Differential Lube?

[The Piddler]

Sounds good, thanks.

Question about the u-joints... All of the joints on this rig have the tamp in type zerk fittings, is that correct? The joints appear to have been changed, so I don't know if the fittings are correct or not. If so, is the needle fitting used to depress the check ball in the head of the zerk to get the grease in there? I'm fighting through it this evening, but I was curious what others have.

[The Piddler]

Disregard the last... I just re-read Rick's post about the zerks, and I have it now.

Sorry for missing it before

[ODRotorHead]

If you're just getting started and you're partial to Lincoln, and need a variety of adapters, this might be a more economical approach long term:

Lincoln 58000 Adapter Kit.jpg

You may be able to find it at a lower price locally, or from a different supplier. Two Lincoln quick change adapters can cost almost as much as the entire kit.

If you don't need that level of quality or variety, you can find individual no-name adapters for a fraction of the cost and they probably work just as well.

[The Piddler]

Thanks to everyone for all of the help and feedback. I ended up finding my small grease gun and put he Lincoln tip on it. It looks just like the rig that Raymond posted a picture of, and it worked perfectly.

I have realized that changing and topping off the fluids in this rig has been a great way to find leaks. I have a front diff seal that seems to have leaked out more gear oil than I put into it when I changed it.

My saga continued from there with initial inspections and base tune up, but I kept running into a stumble/miss that I couldn't quite nail down. I reached out to Rick via PM, and he has helped me immensely with making sure that I was checking the right things. Long story short, I had a bad head gasket.

Someone down the road may find some of this info helpful, so here is what I found:

Compression check (dry) showed #1-114 / #2-114 / #3-120 / #4-107

I think the coolant in #4 helped seal the rings, which is why I had a number like that in the first place... I dunno

Bore scope pic of #4 cylinder:

20240606165126109.jpg

Opened Up:

20240608_185024.jpg

20240608_190921.jpg

I have already run the tap through all of the holes (brand new 7/16-14 bottom tap w/tapping fluid), and I was surprised to find out that all of the holes were tapped to the same depth with no issues. The eight holes that are tapped straight down allowed the head bolt to turn approximately 10 5/8 turns from the point where the threads first engaged, and the two holes with the dowels in them allow the bolt to turn approx 10 5/8 turns until the shank of the bolt binds. The tap went down in all holes until there was approximately 2 1/2 threads of the tap still visible, but that is more than enough for all of the threads of the bolt to be engaged into the head.

20240608_193545.jpg

From looking everything over, it appears to be a simple leak from the coolant port in the head into the chamber of #4 cylinder. I don't think it was much because I never had the white smoke in the exhaust, but it was enough to quench combustion in that cylinder.

20240608_191104.jpg

So I am now waiting for the gasket kit, and while waiting, I will be dropping all of the valves out to see if I need to get a valve job done while everything is apart, or if they just need cleaned up and hand lapped.

If I should start a new thread with this stuff, please let me know. Being new to the group I'm not sure of all of the rules yet, and just wanted to share what I found.

[rickf]

You might want to start a thread on engine repairs, or head gasket replacement. That way people in the future will be directed to that thread when looking for that subject.

As far as the head gasket, I am not convinced it was leaking from looking at the pics. Do you still have the gasket? A pic of that on both side would be helpful. A coolant leak into the cylinder will cause overheating and tend to blow past the radiator cap from the combustion presser in the coolant. I am thinking more along the lines of a worn out valve seal and possible a worn valve guide. While you have the head sitting just like it is in that pic angle it a little towards that cylinder and dump some gasoline into the manifold so it fills that port. Let it set for a while and see if gas comes past the valve. If it starts leaking out in minutes then you have a leaky valve that will need attention. If you only get a damp spot in a half hour they valve seating is good but the valve seals are most likely shot just from age. It can't hurt to pull them out and seat them in but do this first to see if it is leaking. You can do the same with the intake but you will probably have to use a lot more gas since you will no be able to get it into that one cylinder.

[The Piddler]

Correction: The bolts in the non-dowel holes will turn down 13 5/8 turns from initial engagement, doweled holes are 10 5/8

Pictures of head gasket:

Block side face

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Head side face

20240608_185831.jpg

I will be doing the fuel leak down trial this afternoon at some point. That is another good tip.

[rickf]

That head gasket does not appear to be blown. There is no evidence of combustion gases going past the fire ring. It does look like you had a substantial oil leak from the valve cover on that rear corner. I know you were looking for a quick and easy fix but I do not think this is going to be it. And if you were getting antifreeze into the cylinder the top of the piston would be water blasted perfectly clean and the head would not be covered with oil. I think you need to check that intake valve for side play when you take the spring off and I am sure you will find the valve seals are hard as a rock, If they are even still there. One thing that bothers me is it looks like there was a lot of heat around that cooling passage, which is right next to the exhaust valve, check to make sure this block is not plugged up with rust. This was a common problem with these and the M-37's.

[The Piddler]

Dropped the valves and found a couple of interesting things. It appears the head has been worked on before, because the seals were like new. All 4 were soft, rolled easily, and went back to shape when released. There is small mount of side play in the guides, but it didn't seem excessive. The #2 and #3 intake valves weren't seating properly by looking at the wear pattern on the seats, yet both valves for #4 had good seating patterns.

The gas test did show some leakage through the intake valve guide on #4 (drop every 5-7 seconds) but almost none through the valve seat.

I will be taking pictures of everything, and then it's going in to be fixed: hot tanked, inspected, and take care of whatever is needed. I will make sure that I ask about the stem clearance in the guides as well, since I have no idea what normal is on something like this. The guy doing the work builds race engines, so I feel comfortable with his opinion on what he finds.

