strainer after waterpump

[admiralslater]

I am new to diesel engines (3gm30) and have learned a great deal from the CF.
There have been a number of threads regarding impellor failure and repair .A constant theme has been recovery of the vanes and how difficult it is .

There has also been talk of a strainer between the pump and the engine.
On another thread there was a picture of a freshwater system strainer which I feel may not be able to take the load from the pump and also may not be rugged enough .
Has anyone install a strainer in this way and what did you use . I was thinking about another in line strainer like the one already installed before the pump.
The only things that I can think of that might be an issue are
1 flow volume
2 the strainer will be under pressure as apposed to a vacuum
3 would there be any issues with a longer hose into the heat exchanger
BTW the impellors are changed every season ,but this is a good place for a belt and suspenders approach, I an also considering the speed seal covers

[Stumble]

Ideally you would measure the size of the tubes I need your heat exchanger and use a mesh a size or two down from that. But a really fine mesh probably won't cause issues often. Only if you start sucking up seaweed small enough to pass your primary strainer, but large enough to clog the secondary.

As to which side of the pump it's on.... I can't really see it as an issue. Typically the fresh water pump is capable of moving far more water than your engine really needs (or at least it will if it's properly sized) so the minimal amount of head preassure isn't likely to cause any real issues.

[leftbrainstuff]

The normal reason for not having a strainer on the outlet of the water pump">raw water pump is as follows:

1) a strainer before a heat exchanger (outlet side of raw water pump) can become blocked totally obstructing flow. You do not want a fine mesh anywhere in your raw water system.
2) without a strainer the impeller pieces will often become trapped in the heat exchanger. They will restrict flow in a passage but not obstruct total flow. You then get to rod them out, dissolve them, scrap the heat exchanger or leave them there.
3) post pump strainers are likely to not be regularly inspected and become blocked over time anyway.
4) monitoring raw water pump flow will give you both notice of a failing impeller and impeller failure

We have a raw water flow sensor inline after the impeller. It only alerts for no flow not reduced flow.

Even in motorsport we would not have crap catchers (strainers) on oil heat exchangers. This meant everytime you experienced an engine failure you got to scrap all your heat exchangers. Expensive but so is a blocked heat exchanger.

The strainer on the inlet is key to protecting the impeller from ingesting large objects. It has a large surface area. The impellers are intended to still operate even when in a degraded mode. (lost some ribs). You don't want any fine filtration in this circuit which is guaranteed to become blogged. The mesh will form nucleation sites for growth.

[DeepFrz]

This thread started by s/v Jedi in 2009 might be of interest.

http://www.cruisersforum.com/forums/...rts-29389.html

[a64pilot]

I use a strainer that we use in the hopper rinse system of the aircraft we build, its screen is pretty course but you can't see thru the bowl. Have not had a clogging issue yet, but I have not had vanes come off either.
On my generator I got rid of the vane pump completely and went with a March electric pump, no vanes.

[daletournier]

3gm30f has a very to easy to change impeller,just take the whole pump of and do it on the bench.
My experience is impeller pieces get stuck just prior to going through the heat exchanger tubes, and very rarely cause a major raw water flow problem on this engine. Thats only based on my experience with this engine.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[Blue Stocking]

With a range of PVC fittings, some pipe, some hole saws you can build just about any filter/strainer assembly you wish. The hydraulic formulae you may need are all online. My engine intake, shower sump, and both belt-driven bilge pump strainers are all home made.

[admiralslater]

Originally Posted by DeepFrz

This thread started by s/v Jedi in 2009 might be of interest.

http://www.cruisersforum.com/forums/...rts-29389.html

tis the sort of thing I was thinking of ,not a fine mesh. as I said in my op perhaps even another raw water strainer . No one responded to the lenght of hose question .I dont think it is an issue but an not sure
thanks for all the help

[Lepke]

I'm an old guy and do things in a old guy way. I've never had the impeller problems that seem to permeate these blogs. I have 4 impellers. Two big ones in Detroits and two in an Onan and Perkins generators. I inspect them once or twice a year for cracks or undue stiffness. When I reinstall them, I put some waterproof grease on the shaft, keyway, inside housing and inside cover. Now the grease doesn't last too long and maybe goes in the first starting. But all four my impellers were first installed in 2011. The generators have about 700 hours since and the mains way more. Where am I going wrong?