1974 800cc V twin in BMW R80 Frame.

[Mouse]

Slowley. Just toured to Germany on a friends Greves Diesel Enfield, 2000 mile round trip so little project progress but much fun in last 10 days.

The piston repair shop reseated the squiffy valve for £7.50 after the second fail. Then when I got it home noticed that I had also left the other valve with them so I have to go back after the long weekend and see if they've still got it sitting somewhere.

I also think I may have found still in production glow plugs for it.

[richard coles]

hi , i might have an explanation to why this cylinder seized .
Am i right in saying the oil filler is directly in front of this cylinder? also your using a KN air filter.
I beleive the upshot of this is you have a very powerful vacuum in line with the oil which came out of the filler tube when the cap came off.This oil would then enter the combustion chamber and act like over fuelling (making excess heat)which lead to the seizure .
I think this is the case as i run a KN filter,mounted under the seat, and recently had an experience in a heavy rain storm in which the rain was being sucked into the filter causing me to limp home at greatly reduced speed .once it stopped raining i pulled the filter off & it ran fine.
What we have to keep in mind is a diesel engine ,unlike a petrol one , runs an unrestricted inlet tract at all revs so maximun airflow at all times.
I hope this might be of some help
cheers Rich

[thundercougarfalconbird]

seriously?? your dont know what caused the seizure?
its a FAN/ forced air cooled engine.
removing the fan caused the seizure, i dont understand where everyone thinks diesels run cold, or cold euff to dont need cooling, when infact when you put the engine to work it makes more heat then any gasoline engine could ever hope to produce, there is more btu value in diesel then in gasoline and that generates more heat when burned, DUH

diesel engines always have more cooling ability in either liquid cooled with larger rads or bigger fins and more fan then a gasoline engine, so the mystery is not why the engine seized, but what are you going to do to not make it seize again.

i have seen plenty of utube vids of people running all sorts of diesel engines qithout coolant, you may think its a short run time, but you just took a perfectly good engine and turned it to trash.diesels dont run without a cooling system or lubrication and they most definatly do not run forever. i hate when people say " oh its a diesel, they run forever" makes me want to get my gun .

[Anorak_ian]

I'm sorry, but I have to disagree with almost everything you said...

What caused the seizure?
The engine was low on oil, the filler cap was blown off. By what? Pressure.
From where does the engine get excess pressure in the crank space? Passed the piston+rings.

A worn bore+rings is the culprit here I think.

Diesel engines get hotter than petrol engines? Tell that to my diesel bike, 20 miles of riding and the exhaust down pipes are no way as hot as any petrol bikes exhaust. You can even touch them no problem.

[thundercougarfalconbird]

im sure the melted smeared almuinum from being over heated had nothing to do with excess blowby, and there was no damage to the crankshaft, or bearings or camshaft and lifters from being low on oil.

the pistons swell past the expansion limits of the cast iron bore and they stick, that is from running them too hot, i have seem many snowmobile engines with cooling systems look very similar, and it is do to heat.

if you want a simple test, take your lawnmower eninge, make sure it is full of oil and then take the blower housing off, and then start it, time how long it stays running befor it sticks.

[Anorak_ian]

"im sure the melted smeared almuinum from being over heated had nothing to do with excess blowby, and there was no damage to the crankshaft, or bearings or camshaft and lifters from being low on oil."

Pistons are going to get hotter than any other part of the engine, with no oil even hotter until they seize. Have you ever know all the moving parts to fail at the same time?

"the pistons swell past the expansion limits of the cast iron bore and they stick, that is from running them too hot"

Agreed, running with out oil will make them run hot.

"if you want a simple test, take your lawnmower eninge, make sure it is full of oil and then take the blower housing off, and then start it, time how long it stays running befor it sticks."

Well my lawn mower engine has run without a housing for a bout 350 miles so far. But if you think it necessary to alert Centaurus owners, go ahead.

[johnfireball]

Hi,
If the oil level drops too low the crank webs stop throwing oil up into the bores, the oil pump still supplies oil to the bearings etc as its at the bottom end of the sump. Hense the piston overheats and locks up.
John.

[coachgeo]

could an overly hot engine from improper air flow create some initial symptom of excessive blow by... which pops the push on oil filler cap thusly spewing oil. Now ones overheating engine along with rising complications arising from lack of lube is going to seize?

[thundercougarfalconbird]

well, im just going to wait for the second failure to happen , unless he installs the cooling fan and shields.

some engines are designed to be free air, and oil cooled, that one is not, and being the vintage it is and east german, im sure the expansion control of the pistons and the cast iron of the cylinder is nothing like honda or other free air motorcycle engines. expansion rates and materials have to be matched and compatible for free air engines to work.

george thats what is happening to that engine, but there was still a couple liters of oil in it, all the damage happened befor the cap popped off, that was just a secondary effect, the engine was already cooked at that point.

[Mouse]

This has turned into rather a heated debate, if you excuse the pun.

