Help from Bukh Owners please

[morgandlm]

I asked for some advice earlier this month about how to remove the cooling water injection flange from the front of a DV10 crankcase - this is tucked in behind the flywheel. Cut down allen keys (as advised - thanks), ratchet spanners, bleeding knuckles, bad language and quite a lot of time were all it took ! Having got it out I was able to see the extent of the crusty build up in the water jacket which I hope will be resolved by a chemical flush. My engine was not over-heating so the cooling seemed to be working OK - which is an indication of how robust these engines given the amount of furring up. However, I found that the pipe I expected to see projecting into the jacket is only about 10mm long. Is the longer pipe only on the multi-cylinder engines? Please can other Bukh owners comment.

In my earlier posting, I reported that I found carbon build up in the thermostat housing which was a complete surprise ...... until that is I removed the exhaust injection bend to find it 70% blocked. Presumably back pressure was pushing exhaust back into the cooling system. I thought I kept this engine reasonably well maintained! Despite all this it was running well!

Grateful for any comments

David Morgan

 

[davidmh]

I have just removed the pipe on my DV20 after 20 years . My pipe is 100mm long from the back of the flange,. The end of the pipe is pinched to leave a 3mm slot vertically when installed. There are 3 off 6 mm dia holes in the side of the pipe ( right side viewed from flywheel) Spacing of holes from flange are 13mm, 25mm, 90mm. I scraped away all the salt build up and will refit it later. My Bukh Service guy says he uses the thick board gasket but he soaks it in oil for a week before fitting to stop the joint weeping. Also thinking about using hex screws instead of Allen cap screws as it may be easier to use a standard ring spanner in future, I may have to use a longer one with a spacer under the head for the bottom bolt. My engine is running fine , the pipe was partly blocked , the two holes near the flange were completely blocked, the other one and the slot were ok . The bend on the tube before the flange was quite restricted. All clean now by using Kill Rock Kettle descaler.
David MH

 

[neil_s]

Yes - longer pipe is for DV20 engine. It distributes cooling water to the rear cylinder. Well done with your engine maintenance, though! My DV20 runs at 60 C when it's clean. This year it was running at just over 70, so it got a flush through with Fernox DS3. Back to 60, now.

 

[Mistroma]

I had a central heating problem during the first lockdown. I had poor circulation, even after a couple of flushes and removing 2 radiators for manual cleaning. Some things were in short supply and I think I even saw Fernox DS40 on eBay for £40-£60.

I did a quick check and determined that Fernox DS40 seemed to be about 80% citric acid and 20% malic acid. I bought both of these on eBay and had enough to treat my system about 4 times over for a fraction of the cost of DS40. It worked very well and the heating was returned to full flow with no need to power flush.

I think that the only real difference was that Fernox comes with an acid indicator (i.e. changes colour when acid is exhausted) and some sachets of neutraliser.

No big deal. I simply checked for acidity when draining and after a final water flush. Add a drop of the run-off to some baking soda. Lots of fizzing and bubbles means there's still acid present.

I imagine 80% citric acid and 20% malic acid will work well on the Bukh. Of course the price and availability of Fernox will probably have changed by now.

I paid about £15 for 5kg citric acid and £9 for 1lg malic acid. (i.e. £24 for 6kg vs. £40-£60 for 2kg)
You'd only need a small fraction of that to treat a Bukh and smaller amounts were available.

A no-brainer at the time because Fernox seemed to be in short supply and people with some stock were 5-6 time more expensive than my alternative.