Removing the Motor...

[firenut]

So reality has struck and i cannot free pistons #3 & #5 in my 707 motor.. I have decided to remove the motor for a complete overhaul.. Some folks in another forum said that the machine shop can boil the block to remove the stuck pistons... I guess we will see... Any suggestions on how best to remove the motor.? I am guessing that the trans and motor will come out together??

[theakerstwo]

Get on a creeper and go under it.You will find the rear mounts will be on the trans so the trans can stay in the frame

[Brocky]

Strong Arms!!!!! Several ways.. stripped that far down a boom jack (engine lift) should pic it, A strong overhead beam and a cumalong or chain hoist, Excavitor or back hoe, Bucket loader, ETC

[Bigdogtrucker]

That sucks it was that bad...Have a source for engine parts?

[Brocky]

Glenn

That would depend on what the sludge inside the tranny looks like??? I would pull the shift tower and look.. It is about six of one and a half dozen of the other which way to bring the tranny out if necessary??? Partly depends on the tools and jacks available..

[jakebrake86]

I've pulled a complete 2 valve 350 and a 2 stick 6 speed together before. Wasn't bad at all. I used a rolling A frame and a heavy duty chain hoist.

[fxfymn]

My vote would be to remove the engine first without the tranny. Unless you have access to a fork lift or very heavy duty floor crane the weight of the block will be everything you want to handle.

I would start looking for another engine right now. Yeah, I know you probably want to keep it original, but the cost of a re-build, if it can be saved, will be way more than a used engine.

[609albert]

I would put a used 237 Mack diesel in it if I was doing it

[Mack458]

I assisted in the removal of my 707C. We used a chain that was bolted to the top of the motor and a forklift. After removing the forward cross brace, the front mounts and transmission were unbolted.

While bring the engine away from the transmission, it swung forward as we had to pull it away from the firewall. I had everything repainted on the front end while the engine was out, and placing it back in was a little harder. Again we used a forklift but the time used chain and blocks so we could lower the rear end in without damaging any of the new paintwork.We never touched the transmission. I am a novice with all of this work and found it a little overwhelming at times. My friend that did the work had no problems. I felt lucky that we pulled the engine because the clutch was very thin and needed replacement. There is a company in Baltimore that I found the clutch plate at that was very reasonable. I wanted to keep the original motor in the truck. It was a very expensive undertaking - probably 6K for the for the machine shop, parts, gaskets. Labor was free. Albert has a good suggestion in going with a 237 if you are open to that. I understand parts are readily available. If you decide to keep the 707, York, Pa. Mack has a great machine shop and the manager, Rick Riddle, has been doing engine work for over 30 years. We had the cylinders bored and sleeved because we could not locate over-sized pistons. Rick was instrumental in finding all of the parts needed for the rebuild. I used Olsons gaskets in Washington state for gaskets. If you have a timetable to get this done, you may want to replace the engine. We ran into problems finding bearings after the crank was polished, and at one point thought all of the work was wasted. In the end though I have a new engine that I am proud of. In the end it's about money, time, and if you want to keep it original. Best of luck in your venture! Mark

[Vladislav]

From the pic you posted I'd say your truck has rear engine mount on the bell housing, not on the tranny.

It's the L-model and it looks almost similar to my WW2 NR model.

If so it's impossible to keep the transmission in its place.

I pulled the engine with the tranny together with a chain hoist. The total weight was about 1600 kg, 1000 for the engine and 600 for the 10 speed duplex tranny.

Not exactly shure about your truck but the manual of mine said to take a cab off or backwards for a bit.

I would say you're going to go the same track.

There was a difficulty to clear up the steering gear when pulling.

I will put it back without the gear box although I'm going to do it before the cab is on.

[firenut]

Thanks everyone for the feedback.. I am thinking that i will go the forklift route and pull the trans and motor as a whole... i am still holding out some hope that I can pull the pistons and free up the two stuck ones without removing the motor. I removed the pan tonight and found that the underside of the motor is is great shape.... next... i'll try the pistons....

[fxfymn]

Try a solution of 90% acetone with 10% ATF in the cylinders. Let it soak as long as you can before you try moving the pistons. The acetone will thin the oil to let it reach into the cylinder and then evaporate away to leave the lubricating oil.

[farmer52]

Good suggestion Carl. Also, after you leave it soak, try "tapping" the top of the piston with a 2x4 and then soak again. This may create a "crack" to allow oil to seep along the rings. Repeat as necessary.

Update: after reading PZ1's post below - perhaps you can rig a press to put pressure on the piston then soak it like Carl's states. Combination of soaking and pressure may break it loose.

[Phase 1]

Make a press to push the piston down. Take a heavy bar, or angle or channel, etc. and drill two holes to run bolts into head bolt holes with washers or spacers for clearance, and use a large threaded rod in the center to push. Those cylinders may be pitted and will need to be bored - if they are not sleeves.

[Gmerrill0516]

Pulled my engine and trans together but I had a good sized modern loader and operator to run it while I guided it all up and out of the hole. I detailed the trans and didn't have to struggle with the trans input shaft allignment while trying to set it back in place. I've got most of an ENF 707C if that helps. It's in Massachusetts. Need pistons and rods but the rest is there and in good shape.

[firenut]

Thanks all, I tried to pull one of the pistons today and the cap bolts (hex) seem stuck... Are they usually that tight??

[Vladislav]

They're pretty tight.

Tighter than main caps. About 200lb-ft if the memory serves.

[Gmerrill0516]

They are tight alright. If they are hex use a six point socket and adequate leverage to start them turning without jerking them. No impact driver or any funny business. Do it slow by hand and you will be all set.

[fxfymn]

I would be leery of putting too much down pressure on the pistons out of concern that I might break the rings or punch a hole in the piston. Worst case scenario is the piston and rod are in a straight line and you are trying to push the crank out of the block.

Be careful if you are going to try to push the non-stuck pistons out of the top of the block as well. If there is a lot of wear a ridge can develop in the cylinder bore at the top of the stroke that can break a ring or even jam the piston. You can use a ridge cutter to remove it, providing you can find one large enough for this engine.