Rapid Runner repower/refit

[Hondaz]

I can confirm there is no direct aluminium to copper connections. The HX is mounted in galvanised steel pipe clamps, that for peace of mind, were fitted with self adhesive rubber weather sealing strips. I haven't checked with a multimeter but I'm pretty sure it's isolated well enough at least until it's filled with coolant.
How is the ground on your battery system supposed to be connected of not via copper lugs - even tinned. Only possible way would be through a stainless washer setup but gives a pretty poor earth relatively speaking I would think? My mates boat runs his entire negative side system through his hull with no obvious issues - I'm not sure if this is such a great idea though?

[Warwick Marflitt]

Hey Jimmy. You just need to be aware of it.
When two metals of a different potential are connected to each other, and immersed in an electrolyte like sea water, the metals  have their charges ?equalized.?  The less noble metal, stripped of its inherent protective charge, is unable to prevent the chloride ions in the sea water from pulling metal away.  This is electro-chemical corrosion. Less noble metals Alloy are anodic, or negative, and if connected, will sacrifice themselves to any more noble metal they are electrically in contact with while immersed in an electrolyte.  The more noble metal (Copper) is cathodic (either positive, or just less negative). The less noble metal is the giver, and the more
noble metal, the taker. so the copper will eat the alloy....
 If your not in salt water the risk is less but if in one of our volcanic lakes some of that waters got salts and other chemicals in the water. A lot of the older boats with copper HXs are Fiberglass with cast iron blocks and heads. A sacrificial zinc anode like Volvo use has proven to be good. In the past Ive mentioned this issue before and some choose to ignore it. That's cool as it's not my boat. Navies around the world scrapped some of their first big alloy ships after short service life because of Galvanic,Crevice and electrolysis corrosion in their new alloy vessels. Note that these are three different types of corrosion. The results being all the same..... Here's the paper with all the info.
http://www.kastenmarine.com/_pdf/mbqCref.pdf

 I used it to fix trawlers when I used to service them. I even rag the editor Michael Kasten in the US to thank him for sorting it and removing the smoke and mirrors from the problem. He's a great bloke to talk with.
In short.... Its just electrons leaking from the alloy into the copper. Insulate the copper from the alloy hull with rubber. Paint the copper on the outside. Use a good anti corrosion coolant at the right mixture % with distilled water or rain water in the engine cooling system and you'll be in the best position to avoid the problem. "An ounce of prevention is better than a tonne of cure" Keep the bilge dry and it should be fine for years. Boats that live at a mooring in the water are way more at risk than our trailer boats.... Again you just need to be aware of it. Ignorance is bliss as they say? Wood that's been treated with a copper based anti rot treatment will eat alloy if its bolted to it too! 
Any ways back into it. The boats looking awesome and It's making me want to finish off the HJ53! Just have to get farm stuff sorted and put some time aside and get it done... Cheers all....     

[Kakapo76]

It's less of an issue in freshwater- stupidly quick in salt. I wouldn't bother with anodes and make sure everything is earthed correctly and that the HE tubes are rubber mounted.

[Ross Goldsack - JBNZ Immediate Past President]

Battery will be sweet up the front  and easy access to the isolator is a plus  . Mr Holden put the battery in the boot in the later model Commodore

[tmack]

Hay there Hondaz, I have a 4.7m alloy jetboat with an ls1, battery located in the front seat base, with around 2.5m cables to the starter and earth bolted to engine. No worries at all. Been going strong for 11 years now, with no sign of any issues.

Cheers
Terry

[Hondaz]

Thanks Terry. Do you happen to know what size the main battery cables are? Been slow progress last few days - work beckons. Laying out and mounting the fuel system at the moment and fabricating the 9 litre surge tank hahahaha. Had to go for the surge tank setup due to super shallow underfloor tank and trying to get a bit more fuel into the boat.

From the main tank pickup, to a tap, to a 100u filter, to a Carter silver lift pump to inlet a couple of inches down from the top of the surge tank. Return from top of surge to main tank. All 3/8 hoses. Outlet at the bottom of the surge tank, to Bosch 044 to 10u filter, to FPR to rail. Return from FPR to top of surge. High pressure loop all done in nylon braided lines and AN fittings except surge return fitting.

