My overheating problems.

[Iain_S]

(snip)

The skin tank heats up from the top and very gradually gets hot from the top, evenly down to the bottom across the length of the tank.

 

That would seem to indicate that it is baffled.

 

Iain

[blackrose]

What about adding a car radiator and cooling fans? Easy retrofit if you can get the air through it and you'd only need to turn the fans on when required so you could use a thermostat. They use a radiator to cool a 5 litre supercharged V8 so your engine would be child's play. Also wouldn't require you to take the boat out of the water and have some welding done.

 

Thanks, it's not that I am unappreciative, but I have been though all of these ideas before. The 5 litre supercharged V8 moves through the air often at speed and has lots of air ducts and vents for the hot air to escape. How would the hot air escape from inside my cruiser stern engine space?

 

That would seem to indicate that it is baffled.

 

Iain

 

How so? I would have expected horizontal baffles to make the top of the tank heat up say from left to right and then further down from right to left, etc. If it heats up evenly from top to bottom all the way across then where are the baffles?

[Albion]

No disrespect guys, but we've got to about post 127 with no firm diagnosis of what is wrong. Until it is established whether the skin tank has or has not got baffles by, probably, a physical examination, then we are flailing around in the dark. Just proposing that exotic additional cooling methods are required is not based on sound evidence. If I had made decisions based on wild guesses, when dealing with my garage customers, and chosen solutions to problems where I was not sure of the root cause I would not have lasted long. Do the physical diagnosis please Mike. It must be possible, even if a temperature gradient method is inconclusive, to remove the top hose and rusty elbow and then poke a thin wire down to see if it hits a baffle surely?

Roger

[bizzard]

That of course is half the trouble with cruiser stern decks, the radiated engine heat can't escape properly especially with a metal deck with the sun beating down on it during the summer.

 

Now for the best of the rest.

Extend the tanks return tube by miles and lead it into your kitchen.Drill two holes in your fridge,thread the hose through and bundle loads of the hose in, all higgldy-piggldy Spaghetti style,take the end out of tother hole and back to the engine.

Switch on the fridge!

[alan_fincher]

I also think we are some way from proving it has no baffles of any kind.

 

I also wonder if the assumption is now that Mike's tank is "un-baffled", but the apparently identical boat that didn't overheat is still expected to have them ? Whilst I suppost that's not impossible, it sounds by no means a guaranteed explanation to me.

 

It shouldn't be hard, by one of the methods suggested, to prove if Mike's has baffles or not. A lot better than assuming, I think.

[Guest]

No disrespect guys, but we've got to about post 127 with no firm diagnosis of what is wrong. Until it is established whether the skin tank has or has not got baffles by, probably, a physical examination, then we are flailing around in the dark. Just proposing that exotic additional cooling methods are required is not based on sound evidence. If I had made decisions based on wild guesses, when dealing with my garage customers, and chosen solutions to problems where I was not sure of the root cause I would not have lasted long. Do the physical diagnosis please Mike. It must be possible, even if a temperature gradient method is inconclusive, to remove the top hose and rusty elbow and then poke a thin wire down to see if it hits a baffle surely?

Roger

Agreed, then make sure the skin tank isn't being forced away from the swim when under pressure and opening the gap at the back of the baffles (if any.) It might just need a brace across to the skin tank from the engine bearer or similar.

[Chalky]

Thanks, it's not that I am unappreciative, but I have been though all of these ideas before. The 5 litre supercharged V8 moves through the air often at speed and has lots of air ducts and vents for the hot air to escape. How would the hot air escape from inside my cruiser stern engine space?

 

The spec is that the vehicle has to be able to run at high speed then stop - in effect a drive along the autobahn at speed then pull into a service station, so the system has to have a lot in reserve. The airflow is an issue. On MGF one of the side scoops had a fan in it to force cool the engine bay. You could possibly do something like that, but as you say air flow is an issue. We've got a 40' Liverpool trad and although we've not had a cooling issue I recognise a lot of the issues you raise.

