Engine Failure :(

[alexanderfoti]

Hi all

My 178f engine has suffered some damage today.

Pootling along at 40mph, and it started shaking voilently,

It would run, but would stall out without any throttle, I saw no undue smoke or anything like that so I am assuming we have big end failure.

Luckily for me its about get removed for a 186, shame though! I will be tearing it apart to see what has gone on inside!

Alex

[alexanderfoti]

Turns out im a moron and the thing ran out of oil, im convinced this high oil usage (down to below bearings in 150 miles) is due to ring gumming when running on veg oil, will get it apart to check the damage.

[royaldragon]

Let us know what happens with that. I plan to run on veggie as well so more info for the brain is always good.

[coachgeo]

lots has to be known to determine if veg. oil had anything to do with it.

How rings looked prior to veg use.

Compression prior to veg. and while running good on veg.

Was it cold started on veg or on diesel?

Was the engine's IP retimed to match the burn characteristics of veg. or not (often not done) and could well be problem of many veg. failures.

[andrewaust]

You need to modify the top of the piston to run veg or it will gum up, so my gut feeling is yes the veg oil had a significant contribution to kill your engine by gumming up the rings as you said.

Do a web search for modifying direct injected diesels to run veg oil, problem is the top of the piston doesn't run hot enough to burn off the carbon that forms. I don't know if you run veg for a tank then mineral diesel would help, I will never run veg oil, I just run mineral diesel, bio diesel runs clean but keep it in your tank long enough and it goes off.

It would have been nice if these small engines had a pressure switch that let you know when oil pressure drops, I know you can install one yourself, but many overlook it.

I tried to find the pdf file to post, but coming up with everything but the one I want to refer to.



A

[alexanderfoti]

Yeah, I bought the engine second hand so I have no idea of the original condition of any of the parts.

all I know is that it burnt enough oil in 300 miles that it ran dry.

Its a twin tank kit, but I was thinking of fitting a heated filter on the second engine to help prevent this. The new one will also be supercharged, which should push combustion temps up a bit.

We will only see when I dismantle the engine, which is when I can get enough time to remove it.

Also, still trying to figure out how to get access to the fuel screws once the gearbox is attached.

[coachgeo]

You need to modify the top of the piston to run veg or it will gum up, so my gut feeling is yes the veg oil had a significant contribution to kill your engine by gumming up the rings as you said.

Do a web search for modifying direct injected diesels to run veg oil, problem is the top of the piston doesn't run hot enough to burn off the carbon that forms. I don't know if you run veg for a tank then mineral diesel would help, I will never run veg oil, I just run mineral diesel, bio diesel runs clean but keep it in your tank long enough and it goes off.

It would have been nice if these small engines had a pressure switch that let you know when oil pressure drops, I know you can install one yourself, but many overlook it.

I tried to find the pdf file to post, but coming up with everything but the one I want to refer to.



A

Please do search again for the info you found and post up. AlexanderFoti..... if you find it please post it up as well. Sounds interesting
Never seen this info you speak of. Have been reading up on the topic for a good 15+ years.... granted not so much last year or two, BUTTTTTT.... makes perfect since. Elsbett I believe is the orginator of some of the designs that went into direct inject engines. Manufacturer's coppied/stole? his designs from his Multi fuel engines (AKA piston cups) . The cup in the piston acts much like the Swirl Chamber (Pre Chamber) found on Indirect Injection engines. Both are to create a better automization of the fuel.

[oldbmw]

I read somewhere you need to have steel on the upper surface of the piston as this is a poor enough conductor of heat to ensure the piston gets hot enough to burn off the carbon.

[andrewaust]

Your spot on oldbmw, it was made of stainless steel and included a swirl chamber and screwed into the piston.

Cannot locate the pdf , may have been taken off the net.



A