Beta25 heat exchanger assembly

[hunter323]

After some difficulty I have extracted the heat exchanger and cleaned it all up. However when coming to assemble I can't quite figure out exactly how to include the O rings. They don't seem to fit on the end caps so I assume that they must go inside the unit? Would be grateful for advice particularly from a Beta engine owner who has done this task. As ever grateful to the forum which has been very helpful in the past.

 

[michael11]

i have a beta 35 if its the same , there are 2 styles ours is the old style and i must say the newer is better .

old style o ring fits against 2 chamfers on the casing and heatexchanger not a very positive location .

make sure the chamfers are clean .

have fun

m

 

[earlybird]

My 25 hasn't yet had it's HX dismantled, but the pictures in my manual seems reasonably clear. The end-caps are the 3-bolt type. The tube stack is put in place and the O-ring is positioned on the tube plate, just inside the HX body. The end cap then nips the O-ring as it is tightened up.

 

[BabaYaga]

i have a beta 35 if its the same , there are 2 styles ours is the old style and i must say the newer is better .

old style o ring fits against 2 chamfers on the casing and heatexchanger not a very positive location .

make sure the chamfers are clean .

have fun

m

On my Beta 722 from 2006 the two chamfers are on the tube stack ends and on the (single bolt) endcaps. The O-ring sits in the space between these two chamfers and the inside of the flange of the openings into the heat exchanger body. This space is triangular i section.

The main difficulty in my experience is placing the tube stack at equal distance with regard to the two openings in heat exchanger body (perhaps 10mm inside at each end). Then put the two o-rings in place, this should hold the stack in position length-wise. Check distance again and then put the two end caps on, tightning the bolts progressively (and not all too much).

 

[Heat Exchanger Guy]

It looks like this question has been pretty much answered, but for confirmation;

1) Insert the tube stack in to the body so that the remaining space on each end is roughly equal.
2) Place the O rings (preferably brand new ones) in to the groove on each end ensuring that the chamfer is clean and flush.
3) Place the headers over them and as they are tightened the O ring will be compressed inside the groove forming a seal.

Avoid tightening one end to it's maximum before starting on the other, otherwise this can pull the tube stack out of position. It is designed so that it doesn't have to be exactly in a central position to still line up with the internal chambers but it is best to keep it as central as you can.