Beta 30 refitting heat exchanger end caps.

[eddystone]

Just removed the caps to clean the matrix. I have to undo the rear cap (with the hoses attached) and force it ajar so I can push the matrix from the rear. I have done this before but in re-attaching the rear cap there doesn’t seem to be a locating channel or groove for the O ring, unlike the front cap, so difficult to know whether correctly seated as I have to do this by feel from the front of the engine. How critical is O ring positioning?

 

[BabaYaga]

For best answers, could you state if you have the older one-bolt end caps or the more modern three-bolts?

 

[eddystone]

3 bolt caps - the problem is rear access is a big challenge for my 71 year old knees!

 

[BabaYaga]

I am only familiar with the single bolt type, but judging from the photo in the manual for the modern 3 bolt type, it seems that the o-ring is just located around the slightly protuding matrix. It would then be squeezed between the matrix, the heat exchanger housing and the chamfered inner edge of the aft end cap.
The manual also stresses it is important that the matrix is turned to align with the rubber sealing of the end cap. Not sure of how to do this 'by feel'. A hand mirror perhaps?

 

[Humblebee]

Ask Beta themselves? They are always helpful, link here;

Help Desk - Beta Marine Propulsion Engines

 

[eddystone]

I am only familiar with the single bolt type, but judging from the photo in the manual for the modern 3 bolt type, it seems that the o-ring is just located around the slightly protuding matrix. It would then be squeezed between the matrix, the heat exchanger housing and the chamfered inner edge of the aft end cap.
The manual also stresses it is important that the matrix is turned to align with the rubber sealing of the end cap. Not sure of how to do this 'by feel'. A hand mirror perhaps?

Not difficult to align as this is done on forward facing end before attaching front cap. But I’ve been trying to to locate the rear O ring by feel without the matrix in place -maybe that helps to locate it

 

[alahol2]

Not difficult to align as this is done on forward facing end before attaching front cap. But I’ve been trying to to locate the rear O ring by feel without the matrix in place -maybe that helps to locate it

On a single bolt heat exchanger...
I normally remove the matrix towards the rear of the engine. I remove the pipes from the end cap, remove the bolts from front and rear end caps, remove end caps. hook out 'o' rings, push out matrix.
When re-assembling the heat exchanger I put the matrix in, centrally, by feel. Without moving the matrix, I slide the 'o' rings up to the matrix and ensure they are sitting properly, the rear one by feel. The end caps are then introduced to rest against the 'o' rings and the bolts inserted and tightened.
I've never really had a problem with it.

 

[BabaYaga]

But I’ve been trying to to locate the rear O ring by feel without the matrix in place

Presuming that you actually have the o-ring (not trying to locate it as in trying to find it) then I would suggest, judging from the photo in the manual, that you cannot put the o-ring in its correct position without the matrix being in position first.
This is just my guess, because as mentioned earlier my only experience is with the single bolt type.

 

[BabaYaga]

On a single bolt heat exchanger...

Yes, this sums it up, but the OP has the three bolt type heat exchanger, which appears to be very different från the single bolt type.

 

[rogerthebodger]

Can you post some pics of the end caps and the Heat Exchanger ends so we can see how the end caps join the end of the HE body

I don't have a Beta but I do have a bowman heat exchanger

Marine Heat Exchanger Parts

 

[BabaYaga]

Can you post some pics of the end caps and the Heat Exchanger ends so we can see how the end caps join the end of the HE body

I don't have a Beta but I do have a bowman heat exchanger

Marine Heat Exchanger Parts

Not sure if the OP has sought guidance from the engine manual.
There is a pic on page 58 showing the rear end cap removed, matrix inserted with o-ring in place.
I do not see how the o-ring could be installed (located) without the matrix in place beforehand.

 

[rogerthebodger]

I would suggest the hole in the case of the heat exchanger is countersunk so with the stack in place as you suggest creates a sealing face that will seal the stack to the outer casing together

With the end cap in place the O rig would be compressed into the triangle gap between the stack and outer casing by tightening the end cap.

This creates a 3 sided seal sealing the casing / the stack and the end cap

The size of the O ring is very important

My heat exchanger on my boat is sealed in the same way even through its a through centre bolt