 

As a comment on a car the coolant temperature gauge usually has a "non linear" curve where it moves to warm at about 75 / 80 ish and then doesn't move off till about 1 or 2 degrees before it boils, this being well over 100 deg due to the pressurised system.

 

 

I also wonder if the assumption is now that Mike's tank is "un-baffled", but the apparently identical boat that didn't overheat is still expected to have them ?

 

 

Would it be possible to run both boats down the same section at the same speed and look at the hose temperatures? It may be that the other boat also runs equally as hot but that the gauging is different and not reporting it correctly. Also what's the age difference in the boats? Liverpool often made detailed differences between years and there may be something there.

[bizzard]

Can you not get in touch with the other L/boat owner and get him to take photos and measurements of his tank and cooling set up and and send them to you to compare them.They may not be identical.

[blackrose]

No disrespect guys, but we've got to about post 127 with no firm diagnosis of what is wrong. Until it is established whether the skin tank has or has not got baffles by, probably, a physical examination, then we are flailing around in the dark. Just proposing that exotic additional cooling methods are required is not based on sound evidence. If I had made decisions based on wild guesses, when dealing with my garage customers, and chosen solutions to problems where I was not sure of the root cause I would not have lasted long. Do the physical diagnosis please Mike. It must be possible, even if a temperature gradient method is inconclusive, to remove the top hose and rusty elbow and then poke a thin wire down to see if it hits a baffle surely?

Roger

 

Ok, point taken.

 

Can you not get in touch with the other L/boat owner and get him to take photos and measurements of his tank and cooling set up and and send them to you to compare them.They may not be identical.

 

He's down in London now. I've never met him, we just corresponded by facebook, but the skin tanks are the same dimensions and it's the same model of Isuzu 55 (4LE1). My boat was built a year earlier than his.

 

I don't want to hassle the guy too much - perhaps I'll be able to go into London and have a look at his setup.

[bowten]

Or Vortexes.

Bizzard,please have a look at Paul's boat on your moorings,it has the same engine,I fitted out this boat and I am sure he would have no objection.

[Iain_S]

(snip)

How so? I would have expected horizontal baffles to make the top of the tank heat up say from left to right and then further down from right to left, etc. If it heats up evenly from top to bottom all the way across then where are the baffles?

 

If no baffles, and assuming inlet and outlet at opposite corners, I'd expect a cooler area at the corner below the hot input. Still, there are so many variables that some sort of inspection by wire, hammer, camera, angle grinder or plasma cutter is needed to be sure

 

Iain

[bizzard]

Bizzard,please have a look at Paul's boat on your moorings,it has the same engine,I fitted out this boat and I am sure he would have no objection.

Will do Ian. I have the other W/beam boat to service too also with the same engine,i will check them both out tomorrow.

 

Oh i'm so glad my engines air cooled. Wheres me ear plugs.

[nicknorman]

It would all have been so much easier if the OP had not inserted the extra h in the thread title. Then it would just have been a quick referall to Weightwatchers and we could all have gone down t'pub.

 

 

 

 

 

 

To bed for me!

[Albion]

No disrespect guys, but we've got to about post 127 with no firm diagnosis of what is wrong. Until it is established whether the skin tank has or has not got baffles by, probably, a physical examination, then we are flailing around in the dark. Just proposing that exotic additional cooling methods are required is not based on sound evidence. If I had made decisions based on wild guesses, when dealing with my garage customers, and chosen solutions to problems where I was not sure of the root cause I would not have lasted long. Do the physical diagnosis please Mike. It must be possible, even if a temperature gradient method is inconclusive, to remove the top hose and rusty elbow and then poke a thin wire down to see if it hits a baffle surely?

