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BMC 1500 to BMC 1800


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We have had issues with our original BMC 1500 since buying our 48ft cruiser stern project boat with overheating, smoky and noisy,  fluid leaks & general reliabillity issues. And has to be said what seems like an overly complicated system with a large car type fan radiator and two skin tanks one either side on each swim she also has two fuel tanks one each side but with only one filler cap. I understand she was previously an ex hire boat 

 

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We have recently obtained a Heat Exchanger Raw Water cooled BMC 1800 which was refurbished on a millitary seargeants budget with resources availavailble

Which we plan to fit when we get into the marina at the end of August after a total clean and refurb of the engine bay. 

Ideally we would like to convert to skin tank cooling as drawing water from the canal is not reccomended

 

What are the nessacary steps to convert to skin tank cooling. Any advice much appreciated 

 

 

The BMC 1800 recently aqquired for £1000 in a nice millitary green ?

 

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Assuming the new engine has a combined exhaust manifold and header tank then its fairly simple BUT your skin tanks look too small, too thick and the feed and return pipes look too small. I fear you are faced with expense because you will portably need a new much larger well baffled skin tank. This can be welded to the outside of the swim but it might be cheaper and easier to fit keel cooling pipes wrapped around the outside of the swim.

 

A photos of the new engine will help us give  specific advice on hose connections etc. Sorry just fund the second photo.

 

You need a marine thermostat housing gasket and a thermosat. That will point its outlet directly at the hose boss on the exhaust manifold. The join the two by a hose. the extra long head "nut" that will probably get in the way shoudl be an the back corner of the head with another to mount the bracket for the fuel filter that is not there.

 

There should be a larger hose spigot under the manifold towards the back or you can use the larger joint in the rubber end cap. Any smaller rubber spigots in the end cap(s) can be blocked or plain end caps fitted. A sideways on photo of the manifold would help see what you have.

 

Dispose of the rubber hose that joins the manifold to the water pump.

 

You can also remove the heat exchanger core from the manifold if you wish.

 

The water flow through the larger pipes will be thermostat to manifold cum header tank. Header tank outlet (the one with the disposed of hose on) to the top of a properly sized skin tank, lower skin tank  outlet to the engine water pump.

 

Edited by Tony Brooks
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What he said. The present arrangement is a dog's breakfast.

 

New engine, what is all the gubbins under the exhaust manifold,/header that looks like it should have cables attached?  Not a gearbox?? 

Do you have a thermostat housing or are you intending to use the expansion tank off the old one?

 

You could consider running the engine as a sealed system wit antifreeze but add a raw water feed and pump, a heat exchanger  matrix in the header tank/exhaust manifold and a stainless  exhaust elbow with water injection. The thread running at present about a 1.8D that is not cooling will give you a lot of the information. se.Water circulation problems" thread.

 

Otherwise its a new skin tank of 8 square feet area and baffles welded on the outside of the swim.

You will need the thermostat else it will run too cool.

TD'  

 

 

Edited by Tracy D'arth
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11 minutes ago, Tracy D'arth said:

What he said. The present arrangement is a dog's breakfast.

 

New engine, what is all the gubbins under the exhaust manifold,/header that looks like it should have cables attached?  Not a gearbox?? 

Do you have a thermostat housing or are you intending to use the expansion tank off the old one?

 

You could consider running the engine as a sealed system wit antifreeze but add a raw water feed and pump, a heat exchanger  matrix in the header tank/exhaust manifold and a stainless  exhaust elbow with water injection. The thread running at present about a 1.8D that is not cooling will give you a lot of the information. se.Water circulation problems" thread.

 

Otherwise its a new skin tank of 8 square feet area and baffles welded on the outside of the swim.

You will need the thermostat else it will run too cool.

TD'  

 

 

 

Yes and I have a feeling that a 1.8 flywheel, flywheel housing and Starter motor are different to a 1.5 so if the OP is thinking about changing them from his old engine it may not work.

6 minutes ago, Slim said:

The OP did say that there are 2 skin tanks, one each side. 

Yes but they are still too thick and the hose bosses are too small, no wonder they seem to have been disconnected from the main cooling circuit and that radiator substituted.

 

And I can't see a bleed point on the one in the photo.

Edited by Tony Brooks
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// grinding axe mode

I have a feshwater cooled (Beta 50) and no problems on the canals as did all the boats that we have hired in the past.

 

As your  engine has been nicely set up for fresh water, might that not be the easier solution?

It does need an adequate mud box and intake in the side not the bottom of the hull. 

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9 minutes ago, Tony Brooks said:

 

Yes and I have a feeling that a 1.8 flywheel, flywheel housing and Starter motor are different to a 1.5 so if the OP is thinking about changing them from his old engine it may not work.

