Nincompoop

[CHRISEEBOY]

I have been very foolish and would welcome any feedback on my current situation that has led to my 3Cs engine locking up. If you font have the time to read the context, just skip the middle paragraph.

Rewind the clock a few weeks to get the context:
My exhaust spout was so badly corroded that it eventually gave up the ghost and completely broke off. I set about the fabrication of a new spout to prevent the exhaust gases circulating under the hood and sooting everything up.
I decided to use a nice bit of stainless steel dairy pipe that I had knocking around, it had a thread at one end that I decided (in my infinite wisdom) I would aquire a blanking cap for to prevent water ingress and thus no further rusting of the rest of the old exhaust.
It all worked a treat and I was very pleased with myself until yesterday when I absentmindedly forgot to remove the blanking cap.
The engine fired up as normal and I let it idle for a few minutes as per usual. I then opened up the throttle so I could begin operating the hydraulics but they felt almost unresponsive and very lacklustre. I instantly realised my mistake, throttled down and removed the cap from the exhaust spout. Upon getting back into the cab I eased up the throttle - there was a load pop/bang then the engine kind of ground to halt and conked out.

The oil cap had been blown off and the dipstick was on the floor. There doesn't appear to be any loss of oil. The engine is now locked and won't crank at all.
I would be very interested and grateful to hear peoples thoughts on how I should proceed to "unlock" the engine and if anyone could comment on whether or not I may have caused permanent damage?

[dixie-normous]

Remove the injectors and see if the engine will turn over (by hand if possible) If the build up of pressure blew all the oil up to the head it may have gone from the breather into the air filter and into a cylinder and locked it up, I have seen it happen when water got into an air filter. Another possibility is that if the oil ended up in the head it starved the engine and has done some serious damage, it can happen on older ford 2.-0 car engines when the pcv (positive crankcase breather valve) fails. If it won't turn over with the injectors out i think you may have real problems, although even if it does free off there may still be damage. Hope for your sake i am wrong and someone has a simpler explanation for it!
John

[Jeremy Rowland]

Chris, note to self: either buy a hinged rain cap that automatically opens or crank the end of the pipe so that water cannot run down into the exhaust, it is all too easy to forget and start an engine in similar circumstances. Follow what John has said; I am assuming that there is still plenty of oil on the dipstick? Also check the air-filter just in case oil blew through to that, please keep in mind I don't know what type of air filter is fitted to this machine, oil bath type or paper element type?
Will the engine 'rock' partially by hand in any direction, if so it may just be as John has suggested above and could be hydraulically oil locked in which case you have been lucky and just have the aggro of getting the oil out of each cylinder. Best of luck let us know how you get on.

Jeremy

[CHRISEEBOY]

Thank you both for your time reading and responding to my original post. I certainly won't make this mistake again Jeremy, with out without a hinged rain cap!

I had assumed that it was gas pressure that caused the oil cap to blow off, thinking that the trapped exhaust gases had perhaps escaped via the PCV or past the piston rings once sufficient pressure had built up? The fact that the engine is now locked - I had put that down to unburnt diesel trapped in the cylinders, not oil? Surely if it was oil pressure that had blown the cap off there would have been a lot of oil leave the engine along with the cap?

If I were to take off the rad so I could get to the prop shaft that powers the hydraulic pump I should be able to get a pipe wrench on it. In theory, if I rotate the engine in the opposite direction could I expel whatever is in there through the valves? I dont really want to mess with the injectors because bleeding the fuel system is a nightmare on this machine!

[essexpete]

Massive back pressure past the rings I would guess caused the dipstick and cap to blow off. I am no mechanic but you might see if you can move the engine a small amount if you can get something like a socket extension through the uj on the pump drive. You might get underneath to do this without initially removing the rad.

[dixie-normous]

You are right, they can be a proper pig to bleed! If there is oil in the cylinders you won't get it out through the valves as at least one cylinder will have both valves closed and you can't turn it over to open them. If the engine hydraulic locks with water it will sometimes drain past the rings after a few days but means you have to change the oil, if it locks up with oil in the cylinders it won't drain past the rings as it is too thick. Taking the injectors out or the head off are the only ways, and either way you'll still have to bleed it! Turning it backwards may get some out if you are lucky, but you probably wouldn't get enough out, as soon as you start injecting diesel in you run the risk of it locking up again. By removing the injectors you can get alot out by hand, then spin it on the starter which will blow it out under pressure and clear the cylinders

[CHRISEEBOY]

OK that all makes sense, I feel a lot better about taking the injectors off if I know there is no other way.

Good idea Pete, there are 2 ujs accessible from underneath. I've got a nice big pry bar that should be able to get in there.

[dixie-normous]

Just dont forget there is a copper washer under each injector, and as Jeremy said, make sure the air filter is clear before you start. Good luck!

[gecko.cx]

I'm watching with interest to know what you find.
Essentially, what you have done is no different to operating an exhaust brake, so I wouldn't 'expect' any damage to be done.
Having said that, obviously something is NQR, but I can't think what/how.

[dixie-normous]

Totally agree, aside from oil getting in to a cylinder and hydraulic locking it I can't think of what else it could be, if that is the case then it could have bent a conrod. I have seen a fordson major that was started with an air filter full of water and that blew the side out of the head gasket. As you say, it's just created an exhaust brake so in theory shouldn't have caused damage, the first JCB to have a jake brake!