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ivan&alice

Cracked part on heat exchanger Beta 38 / PRM 150 - what's it called?

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29 minutes ago, ivan&alice said:

Even though it has already passed through one skin tank? I would have thought that pre-heating the engine's coolant with the gearbox would be more of an issue than pre-heating the gearbox coolant with the engine. But perhaps gearboxes like heat less than engines do?

Just had another thought. When the calorifier is cold, I believe the cooling is diverted to the calorifier rather than the skin tanks. In this case, won't the coolant stop circulating through the oil cooler / skin tank circuit, and potentially cause overheating of the gearbox?

 

The fact that Beta no longer put Greeenline gearbox oil coolers in the manifold should tell you something about the heat the gearbox likes. I understand its the clutch [plates that suffer - they are wet multi-plate clutches. However yours is a canal boat that spends most of its time developing maybe about six HP so putting the oil cooler between the two skin tank would be OK.

 

That is not how calorifiers work unless you have a twin thermostat system like Barrus Shire engines. Not much water will circulate through the skin tanks while the engine thermostat is shut but within minutes of starting the thermostat will start to open so circulation through the calorifier will start. We come back to exactly why Beta altered their placement of the oil cooler. I understand the cooling was insufficient to prevent gearbox problems, perhaps I am wrong but its your call on your boat. In any case if your assertion about overheating when cold is correct all those thousands of boats with the gearbox oil cooler in the conventional (non early Beta) position would be having problems, They are not.

 

Personally I would make up a couple of brackets  (maybe flattened 22 mm copper pipe) and mount the cooler across the back of the engine with the brackets secured to a pair of gearbox adaptor mounting plate bolts. This keeps the oil pipes short but it will make the coolant pipe run more complicated.

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1 hour ago, ivan&alice said:

Decision is to attempt a temporary repair what I have with Araldite (any suggestions which one?

Not ‘rapid’. The slower the cure, the stronger the epoxy 

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If going down the Araldite route, remove the damaged part, pop it in a saucepan with some washing powder and water and give it a good boil up to remove any traces of oil before attempting to glue it!

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Ivan&Alice

Sorry not to have replied sooner, it's a crazy world at the moment. Regarding the engineering firm I mentioned. I'm pretty sure that IF they're open for business and IF you can get the part to them they will be able to weld it. I've goggled them and here's some info. From Cassio Bridge they are 9.3 miles away (walking) I guess you would be on a bike. Contact details, Middlesex Re -Boring Co, 198 Lawrence Street, Mill Hill, NW7 4JH. Tel. 0208-959-2567 . I had problems with my Polor Ali exhaust where the filler neck went in. They built up where the original neck went in with weld, drilled and tapped 2 holes as required and even supplied 2 cap bolts as ordinary ones wouldn't have fitted.

If I can do anything more let me know.

 

Frank

 

 

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Two other possibilities:

 

1.  Many years ago we replaced the LH150 gearboxes on a number of air cooled Lister engines in some of our large hire boats with PRM 160 (now 260) gearboxes. As a temporary measure we ran a coil of 3/8” copper pipe round the drip tray and made sure we never pumped out the drip tray fully. We were advised at the time by Newage that the heat output from those 160 gearboxes was minimal. Whether that has changed with the newer smaller boxes I do not know. This Heath Robinson system worked fine, so well in fact that we never moved on to the next stage of the plan, which was:

 

2.  To fit a small cooling tank in the swim when we next docked the boats. This avoids pipe work complications, just let the gearbox pump the oil through the tank. It does require the tank to be nice and clean, flushed out well, after welding but the idea seemed to work well on some other boats we knew at the time. The concept could be improved in terms of potential cleanliness by making the tank out of stainless steel, bolted tightly to the swim or the bottom of the boat.

 

The correct heat exchanger for a PRM box is about £80.00 from the likes of ASAP. I also wonder whether a small plate plate heat exchanger or similar is worth thinking about, as used in many car engines now.

 

 

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1 hour ago, Captain Fizz said:

If going down the Araldite route, remove the damaged part, pop it in a saucepan with some washing powder and water and give it a good boil up to remove any traces of oil before attempting to glue it!

Then rinse thoroughly to get rid of the soap and make sure it is completely dry before gluing - a while in a low oven would be best.

2 hours ago, WotEver said:

Not ‘rapid’. The slower the cure, the stronger the epoxy 

 

Absolutely. Full strength araldite. If tying with wire, araldite the crack first, forcing glue into the open crack if possible, then a pad of glue over and around the crack, then fit the wire, then wipe over the wire with glue to fill any gaps between the wire and the part, and to stop the wire rusting. Before the glue sets, screw the hose fitting in until lightly finger tight to clean the female threads in the cracked part, then remove the hose fitting and clean off any glue which may have transferred to the male threads. Wait until the araldite has completely set (24-48 hours) before reassembling.

And don't overtighten the fitting!

