cleaning beta heat exchanger stack - easy or not?

[Burnham Bob]

As part of the maintenance regime I am supposed to clean the heat exchanger stack on my beta 13.5.

Normally I wouldn't worry, but the engine is installed in the bare minimum of space and to remove the stack I'm going to be working blind and for a large part of the time by feel - especially when removing the rear bolt.

Never having done this job before I'd welcome some advice. Is the stack one unit that comes out in one piece or does it disassemble for cleaning? If it does I don't want to drop bits in the bilge as I draw it out.

Are the O rings captive? Am I likely to find one stuck inside the heat exchanger? Will they stay on when I replace the unit?

As I say, normally I wouldn't worry but never having done the job, and working blind I want to be prepared for every possible cock up and the manual isn't exactly helpful - with small grainy pictures.

 

[sailorman]

done my Nanni 37.5 last Feb @ seven yrs old found no build-up at all. changed to "O" rings as recomended.
both ends of the Nanni H/E caps are the same, one bolt through the centre

 

[onenyala]

Beta Heat Exchanger

I have exactly the same problem.
I decided not to try and take out the stack. I carefully removed the accessible bell housing so as not to disturb the seal. I then rodded each tube through with a piece of bike mudguard stay which was exactly the right diameter as the tubes. Any deposit removed would be small fragments and would be washed out when the engine was re-run.
I was able to successfully replace the bell housing without disturbing the seal.
Another problem I have encountered is that the impeller had shed a fin which would finish up in the lower half of the inaccessible housing.
When I recommision the engine I intend trying to blow the crud plus the lost fin back towards the seawater pump using either water or air injected through the sacrificial anode plug.
Good luck !

 

[Burnham Bob]

ah.....further www searches - am I right in thinking that the O rings actually seal the end caps? that would seem to make sense.

if the end caps come off......can i draw the stack out in a forward direction as opposed to backwards as shown in the gray and grainy photos?

 

[doug748]

I think you may find this tricky. My comments concern the three cylinder 20hp but I think it may be very similar, if not identical, to yours.
The bolts holding the ends on screw into the copper/brass matrix itself, so that with each in place they pull down onto the rubber gaskets. Having removed the bolts and brass end fittings you can then remove the matrix, sliding it forward or (in theory) back. In practice you may have to take it out via the front, and certainly if you have a high rise exhaust fitted. To bring it out forward I have to move the alternator on its mount. The seals will probably stay in place if you are careful, but this is no matter if you intend to fit new ones.
The problems will arise in re-fitting the ends. The seals are simple O rings and in a confined space it is difficult to check if they are correctly in position, or have slipped. There is very little to hold them in position, a dap of goo may help. Holding the end cap in position and gently revolving it backwards and forwards it is possible to discern the even feel of the rubber seal; and, of course, if it is nipped or a loop falls out it will leak.
As my pre filter was quite clean I put this off for 3 seasons from new. The matrix was pretty clear but it was worth doing to remove the ends of old anodes which tend to accumulate in the rear end cap (plus, in my case, the remains of a broken impellor). It is also a most useful check for any signs of corrosion in the set up. The matrix is in one lump with no bits to fall off.
I re-used the seals and they were ok, but then I am particularly mean.

 

[sailorman]

ah.....further www searches - am I right in thinking that the O rings actually seal the end caps? that would seem to make sense.

if the end caps come off......can i draw the stack out in a forward direction as opposed to backwards as shown in the gray and grainy photos?

change the rings they are a service item Nanni recommend 400hrs

 

[dulcibella]

A fairly straightforward job on my 4-cylinder Beta but access is relatively good on mine. Beta dealers usually have the O-rings.

 

[Matata]

Ours is a Beta 20 but I think very similar. When we removed the matrix it was full of crud and in the far bell housing was the remains of the anode which had begun to fall apart and a blade from the impellor. So it was def worth doing ! I think we had to rotate the matrix to get it to align to remove,I've forgotten!The heat exchanger matrix is one piece and the forum suggested cleaning it in brick cleaner which worked fantastically,wash with plenty of fresh water after. Putting it all back is tight but the far bell housing has a slot in it that helps to locate the heat exchanger with the housing. The are also sealing washers behind the stack bolts.These easily locate them selves.Beta said that some of the early retaining bolts corroded so we replaced with new ones. The giant o rings we replaced with a little lick of silicon grease which helped. It is definately a fiddly job but if you dont do it now you wont know the condition of the stack, any debris present, condition of the anode etc. I think we will do the same next year but once we get a feel for how often the stack furs up we will do it every two years after.

 

[PetiteFleur]

As part of the maintenance regime I am supposed to clean the heat exchanger stack on my beta 13.5.

