Temperature of exhaust gas leaving the cylinder

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Avocet

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Would anyone be able to provide any figures for the sort of temperature that the exhaust gas leaving my 10 horse, single cylidner raw water cooled diesel might be, please? I've had a bit of a bad evening today. I was taking the valves out of the cylinder head and just couldn't resist trying to chip a very annoying looking bit of flaky rust off the inside of the exhaust port. That was when my screwdriver went right through it and into the water jacket! It's a BMW D12, so there's no chance of sourcing a replacement head. They're just not available any more.

I was wondering about trying to clean the surrounding area with a die grinder and brazing a patch on. Daft idea?
 
Bad luck mate. I do not know the actual temperature but do know that the exhaust valve would be glowing red hot when running. Not sure if braze would stand up to it. I have brazed cracked water jackets but of course much cooler.

If the corrosion is so bad that a screwdriver punched through it, I doubt there is enough good metal to weld in any case.

Hope I am wrong though.

Steve
 
Avocet said:
Would anyone be able to provide any figures for the sort of temperature that the exhaust gas leaving my 10 horse, single cylidner raw water cooled diesel might be, please? I've had a bit of a bad evening today. I was taking the valves out of the cylinder head and just couldn't resist trying to chip a very annoying looking bit of flaky rust off the inside of the exhaust port. That was when my screwdriver went right through it and into the water jacket! It's a BMW D12, so there's no chance of sourcing a replacement head. They're just not available any more.

I was wondering about trying to clean the surrounding area with a die grinder and brazing a patch on. Daft idea?
Click to expand...

I reckon you are onto a loser with that one. If you can put a screwdriver through in one place its likely to be very thin in other places too, and any application of the heat necessary to weld or braze will cause problems of itself. At best any repair will be shortlived.

As I write this I know damn well that in the same situation I would try a bodge. But I also now that the reliable sensible approach is an engine change.
 
birdseye said:
As I write this I know damn well that in the same situation I would try a bodge. But I also now that the reliable sensible approach is an engine change.
Click to expand...

A man after my own heart!! Never a truer word spoken. Yes, my "head" knows I'm looking for a new engine, really. Hell, this one is the best part of 30 years old and owes me nothing. No chance of a second hand head, I'm afraid. The casting patterns were lost by the Eastern European foundry some years ago. I'm a member of a Yahoo user group for these engines and I think the last new head sold for about £1200 a couple of years ago. The cores were in a dodgy place in all of them and they all suffered from a thin wall on one side of the exhaust tract. I've asked on the user group but realistically, I know that the chances are slim to non-existant.

My immediate problem (apart from funds), is that the boat is in a boatyard with a "NO MAINTENANCE" policy. It's also about 40 miles from my workshop, so doing a new installation between now and next spring is going to be a "challenge"! At present, I'm thinking of trying to bodge it for this season (the boat's only on a lake, so I'm not especially worried about dying horribly on a rocky lee shore in a storm if it fails). I also have (by exhaust port standards!) good access to both sides of the hole, so I'm leaning towards a simple nut and bolt right through it and a curved washer on each side with some exhaust bodging paste on it. I've just e-mailed Santa and added a die grinder and some burrs to my Christmas list!
 
The OP should count himself lucky really. At least the problem was found when it didn't matter. It does show the value of inspection and tinkering around.

The OP could try a cast iron rod, high nickel or stainless as a temp repair.
 
I seem to recall a system of stitching cracked blocks back together. could this method be used in your situation? a solid lump of cast fitted and stitched in properly would be a better fix than bolt I suspect.

I would think there has to a part laying around somewhere though, so don't give up your search.

Good luck and fair winds.

Consider a post with a mystery prize for the first forumite to locate one.

Good luck and fair winds.

PS I found and old B&G wind speed gauge in the shed a few weeks back when looking for a bit of stsinless bar.
That gauge must be over 50 years old and still working.
 
I wonder if the exhaust tract is straight enough for a machine shop to bore it clean and press fit in a bit of stainless tube? Forget washers and exhaust seal. That definitely wont hold.
 
Nah. I was given a scrap D12 with the same failure a few years ago and thought the same. I took it into the machine shop where I worked, with the intention of putting it on a milling machine and boring it out, then sinking a sleeve in, but the duct follows a compound curve and the cutter just breaks through the sides pretty much everywhere. Even the "good" side wasn't more than 3mm thick at any point.
 
Beamishken said:
Try a US company called V12 engineering they specialise in all things BMW marine so might just be able to help
www.bmwmarine.com
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Thanks for that. I think Richard Langtry is the chap who runs it. I'll certainly send him an e-mail, but I fear I know the answer. A few years ago, I think he was looking at getting new patterns made if he could get enough orders. Trouble is, there are so few of these engines left anyway now, that I'd probably be looking at half the cost of a brand new (more mainstream) engine just to get this one another head.
 
OK, some piccies:

IMG_20141222_092751sa_zpsa28260f4.jpg


IMG_20141222_094133sa_zps9bef3240.jpg


IMG_20141222_094105sa_zps1e36c28c.jpg


IMG_20141222_093945sa_zps533ad01a.jpg


IMG_20141222_092902sa_zps7471e05e.jpg
 
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Avocet said:
OK, some piccies:

IMG_20141222_092751sa_zpsa28260f4.jpg


IMG_20141222_094133sa_zps9bef3240.jpg


IMG_20141222_094105sa_zps1e36c28c.jpg


IMG_20141222_093945sa_zps533ad01a.jpg


IMG_20141222_092902sa_zps7471e05e.jpg
Click to expand...
Many years ago had a Meadows side valve petrol engine in a wooden double ender, same situation between the inlet manifold and waterway. I used metal epoxy to fill it, got me from Beaumaris, thru the Swellies to Caernarfon before the home made head gasket expired!
If only on a lake, and not a big issue if it fails. The penny washer idea sounds good. Use some Walkerite gasket material to make up the gasket on the washer and use a heat proof epoxy to help seal a 5mm bolt and washer should do it?
Nothing to lose, even put the old rings back in?
S
 
Ta Stu, yes, it certainly does put even the relatively modest investment in a set of piston rings in a new light! To think, 24 hours ago, my biggest worry was a grubby transom and a bit of oil consumption!

I am also starting to hatch a "Plan C"...

...I reckon I could get a Jubilee clip right round that duct, inside the water gallery...
 
You can get a 10hp, electric start, water cooled Chinese diesel engine for about $300 apparently.
There must be some mileage in marinising one?
 
Avocet said:
Ta Stu, yes, it certainly does put even the relatively modest investment in a set of piston rings in a new light! To think, 24 hours ago, my biggest worry was a grubby transom and a bit of oil consumption!

I am also starting to hatch a "Plan C"...

...I reckon I could get a Jubilee clip right round that duct, inside the water gallery...
Click to expand...
Jubilee clip sounds good, didnt realise you could get round the back. Thing is that the inside will be running relatively cool, the coolant runs at 180ish deg? We used to do hot welds to oil producing pipes, the flowing oil took the heat away from the welds that quickly that it wasnt a prob, same thing here, so a relatively lo temp resin would be ok as a sealant on a patch.
Here you go http://www.ebay.co.uk/itm/Bakerlok-...534?pt=LH_DefaultDomain_3&hash=item4189458b86 this is what I used to use, used that in my anecdotal story about repairing an engine cylinder
S
More info here http://www.drillingsupplystore.com/thread-locking-compound.html
 
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