Connecting BMC 1800 to a Calorifier

[alan_fincher]

Most helpful.

 

That's exactly where on the head I was hoping to tap into.

 

If the ASAP supplied part is not for that tapping, it sounds worth talking to AMC, then.

 

BTW, I don't have the remote oil filter option, but have changed the fuel filter so that it's spin on, thereby removing several possible leak points in one operation. Seems to work well. (Also from ASAP).

 

Perhaps we should have a BMC owners club for those of us not blessed with the latest Japanese motors.

[alan_fincher]

I'm reopening this thread, now I am actually trying to do the job of connecting a new calorifier to our BMC 1.8.

 

I'm having a few problems!

 

Firstly tapping into the top of the cylinder head.

People have previously pointed to issues with getting a connector with appropriate threads to fit in the hole which is exposed by removal of a threaded plug.

 

So I shouldn't have been surprised when 2 different suppliers sent me two quite different parts.

 

The Calcutt Boats offering has a tapered thread with OD from 16.52 to 17.06 mm (0.649 to 0.671 inches), whereas ASAP supplies sent a connector that appeared to be parallel and only about 15.5mm (0.610) OD.

 

Based on advice earlier I was expecting it to be the Calcutt one that fitted, but the plug when removed was also about 15.5mm (0.610 inches) OD.

 

The Calcutt connector clearly will not fit, despite being described as for a BMC 1800. I have wondered before if I have a BMC 1500 head on a BMC 1800 engine, and maybe this is what's wrong? Does anybody know if the hole for this take off differs between a 1500 and an 1800 head, please ?

 

The ASAP one screws in easily, but frankly a but too easily. Anyway, I've given that a lot of PTFE tape, and hope its OK. Despite what everybody has said about this being a non standard thread, I'm not convinced that what my engine has is anything more esoteric than 3/8" BSP.

 

So on to main problem

 

The adaptor results in an upward facing pipe.

 

Once I've pushed 1/2" heater hose on to this, and it's been curved over to horizontal, and then downwards towards the calorifier, it has got an upward "hump" that is higher than the water level in the Polar header tank. In fact it's hard to arrange things so that it's not higher than the filler cap, let alone the water level, (these header tanks need the coolant level an inch or two below the filler, to allow for expansion).

 

I can't see any way of reducing the high point in this take off. The ASAP connector is barbed, so I don't think it eill take a 90 degree compression fitting, without leaking. On the other hand, I can't bend the heater hose too rapidly, or it just collapses into a flat spot.

 

Short of blanking the current header tank filler cap, and connecting to a separate higher level expansion bottle, with the pressure cap relocated, I can't see how to get the coolant level higher than the high point in the calorifier circuit.

 

Or if I can get the air out, is it possible to operate with this high point present ? If I introduced a bleed point at the top, would the water pump produce enough force to expel the air, even though it's above the coolant level in the header tank ?

 

I think I must be missing something obvious, as other people's set-ups seem to work with a vertical hose from the top of the head.

 

Any help would be much appreciated!

 

Alan

[bottle]

Alan

 

Not knowing anything about the engine or how they are set up.

 

A thought, would it be possible to fit a pre-formed hose, maybe a visit to Halfords or similar to have a nose.

[alan_fincher]

Alan

 

Not knowing anything about the engine or how they are set up.

 

A thought, would it be possible to fit a pre-formed hose, maybe a visit to Halfords or similar to have a nose.

Hi Keith, yes, I wondered about that, although from what I've seen of them recently Halfrauds are fine for sat navs and boy racer alloys, but are unlikely to see heater hose, even from a roll.

 

Ringing around a few motoring outlets might produce a 1/2" hose with a pre-formed 90degree bend, I suppose.

 

I came to the conclusion looking at pictures earlier in the thread that this might help - thanks for suggesting it!

[bottle]

Alan

 

Another thought, tap off with a short straight hose, connect to copper pipe (water) with a suitable bend.

[Big COL]

Hi Keith, yes, I wondered about that, although from what I've seen of them recently Halfrauds are fine for sat navs and boy racer alloys, but are unlikely to see heater hose, even from a roll.

 

Ringing around a few motoring outlets might produce a 1/2" hose with a pre-formed 90degree bend, I suppose.

 

I came to the conclusion looking at pictures earlier in the thread that this might help - thanks for suggesting it!

 

Alan

 

If you are convinced that what you have in your block is 3/8'' BSP then use a male-female elbow, or use two elbows put together, and your hose will then hang straight down.

Edited November 25, 2008 by Big COL

[alan_fincher]

Alan

 

If you are convinced that what you have in your block is 3/8'' BSP then use a male-female elbow, or use two elbows put together, and your hose will then hang straight down.