Yes but they are still too thick and the hose bosses are too small, no wonder they seem to have been disconnected from the main cooling circuit and that radiator substituted.

 

And I can't see a bleed point on the one in the photo.

Its the engine back plate that is different, there are several different ones but as far as my memory extends they will all fit on the engine block. Using the right back plate will allow the starter to fit. The flywheel is another matter. Hopefully he has the 1.8D flywheel on the new engine.

TD'

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10 minutes ago, OldGoat said:

// grinding axe mode

I have a feshwater cooled (Beta 50) and no problems on the canals as did all the boats that we have hired in the past.

 

As your  engine has been nicely set up for fresh water, might that not be the easier solution?

It does need an adequate mud box and intake in the side not the bottom of the hull. 

We are hearing mixed advice on this. It's something we are used to both coming from sea and sailing where saltwater corrosion is the biggest issue but we are hearing nasty things about silt and weed being too much of a problem on the canals 

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If anyone can shed better light on the idea of drawing water from the canal then please feel free as this was our original option idea (as said being sailors this is am quite common on saltwater boats) but some seem to think it's a bad idea with reports of inlets clogging up within 90 seconds through silt and weed build up.

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Looking at both photos of the new engine it would seem to already be set up for raw water secondary cooling with water injection for a wet exhaust.

Seems to be a complete power unit except the thermostat housing.

TD'

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4 minutes ago, Tracy D'arth said:

Looking at both photos of the new engine it would seem to already be set up for raw water secondary cooling with water injection for a wet exhaust.

Seems to be a complete power unit except the thermostat housing.

TD'

We are more than happy to keep it indirect raw water but have heard bad things about weed and silt  if anyone can shed light on this or any solutions to prevent problems 

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Drawing canal cooling water into a secondary cooling circuit is no problem once you accept that the water inlet has to be clear of the bottom because of mud and that a proper inlet strainer that you can see into is required, the clear plastic one like Vetus use is good.

It will be the easiest way to cool this installation, no new skin tanks and you seem to have everything else already, oh, you need a water exhaust hose, its special stuff. 

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Now we have the second photo now showing a raw water pump the engine may be complete so for simplicity and probably least cost I suspect a decent mud box and strainer would be far easier than going to dry exhaust and  skin tank cooling.

 

In general I disagree with Old Goat re heat exchanger cooling on canals but in this case it may be the best option.

Edited by Tony Brooks
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2 minutes ago, Tony Brooks said:

Now we have the second photo now showing a raw water pump the engine may be complete so for simplicity and probably least cost I suspect a decent mud box and strainer would be far easier than going to dry exhaust and  skin tank cooling.

 

In general I disagree with Old Goat re heat exchanger cooling on canals but in this case it may be the best option.

It would be awful if everybody agreed - removes all the fun....

 

FWIW when we  started boating we hired from Teddesley and all their boats - those that they had built - were FWC. They ran quieter, the engine bays were cooler and the final clincher was that when I had the inevitable visit down the weed hatch, there was no red hot (erll very hot) exhaust pipe sitting there waiting to burn your arms. Couple that with when we hired a boat from "the Wing Commander" (actually a squadron leader) if anyone knows to whom I was referring - it got very hot indeed when going upstream on the tidal Thames (because the skin tanks were inadequate for that use).

When I ordered my hull I asked for a 'decent sized mud box' - and that's what I got and it's been great for some 20 years....

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1 hour ago, TheSaintlyOne said:

 

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One big problem you are going to have with that raw-water pump is that access to the cover plate to replace the impellor will be all but impossible once the engine is fitted into a Narrow Boat.

 

As I suggested in another BMC thread it'd be far simpler to remove the two-bolts and take out the whole pump, replace it with the spare then service it at your leisure working in the comfort of sitting down at a table, you wont loose the plate-bolts, or drop the plate into the bilge.

Edited by Alan de Enfield
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9 minutes ago, Alan de Enfield said:

 

One big problem you are going to have with that raw-water pump is that access to the cover plate to replace the impellor will be all but impossible once the engine is fitted into a Narrow Boat

There was a raw water pump on his old engine so presumably the OP knows about the access. However that pump may not be in use. If it is difficult I think the Speedseal easy access (easier access) cover may now be available again in the UK.

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1 hour ago, OldGoat said:

It would be awful if everybody agreed - removes all the fun....

 

FWIW when we  started boating we hired from Teddesley and all their boats - those that they had built - were FWC. They ran quieter, the engine bays were cooler and the final clincher was that when I had the inevitable visit down the weed hatch, there was no red hot (erll very hot) exhaust pipe sitting there waiting to burn your arms. Couple that with when we hired a boat from "the Wing Commander" (actually a squadron leader) if anyone knows to whom I was referring - it got very hot indeed when going upstream on the tidal Thames (because the skin tanks were inadequate for that use).

