smart51
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| posted on 8/3/09 at 12:43 PM |
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scooter engined trike cooling system problem
My 3 wheel project has a 250cc scooter engine. The cooling system is as per the donor with 2 modifications. First I've extended all the hoses
to suit the new layout (about 3.5m extra). Second, I've fitted a bypass valve and a heater matrix between the thermostat on the engine and the
rad. All of the coolant can pass through the matrix if needed to make use of the small volume of heat. The bore of the matrix inlet / outlet is the
same as the engine and rad, conveniently.
I ran it at idle yesterday to check the heater function. The engine gets so hot that the ECU switches the fan on (temp sensor on the thermostat on
the cylinder head). The hot water hadn't got as far as the radiator.
This morning I took the hose off the heater matrix and ran it. Water trickled out until I revved the engine a bit, with the brake on to stop it
rolling forwards. Water flowed out at a reasonable rate. My conclusion is that the pump isn't up to the job of 2 rads and the extra hose.
Do I ...
1) fit an electric pump to help it along
2) fit bigger diameter hoses to cause less restriction
3) do something else (suggestions please)?
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ReMan
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| posted on 8/3/09 at 12:47 PM |
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I'd guess a s you say that the pump is just not efficient enough at log speed to reach the extra pressure needed.
Electric woul be an option, but do you need all the extra cooling, you may find the existin albeit moved rad and fan good enough, they are often over
cooled
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smart51
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| posted on 8/3/09 at 12:59 PM |
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The heater matrix is to heat the cabin, nothing to do with cooling the water. The hose up to the matrix gets warm but the matrix itself doesn't
so the water flow is pretty poor.
This afternoon I'm going to jack the rear up and let the wheel spin so I can put some revs on the engine and pump, just to check the water will
flow as desired.
Here's a thought, do any production cars have an electric coolant pump that I can salvage, so I don't have to buy one of those craig davis
pumps new.
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dinosaurjuice
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| posted on 8/3/09 at 01:10 PM |
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an electric water pump would be my choice. used on quite a few VW turbo cars.
something like this
will
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prawnabie
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| posted on 8/3/09 at 01:41 PM |
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Renaults older 16v range had a secondary electric water pump in addition to the normal mechanical one.
Id be looking at F7R engines in older clio / 19 16 valves
Shaun
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smart51
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| posted on 8/3/09 at 02:39 PM |
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Thanks guys. I bit of throttle does circulate hot water all the way round but slowly. An electric pump for assistance seems the way to go.
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britishtrident
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| posted on 8/3/09 at 03:18 PM |
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By-pass/heater circuit should go directly from before the thermostat to the bottom hose/water pump inlet ..
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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smart51
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| posted on 8/3/09 at 03:53 PM |
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quote:
Originally posted by britishtrident
By-pass/heater circuit should go directly from before the thermostat to the bottom hose/water pump inlet ..
Ideally yes. On the Piaggio engine the thermostat bolts to and sits directly inside the cylinder head. When closed, the water pump purely circulates
water through the head. Once the stat opens, all the hot water is mine for the heater. Only left over heat in the water goes to the rad. Its only a
250cc single after all. Not much heat to go round.
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v8kid
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| posted on 8/3/09 at 03:57 PM |
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Interesting project. Sure the thermostat/pump are OK? Like you I would have expected them to cope. Electric pumps are hastle although mine has been
100% reliable.
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ss1turbo
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| posted on 8/3/09 at 03:57 PM |
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I've got the pump from a LR Discovery auxiliary heater - 19mm ends. Similar ones live on V6 Omegas, later XJ6's and the aforementioned
VAG turbo stuff.
Long live RWD...
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MikeRJ
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| posted on 8/3/09 at 05:25 PM |
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quote:
Originally posted by smart51
Ideally yes. On the Piaggio engine the thermostat bolts to and sits directly inside the cylinder head. When closed, the water pump purely circulates
water through the head. Once the stat opens, all the hot water is mine for the heater. Only left over heat in the water goes to the rad. Its only a
250cc single after all. Not much heat to go round.
In which case I can't see why your heater matrix has lead to a reduction in cooling unless you have an airlock or your heater matrix is causing
a significant restriction. Is it an old s/h unit that could be clogged up?
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smart51
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| posted on 8/3/09 at 06:05 PM |
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quote:
Originally posted by MikeRJ
or your heater matrix is causing a significant restriction. Is it an old s/h unit that could be clogged up?
It is second hand. It looks tidy from the outside and I could blow through it. I'll try flushing it out.
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