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Araldite is brilliant stuff but it is not "loaves & fishes" there is almost no possibility of chemically cleaning that crack sufficiently, an added disadvantage is that the forces on the repair are in tension, (a bursting force) and any such repair is mechanical not chemical and therefore weak.

 

Welding is the way to go, any coded welder with a TIG set will have little trouble. I would suggest cutting a "Vee" in the casting but only down to the top of the thread, obtain a steel parallel threaded fitting of the correct thread form and have it screwed into the thread finger tight while the welding is done.

 

The object here is to retain as much of the thread as possible, full depth welding will make cleaning up with a tap almost impossible, trust me, I've been there! The thread will probably still need cleaning up but a tap should be able to. cope.

 

Finally make sure that the end face of the thread is cleaned up nice and flat and square with the thread.

 

An yes, I am an oily old engineer who has dabbled with welding. I have done repairs like this and they worked.

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If you are heading north up the G.U. and still haven’t got it sorted, there is a good canal boat oriented engineering works in Braunston. Literally on the canal next to Midland Chandlers. They are very helpful (and creative) and have sorted a couple of similar problems I have had in the past. Very reasonable charges as well.

 

Unfortunately I cannot remember their name as I just used to pull in and moor up alongside them. It is a very small industrial complex between Midland Chandlers and the Boathouse Pub/Restaurant. I think Days Afloat marine engineers are in the same complex.

Anyone know who I am talking about?

Edited by KJT

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29 minutes ago, Man 'o Kent said:

obtain a steel parallel threaded fitting of the correct thread form and have it screwed into the thread finger tight while the welding is done.

I understand the point behind this, but don't you run the risk of unintentionally welding the fitting in?

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1 hour ago, KJT said:

If you are heading north up the G.U. and still haven’t got it sorted, there is a good canal boat oriented engineering works in Braunston. Literally on the canal next to Midland Chandlers. They are very helpful (and creative) and have sorted a couple of similar problems I have had in the past. Very reasonable charges as well.

 

Unfortunately I cannot remember their name as I just used to pull in and moor up alongside them. It is a very small industrial complex between Midland Chandlers and the Boathouse Pub/Restaurant. I think Days Afloat marine engineers are in the same complex.

Anyone know who I am talking about?

Tony Redshaw used to be there, but is now on the offside at Bottom lock.

Jonathon Hewitt on the towpath side of Bottom lock at UCC is also a capable mechanic.

N

 

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1 hour ago, David Mack said:

I understand the point behind this, but don't you run the risk of unintentionally welding the fitting in?

Not really, aluminium will not readily fuse with steel and there are preparations , antii-splatter coatings for example to coat the fitting, most welding shops will have it or something like it but heating the steel to black would provide an oxide  layer that would be sufficient.

 

As I have said, I have done repairs like this in the past that have lasted, the part is currently scrap so there is little to loose but if sucessful it'll cost a lot less  than the prices quoted for a new part or alternative cooler.

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17 hours ago, Slim said:

From Cassio Bridge they are 9.3 miles away (walking) I guess you would be on a bike. Contact details, Middlesex Re -Boring Co, 198 Lawrence Street, Mill Hill, NW7 4JH. Tel. 0208-959-2567

Thank you Frank! Yes would be on a bike. I'll give them a call tomorrow but my guess would be that they are not working at the moment.

 

 

14 hours ago, Man 'o Kent said:

Welding is the way to go, any coded welder with a TIG set will have little trouble.

 

13 hours ago, David Mack said:
14 hours ago, Man 'o Kent said:

obtain a steel parallel threaded fitting of the correct thread form and have it screwed into the thread finger tight while the welding is done.

I understand the point behind this, but don't you run the risk of unintentionally welding the fitting in?

Why not intentionally weld the fitting in? Essentially turn the connector into a male for screwing the hose directly on?

 

Thanks for the detailed description of the repair. It does seem like welding would be the answer, from both a cost and a neatness perspective. The oil cooling arrangement may not be ideal but it has worked well enough for many years. (That said I do wonder if the overheating oil might be the reason for the hoses' failure).

 

 

 

13 hours ago, KJT said:

If you are heading north up the G.U. and still haven’t got it sorted, there is a good canal boat oriented engineering works in Braunston. Literally on the canal next to Midland Chandlers. They are very helpful (and creative) and have sorted a couple of similar problems I have had in the past. Very reasonable charges as well.

Thank you - this is a long way and I'd like to have it sorted before then, especially considering that we should not be cruising during the lockdown. But I'll keep this in mind if i don't find anything closer.

 

15 hours ago, Balliol said:

fit a small cooling tank in the swim when we next docked the boats.

This to me sounds like the best of the best solution, to avoid having to impact the engine cooling system at all. But it is also by far the most invasive :) the other idea, to roll my own heat exchanger with copper pipe, could work to avoid having to mess with the engine cooling...

