4A084 compression test

[cranetruck]

Eric, having the engine on a table is really nice, it only weighs about 225 lb without the muffler, cowling and intake/exhaust manufolds.
As you can see from the pictures above, replacing the rings is no big deal either.
Doing the compression test was a wake-up call, it explains a lot...

 

[cbvet]

As I mentioned in an earlier post, it's just too hard on my back trying to work on that engine while it's in the shelter trailer.
Looks like I should just pull the whole thing & put it on a work bench. I'd be much better off.
Good idea.
Thanks!

 

[cranetruck]

Simply pulling the engine and working on it while on a bench may not be so easy after all. The motor and generator head are bolted together and the two supported by three bolts, two at the generator end and one at the engine. There is only a rubber bumper below the center and the coupling is safety wired so I rather keep it together at this time.
I'll be working on the 084 as it sits, lifting it enough only to remove the exhaust manifold...

 

[cranetruck]

Images show the exhaust manifold and the oil pan shroud removed.

 

[cbvet]

I see what you mean, Bjorn.
In my chemical shelter trailer, the generator & Paxton blower are belt-driven, so removing the engine only shouldn't be a big deal.

 

[liftman]

I also had a valve seat come out of the head when I was first trying to get the engine to run. I blamed myself for trying starting fluid. I guess the self removal of the valve seat by the engine is more common than I thought.

As far as removing the head with the jug, I didn't have to do that. But you are replacing ringgs as well, so it all had to come off anyway. It has been quite a while since I did this, but I remember rocking the head around with a couple of small pry bars to loosen it before pulling it off the studs after soaking with penetrant. There is no head gasket to the best of my recollection.

It should go back together fairly easily if you have the ring compressor that comes apart and looks like a pair of pliers.

 

[cranetruck]

I also had a valve seat come out of the head when I was first trying to get the engine to run. I blamed myself for trying starting fluid. I guess the self removal of the valve seat by the engine is more common than I thought.

As far as removing the head with the jug, I didn't have to do that. But you are replacing rings as well, so it all had to come off anyway. It has been quite a while since I did this, but I remember rocking the head around with a couple of small pry bars to loosen it before pulling it off the studs after soaking with penetrant. There is no head gasket to the best of my recollection.

It should go back together fairly easily if you have the ring compressor that comes apart and looks like a pair of pliers.

I'll be using one of the cylinder heads ("jugs" as airboat people call them) from my replacement engine to replace the one with the loose valve seat.
So you think starting fluid could have been the cause? In that case I'm guilty as sin and that's why I want the compression back up, so it'll start right away.

Need to find a good valve spring compressor too, it's kind of a tight space for the one I have.
Do you have a picture of your ring compressor?

 

[liftman]

Jug (cylinder) is the term from my air cooled VW days. As far as the starting fluid goes, now that you say you use it, there probably is an issue with the interference fit of the seat in the head. More than likely doesn't mean anything as long as starting fluid is not used.

My ring compressor is a KD model 1114. The photo shows it.

 

[cranetruck]

Thanks, also, my valve spring compressor is marginal, do you have any recommendations for the 4a084, where there is little room to spare?

The loose valve seat is on the engine from the metal recycler and its history is unknown. They hauled off the trailer it was on the other day and I'm glad that they let me buy/save the engine.

 

[cranetruck]

I see what you mean, Bjorn.
In my chemical shelter trailer, the generator & Paxton blower are belt-driven, so removing the engine only shouldn't be a big deal.

The engine I bought from the metal recycler here, was on an M68 trailer, possibly like yours. It was easy for two of us to remove...no pictures though...TM 3-4240-264-20P

 

[liftman]

I don't have a c-frame valve spring compressor. I dug through the garage to find the old, damaged cylinder head from the engine. My spring compressor is shown in the photo. It seems that it would work, although it might be a bit slow. There are only eight springs to remove and replace on both heads if you are also doing a valve job, so it shouldn't be too bad. It is also a KD tool, no. 2078.

There is also one photo of the loose valve seat in the head.

 

[cranetruck]

Thanks liftman,
I improvised and made a "spring compressor" from a piece of angle iron (the rocker arm "pin" comes from a damaged cylinder).
This works for me since I only needed access to the head bolt.

I couldn't find a reasonably priced ring compressor, so the larger (longer) one I already had was used to install the piston into the cylinder removed from the engine. The whole assembly was installed as a unit by fitting the connecting rod pin only. All in all it worked well and I should be ready to reassemble the engine soon.

 

[liftman]

Pushing the piston with the new rings through the barrel before connecting it to the rod was going to be my next suggestion, but you thought of it first! You had to take the piston off the rod to install the new rings, so why spend the extra cash for a ring compressor you will probably only use once?

That's is one nice thing about floating wrist pins held in by circlips.

Did you need to remove the spring for access to the head bolt? I didn't have to do that when I took mine apart.

Looking good, should run really well.....

 

[cranetruck]

Got the engine put back together a couple of days ago and it now starts and runs beautifully. I did replace the fuel pump (used the one from the spare engine) and cleaned the carb one more time as well as getting a missing clip for the automatic choke from that spare engine.
Fuel consumption is also down, running at 3/4 to 1 gph with no load.
Still have a problem with the generator, don't know if the replacement power transistor I bought on ebay is any good, so the regulator needs a little work.

Since the NiCd battery pack is located near, I decided to eliminate the lead-acids and the genset now starts off the NiCads after a simple connection directly to the 04a084 starter motor.