Normally I wouldn't worry, but the engine is installed in the bare minimum of space and to remove the stack I'm going to be working blind and for a large part of the time by feel - especially when removing the rear bolt.

Never having done this job before I'd welcome some advice. Is the stack one unit that comes out in one piece or does it disassemble for cleaning? If it does I don't want to drop bits in the bilge as I draw it out.

Are the O rings captive? Am I likely to find one stuck inside the heat exchanger? Will they stay on when I replace the unit?

As I say, normally I wouldn't worry but never having done the job, and working blind I want to be prepared for every possible cock up and the manual isn't exactly helpful - with small grainy pictures.

I did my 25hp Beta about three weeks ago. Easy, I just removed the end caps carefully, although I did have to remove the alternator first for better access. As long as you don't disturb the 'O' rings you should be able to reuse them. I used a bit of stiffish wire to poke through each lower hole to clear the crud - about half were blocked up. As my wire was not very stiff I tackled it from both ends. Found a lot of crud at the rear end including bits of impellor rubber. Make sure you change the anode at the same time. I replaced the end caps, refilled the tank and had no leaks.
Since then I've found an old welding rod of 2.5mm Diameter which I will keep in my toolbox on the boat so I can unblock it when aboard.
PS - doing this cured my overheating earlier in the year.

 

[alahol2]

I clean the stack on my 13.5HP every year as it's a relatively easy job.
Remove the hose from the rear end cap.
Undo the bolt in the rear end cap. Remove the rear end cap.
Undo the bolt on the front end cap. Remove the front end cap.
Pick out the 'O' rings from rear and front of the stack housing.
Remove the stack, it should slide either forward or back relatively easily. If it is stuck, put a block of wood on the end of the stack and tap it with a hammer until it moves, then slide it out.

Clean the rear of the stack housing.
Rod through all the tubes in the stack and ensure everything is clear and clean.
To refit...
Temporarily replace the rear end cap with the 'divider' horizontal.
Slide the stack back into place ensuring the slots in the end ring mate with the 'divider' in the end cap.
Carefully remove the rear end cap without twisting.
Grease the 'o' rings and fit into the front and rear of the stack housing, pushing them up to rest on the ends of the stack.
Replace the rear end cap keeping the 'divider' horizontal and ensure it mates with the slots on the stack again. Replace the bolt and do it up finger tight.
Replace the front end cap and bolt. Do it up finger tight.
Tighten both bolts to compress the 'O' rings.
Replace the flexible pipes on the rear end cap.
Top up the fresh water coolant. Job done.

By the way, the manual downloadable from the Beta web site now has much better layout and photos.

 

[NickNap]

Cleaning stack

As per alahol's advice, you'll almost certainly need to do it each year - mine looks like his at the end of each season. Just two points to add to the others' excellent advice:

The rear end cap has a horizontal flange which locates with a slot in the end of the stack (see alohol's pic). It's obvious now, but the first time I did this job I didn't have the stack at the right angle so the cap wouldn't go into the housing enough and wasted about two hours trying to get it right. If you fit the rear cap first you can check the stack's located correctly as it won't turn on its axis, if it will turn, it's not in properly (also you can see the pipes aren't random, there's a horizontal gap which idicates where the slot is at the other end, if you see what I mean)

I found the best way to clean the dissoved anode crud out of the stack is to use a drill bit of the correct size and gently do each hole from both ends, finishing with pipe cleaners. I daresay VicS would be able to suggest something to leave it in overnight to dissolve this...

I also get a lot of crud in the rear end cap itself, so this season I smoothed out the inside to make it harder for the stuff to stick (rather like 'porting' if you're old enough to remember doing that on cylinder heads?) but haven't taken it apart to see result yet.

Nick

 

[sailorbil]

Should there be a seal on the horizontal divider at the back end?
My Beta 10 heats up when revved up and I suspect that the raw water is taking a shortcut and bypassing the H>E> altogether when under pressure

 

[alahol2]

Should there be a seal on the horizontal divider at the back end?
My Beta 10 heats up when revved up and I suspect that the raw water is taking a shortcut and bypassing the H>E> altogether when under pressure

No, there is no seal on the divider. I can't imagine the water taking a shortcut unless either the tubes are blocked or the divider is damaged. It maybe that you are not passing enough water through the system as a whole. Too small an inlet? Collapsed inlet tube somewhere? Damaged impeller?

 

[sailorman]

I clean the stack on my 13.5HP every year as it's a relatively easy job.
Remove the hose from the rear end cap.
Undo the bolt in the rear end cap. Remove the rear end cap.
Undo the bolt on the front end cap. Remove the front end cap.
Pick out the 'O' rings from rear and front of the stack housing.
Remove the stack, it should slide either forward or back relatively easily. If it is stuck, put a block of wood on the end of the stack and tap it with a hammer until it moves, then slide it out.

