Jump to content

bowman end cap


dreadnought

Featured Posts

hi all,the the rubber end cap on my bowman heat exchanger split today,so i took it off to sort out a replacement and noticed an array of tubes inside the heat exchanger,my question is if i remove them,can i remove them? would the cooling system be more efficient or should i leave them alone, the engine is a bmc 1800 with skin tank cooling

many thanks

Link to comment
Share on other sites

The tubes pass water to cool the gearbox oil. That's the whole idea of the heat exchanger. The only problem you may have is sourcing a replacement cap. There were bowman and polar caps available, one of which is no longer around, slightly different sizes, Stanley knife modification may be required if you can't get an exact match. The cap will have a number on it.

Link to comment
Share on other sites

5 minutes ago, Exturnaroundman said:

The tubes pass water to cool the gearbox oil. That's the whole idea of the heat exchanger. The only problem you may have is sourcing a replacement cap. There were bowman and polar caps available, one of which is no longer around, slightly different sizes, Stanley knife modification may be required if you can't get an exact match. The cap will have a number on it.

I don't think that is normally correct. 

Generally if there is a gearbox oil cooler it is a completely different fitment from a Bowman (or Polar) header tank, (not all gearboxes firred to BMCs have an oil cooler, of course).

Usually these header tanks have the array of tubes only if actually being used as a heat exchanger. In canal use, this will generally only be if the engine is raw water cooled, without a skin tank.  (In which case the engines own water pump will circulate the water through the engine and one side of the heat exchanger, and a separate pump will pump the raw water from the canal through the other part of the heat exchanger, and then overboard.

With a skin tank there would normally only be the engine pump, and the Bowman acts only as a header tank, without the tubed heat exchanger.

We need to be clear exactly what the OP has before advising if it would be wise to change anything.  With a typical skin tank set up, the tubes should not I believe be present.

As an aside you can still buy end caps badged both as Polar and as Bowman, but the Polar ones are nasty copies, and fail quickly. They are also far more expensive than Bowman, despite being crap.  A Bowman cap can be persuaded on to a Polar tank, and is the best option if you have a Polar tank.  Stanley knife modifications are not required, and it is hard to imagine what modification could possibly be a good idea.

Link to comment
Share on other sites

9 minutes ago, Exturnaroundman said:

Bowman caps are on the end of gearbox oil coolers not skin tanks. Worked on hire fleets for years !!! Know where they are.Unless the op is posting about a non canal boat, in which case wrong forum.

If you think I have suggested they go on skin tanks, that was not my intention - where have I said that then?

You are correct that there is a type of Bowman cap that goes on gearbox oil coolers, but that is not what the OP is talking about here.

However there is also a type of Bowman end cap that goes on the engine mounted Bowman header tank, (which may, or may not actually also be a heat exchanger).

That is this type, and has a very much larger end than the oil cooler type (70mm diameter on many of them).

bow-2679np_3.jpg

 

and this type almost certainly has nothing to do with cooling the gearbox.

You don't actually need to have worked on a hire fleet, (although I have), to know this stuff.  Owning a boat that has one, and having to sort it out when it fails tells you all you need to know.

EDIT:

Actually reading it again the OP refers only to "my Bowman heat exchanger", so to be completely certain we need them to tell us which part they are talking about.  A picture would save a lot of words, and a picture might indicate something unusual about the installation to explain why the core is present, (assuming we are talking about the engine mounted header tank).  I have only assumed they man this part, because the caps on them split regularly, those on oil coolers almost never, in my experience.

Edited by alan_fincher
Link to comment
Share on other sites

15 minutes ago, Exturnaroundman said:

Bowman caps are on the end of gearbox oil coolers not skin tanks

Who said anything about them being on skin tanks? OP is talking about his heat exchanger (which, as he has a skin tank is probably just a header tank). 

8 minutes ago, alan_fincher said:

Actually reading it again the OP refers only to "my Bowman heat exchanger",

Yes, but he also states that the engine is an 1800 and that he has a skin tank so I think your assumptions of it being on the engine and probably just a header tank are both correct. 

As you say, a photo will quickly confirm. 

Link to comment
Share on other sites

56 minutes ago, alan_fincher said:

I don't think that is normally correct. 

Generally if there is a gearbox oil cooler it is a completely different fitment from a Bowman (or Polar) header tank, (not all gearboxes firred to BMCs have an oil cooler, of course).

Usually these header tanks have the array of tubes only if actually being used as a heat exchanger. In canal use, this will generally only be if the engine is raw water cooled, without a skin tank.  (In which case the engines own water pump will circulate the water through the engine and one side of the heat exchanger, and a separate pump will pump the raw water from the canal through the other part of the heat exchanger, and then overboard.

With a skin tank there would normally only be the engine pump, and the Bowman acts only as a header tank, without the tubed heat exchanger.

We need to be clear exactly what the OP has before advising if it would be wise to change anything.  With a typical skin tank set up, the tubes should not I believe be present.

As an aside you can still buy end caps badged both as Polar and as Bowman, but the Polar ones are nasty copies, and fail quickly. They are also far more expensive than Bowman, despite being crap.  A Bowman cap can be persuaded on to a Polar tank, and is the best option if you have a Polar tank.  Stanley knife modifications are not required, and it is hard to imagine what modification could possibly be a good idea.