Lots of talk about heat / cooling / too hot / lubrication and the like but its all remained relativity anecdotal. I've got some thermocouples and an LCD display. Before I test ride it again I'll have functioning temperature sensors on both heads. The thing I cant find any information on is an acceptable temperature range for an air cooled diesel engine. I know its a bit like asking how long is a bit of string but theres got to be a several bands of temperature for ball park operation, ie Its melted / Much to hot / Too hot / Normal / Still warming up etc

I've had a search out on the internet and cant find anything other than vague references to VW beetles

As for the oil cap, it was a bit loose and probably became free from engine vibration. My own fault really. It was on the list of things to fix properly after the test rides were over with,

[TedV]

I can't find anything much on gas air cooled bike engines either. I have a temp sensor on the base of the left spark plug of my CB250. Usually it is in the 300 to 320 degree F range, with high temps in the 345 to 355 degree F range when WFO (wide friggen open). I think the danger zone on the Beetles was someplace after/around 380 degree F (from memory). I been told the ethenol mix fuels here will cause em to run hotter. Only info I been told is "its an air cooled engine, it's gonna be HOT!!" Thank you Sherlock Holmes.

yeah, I know, not much help on the temps for air cooled diesel. I do know the EGT for my turbo diesel VW's are 400ish cruising and about 1300 deg F WFO. Turbo wants to stay under 1500 degree F.

[albertaphil]

For temperatures, search info on Deutz air cooled diesels. They made thousands of them. I've never owned one, so I can't go and look at the head temp gauge, but you'll likely be able to find something. However, since it was a cylinder seizure, head temp may not tell you what you need to know. To be honest, I'm leaning toward what thundercougarfalconbird is saying. Just because the centaurus drivers, (and stuart on his Ruggerfield) can get away with no forced air to their ruggerini engines, doesn't mean that old Cunewalde with the oil filter blocking the cooling fins on the right cylinder bank can do the same thing. I think it says something that the right cylinder failed while the left one was fine (I assume).

If the failure was due to low oil level, both cylinders should have been affected equally.

Phil

[Mouse]

I've removed the oil filter and repositioned the filler to give a totally blockage free flow of air to the right cylinder. The next task is to plumb in an canister paper filter before I fire it up again. and I'll be keeping an eye on head temperatures next time I take it out for a ride.

I've also lost the exhaust valve somewhere, I remember leaving it at the piston shop but cant be definite. They are having a look for me as I'm hoping it became separated at some point between me leaving it with them and them reseating the valve.

[pietenpol2002]

My vote is for an oil cooler as one of the solutions. Although these engines claim to be air cooled, air is fact relatively poor at transferring and dissipating heat. The oil thus carries much of the burden of cooling when it fact it is limited to the minimal cooling of the crankcase/oil pan. Motorcycle oil coolers are readily available on Ebay for our little air-cooled rattlers - I got mine for $1.00. I consider it cheap insurance.

[albertaphil]

Good call on the oil cooler, Ron. My Ruggerini has a finned oil pan. I've also seen the same on Onan gas engines. In fact the 20hp Onan gas twin in my lawn mower ran about 250degree F oil temp before I put an oil cooler on it...now it mostly stays under 200. That model of Onan had a bad reputation for poor longevity, but I know that they would have lasted much longer if the oil didn't run so hot.

A finned aluminum heat sink could be glued to the bottom of the oil pan to help, Mouse. Around here such things are not hard to come by, but I don't know about where you are.

Phil

[andrewaust]

The engine was designed for "forced air" cooling, it's like getting an air cooled aircraft Lycoming or Continental engine, pulling the prop and air ducting and running it with limited air flow - it won't last long. The way you might get around heat seizing the engine would be some kind of shrouding/ducting to scoop air across the cylinders.

Run a google search for heat seized engines and look at the kind of damage, you'll notice a similar pattern.

Get rid of the Old filter from obstructing the offending cylinder and run some kind of ducting on the cylinders, the best bet would be running a blower fan but in this case it wouldn't fit by the looks of it.

An oil cooler is good security but it won't stop heat seizures.

Drastically increasing the engine fin size is another way, it increases the surface area to radiate the heat away from the head and cylinder.



A

[Anorak_ian]

A push over finned alloy cover for the cartridge was available on ebay, no where near as good as a real cooler though (I can't find one on eBay at the moment).

Here's an adaptor for cartridges, a take off and return point for the cooler.

Adapter. http://cgi.ebay.co.uk/CHROME-HARLEY-OIL ... 1c11872239

I noticed that Stuarts bike has an oil cooler that uses the air from the engines fan. A cool idea.

[Sphere]

I understand that an oil cooler may help to keep the temperature of the oil down, but it wont help much in places where little oil goes... e.g. in the cylinder?

[Anorak_ian]

Yes I have been thinking on that one.

There's a dirty great fan on the side of the engine, blowing a hell of a lot of air on to the side of the alloy engine case, what’s on the other side of the alloy, oil.