Clean the rear of the stack housing.
Rod through all the tubes in the stack and ensure everything is clear and clean.
To refit...
Temporarily replace the rear end cap with the 'divider' horizontal.
Slide the stack back into place ensuring the slots in the end ring mate with the 'divider' in the end cap.
Carefully remove the rear end cap without twisting.
Grease the 'o' rings and fit into the front and rear of the stack housing, pushing them up to rest on the ends of the stack.
Replace the rear end cap keeping the 'divider' horizontal and ensure it mates with the slots on the stack again. Replace the bolt and do it up finger tight.
Replace the front end cap and bolt. Do it up finger tight.
Tighten both bolts to compress the 'O' rings.
Replace the flexible pipes on the rear end cap.
Top up the fresh water coolant. Job done.

By the way, the manual downloadable from the Beta web site now has much better layout and photos.

after how many hrs is that photo

 

[aslabend]

Did mine for only the second time last week and it's really not that difficult (please suck out the coolant first or it's messy ).
I have to remove the alternator & bracket to get the stack out the front of the exchanger (the exhaust riser blocks in coming cleanly out the back) but that means that the alternator belt gets assured of an adjustment. I had quite a lot of fine weed (a lot more than I expected) on the front of the stack but that cleaned off easily. Any tubes that looked a bit narrowed I just rodded through with stiff wire. I used new seals, they're cheap so what's the point in not. Putting it all back together is a slight pain as, like the OP, access to the rear of the stack is by feel only. I put the stack in to about the correct position, seat the seals and then try and get the rear cover aligned and the bolt half in (without pushing the stack out the front again) then do the front cover and slowly tighten them both a bit at a time. It's a bit of a fag getting it back together but it's just a case of working through it to make sure it's all aligned. Clean everything off with paper towel before refilling and then run a clean tissue round all the joints and check for dampness on it from any leaks.

While it's all apart I replace the pencil anode and check the impeller and then I'm pretty much assured that that side of the engine is tickety-boo.

 

[alahol2]

after how many hrs is that photo

That was at the end of three years, about 220hrs (I didn't then know I was supposed to clean it ). There is a load of very fine weed in some of the tubes. The weed had already got through 2 filters to get to that point in the system. Since starting to clean every year it has never been in anything like as bad a state.

 

[sailorman]

That was at the end of three years, about 220hrs (I didn't then know I was supposed to clean it ). There is a load of very fine weed in some of the tubes. The weed had already got through 2 filters to get to that point in the system. Since starting to clean every year it has never been in anything like as bad a state.

done mine @ 500 hrs from memory, it was clean

 

[Halo]

Excellent advice from Alahol2. I fitted a new 13.5 in my old Westerly 25 and it is a great engine. I was very tight for space and had a tough job cleaning the tube stack each year - it came out looking nearly as bad as in Alahol2's picture. Shifting the stack was not as easy as you might think and needed a fair bit of gentle persuasion with a mallet and wood. The stack and O rings seemed to settle in and not want to move. I found a long thin screwdriver the best tool for removing deposits down the blocked up tubes. Definately do it each year and have spare O rings on hand. The assembly is sort of self centering and I found that a liberal coat of vaseline helped with teh installation Good luck
Martin

 

[sailorman]

Excellent advice from Alahol2. I fitted a new 13.5 in my old Westerly 25 and it is a great engine. I was very tight for space and had a tough job cleaning the tube stack each year - it came out looking nearly as bad as in Alahol2's picture. Shifting the stack was not as easy as you might think and needed a fair bit of gentle persuasion with a mallet and wood. The stack and O rings seemed to settle in and not want to move. I found a long thin screwdriver the best tool for removing deposits down the blocked up tubes. Definately do it each year and have spare O rings on hand. The assembly is sort of self centering and I found that a liberal coat of vaseline helped with teh installation Good luck
Martin

dont over tighten the end caps the "O" ring also acts as a separator between the H.E. & the end caps

 

[stepcor]

Some years on from original but problem remains unsolved for me and I'm getting no advice from Beta UK. For whatever reason, my oil dipstick tube sits directly behind the alternator end of the tube stack cap. I've unscrewed the bolt partially but can go no further. That movement has screwed the O ring seal and any attempt to re-position the cap, water leaks, so I now have an unsealed HE and I cannot get the cap off in order to replace the O ring and reseal. I looked at cutting the dipstick tube off by 1 inch, which would allow me to remove the cap, if not the stack but the area is so confined that a Dremel cutter may do more damage than intended. I'm at a loss and grateful for any thoughts