 

Thanks to everyone else for the replies, especially Tony for the description of where to mount the cooler. I think I'm still keen on trying a repair, weld if possible to have it done in these difficult times, and araldite if not, at least for now.

14 hours ago, Man 'o Kent said:

 

 

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I'd use JB Weld rather than standard Araldite. It's basically the same sort of two-part epoxy resin, only JB Weld is a steel reinforced epoxy and probably has greater mechanical strength and higher heat resistance.

 

https://www.ebay.co.uk/p/24033516626?iid=273821192351&chn=ps&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=273821192351&targetid=878706529565&device=c&mktype=pla&googleloc=1006959&poi=&campaignid=9441050760&mkgroupid=95284779785&rlsatarget=pla-878706529565&abcId=1139126&merchantid=101724959&gclid=EAIaIQobChMI1-ydxpa46AIVFuDtCh22pAWPEAQYASABEgLw7_D_BwE

 

Edited by blackrose

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I agree with Man 'o Kent - that is not repairable, bar welding...good idea to insert the correct size fitting to maintain the thread - A decent TIG welder can sort it.

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I'm actually just leaving it for now. Haven't even done the araldite. It is leaking so slowly that it's barely a problem. I just keep checking on the gearbox oil level. Going to wait until the covid thing calms down and then find someone to weld it. I think I prefer them welding the male-male fitting right into the unit - don't see why that needs to come out.

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I think you'd have to remove it - it needs to be absolutely clean - free of any oil dirt etc. for a decent weld - also, as it is Aluminium, it would require a AC TIG welder and I don't whether you'd find anyone arsed enough to drag such a machine to your boat... If you contacted a weld shop and sent the part and the fitting to them - even by post, I'm fairly sure you'd get it done - there must be loads of welders looking for business right now?

Edited by alistair1537
Duh, spelling

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3 hours ago, alistair1537 said:

you'd have to remove it - it needs to be absolutely clean - free of any oil dirt etc. for a decent weld

I'd remove the part from the engine and take it apart and clean it. And then take part to the welder. I just meant weld the male/male fitting right in place - I don't see why that fitting needs to be removable.

 

3 hours ago, alistair1537 said:

as it is Aluminium

How do you know that its aluminium?

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Well, I don't, but based on what Man 'o Kent has observed and his experience I'd be surprised if he was wrong - easy to test if it's ferrous though, use a magnet? If it is cast iron, you'd still be in for similar repair - but it could be done. 

 

As far as the welded fitting is concerned - that is doable,  if it does turn out to be cast iron - you could braze the entire lot together? If it is aluminium - no chance...dissimilar metals.

 

I had another look at the pics - there appears to be rust spots where the paint has chipped? So maybe it is cast iron? If so, braze it.

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7 hours ago, ivan&alice said:

How do you know that its aluminium?

The two most likely options when Beta Marine came to have that thing made were cast iron, or aluminium. A magnet will tell of it is the former. If a magnet doesn't stick then it is almost certainly aluminium. There are all sorts of exotic possibilities you could use to make something like this, but in practice a few decades ago for a cheapo, not particularly stressed part designed by a relatively small engineering company like Beta Marine and sub'd out for manufacture, it would have been either cast iron, or cast aluminium.

When I say cheap, it would be cheap for Beta Marine to buy, not cheap for you to buy from Beta!

Jen

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A magnet! Brilliant. I feel like a 5 year old.

 

Great thanks for all the advice.

 

I will still do nothing except regularly  check the oil level until the social situation calms down. We rely on the engine for electricity (fridge) and hot water and I can't not have it for even more than a day right now.

 

Then I'll take it to get welded/braised. I'll follow the advice of the welder I choose as to whether to leave the fitting in or not.

 

Thanks again.

 

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    4 hours ago, alistair1537 said:

    I had another look at the pics - there appears to be rust spots where the paint has chipped? So maybe it is cast iron? If so, braze it.

 

Looking  more carefully at what I thought was aluminium grinning through the paint is quite possibly highlights, the camera can lie or at least tell fibs! I must confess that those two spots do look very rust like.  My only excuse is that I am using a borrowed lap-top thing with that ghastly Windows 10 on it and we really don't get on!

Come back Uncle Clive and the ZX81 all is forgiven!

 

Sadly cast iron is if anything more of a problem to repair than aluminium. It is a brittle material and a relatively poor conductor of heat that does not respond well to localized heating. The part would probably need careful pre-heating and the crack Sifbronze welded. There is also a remarkable "stitching" process for cast iron but I doubt that is applicable in this case.

 

As the OP has reported "minimal leakage" I'd be tempted to have a look at the Loctite range of products. These days they have something for every day of the week and two on Sundays, do some research and I'd bet there is a product that will seal the joint/crack at least until more "normal" times return or it is more convenient to have a repair done or a replacement obtained.

 

 

 

 

  • Greenie 1

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