All fittings on surge tank are alloy hose tails that will be TIG'd on. All good?

Running out of room to mount stuff under the transom.

[Hondaz]

XX oversized surge tank built and pressure tested. 1 pinhole found at 3 x operating pressure so should be good Slightly different to how I imagined due to physical constraints (forgot about the steering pulley back there).

Fuel system layout sorted and nearly all mounted. Just got to wait for the AN fittings to turn up.

[APE]

Hi,great build looks good.just a note an 044 pump a hi flowing pump it is going to cycle your fuel alot and heat it up.have heard vapor lock can become an issue.some others on here may have more insight.

[Hondaz]

Thanks APE. I did consider vapour lock and fuel heat when I was putting it all together in my head. I considered removing the Schrader valve from the end of the fuel rail and running a bypass system instead of the dead head style also but decided against that setup due to complexity.

I was hoping the oversized surge tank would also help by providing extra surface area for cooling and by cycling the warmed fuel back through the main tank. The 044 pump feed is about 500mm away from the fuel regulators inlet to the surge tank (right at the top of tank vs right at the bottom). The outlet back to the main tank is physically close to the fuel regulators inlet. The main tanks feed into the surge tank is about 100mm down from the top. Sure there will be a bit of mixing but I'm hoping hot fuel goes back to main tank and cooler fuel goes to engine. Dunno till I try it though hahaha.

[Hondaz]

All fuel hosed up and ready to go.... Or at least ready to set regulator. Bilge pumps fitted.

Pretty much ready for the start on the electrical.

Just one thing I'm still undecided about - I had a fuel computer in the boat previously but can't get that to work with EFI. Has anyone done any electrickery with measuring injection timing cycles and multiplying it out at the known injector flow rates to get an accurate fuel burn/L remaining? Thinking of a system using a simple microcontroller setup and display. Only reason I ask is the underfloor tank is super shallow so getting an accurate fuel reading is going to be a bit of a guess from a floaty sender. I do have a fuel gauge in the boat (part of a multi-gauge setup) just no existing fuel sender.

[tmack]

Hi Hondaz,  Sorry not sure of the battery cable size, a sparky wired it up for me. They do look reasonbly heavy cables tho. Was just reading about your fuel setup, I have 2 deep tanks in the back corners so didnt require a surge tank, but I'm running the dead head setup, and run a corvette fuel filter between the pump and the fuel rail. Has a built in fuel pressure regulater and a return fitting attached. Just returns back into the fuel tank. Found it a really simple system with no worries

Cheers
Terry

[Hondaz]

Engine loom stripped of all the surplus crap. I think...

Now that I can see what's going on with it all, I believe I will mount the computer down under the header tank (hopefully no leaks - waterproof ECU?) just so I don't have to re-wire the whole lot. And if I need to take the engine out for whatever reason the ECU and loom can go with it.

[Hondaz]

Found these (similar to what I was going to build but ready to plug and play).

https://www.scintex.com.au/products/engine-fuel-consumption-gauge

Anyone used one? Was thinking of just running that in 'injector' mode. Probably still more accurate (at least after a couple of calibration runs) than a floaty sender.

[Paul]

Found these (similar to what I was going to build but ready to plug and play).

https://www.scintex.com.au/products/engine-fuel-consumption-gauge

Anyone used one? Was thinking of just running that in 'injector' mode. Probably still more accurate (at least after a couple of calibration runs) than a floaty sender.

Wow, a $500 display gauge with no senders...  NMEA is the nautical equivalent of CANBUS and data can be shared around the boat.  So if you have another device with fuel-flow rate/ GPS speed/ water speed/ etc it will use that as input.  Coming with no senders (and assuming the boat doesn't already have them), then that will end up being a rather pricy solution.  You can buy quite a lot of hours boating for $1000 in fuel monitoring parts....

[JohnR]

Why.  If your worried about running out carry a spare 20L or 2 for the first few trips. Usualy after a while ya work out how many hrs ya get per tank. Spend the extra money saved from not buying it on fuel