beta marine heat exchanger tube stack problem

[dave c]

Hi All,
I removed the tube stack from my beta bd722 - with a bit of trouble - and cleaned it out.
I put new o rings in, but it's leaking at the exhaust end.
I actually assembled it outside the heat exchanger to see what the problem was and the divider bar that goes across the exhaust end cap ( when it's fitted into the slot ) keeps the two chamfered edges about 3'16 of an inch apart. The o ring looks and feels slack as well.
Is there a thicker o ring for the exhaust end cap?
The other end cap fits right up to the tube stack and the o ring fits a lot better.

Anybody else done this?
THanks
Dave c

 

[wrr]

On my BD1005, the two O rings are identical, both being fairly large diameter. I wonder if the stack in not properly in place? It can move forwards and backwards. If it too far aft, it may be preventing the seal between the cap, O ring and the heat exchanger casing. Beware of over-torquing the phosphor-bronze bolt, they can snap!

 

[dave c]

Thanks for the info, mate.
I'll try re-positioning it.
It looks like the actual casing is badly pitted/worn at the exhaust end and someone advised me to use a metal epoxy filler to smooth it out a bit.
But every little bit of info helps!
Thanks,
David

 

[DoubleEnder]

Hi All,
I removed the tube stack from my beta bd722 - with a bit of trouble - and cleaned it out.
I put new o rings in, but it's leaking at the exhaust end.
I actually assembled it outside the heat exchanger to see what the problem was and the divider bar that goes across the exhaust end cap ( when it's fitted into the slot ) keeps the two chamfered edges about 3'16 of an inch apart. The o ring looks and feels slack as well.
Is there a thicker o ring for the exhaust end cap?
The other end cap fits right up to the tube stack and the o ring fits a lot better.

Anybody else done this?
THanks
Dave c

How did you get it out? Mine seems stuck...I use a bottle brush but I'd like to take it apart really

Thank you

Graham

 

[sailorman]

Hi All,
I removed the tube stack from my beta bd722 - with a bit of trouble - and cleaned it out.
I put new o rings in, but it's leaking at the exhaust end.
I actually assembled it outside the heat exchanger to see what the problem was and the divider bar that goes across the exhaust end cap ( when it's fitted into the slot ) keeps the two chamfered edges about 3'16 of an inch apart. The o ring looks and feels slack as well.
Is there a thicker o ring for the exhaust end cap?
The other end cap fits right up to the tube stack and the o ring fits a lot better.

Anybody else done this?
THanks
Dave c

did u use silicone grease on the O ring
the end plate is designed to use the O ring as a spacer to hold the cap away from the h/e body

 

[BabaYaga]

Hi All,
I removed the tube stack from my beta bd722 - with a bit of trouble - and cleaned it out.
I put new o rings in, but it's leaking at the exhaust end.
I actually assembled it outside the heat exchanger to see what the problem was and the divider bar that goes across the exhaust end cap ( when it's fitted into the slot ) keeps the two chamfered edges about 3'16 of an inch apart. The o ring looks and feels slack as well.
Is there a thicker o ring for the exhaust end cap?
The other end cap fits right up to the tube stack and the o ring fits a lot better.

Anybody else done this?
THanks
Dave c

I have the 722. The o-rings are identical fore and aft, but I believe the o-rings for newer Beta engines (from 2011 or so) are different in size to the older ones. Could you have bought the wrong ones?
As already pointed out, adjust the tube stack lengthwise, so that it is positioned equal in regard to the flanges. When done up, none of the end caps should be in direct contact with the h/e or the stack, the o-rings should prevent this.

 

[ballyabroad]

I had a similar problem with my Beta 25. Seems a bit of an art to get back together, but once done it makes sense. Double check that the heat stack is going in the right way round, mine definitely only goes in one way round, with the 'divider' tabs locating with the correct end cap. When I phoned Beta they were really helpful and talked me through the technique to locating. Only tighten the end caps up finger tight, swapping ends so the tubestack sits even in the Heat Exchanger tank. Double check the tubestack is sitting correctly before tightening and it shouldn't be over tightened. Silicone grease on the O rings helps as well. If it all doesn't sit correctly then the Coolant and Raw water go to places they shouldn't and as in my case a new tank was required.

Give Beta a call, a helpful bunch.

 

[dave c]

Hi Graham,
With a bit of welly!

I replaced the end bolt with an old one and tapped it out with a hammer and a metal drift. I had to persuade it! Be careful tho' as it can cause damage.
If I were you, I'd leave it in position and push a bit of wire or whatever thru the holes cos it seems when you remove it, you are creating a problem with trying to get it to reseal.
P.S. the heat exchanger body is aluminium and can get worn/damaged easily which causes the problems with sealing.

