Beta diesel corrosion

[tadpole]

Has anyone had a problem with corrosion on Beta diesels. On returning to my mooring one day I found the engine compartment in my Pageant covered in soot, oil and grease. My friendly local engineer told me he was astonished that a so-called marine diesel had no helicoils where the heat exchanger is attached to the block and all the threads had been eaten away by corrosion - the result of poor design.
Result: a £180 bill. The engine is a 13HP twin, only three years old and little used. Potential purchasers beware.

 

[Guest]

I suspect that your friendly local engineer is talking bo....ks. Helicoils are primarily used to repair threads, and whilst they might not corrode being stainless, the metal they are screwed into would be exactly the same and would corrode in the same way with same result

In the old days, diesels were big heavy lumps of iron, that might corrode on the surface but lasted for ages. The Beta (along with most others) is based on a lightweight Jap diesel which performs excellently but cannot be ignored in the same way. Needs preventative maintenance against corrosion in a marine environment.

 

[vyv_cox]

I'm not familiar with the design of your engine, but normally in joints such as you describe there is no contact between the bolts and the coolant. The bolts are usually surrounded by the gasket to prevent localised corrosion. If water gets to the bolt, the implication is that the joint worked loose, which sounds to be a logical explanation for your problem.

 

[johnt]

and I go along with VYV and Howard on this one ...Im just a little suprised that VYV didnt jump on the helicoil thing as well!

Maybe she was just being ladylike

 

[stevebirch2002]

I must agree with the other reply to this comment The so called "Friendly Engineer" is talking the proverbial "b***s"! Almost all new marine diesels are based on Japenese blocks. Helicoils are certainly not used in any of them that I know. I would suggest that standard preventative maintenance should be carried out by all competent boat owners on their inboard engines, whether the engine is one year or thirty years old. I changed my old Volvo MD6A for a Beta 13.5HP and I have not looked back. The difference is fantastic - smooth running, plenty of power, easy to install and spares are at a reasonable price. No I do not work for Beta just a very satisfied customer.

 

[vyv_cox]

My wife doesn't like me being ladylike.

In fact I have come across aluminium castings that are fitted with helicoils, or an insert very similar, in production. This is intended to avoid the very real likelihood that threads will be stripped by overtightening by enthusiastic maintainers. The alternative is to fit bolts and studs that have a very coarse pitch, contributing to the possibility that they will loosen themselves in service.

 

[stevebirch2002]

I think you will agree that the helicoils are fitted to prevent stripping threads rather than as an anti-corrosion system? If anything I would expect the stainless to react just as much with the aluminium as the bolts. I see no advantage of fitting helicoils as an anti-corrosion measure.

 

[vyv_cox]

I think that's what I said.

In my earlier post I said that there should be no contact between coolant and the stud/block threaded interface, regardless of whether there are helicoils or other inserts present.

So what's your point?

 

[stevebirch2002]

Hi

I was just agreeing with you and trying to explain to "TADPOLE" that his engineer did not seem to know what he was saying. I have not got used to the forum reply system yet and was trying to explain to Tadpole. I agree totally with your comments on this subject.

Kind Regards

Steve birch

Albin Vega "Southern Comfort" V1703

 

[Shanty]

I have a Beta 13hp about four years old. This winter, I discovered that there is a pencil anode in the heat exchanger. Mine had completely eroded away - How is yours? Lack of this anode could be allowing corrosion to take place. Beta Marine can supply replacements at reasonable cost.

 

[tadpole]

I'll check out the pencil anode, Tim, thanks for the tip. My engine bloke is a bit old-fashioned and probably not too au fait(?) with relatively recent diesel technology.
Steve