MD20-30 Raw Water flow rate

These engines tend to block at the exhaust elbow water injection point,have had it happen,remove elbow and clean it.
 
I know its not a straight answer to OP's question ... but I think worth pointing out ...........

Closed system cooling can run hotter than raw systems and in fact such as Perkins state this in their manuals .... I don't think the data can be any different for any engine run on a boat ...

Raw cooling is advised not to have engine temp exceed 140F (60C) to avoid salt build up in waterways etc.

Closed cooling can be higher without the salt deposits risk ...

My point for posting this .... flow rate is a good matter - but the engine temperature is the main factor to consider IMHO.

Various engine manuals mention using the seawater inlet valve to control engine temp .... but I doubt many people actually do that. I know I don't - I like idea that my flow is enough to put out a fire !! Better running cool and no build up of crap in the waterways !!

Last thing .. if OP is getting 7L / min ......... that agrees with other post of 420 L / Hr
 
peteK said:
These engines tend to block at the exhaust elbow water injection point,have had it happen,remove elbow and clean it.
Click to expand...

The Elbow was replaced with a S/S Unit 2 years ago. I'm hoping not to need to access the End Cap Boot due to the extreme access problems but thank you anyways, and I might well have to go look at it.
 
Refueler said:
I know its not a straight answer to OP's question ... but I think worth pointing out ...........

Closed system cooling can run hotter than raw systems and in fact such as Perkins state this in their manuals .... I don't think the data can be any different for any engine run on a boat ...

Raw cooling is advised not to have engine temp exceed 140F (60C) to avoid salt build up in waterways etc.

Closed cooling can be higher without the salt deposits risk ...

My point for posting this .... flow rate is a good matter - but the engine temperature is the main factor to consider IMHO.

Various engine manuals mention using the seawater inlet valve to control engine temp .... but I doubt many people actually do that. I know I don't - I like idea that my flow is enough to put out a fire !! Better running cool and no build up of crap in the waterways !!

Last thing .. if OP is getting 7L / min ......... that agrees with other post of 420 L / Hr
Click to expand...

You beet me to getting out the calculator!!!
I haven't had any heating issues as I rarely run the engine over 2,000 rpm, but I'm convinced the flow out of the 'Tailpipe' is less than it was..it also seems less after the engine has run for a long time, say over 4 hours.
 
Cariadco said:
You beet me to getting out the calculator!!!
I haven't had any heating issues as I rarely run the engine over 2,000 rpm, but I'm convinced the flow out of the 'Tailpipe' is less than it was..it also seems less after the engine has run for a long time, say over 4 hours.
Click to expand...


Its good you don't have heating issue .... my point was that the real factor is the engine / coolant temperature ... flow rate will affect that ... so if your engine is running 'cool' - then flow rate is fine.

Of course there's always risk of crud build up in pipes ... that's part of life .......
 
A chap I met reckoned that our engines, V 2030s, should pass his ‘15’ test. When running at 1500 rpm it should fill a bucket in 15 seconds.
 
Cariadco said:
You beet me to getting out the calculator!!!
I haven't had any heating issues as I rarely run the engine over 2,000 rpm, but I'm convinced the flow out of the 'Tailpipe' is less than it was..it also seems less after the engine has run for a long time, say over 4 hours.
Click to expand...
Reduced flow of raw water is most likely a raw water pump issue, or restriction of the intake/filter. Running at below 2000rpm is not necessarily a good thing. The optimum revs for a 2030 is 2400rpm and boats are usually propped to give around 55.5knots at 2400 while still being able to use the full power range up to 3400-3600rpm.
 
Tranona said:
Reduced flow of raw water is most likely a raw water pump issue, or restriction of the intake/filter. Running at below 2000rpm is not necessarily a good thing. The optimum revs for a 2030 is 2400rpm and boats are usually propped to give around 55.5knots at 2400 while still being able to use the full power range up to 3400-3600rpm.
Click to expand...


Decimal point ??? :rolleyes:
 
The matter of crud build up in pipes / waterways is somewhat reduced by making sure raw water flow and cooling maintains a below 140F (60C) temperature.

Yes - too cool an engine will slightly reduce its power ... but for me - I prefer no crud build up than a small bit of extra power.
 
Took some more measurements this morning.......
750 and at 1000 RPMs, still gives 7 ltrs/min
2000 rpms gives only 10 ltrs/min. Thought at this rpms it would pump more, say 14 ltrs/min
Humfff.........

This week I'll take the Heat exchanger discharge Boot off and inspect the feed into the Elbow.
I've already inspected the inlet Boot and the exchanger tubes and all was clear.
 
Cariadco said:
Took some more measurements this morning.......
750 and at 1000 RPMs, still gives 7 ltrs/min
2000 rpms gives only 10 ltrs/min. Thought at this rpms it would pump more, say 14 ltrs/min
Humfff.........

This week I'll take the Heat exchanger discharge Boot off and inspect the feed into the Elbow.
I've already inspected the inlet Boot and the exchanger tubes and all was clear.
Click to expand...


Methinks you over-worrying .....

If this is correct - which I believe is :

vyv_cox said:
Some figures obtained by ybw contributor.
Old pump flow rate ~180L/h at 1000 rpm.
New pump flow rate ~420L/h at 1000 rpm.
New pump flow rate ~630L/h at 2000 rpm.
Click to expand...

You have 7 x 60 at idle / low revs ..... 420 L/hr
You have 10 x 60 at 2000 ...... 600 L/hr

I don't see a problem ????
 
Refueler said:
Methinks you over-worrying .....

If this is correct - which I believe is :



You have 7 x 60 at idle / low revs ..... 420 L/hr
You have 10 x 60 at 2000 ...... 600 L/hr

I don't see a problem ????
Click to expand...

Yes, maybe it's the Heat out here......!
I'll also take some reading later this week, when I'm out there, when the engine's really warm and see if there's any shortfall.
 
Fixed it!!
I removed the outlet Boot and everything was clear, including the feed into the exhaust elbow.
Following Mr Cox' and others advice, I re-inspected the Pump end plate and hadn't really realised how Groovy it actually was. Cleaned and flattened up it's outside, fitted a new gasket , no sealant and fitted it with the old inside face on the out!!
Boom!! Flow measured at 15 liters at 1500 rpms.
I did read on another forum that there's an old guide of 15.....meaning 15ltrs at 1500 rpm!!
Visually the flow looks more now, as well.
Thanks to all the contributors.
Regards.
 
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