manifold drain

[geronimo]

have a scarab 34FT with twin 454 AND INTEND TO INSTALL an automaticcoolant drain which becomes operative when engines are shut down.<br />any idea wether i can buy a system to install at engine and at manifold.<br />THANKS and merry X mas and happy new year

 

[Boatist]

Re: Engine and exh manifold drain

Why do you want to do this. If it is because you live in a freezing climit but still use the boat in winter it might save you a little work at the end of each day. In general it is not a good idea to drain. Factory rep I have talk too says get less damage if keep parts in water. When the air hits parts actually rust does more damage.

 

[geronimo]

Re: Engine and exh manifold drain

reason for question are current problems with leaking mercruiser manifolds and risers. when problem occurs with manifolds and risers filled with salty seawater this salt water runs into engine and i o not have to tell you what happens next....<br />we already replaced the lousy merctuiser manifolds by stainless steel headers to overcome this problem...<br />and we have a solution to avoid rust formation by filling engine after draining for winter with nitrogen gas.... no oxidizing with nitrogen around.<br />thanks for reply anyway and happy and prosperous 2003

 

[Bondo]

Re: Engine and exh manifold drain

I think you're on your own, to engineer a system like that..... there are easier ways to live with corrosion........

 

[Boatist]

Re: Engine and exh manifold drain

You said you replaced manifolds with STAIMLESS STEEL manifolds. You got my attention with that. Can I ask how long they are expected to hold up in salt water?? If I can find a stainless steel manifold and riser I would then consider a fresh water cooling and forget about salt water problems. Would be interested in any info on your manifolds.<br />Thanks and good luck with your project.

 

[geronimo]

Re: Engine and exh manifold drain

i did install custom marine replacement headers to replace the leaky mercruiser manifold and risers which should last many more years han the cast iron mercruiser manifolds;;<br />after one season salt water there are no traces of rust formation even inside where we can see so i assume this will work...<br />DRAINING THE BLOCK IS ANOTHER THING TO SOLVE WITHOUT HAVING TO CREEP UNDER THE ENGINES; <br />we meanwhile have found electro valves which we will install in tubing system coming from the blocks drainplugs...WHEN ENGINE IS SHUT DOWN THE VALVES OPEN AND SEA WATER IS DRAINED;<br /> we keep you posted when installation complete

 

[magicbandit]

Re: Engine and exh manifold drain

seems to me that these automatic systems are problematic<br /><br />GOOD LUCK

 

[Bondo]

Re: Engine and exh manifold drain

I think Boatist is got it right.... Stainless aftermarket marine headers... Then install a freshwater cooling system..... No Problem......<br />I also see a couple issues with your auto-drain system.... 1 is that there'll be Severe Hot Spots in the block,+ heads upon shut-down.... the water in the block i believe is a good heatsink to slowly cool the cast iron... Also, the air that's in the block, along with the salt,+ moisture will rust it Quicker, than leaving it full....<br /><br />Boatist, Stainless Manifolds are ava. from the "hot rod" aftermarket outlets... they can be had in nearly "stock" app.s....<br />How long they'll last in salt i don't know.... they run into the $2000/ $3000 range.....

 

[geronimo]

Re: Engine and exh manifold drain

thanks to bondo good thoughts about the hot spots and cooling after engine shut down .take this comment into account and will install supplementairy valve which is handoperated...so we can drain just before we leave the boat and rinse with sweet water<br />thanks again and happy holidays

 

[Boatist]

Re: Engine and exh manifold drain

Bondo<br />Thanks for the info but tooo high A price for me. Now that I know they exist I will be looking for them. Problems with manifolds is one of the reasons I am still running a 4 Cylinder, only have one to worry about.

 

[Bondo]

Re: Engine and exh manifold drain

Ya, you boys out in the salt really have to pay the price..... Full freshwater cooling is the Only way to go........<br />Then all you need is SS Risers......

 

[Boatist]

Re: Engine and exh manifold drain

Bondo<br />I looked for a full system for years and never found one for a 4 cylinder. Do you know of a source for a OMC 140 HP. Then the next Question is how long does the heat exchanger last.

 

[Bondo]

Re: Engine and exh manifold drain

Boatist,<br />I don't know about an OMC, But Merc. 470s are freshwater cooled... Once you find a heatexchanger, a little creative plumbing would get you a freshwater system.....it could be built for Any Motor... BUT, you'd Still have the problem that jos is going to have.... the salt gets into the pores of the cast iron,+ doesn't come out with a "sweet water rinse".. your motor has been in the salt... the damage is already done.. you could slow it, but never Stop it...once every year or 2, i go home to Maine... when i boat in the salt, i boat the next day in freshwater to run, heat up,+ flush the motor in a "sweetwater" pond... i'm Sure that abit of salt is left,but it's a risk i'm comfortable with... 560hrs. in three seasons, with only about 10hrs. in the salt....<br />As to "how long does the heatexchanger last?".... i haven't a Clue..... i boat in Lake Ontario,+ the St. Lawrence river.....Probably as long as your engine block will with raw salt water cooling....

 

[charleswmoore]

Re: Engine and exh manifold drain

I just couldn't resist this one. I boat primarily in salt water year around. Add the freshwater cool kit to the engine for a few reasons. One is they run warmer which means your going to be more fuel eficent, The engine doesn't get shocked with cool water on initial start up after a long hot run, Anti freeze is a rust inhibitor by its nature and we don't even want to talk about the obcious reasons regarding electronic control modules controlling those fuel injectors. The only thing sacrificial is the maniflods and by the nature of the beast the riser is drained everytime you shut down the engine anyway. I would rather have salt water in my maniflod blocking the air than no water allowing corrosion to set in. (That why items brought up off the bottom are kept submerged untill treatment can <br />begin?????) PS, How does nitrogen gas stay in the engine block anyway????????? Everytime that amount of cast mass cools down it will pull in <br />ambient air???????? Ie: Top off your fuel tanks!!!<br />Just a thought or two.

 

[Boatist]

Re: Engine and exh manifold drain

Charleswmoore<br />I agree with you better to leave water in manifold. I do flush with fresh for 10 to 15 minutes as we wash the boat down. Bondo said to use a full system (which includes the manifold) but I have been looking for years and only found half system for 4 cylinders (which only protects the engine).<br />I agree with every thing you said about the engine but do have some Qusetions. 1: What is the heat exchanger made of and how long does it last?? 2: How do you make sure system is full of coolent, is there a sensor that tell you low?? 3: Most units I have seen mount down on the side so how do you get all the air out??? 4: Do they come with a overflow tank??? I guess that too many sorry.

 

[Bondo]

Re: Engine and exh manifold drain

Boatist,<br />the tanks are Usually Copper/Brass.... don't know how long they last... there's a rad. cap mounted somewhere Above the T-stat housing to fill/ check the level....it can be either on the heatexchanger, or a seperate fill/ overflow tank....<br /><br />I think jos is doing what I've tried to do a Few times...... Over-Engineer a cure to a Simple Problem........<br />remember the FIRST Rule of Creative Engineering;<br />Keep<br />It <br />Simple<br />Stupid<br />...............................................