Hi Col,

 

I'm wishing I hadn't said that, as on further reflection, I'm not at all sure it is 3/8" BSP tapping in the head.

 

Unfortunately I didn't measure up the fitting I've left in there, and all I have here is the plug I removed. That has an unbelievably damaged thread on it - it looks like Calcutt deliberately spent some time crushing it in a vice and/or mole grips before they installed it in the rebuilt engine. I'm amazed it threaded in at all, and wonder what it must have done to the threads in the head.

 

The plug will screw about 3.5 turns into a 3/8" BSP female fitting, before coming to a stop, but I can't tell if it's halting because of thread damage, or because threads are a different pitch.

 

From what I can see 3/8" BSP should be 0.656 OD and 19TPI, whereas the plug seems to be more like 0.620 and 17TPI, (though hard to measure the TPI).

 

If it were a 3/8" NPT thread it should be 18TPI - closer, but I still think it seems like 17TPI. (Why would an NPT thread be used on an English "lump" ?)

 

So I really have no idea what I've got, and I can't find a thread that matches what I'm trying to measure on the plug.

 

I somehow expected this to be hard, but perhaps not this hard!

 

Alan

[LEO]

Hi Col,

 

I'm wishing I hadn't said that, as on further reflection, I'm not at all sure it is 3/8" BSP tapping in the head.

 

Unfortunately I didn't measure up the fitting I've left in there, and all I have here is the plug I removed. That has an unbelievably damaged thread on it - it looks like Calcutt deliberately spent some time crushing it in a vice and/or mole grips before they installed it in the rebuilt engine. I'm amazed it threaded in at all, and wonder what it must have done to the threads in the head.

 

The plug will screw about 3.5 turns into a 3/8" BSP female fitting, before coming to a stop, but I can't tell if it's halting because of thread damage, or because threads are a different pitch.

 

From what I can see 3/8" BSP should be 0.656 OD and 19TPI, whereas the plug seems to be more like 0.620 and 17TPI, (though hard to measure the TPI).

 

If it were a 3/8" NPT thread it should be 18TPI - closer, but I still think it seems like 17TPI. (Why would an NPT thread be used on an English "lump" ?)

 

So I really have no idea what I've got, and I can't find a thread that matches what I'm trying to measure on the plug.

 

I somehow expected this to be hard, but perhaps not this hard!

 

Alan

 

Hi,

 

I note your problems. When I converted my BMC 1.5 the sealing nut in the block was virtually welded in, it came out eventually and I had to clear all the threads in the block with a small chisel. The replacement part was from AMC (excellent service and very helpful people), slightly tapered and did not need too much PTFE tape. The pipe bent over from this fitting and the water pump from the engine pushed the water round easily, in fact as the HW outlet from the calorifier was about 10" above the level of the engine it achieved a good head of water.

 

The system worked really well and I never had any problems with air locks or the heat exchanger overflowing.

 

Back in the early 1970's a friend had a boat built by Charlie Fox (March Hare), the BMC engine water pump used to pump water round a system of pipes within the boat after going through the calorifier to dissipate heat and the expansion vessel for the hot water system was an empty champagne bottle. It all worked well.

 

Have we progressed or over complicated things?.

 

Leo

[alan_fincher]

Yet another twist in the story.....

 

Having spoken to Calcutt this morning it appears that the "Turkish" BMC 1800 head had a different thread for the take off adaptor to that on an "original" British BMC 1800.

 

It appears that they have sent me a part suitable for a Turkish engine, and say they would have sent something different when I ordered if it had been stated it was for a British engine.

 

So if they knew there are different parts, why was the only question they asked me if it was for a 1500 or an 1800 engine?

[Batavia]

5/8" UNF? 0.625" major dia x 18 tpi

 

The data on this web site is very helpful...

 

http://mdmetric.com/tech/tic1e.htm#helpnote

 

but you need to go to Parts 1 to 11 to find out the useful stuff!

 

Chris G

[Denis R]

Alan, regarding your quest for a pre-formed heater elbow - try Demon Tweaks, they do all sorts of pipes and hoses for home builds and kit-cars. A bit flash and perhaps pricey, but good.

Else a rummage round your local motor factors for a heater hose for an Escort or whatever, anything with an elbow end, then cut the straight portion to suit your installation?

[LEO]

Hi,

 

Sorry forgot to mention, I got over the pipe needing a right angled bend by using a 15mm right angle bend coupled to the engine outlet by hose and then from the bend to the male connector on the calorifier, All sealed by jubilee clips.

 

These bends were standard soldered fittings but without the solder ring, I may have some if you want - let me know.

