Why do my engines run cool??

[Dave_Snelson]

Two x Volvo V6 Vortec 4.3L (1999). New thermostats fitted a week ago. 290 DP outdrives. Dual fuel, LPG and petrol.

So why can't I get better than 50C on the temp guages? Are the gauges or sensors wrong? Anything else I should know?

It's no great shakes, and replacing the stats got the guages to actually lift off the bottom stops!! Really I need higher temperature because that's what vaporises the LPG. It's working fine but I would prefer 70C.

Any ideas chaps?

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>

 

[Freebee]

I dont know about volvo's but sometimes you can get stats of different temp ratings are yours suitable for 70 deg?

<hr width=100% size=1>

 

[Dave_Snelson]

They are standard stats, so should deliver 70-80C. Hot stats (which are available, but I didn't want to risk them) run upwards of 90C but below 100C.

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>

 

[britemp]

Assuming LPG works the same way in boats as it does in my Land Rover, the engine temperature shouldn't affect the vapourisation of the fuel as LPG vapourises without help down to -37C when released from pressure.

What could be causing the low temp running is the ignition settings - does it run petrol and lpg? If so do you run both at the same ignition timing. I have an ignition advance unit fitted which automatically detects when it changes from petrol to LPG and advances the ignition a preset amount, in my case 16 degrees. The transformation has to be felt to be believed, the vehicle performs notably better on lpg than petrol with the ignition suitably advanced. It also runs at the correct temp, with the petrol ignition settings it ran a little cool on lpg. Although lpg is 114 octane it is slower burning than petrol and really needs the ignition advancing to get the best.

Scroll down to the end to see what I mean:

http://www.v8engines.com/Acrobat/LPG_Infofinish_2003.pdf

Also have you had it set up properly on a dedicated lpg testbook? A good friend of mine runs a Land Rover dealer that converts hundreds of them - I'm sure he could be convinced to come and set it up for you!

<hr width=100% size=1>

 

[tr7v8]

Aren't the Volvo V6s raw water cooled as standard? If so then you aren't going to get much higher temps because they keep the temp down to minimise corrosion.
It makes a change to hear someone complaining about engines being too cool as most struggle with the b^&dy things overheating.

<hr width=100% size=1>Jim

Draco 2500

 

[Dave_Snelson]

Thanks for this, it must be sound advice, as I have had someone do this for me already. The whole setup on my boat is reletively unsophiticated, with automatic nothing! I took the boat to Hardy's at Pwllheli and had new gas carbs fitted and I got Simon Hardy (who knows a thing or two about LPG) to set it up to run on gas best and first, then petrol, as a secondary fuel. You are right about the transformation - it was something else! People say that LPG doesn't generate the same power, but my engines love it. They run much smoother and cleaner and deliver a big wallop when opening it up!

The reason for wanting the higher temperature is that (I was told) the vaporiser can ice up when delivering large amounts of gas, and therefore jam the valves open. To be honest, I didn't find this problem prior to fitting the new stats, so I'm unlikely to find it now. That and the fact the boat, when opened up, does 45kts, so you wouldn't want to stay at that speed for too long anyway!

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>

 

[ccscott49]

If they are raw water cooled, ie no heat exchanger, you do nmot want them running any hotter than that, as very hot salt water, is highly corrosive, so they try to keep the temp down, to reduce the corrosion. If they are heat exchanger cooled, try a hotter thermostat. Ignition timing will make your engine run hot, but not cold. If you get my meaning.

<hr width=100% size=1>

 

[tcm]

I wonder if the answer is praps partly - cos it's bleedin cold? I stopped on a french motorway to check coolant and worry worry worry, but is was around 3degrees C outside. When warmer it'll run hotter, praps ?

<hr width=100% size=1>

 

[Xenopus]

Hi Dave,

Glad to hear you're getting on with LPG so well - we do too. We have 2 7.4L mercruiser magnums that also run beautifully on LPG and cool as well - 45 to 50 - I've always put this down to raw water cooling. We've never had a problem with the gas failing to vapourise despite the fact that we can be putting a whole lot thru the engines at high throttle settings. On a different note - have you tried to contact the LPG users club as in MBM, we've heard nothing back.

all the best,

Matt

<hr width=100% size=1>

 

[Dave_Snelson]

I have been looking for an LPG users club and not found one. I do recall some chap in MBM wanting to start such a thing, but with pressures of work, I just haven't got round to contacting him - I'll dig out the magazine in question.

By the way, did your Hunton 36 (lovely boat) feature in some LPG write ups some time back (MBM again, I think?).

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>

 

[Johnjo]

If you have a Thermostat set to run at 70-80 degs and your temperature guage says 50 degs
does this indicate that your engine is not getting hot enough to open the thermostat !....
Very unlikely I would have thought ! Unless the Thermostat is stuck fully open.
Faulty sender maybe !

I would have thought that if the engine was meant to run at a low temp it would have a low temp thermostat fitted !On a old raw water cooled Volvo diesol I had the therm was set to open 60 degs.

Always my understanding that a Thermostat set to 70-80 degs would not open until the engine cooling water reached that temperature or there abouts. Irrespective of it being fresh or salt, or have I got it all wrong again !



<hr width=100% size=1>

 

[britemp]

I agree, the only people who think lpg isn't as good as petrol haven't driven a properly set up lpg motor! The V8 in my LR has been dyno'd - should produce 182hp and 231lb-ft on petrol, on lpg with magnecor leads (V. important for gas!) with amplified ignition it produced 211hp and 248lb-ft at lower revs! All this with the cost equivalent of 34mpg and much better throttle response!

Don't worry about running temp - I've used the LR in temperatures down to -18C and run it straight on lpg with a stone cold engine with no vapourisation problems. You're a brave man if you go boating in North Wales when it's colder than -18C!!!!!


<hr width=100% size=1>

 

[Dave_Snelson]

Nice one! - thanks for your reassuring experiences.

And thanks to all other respondants to my thread. All very useful.

<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>