Roger

Forget that idea because I have just realised that there is an even easier solution. Leave the hose and elbow alone, remove the vent bung a few inches away and poke a stiffer straight wire vertically downwards this time. You'll soon feel whether there is a baffle in there and get an idea if they exist or not. Couldn't be simpler.

Roger

Edited May 30, 2012 by Albion

[RobinJ]

Yes the hose from the engine to the top of the skin tank passes beneath the hose from the bottom of the skin tank to oil cooler, but what you can't see in that picture is that it loops down and then rises up.

It is these sorts of things that can lead to air locks!

Could be, I put on 2 coats of Primocon underwater primer and 2 coats of Rytex and 2 coats of Rylards Premium. But I think it was slightly overheating when it was first delivered and LB only put on a couple of coats. I first noticed it on a hot day about 2 weeks after I got it when I turned into the current and the temp went up to 90C and I wasn't even pushing it.

I've seven coats and three coats on at different times and it doesn't seem to make that much difference!

Yes, ok. So how easily can baffles be retrofitted?

I fitted raw water and a shell and tube in the heat exchanger, butthsi was purely to stop the gearbox oil getting hot, which cooked the first gearbox.

There are still no baffles fitted as I would prefer to have it out of the water and lift the engine out to do it!

My plan was to cut a third of the inner face of the tank out in the centre, weld two horizontal baffles in with the correct gaps at the relevant ends and then weld back the removed face between them.

You could either cut slots from the outside or the inside and insert the baffles form one side, but I wanted to make sure they were securly attached at both sides.

 

By increasing or decreasing the flow through the skin tank, it mostly only alters the rate at which heat is moved from one place to another and not how much heat is discharged. When there is no temperature gradient across the skin tank, it is clear that more heat is being generated than dissipated.

 

I worked out that water enters the engine through the pump, circulates round the block, exits to the heat exchanger and circulates round that before going to the skin tank. This amounts to about 3 metres of travel, so I concluded in order to dissipate the same amount of heat it needed to travel at least 3 metres through the skin tank, mine only travels about 2 metres without baffles. Inserting two horizontal baffles, would increase that to over 5 metres!

[smileypete]

Thinking about it, if I went for the "gash n' fill" option, I think the best method would be to have a 5mm raised edge after knocking each baffle fully in. That way would ensure the welder could weld both sides of the protruding baffle edge while sealing it at the same time, and it would also prevent the possibility of the baffle falling inside the tank while it's being welded in.

 

If it's expensive to call a welder out it might be worth hiring an inverter set and practicing on scrap.

 

cheers, Pete.

~smpt~

[Tony Brooks]

Whilst reading through the latest posts I had a thought about another long shot. We now know the IR readings can not be relied upon and a similar boat does not appear to overheat.

 

Can we be sure the boat's temperature gauge is correct? If the engine has not had steam coming out of it I do not think we can so just maybe its a gauge/sender issue. The sender and gauge have to be matched and if somewhere down the line the parts have been mismatched e.g American standard gauge and European standard sender you will end up with a gauge that either reads about twice or half of the true value.

 

Hopefully Liverpool did not mess about with the Isuzu equipment but you never know.

[Grace and Favour]

Whilst reading through the latest posts I had a thought about another long shot. We now know the IR readings can not be relied upon and a similar boat does not appear to overheat.

 

Can we be sure the boat's temperature gauge is correct? If the engine has not had steam coming out of it I do not think we can so just maybe its a gauge/sender issue. The sender and gauge have to be matched and if somewhere down the line the parts have been mismatched e.g American standard gauge and European standard sender you will end up with a gauge that either reads about twice or half of the true value.

 

Hopefully Liverpool did not mess about with the Isuzu equipment but you never know.

 

Would it be possible/practical, to measure the water temperature in the header tank with a thermometer to test the validity of the current temperature gauge?

[Tony Brooks]

Would it be possible/practical, to measure the water temperature in the header tank with a thermometer to test the validity of the current temperature gauge?

