Head gaskets on air cooled diesels

[hoseguy]

Hi all,

Anyone changed a head gasket on an air cooled diesel?
This one has been blowing gas out of the gasket for a while and just wondered what people have been doing to prepare the top of the cylinder.

It seems to have a lot of carbon build up round the top of the bore and on the surface the gasket sits on.
Whats an acceptable way to get rid of this build up?
Fine emery cloth or solvent and a plastic scraper?

Any other ideas?

Thanks, all

:thumbsup:

 

[Harry in Ky]

Don't know what brand engine you're working on, but I used to do a lot of work on Deutz 912 and 913 series. They are prone to gasket failure if over heated. First one to go is #2 cyl. the second from the flywheel. The head is aluminum so it burns across first. My technique is to remove both adjoining heads to provide room to work. Then take a dab of valve lapping compound on a finger tip, spread a thin film on the top surface of the barrel, set the head on it, press down a bit and rotate back and forth for a minute or so. Wipe the film off the head surface and examine the burnt spot. Use the entire gasket surface to keep things even. Repeat the process until the dark spot disappears and it looks like a flat true surface again. Takes a while if the engine has been run on a bad gasket for very long, but it does work, and can save a head or machine work if done properly.

 

[hoseguy]

Hi there.
Thanks for that.
You've certainly jogged my memory enough to start the wheels turning in the grey matter.
I lent a hand to a buddy of mine back in the day doing the 'fire rings' on a Deutz engine in a Liebherr excavator and I do now vaguely remember lapping the head now that you mention it.
I do remember the springs that held the pushrod tubes in. Needed a few goes at that IIRC.
Now I remember cleaning the threads in the crankcase for the head studs and the many stages of torquing down the heads (1 torque setting and 3 seperate degree stages. Is that correct?)

The engine I have is a Lombardini 833. 3cyl, 2474cc, 50hp. It is attached to a Valpadana 6055 4wd orchard tractor. Apparently this is the old version of the 5LD825-3 engine still available new. There are 2, 3 and 4 cylinder models and even a turbocharged 3 cylinder (60hp) version (5LD825-3T)
It doesn't seem to be as sophisticated as the Deutz (is sophisticated the right word? maybe refined) but considering the apparent dire state that it is in it seems a miracle that it actually ran at all.
It was smoking terribly (all 3 colours) and appeared to be leaking oil but this turned out to be the gaskets blowing on all 3 cylinders.
I've just been out to have a look at the barrels and they are really shiny so I am going to do as you describe and refit the heads with new pushrod tube seals and run it for a while and see what happens.
If it runs ok (ie if I can see through the clouds of smoke or not) I will then know that it needs the bores done (or the valves) then i can save up to get the barrels re-bored with new pistons and recondition everything else.

It seems that it is a good strong little motor and I really like the simplicity of the whole thing and with parts still available I would like to keep this running as long as possible.
So far it has been super easy to work on. Only needed 4 spanners and an allen key to strip it down. No special tools required.
Everything is quite modular and solidly built and nothing there but what needs to be.
As a hobby engine I think this is perfect for me as it is still very basic to repair but also has a bit of power to it. The injector pump is the plunger type so it couldn't be easier.
It has a decent hydraulic pump on it so splitting logs will be a breeze once it is up and running again.

Any other fans of air-coolers out there?
I did enjoy running the 6cyl Deutz engines.
It's a good sound!

Thanks again Harry in Ky :drink:

:thumbsup:

 

[Harry in Ky]

Does your engine have exposed springloaded pushrod tubes like the Deutz? If so,there is a a tool for installing them on the Deutz. I still have one, it's a U shaped piece of flat strap with a half moon on each leg. The half moons fit over the pushrod tube from the side, and you fit one leg under one end of the spring, wind the spring until it compresses enough to fit under both legs of the tool. Slip the tube into place and pull the tool off. Works slick.

 

[hoseguy]

Hi there,
Actually, they're not spring loaded which I was a little dissapointed at but I believe the later model did have them sprung and I'm not yet sure if they are able to be retrofitted or not.

Presumably the spring tension helps keep the oil in a bit, does it?

May be a worthy addition.

i remember the spring tool for the Deutz. Took a lot of swearing and head scratching to get the springs in the tool but once we'd figured out the threading motion it was much easier. :laughing:

:thumbsup:

 

[hoseguy]

Afternoon all.

Just pulled one of the barrels off this engine to reveal a cracked piston

Guess it's been blowing for a good while then :smiley_aafz:

 

[Harry in Ky]

Just curious, does your engine have shims under the barrels with which to adjust the piston to cylinder head clearance?

 

[huskerhayman]

Hi all,


This one has been blowing gas out of the gasket for a while and just wondered what people have been doing to prepare the top of the cylinder.



:thumbsup:

I don't know much about air cooled diesels but I do know if it is blowing out gas you got real problems.

 

[hoseguy]

Blowing out gas by itself isn't really a problem other than the mess half burnt diesel makes.
It's the damage that occurs incidentally that is the worry (cracked/burned pistons etc) which is why a dodgy head gasket needs to be addressed fairly smartly, especially with water cooled engines.
Luckily I don't need to worry about water damage other than what blows in with the latest chilly Sou' Wester (no shed. all done out of doors)

Need the tractor running to collect the material to buildl a shed :confused2:

:thumbsup:

 

[hoseguy]

Just curious, does your engine have shims under the barrels with which to adjust the piston to cylinder head clearance?

Yes it does.

I think that the original problem with this tractor is that it has not had the fins and airways cleaned out and it has overheated thus blowing the gaskets and has been run for some time after this.
I have also noticed a valve mark on the top of the cracked piston (exhaust) so I need to pull this valve and check it out.
i may need more shims under this barrel.
Just need to find out how much a new piston is. :thumbdown:

I've also got them to price a set of oversize pistons /rings and a complete new Barrel/piston/ring assembly too. Will just need to make sure I'm sitting down when that quote comes through.

My immediate worry is all the crap that is being blown/dropped into the crankcase by the aforementioned south Westerly.
Looks like I need to drop the sump now too and hope none of that stuff sticks in the crank.
Reckon a diesel or kerosene flush will get rid of it or am i lookin to destroy the bottom end here?

Definately a fun project.....

:thumbsup: