Crossover valves

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BillyK

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I have recently removed the old copper fuel lines and am starting to put things back together. I have two 250 gallon fuel tanks, with seperate filters, to twin 8v-71 detroit diesels. The original system had crossover manifolds. Should I put them into the new system?

Thanks,

Billy K.
 
With the crossover system removed would you still be able to connect one tank to both power plants?
 
Without the crossover manifold each tank will feed the corresponding engine only.

Billy K.
 
I had a crossover on my gas boat, never really used it except to switch genny to pull from different tank to keep them even.
Diesel boat has no crossover but does have a transfer pump which allows me to transfer fuel from one tank to another.
I use that to balance if boat seems uneven.

I guess the benefit of crossover is a contaminated tank could be switch off and you can run off one tank.

Guess it comes down to what you feel you need.
 
I'm thinking in an emergency, if I had a bad tank and the other tank was not contaminated also, it would be a solution. But is it necessary. I would also rather have a tank balancing pump. I know old school wants the manifolds, but how often have they ever been used.

Billy K.
 
quote:
Originally posted by BillyK

I'm thinking in an emergency, if I had a bad tank and the other tank was not contaminated also, it would be a solution. But is it necessary. I would also rather have a tank balancing pump. I know old school wants the manifolds, but how often have they ever been used.

Billy K.

Click to expand...


That is the classic argument. However, the antithesis is how many times do you only fill one tank at one marina and the other tank at another marina. I wish I had a crossover. There have been times I have had to go for hours on one engine. Not fun!
 
Where I come from it is compulsory if you have more than one tank to be able to both isolate or connect the tanks together, most people leave them connected and the only time I have heard of using isolation is when someone has accidentally put water in a fuel tank or one tank is leaking

Regards Brad
 
It is possible to return to the wrong tank and over fill it. If you are careful that wont happen.

I had a transfer pump on my boat. Never uses it though I could see using it if I ran the genny a lot or had a leak that needed me to lower the fuel level.

I often thought of adding valving to the transfer pump to allow a hose to be added to fill an empty filter.
 
BillyK, include the cross over system. There too many positives that out weigh removing the cross over system.
Bill
 
1 tank can be contaminated by a bad deck fill o-ring , water through the vent , or a faulty tank sender or un-reset flowmeter totalizer or even theft siphoning could leave a tank below usable level or an A/S valve could get clogged, pickup clogged or it's tube fall off or become porous, etc. .
I'm a believer in having crossover valves, but also in always keeping them closed except for emergency use. When he crossover is open, 1 tank will usually draw-down faster than the other when fuel takes the path of least resistance.
 
My old Trojan had 4 gas tanks with a maze of plumbing to be able to run off any of them. Being a gas boat with one newer and more efficient engine, I would run on one to balance when on a long trip. When ethanol was first introduced, I wound up running on one tank due to contaminated fuel.

On a diesel boat, if I had 2 tanks I would still want the ability due to the contamination risks cited above.
 
If I were doing the work I would just leave them and add some sort of priming pump
 
Thanks everyone for your votes and comments. Crossover manifold it is.

Billy K.
 
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