 

 

Yes - thats the best way once he sorts his IR thermometer.

[Chalky]

Whilst reading through the latest posts I had a thought about another long shot. We now know the IR readings can not be relied upon and a similar boat does not appear to overheat.

 

Can we be sure the boat's temperature gauge is correct? If the engine has not had steam coming out of it I do not think we can so just maybe its a gauge/sender issue. The sender and gauge have to be matched and if somewhere down the line the parts have been mismatched e.g American standard gauge and European standard sender you will end up with a gauge that either reads about twice or half of the true value.

 

Hopefully Liverpool did not mess about with the Isuzu equipment but you never know.

 

Having a Liverpool boat with the wrong engine fitted (4LB33 instead of the 25Hp it should have had) anything's possible. Are all of the Isuzu senders and gauges compatible? Could it be that they picked the wrong one up off the bench, swapped them over and there's another boat that's got a gauge that's also wrong?

[alan_fincher]

If the gauge or sender is faulty or a wrong combination, and the thermostat is doing its job, then even if the engine was only being lightly worked, you would get a falsely high reading all the time.

 

If Mike sees the temperature consistently going higher over time if the engine is worked hard, but staying at a more expected reading if not, then surely it means the water is indeed getting hotter in one situation than the other, and for whatever reason the system is NOT coping well at higher power outputs.

 

First thing, as it still seems to be in doubt, is to find out if this tank has baffles. If it has a removable vent plug on top, how hard is it to stuff a bit of stout wire down it, and see how far in it goes before it hits something ?

 

Given how many threads there have been about this engine and skin tank over the years, 5 minutes effort would give us some solid information, rather than the non stop speculation!

Edited May 30, 2012 by alan_fincher

[larkshall]

If it's expensive to call a welder out it might be worth hiring an inverter set and practicing on scrap.

 

cheers, Pete.

~smpt~

 

 

Or take an evening course at the local tech, the skill is always useful

 

If the gauge or sender is faulty or a wrong combination, and the thermostat is doing its job, then even if the engine was only being lightly worked, you would get a falsely high reading all the time.

 

If Mike sees the temperature consistently going higher over time if the engine is worked hard, but staying at a more expected reading if not, then surely it means the water is indeed getting hotter in one situation than the other, and for whatever reason the system is NOT coping well at higher power outputs.

 

First thing, as it still seems to be in doubt, is to find out if this tank has baffles. If it has a removable vent plug on top, how hard is it to stuff a bit of stout wire down it, and see how far in it goes before it hits something ?

 

Given how many threads there have been about this engine and skin tank over the years, 5 minutes effort would give us some solid information, rather than the non stop speculation!

 

 

True Alan, but I would like also to take a few temperature measurements with a contact type thermocouple against several areas of the skin tank, from cold that is. It might help determine the heat flow through the tank.

[Old Son]

If the existing tank has baffles Mike will still have the issue. If it doesn't he has a rather tedious job of draining, cutting and welding. Surely the easiest way is to add a second skin tank, built the correct size and including baffles. If he ends up with too much cooling he could amend his pipe work and leave the existing tank dormant.

[alan_fincher]

If he ends up with too much cooling he could amend his pipe work and leave the existing tank dormant.

On a modern engine with a thermostat and skin tank you simply can't have "too much cooling" - its a common misconception.

 

Other than needing more antifreeze than you might, and needing to cope for potentially greater expansion, there are no downsides to having an overly large area skin tank (or tanks), as the thermostat operation should prevent "over-cooling". What a nice big area tank does give you is a lot more margin that the engine should never overheat, even if thrashed hard - no bad thing!

[Old Son]

You may have missed my recent thread when I asked why my engine does not get hotter than 155 degrees F. I have two large skin tanks and a standard Beta thermostat which has been checked and is operating correctly. It was never suggested that I can't be over-cooled but I understand your reasoning.