 

[dave c]

HI all,
Problem solved - eventually!
I'm lucky enough to be able to remove the cockpit floor and get in beside my engine so I could see what I was doing!
I tried the metal epoxy - but wasn't too happy with it. I thought the exhaust end casing lip was too far gone. The alternator end was like brand new.
Beta wanted £245 + vat + delivery for a new H/E case. About £325.
As I have room to remove the unit, I did.
All was going well till I snapped the heads off two of the exhaust bolts, leaving two studs in the H/E body!
I epoxied the lip as good as I could, but it still wouldn't seal.
I took it to a small engineering shop and the guy cut out the lip put an insert into it. £100.
He saw the end cap for the exhaust end and said straight away that it was out of shape - I hadn't noticed this!
I put it together - centred the stack , tightened the bolts evenly, etc - and it still leaked.
By this time I was looking for a length of rope!
I contacted beta and they reckoned I needed a new end cap. I ordered one.
What a difference!
I could tell as soon as I put it up against the tube stack and it fitted into the slots that this was not going to leak - the way the old one wobbled about, there was no way it was going to seal.
I also ordered 3 new exhaust manifold gaskets for between the heat exchanger, the exhaust gasket, and new nuts bolts and washers. About £35/40. ( including end cap at £25)
I got the broken studs out easily and put it all together.
Started her up today and it's purrrrrrfect!
Thanks for all your help.

P.S.
I take my hat off to all the guys who have managed to do this without taking the unit out!

 

[ganter]

I'd beef up the o-rings, both ends, to take into account general wear, vibration and inevitable corrosion.
I'd also ignore the book about torque. You know when it's tight on a slightly worn engine.
Blue gasket has its uses here as well.

 

[Scomber]

i always dismantle tube stack annually and clean and replace with new o rings-just be careful as already stated to align / tighten carefully then each year there wont be problems extracting the stack and you'll be sure all is clear

 

[sailorman]

i always dismantle tube stack annually and clean and replace with new o rings-just be careful as already stated to align / tighten carefully then each year there wont be problems extracting the stack and you'll be sure all is clear

Why every year

 

[alahol2]

Why every year

I do mine every year (although I don't replace the o ring) because one year I found it chock full of seaweed. The very thin 'grassy' type weed. The weed had already gone through two filters to get that far. If you do it every year it does not allow build up of any calcium products which can make it hard to remove the core. It takes about an hour all told to remove, clean and reassemble. Quite therapeutic.

 

[dave c]

I do mine every year (although I don't replace the o ring) because one year I found it chock full of seaweed. The very thin 'grassy' type weed. The weed had already gone through two filters to get that far. If you do it every year it does not allow build up of any calcium products which can make it hard to remove the core. It takes about an hour all told to remove, clean and reassemble. Quite therapeutic.

Do you renew the anode every year as well?

 

[alahol2]

Do you renew the anode every year as well?

Yes I do. When I initially installed the engine it was using two anodes per season. Now, ten years down the line, it is using about half an anode per year. Cheapest source I have found is http://www.zincsmart.com/. Get the screw in holder and anodes separately.

 

[dave c]

I've replaced the anode three times since 2006 - and there has only been about a quarter of an inch wasted away, at the most. Yet the amount of white crud I scraped off the end of the tube stack and end cap ( to get it out ) was amazing!
Most was around the edge of the tube stack tho' and only about 4 or five holes were blocked.
My problem was - I think - that I was losing coolant thru the o ring ( because of the badly eroded lip at the exhaust end ) and out the exhaust as I was having to top up quite a lot. ( About a cupful every couple of hours )
Hence the overheating.

 

[Scomber]

I do mine every year (although I don't replace the o ring) because one year I found it chock full of seaweed. The very thin 'grassy' type weed. The weed had already gone through two filters to get that far. If you do it every year it does not allow build up of any calcium products which can make it hard to remove the core. It takes about an hour all told to remove, clean and reassemble. Quite therapeutic.

well said sir-exactly my thoughts!!!!

 

[LittleSister]

I was having to top up quite a lot. ( About a cupful every couple of hours )

I can't remember ever having to top up ours in 7 years! (That includes running for hours on end at times, including one trip 20+ hours into a headwind.)

 

[arenyi]

BD1005 heat exchanger

On my BD1005, the two O rings are identical, both being fairly large diameter. I wonder if the stack in not properly in place? It can move forwards and backwards. If it too far aft, it may be preventing the seal between the cap, O ring and the heat exchanger casing. Beware of over-torquing the phosphor-bronze bolt, they can snap!

Are you sure that the end cap bolts are phosphor bronze? On mine heat exchanger was simple iron bolts, and they are wry corroded. I plan to change them to stainless steel. Is it the right solution?

S. Renyi