I give up with this forum, so many times you try to help with your longstanding canal expierence, but get shouted down by others who obviously haven't lived it. Maybe it should be renamed live on something afloat London discussion world. 

  • Unimpressed 1
Link to comment
Share on other sites

1 hour ago, Exturnaroundman said:

I give up with this forum, so many times you try to help with your longstanding canal expierence, but get shouted down by others who obviously haven't lived it. Maybe it should be renamed live on something afloat London discussion world. 

Probably not a great idea either, as I actually think only a very very small proportion of our members live on something afloat (in) London.

My canal boat experience is not far off 50 years - how long do you reckon I need before I'm qualified to have an opinion then?

  • Haha 1
Link to comment
Share on other sites

1 hour ago, Exturnaroundman said:

I give up with this forum, so many times you try to help with your longstanding canal expierence, but get shouted down by others who obviously haven't lived it. Maybe it should be renamed live on something afloat London discussion world. 

Just to assist??or annoy  you further, I have never seen a skin tank with any kind of rubber fitting like the above described.

Link to comment
Share on other sites

5 hours ago, dreadnought said:

hi all,the the rubber end cap on my bowman heat exchanger split today,so i took it off to sort out a replacement and noticed an array of tubes inside the heat exchanger,my question is if i remove them,can i remove them? would the cooling system be more efficient or should i leave them alone, the engine is a bmc 1800 with skin tank cooling

many thanks

If it's skin tank cooling, normally the core isn't fitted. Do your end caps have a pipe connection as per Alan's picture, or are they blank?

Link to comment
Share on other sites

3 hours ago, Exturnaroundman said:

I give up with this forum, so many times you try to help with your longstanding canal expierence, but get shouted down by others who obviously haven't lived it. Maybe it should be renamed live on something afloat London discussion world. 

Bowman manufacture a wide range of heat exchangers (gearbox oil included), water cooled exhaust manifolds (with and without heat exchanger tube stacks) and header tank heat exchanger combinations; all of which have rubber components, and all of which could in some combination be applied to a BMC 1.8 engine. So already knowing this allows you to diagnose the issue without the op actually confirming what they have? Perhaps adding the word "mystic" to your forum name would help. 

Just joking of course; it's the Guinness talking.

  • Happy 1
Link to comment
Share on other sites

So I think we need to know if the end caps are blank or are the sort phototgraphed above ie with some pipes that go somewhere else. I upgraded mine a few years ago to heat a couple of radiators in the cabin. https://nbsg.wordpress.com/2014/03/01/repainting-and-radiators-march-2014/

The tube thing inside didn't have the small pipes. so I had to upgrade it (rather expensive). It made no difference to the cooling performance. If you do remove the stack then there is nowhere for the smaller of the two jubilee clips to grip onto, and I would think a higher risk of failure under pressure ?

Link to comment
Share on other sites

12 hours ago, Exturnaroundman said:

I give up with this forum, so many times you try to help with your longstanding canal expierence, but get shouted down by others who obviously haven't lived it. Maybe it should be renamed live on something afloat London discussion world. 

Ok - I had over 10 years experience in charge of engineering on a large Thames hire fleet that was almost all BMC powered once we got rid of the SL4s. Almost all keel cooled which is the same a tank cooling. Now tell me I haven't lived it! I can also add a string of professional engineering qualifications if you want.

On BMCs any gearbox oil cooler is normally a separate item (as has been said). This is because mechanical and the odd hydraulic box does not require an oil cooler or its integral in the box casing.

Beta tried using the redundant heat exchanger core as you say to cool the gearbox with "interesting" results. I say no more about that. If you tried that on a BMC you would bring oil into contact with the  rubber end caps and make an already weal spot even  weaker. This does not mean your fleet engineer did not do something odd just for the fleet.

On a tank or keel cooled boat the core is redundant and may be removed. On our keel cooled boat we eventually had the ends of the manifolds caped by welding a plate over them but we did have a decent sized hole for the hot flow outlet in them. On yours I would be temped to ditch the core, get two metal plates with a hole in the centre of each and with a rubber sheet use a long stainless through bolt to clamps them in place of the rubber caps a bit like some Vetus ones.

 

 

Link to comment
Share on other sites

2 hours ago, Scholar Gypsy said:

So I think we need to know if the end caps are blank or are the sort phototgraphed above ie with some pipes that go somewhere else. I upgraded mine a few years ago to heat a couple of radiators in the cabin. https://nbsg.wordpress.com/2014/03/01/repainting-and-radiators-march-2014/

The tube thing inside didn't have the small pipes. so I had to upgrade it (rather expensive). It made no difference to the cooling performance. If you do remove the stack then there is nowhere for the smaller of the two jubilee clips to grip onto, and I would think a higher risk of failure under pressure ?

Here's the original stack - top - with no pipes inside it, and then the rather expensive replacement below it. As far as I could see the only function of the original one was to provide something to secure the end-caps to. Tony's solution is very elegant!

 

072964716ca89dd7ead8521435047364cdc7b89d3f4886522eeadf6e7cc326d5fc15cd9d.jpg

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.