When I ordered my hull I asked for a 'decent sized mud box' - and that's what I got and it's been great for some 20 years....

Interesting that you mention Teddesley boats as Although my boat is of an unknown to me make I have had people suggest it was a Teddesley due to the rear mounted gas lockers 

 

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28 minutes ago, Tony Brooks said:

There was a raw water pump on his old engine so presumably the OP knows about the access. However that pump may not be in use. If it is difficult I think the Speedseal easy access (easier access) cover may now be available again in the UK.

Have they not shut down due to illness I followed another link earlier from another thread 

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So upon reading about how raw water intakes get blocked up meaning a trip into the canal. Is there any reason that the intake could not be mounted near the weed hatch or at least with touching distance so if something was to catch/block the inlet hole a reach around via the weed hatch would be a much more civilised way of clearing the debris ????

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5 minutes ago, TheSaintlyOne said:

So upon reading about how raw water intakes get blocked up meaning a trip into the canal. Is there any reason that the intake could not be mounted near the weed hatch or at least with touching distance so if something was to catch/block the inlet hole a reach around via the weed hatch would be a much more civilised way of clearing the debris ????

You don't clear it from 'outside' the filter is inside.

A hull fitting (sea-cock) allows the water in, thru a pipe to the filter, then piped from the filter outlet to your cooing system - exactly the same as on 'lumpy water' boats.

 

Check the filter each morning - unscrew the lid, remove filter, rinse. replace and screw lid back on.

1 minute job.

Check the water is coming squirting from the exhaust a couple of times a day. - Simples !!

 

Vetus Type 330 Water Strainer | Force 4 Chandlery

Edited by Alan de Enfield
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2 minutes ago, Alan de Enfield said:

You don't clear it from 'outside' the filter is inside.

A hull fitting (sea-cock) allows the water in, thru a pipe to the filter, then piped from the filter outlet to your cooing system - exactly the same as on 'lumpy water' boats.

I don't mean the vetus raw water strainer but some suggest on another thread the actual inlet can get blocked on the outside via plastic bags crap etc meaning they have to go in the water or at least find a method of clearing it 

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13 minutes ago, TheSaintlyOne said:

I don't mean the vetus raw water strainer but some suggest on another thread the actual inlet can get blocked on the outside via plastic bags crap etc meaning they have to go in the water or at least find a method of clearing it 

In 40 years of boating (on both the canals and the sea) the only time I have had a blocked raw water inlet was half-way between Holyhead and Douglas (IoM) where a plastic bag got caught up, the overheat alarm went off, switched off the engine, the bag dropped off and away we went again.

 

Even with the water inlets full of mussels, sufficient water got thru to get us from Hull to Plymouth.

 

 

 

 

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I think you may be 'over thinking' & 'over worrying' about this and have been put off by some bad-press. Remember if the worse happens you can get off and walk, most of the canals are only waist (3 feet) deep

Edited by Alan de Enfield
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29 minutes ago, TheSaintlyOne said:

I don't mean the vetus raw water strainer but some suggest on another thread the actual inlet can get blocked on the outside via plastic bags crap etc meaning they have to go in the water or at least find a method of clearing it 

They can and do but as Alan says they often float off. the problem you have on hire boats is that customers do not check the exhaust often enough. If you have a bronze sea inlet and strainer as was common before those horrid plastic things became common you just took the cap off and pushes rod or stick down through the whole assembly to push the plastic off.

 

You can get grills of one sort of another to fit over the inlet on the outside of the hull but I found they made shifting any such plastic harder because of the small holes or slots.

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3 hours ago, TheSaintlyOne said:

If anyone can shed better light on the idea of drawing water from the canal then please feel free as this was our original option idea (as said being sailors this is am quite common on saltwater boats) but some seem to think it's a bad idea with reports of inlets clogging up within 90 seconds through silt and weed build up.

That is becaus 99% dont have a decent mud box before an inline strainer. Biggles made a good one http://boatbuildblog.blogspot.com/2012/03/mud-box-mods.html

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2 hours ago, Alan de Enfield said:

 

One big problem you are going to have with that raw-water pump is that access to the cover plate to replace the impellor will be all but impossible once the engine is fitted into a Narrow Boat.

 

As I suggested in another BMC thread it'd be far simpler to remove the two-bolts and take out the whole pump, replace it with the spare then service it at your leisure working in the comfort of sitting down at a table, you wont loose the plate-bolts, or drop the plate into the bilge.

 

As I recall ASAP used do some form of captive screws for the pump plate

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