While the head is being done I will make sure to check all of the cooling passes for the rust and blockages, and clean everything out the best I can.

I found most of the bolts for the exhaust manifold barely snugged, and there were no gaskets between the manifold tube and the head... I have to look at the drawings, but I'm pretty sure there should be gaskets in there?

At this point I'm pretty sure that I will be uncovering more "interesting things" on the way to getting this engine straightened out, but it is definitely a good teacher so far!

[rickf]

If it is an early A1 or straight 151 head there is no gasket. The exhaust manifold sits very snug in that recess, the original sealant was Moly grease. Check the torque specs in the -20 manual for that exhaust manifold and you will see the specs are a lot lighter than you would think for a 3/8 bolt. This is to prevent crushing the very thin stainless manifold. But if all of the bolts were just above hand tight then that may have had something to do with your running issue. There was probably a vacuum leak somewhere on the intake manifold since the center section of bolts tightens both the intake and exhaust. As far as exhaust manifold sealant I use Permatex high temp silicone. I also put a thing layer of Permatex #3 on both sides of the intake manifold gasket. On the valve cover I use the #3 but only on the cover side and leave the head side with no sealant. Also be sure the valve cover is seated on the head, there is a double lip on the cover that frequently gets bent from misalignment and then the cover never touches the gasket.

[The Piddler]

I did check the cooling passages for blockages and rust, but they all appeared open and fairly clean. The was one of the smaller holes that looked like it was not completely open due to machining, but the port is open enough to allow for some flow. It was the small hole between to pushrod openings for #2 cylinder.

20240610_151621.jpg

The exhaust manifold design was completely new to me for sure, but the saddle surfaces were still smooth enough to offer a good sealing surface. When the head comes back I will have to drill and tap out one of the exhaust bolts that broke when I was taking things apart.

Rick, it probably is an early head... I found the date 2-20-1967 cast on the underside of the intake manifold, so I will be using the sealing techniques you mentioned for sure after I look into the torque specs.

The guy doing the head said the valves looked a little thin already, so he is going to clean up the valve and seat faces without removing too much material. He also said the guide clearance wasn't terrible, but also said it wouldn't be a 100,000 mile engine either.

I don't plan on any serious mileage in the near future, so getting things cleaned and sealed up to resolve the diveability issues is ok for now.

Do the replacement valves with the + .005" stems work good once the guides are reamed? Seems like will be a good solution for long term reliability if I get everything else straightened out.

[rickf]

It would pay to have him remove the broken bolt since he has the jigs to hold it flush to the drill. If you decide to do the job be aware that the bolts used were most likely stainless steel, that was what was in it new and also in the gasket kits they included new bolts. Stainless steel is a bear to drill!! Be sure to have NEW drill bits and patience. Do not replace with stainless steel bolts!! Go to Tractor supply and get anodized grade 8 3/8" fine thread bolts. I say fine thread since everything on a military vehicle is fine thread and it has been a while since I did one of those bolts, check thread count before buying. The steel bolts will never break in your lifetime. The stainless bolt threads gall when going in so they are not coming out without a fight. And if they do gall then no amount of lubricant will release them, the threads are shaped like fish hooks and have jammed.

[The Piddler]

It's been a while, but a whirl-wind of life has happened in the last couple of months. Anyway, the source of my troubles ended up being one of the chinese coils that the previous owner had installed. With the new coil, all the previous work I had done finally panned out. The head work and new gaskets may not have been the culprit as Rick had said, but the engine now has steady compression of 110 to 112 psi compression across the cylinders. I haven't had much wheel time with it, but she starts and runs like she's supposed to. One of the things that irritated me was the price and availabilty of plugs and wires, so I did some shade-tree engineering that worked out fairly well. I used the Champion J8's and scavenged an old wire set from my brother to adapt the donor plug wires to the original distributor cap. I will eventually buy a new set of wires and clean up the install, but just having it running correctly is as far as I have gotten so far. Thanks for everyone's help and advice, it all came in handy.

20240704_203033.jpg

[steveo]

Been followin your thread.

Looks like your gettin-r done and an interesting fix on the wires. Hope it works great for ya.


Steveo

[The Piddler]

The wire project was born out of frustration. I was going in circles trying to figure out what was causing the constant stumble I was having, and even after the head work, carb work, and multiple passes of setting timing and idle, it still wouldn't accelerate with out puking and coughing. After getting the wire mod done, only the swiss controls and the coil were left on the table. So I ordered both. Since the coil was the easiest to swap, I dropped a new surplus coil in it, and that did the trick. It starts and runs like it's supposed to, and I now have some known good spares parts in case I need them. It still needs a lot of TLC, but with winter coming, I'm afraid it will have to wait.

[rickf]

Glad to see you got it going. This is why I prefer a full diagnosis before shooting the parts cannon. Parts for these used to be cheap but not anymore. 50.00 for a stock spark plug if you can even find them!!!! Nothing but Chinese parts for all of the electronics. Last time I checked a full set of plug wires was 150.00 plus. 90% of all problems can be found by following the proper testing procedure IN THE PROPER ORDER. I highlighted that last part because I see so many people jump around trying the latest thing they were told on the net. This can lead to false diagnosis and also false repairs where a new part covers the real problem and it eventually fails. When I am helping someone with a problem I tell them they have to do what I ask in the order I ask for it to be done. If they jump to something else I tell them I am sorry but I can't help if you will not follow the procedure. I have been doing this for 55 years and I have found out the hard way about jumping around. And when I had my business I had to make sure I had it right before replacing parts, if those parts did not work then anything else was on my dime.