As far as over heating top end, I have come up with something I think may well be a good idea, all be it in a small way.
Remember the old Triton cafe racers? Often between the Amal carbs and the cylinder head was a finned alloy extension tube, they still make them, and on sale on eBay.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT
Here's the idea, get them to make a blank (no holes) drill a small hole through the middle (where the air was intended to go), use thermal grease, and bolt one on each flat side of the cylinder head (my heads have unused threaded holes on the sides).
They will stick out from the heads about 1.1/2 - 2 inch. The air will flow up the diamond until it gets to the top and bottom edges, and then cause a swirl of air around the back, dragging the heat with it.

I guess you could use anything like this to do the job; a timing cover off an Enfield bullet has fins etc.

I've got a bit paranoid about over heating now, although with an un gloved hand I can grip my bikes down pipe after 45 miles, it's still in the fore front of my mind when riding.

[albertaphil]

The thing about keeping the oil cool is this: oil that is too hot does not lubricate well=seizure of parts...particularly those that don't get much oil i.e. pistons. The life of oil drops exponentially as the temperature rises above 220 degrees F or thereabouts.

Phil

[zarquon]

Today I realised some new informations about this V2-Diesel Engine.
Thanks to the user "WingLight" of my site. He told my that these engines from Cunewalde in GDR were only licensed builds. Originaly they was build and developed by a company in Vienna, Austria, named "Warchalowski" and used in tractors.
Use this name for a google Search, or drop it on YouTube you'll gonna find some nice stuff.

Like this little Vid from a running V2-Diesel: http://www.youtube.com/watch?v=Ga7BLJRMh4w

For those who understand german, there is entry on wikipedia about "Warchalowski", no english Version, sorry:
http://de.wikipedia.org/wiki/Warchalows ... steller%29



Maybe this helps to find some parts or needed informations. Hope so!

Rafael
http://www.dieselkrad.info

[coachgeo]

...For those who understand german, there is entry on wikipedia about "Warchalowski", no english Version, sorry:
http://de.wikipedia.org/wiki/Warchalows ... steller%29...

Google German to English Translation

[Mouse]

The overheating on one side was tracked down to a little valve thing bit that opened when the decompressor was operated that dropped a drop of oil into the inlet manifold. The 35 year old rubber had gone hard and as a result it was continuously dribbling sump oil into the intake and over fuelling the engine which I've learned is a very very bad thing for a diesel engine. It was a simple fix that took 10 mins but I think the damage had already been done by this point. This would also explain why it was so hyper sensitive to crank breathing / pressure and I had resorted to having a rag stretched over the oil filler to stop it smoking badly. After this the cylinder head temperature dropped and both were between 120°C and 145°c depending on the conditions and it even sounded like it was running a lot better, it was certainly more responsive.

Prior to the last and final fail I had got it working very well. It was starting straight off the button and running well and for a brief moment I had it at the staggering speed of a mile a minute. The last outing was in idyllic late afternoon summer sun and warmth through some country roads and then over the old Severn bridge to Bristol which including a few stops to check temperatures took about an hour. I thoroughly enjoyed it and the bike was running well and was everything I dreamt it would be.

The engine then died again when I tried to start it to return home. No compression which could have been something simple but as I couldn't start it the recovery bloke came and took me home. When I took the head and barrel off of it the piston skirt was cracked and I gave up looking for further faults. Spares are hard to get and very very expensive. So that's the end of the line for that particular engine and indeed the whole project.

I never got to the bottom of why the valve clearances keep closing up which is also worrying me so I've now given up hope on the whole engine as a badun.

RIP the V Twin Diesel Project.

[Anorak_ian]

I'm so sorry to here of your bad luck.

Don't give up on diesels though; every time I improve mine, and go a bit faster it gives me a big smile. It's just getting the right engine.

[Dan J]

Such a shame after all that sorry to hear it hasn't worked out this time. What about keeping an eye out for one of these kind of engines http://www.alibaba.com/product/hk101132 ... etail.html aka the kind of v-twin air cooled engine like Whiskers has used in his bike?

I hope the BM will live again, just sadly not with this engine - good luck with whatever you do with it...

[Sphere]

Indeed Dan. Someone should start selling these on Ebay, straight from China.

[Crazymanneil]

That sucks. I was impressed by your build and resourcefulness. It was also a very interesting engine! As others said, hopefully you'll have luck with diesels (or whatever you choose) in the future.

Neil

[IgorVigor]

keep the engine (if you have room)...

you never know on your travels, you might find another one cheap, or spares for it...

good luck with the project though...

[pietenpol2002]

interesting that a Canadian build turns up using what appears to be the East German V-twin.

http://www.youtube.com/watch?v=fRFVZnrf ... re=related

http://www.youtube.com/user/miskealp1#p ... aIndRZ8KqY

[Mouse]

interesting that a Canadian build turns up using what appears to be the East German V-twin.

Yep thats the same engine.
Looks like the starting battery is separate to the bike.
From the sound of its response to the throttle it still has the full weight flywheel on it.


PS I've found some non collectors item applications the engine went into so there's now the chance of some cheaper parts.