 

Leo.

[stuart]

Excellent posts here folks, I'm going to be attempting the same in a few weeks time !

 

Just got to get the engine running first :-)

[stuart]

Just spoken with Calcut and I'm surprised at the cost of the water heater adapter to fit onto the cyl head!

 

partt no 12A2075 and costs £11.54 plus carr & pack of £6.73

 

Blimey £7 for postage !

[alan_fincher]

Just spoken with Calcut and I'm surprised at the cost of the water heater adapter to fit onto the cyl head!

 

partt no 12A2075 and costs £11.54 plus carr & pack of £6.73

 

Blimey £7 for postage !

Stuart,

 

There seems to be a lot of ambiguity, because....

 

1) 1500cc and 1800cc may (or may not be) different threads.

2) Turkish 1800cc head is apparently different threads from original English 1800.

3) A 1500 head may be fitted to an 1800 block, (I suspect this is what I have....)

 

All I can say is that Calcutt sent me two different parts, and neither was correct for my (British) 1800cc.

 

The one that ASAP supplies do may be what you want, but nothing seems certain with this aspect of these engines.

 

Alan

[stuart]

Yeah, I'll have to take the bolt/plug out of the engine and look at it !

 

ASAP supplies:

 

Part 206799

OUTLET BMC HEAD TO 1/2 in.HOSE FOR HEATER

£5.69

 

 

 

Whilst I'm here found a good cheaper alternative to Vehicle Wiring Products - http://www.thewiringproject.co.uk

[alan_fincher]

Yeah, I'll have to take the bolt/plug out of the engine and look at it !

Good luck! The mangled plug in mine didn't measure up as any size I could recognise, UNF, or otherwards.

 

I am using the ASAP fitting though, albeit with quite a lot of PTFE tape to take up the slack!

 

EDIT:

 

Here's my blanking plug, and Calcutt's second attempt to provide a connector.

 

It's been fairly crudely made from a piece of mild steel rod, but I've no idea how they think you can fit a heater hose to it.

 

Irrelevant for me, as the thread was still wrong.

 

Edited February 17, 2009 by alan_fincher

[springy]

Hi alan

 

I have an 1800 to which I fitted a Calorifier, using a slightly more complex setup but which I find works well. The main difference involves adding a second thermostat in line after the outlet from the water cooled manifold and taking the feed to the calorifier via a T junction before this thermostat. Sounds complex but it was fairly simple to achieve in my circumstances and produces a system which allows the engine to warm up properly before diverting heat to the calorifier coil.

The mariniser had used a fairly crude "home made" manifold with a 2" outlet on the bottom (mariniser unknown - this was fitted when I bought the boat) which was plumbed to the skin tank using 2" reinforced plastic pipe - a situation I was not happy with as the pipe became very soft when the engine reached normal running temperatures. Most of this I replaced with 35mm Copper (available from serious plumbers merchants not normal DIY outlets) using short peices of rubber hose to join the ends to the skin tank and engine.

The additional thermostat is as fitted to some Volvo car engines (440 series IIRC) which actually fits inside the hose and has a higher opening temperature than the standard BMC 1.8 (IIRC 92 deg C where the BMC is 86 deg C).

 

So from manifold outlet (2") -> Rubber Hose (2") -> T Junction (2" with 1/2" Branch) -> Rubber Hose (2") with 92 deg themostat inside -> 35mm Copper "Solder Ring" fitting -> 35mm Copper -> Skin Tank. The feed to the Calorifier comes off the 1/2" Branch. The 35mm "solder ring" fittings provide a good ridge for the hose clamps.

 

Sequence

- Cold start - both thermostats Closed -> water circulates around engine block only.

- Warming Up - Original thermostat in head Opens -> water circulates around engine, manifold and calorifier coil.

- Full temperature - Additional thermostat opens allowing water to circulate around the skin tank as well. Restriction provided by second thermostat means that circulation is maintained through calorifier coil.

 

I realise that this is a little more complex but a) it saved messing with any conections actually on the engine, means that the engine reaches and maintains its proper running temperature quicker and therefore runs cleaner, and c) produces piping hot water in the calorifier.

 

The Calorifier return goes to a "T" moulded into the "bottom hose" i.e. between the skin tank outlet and the water pump inlet - a suitable hose was found by simply mooching around a scrap yard looking at car engines until something usable was spotted.

 

Taking the feed from below the manifold also removed problems I would have had with high points and venting.

I've been running this setup for 10 yrs + and am very happy with it.

 

Hope this helps

 

Springy

[stuart]

Interesting stuff there Springy. A few good ideas and I like to idea of 2 thermostats.