M8 Greyhound help

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WillWagner

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Does anybody out there have an oil pump out of the Hercules JXD out of a greyhound? The M8 at the museum has had a hard start condition since the last time it was parked. I dropped the oil pan today and found the whole inside of the engine dry. The oil pump is really funny it has 3 inlets on it. This engine came out of a Searchlight, I don't know what the oil pump looks like in the Searchlight but this pan is a lot bigger. The books I have for the Scout car that uses the same engine shows a different oil pump. So if anybody has a picture of one, has one that can take a picture of or has a rebuild manual for the JXD that shows a picture of the oil pump, it would be greatly appreciated
 
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dgrev

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You need the special Greyhound version of the oil pump. Try Brent Mullins, but be warned, the one he sold me had been dropped and teeth were chipped off the drive cog. I didn't find that out until I de-cosmolined it.

Does anybody out there have an oil pump out of the Hercules JXD out of a greyhound? The M8 at the museum has had a hard start condition since the last time it was parked. I dropped the oil pan today and found the whole inside of the engine dry. The oil pump is really funny it has 3 inlets on it. This engine came out of a Searchlight, I don't know what the oil pump looks like in the Searchlight but this pan is a lot bigger. The books I have for the Scout car that uses the same engine shows a different oil pump. So if anybody has a picture of one, has one that can take a picture of or has a rebuild manual for the JXD that shows a picture of the oil pump, it would be greatly appreciated
 

CMPPhil

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Hi

Just out curiosity have you checked if that engine is used in civilian equipment, I'm thinking tractors.

Know that some of the smaller Hercules engine were used in tractors, when looking for parts military application no luck when looking for tractor parts for the same engine they are available. Just a thought.

Cheers Phil
 

dgrev

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Phil

He needs the correct pump for the Greyhound. It was unique to that vehicle.

Regards
Doug

Hi

Just out curiosity have you checked if that engine is used in civilian equipment, I'm thinking tractors.

Know that some of the smaller Hercules engine were used in tractors, when looking for parts military application no luck when looking for tractor parts for the same engine they are available. Just a thought.

Cheers Phil
 

WillWagner

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1565791872167860103959.jpg1565791858065926818561.jpg15657918339101964226454.jpg

This is what I have, the big ugly monstrosity with the two pickups coming off of it is the one that came out of it. The rusty one is one that came out of an industrial engine in a Searchlight generator. So I'm not understanding the multiple pickups. We do not have a manual for it at the Museum so I'm looking for advice.
 

WillWagner

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Okay, today is my Friday, so I did some searching in the libraries here at the Museum. I actually found two books for the M8 and M20. Turns out the oil pump is correct. Still not getting multiple pickup points, but found that it was missing some pieces inside namely, the two seals for the pickup that goes into the strainer and the one that goes on to the windage tray in the pan and it was missing the gasket between the block and lube pump. That is an easy fix.15657957193651260319604.jpg1565795699966207446058.jpg

Seals lettered S and P we're missing when I dropped the pan. The mounting gasket, labeled C, was not there. I think what's happened to this engine is it had a problem with fuel in the oil and ran like that. The amount of gas in oil washed the oil film from all the bearings and then the gas evaporated when it's sat for 10 years. The main that I dropped was not damaged, it has some particles through it, but I believe it is serviceable. This morning Craig ordered a pre Luber from Jegs. I'll be gone next week so it should be here the week after I get back, today I'll work on making a gasket remounting the lube pump and getting some seals made for the pickup tubes and when I come back in 2 weeks we'll pig it to see if we have oil coming out of everything. Hopefully it doesn't need an engine
 
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WillWagner

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Reading is a wonderful thing. As I was going through the Hercules engine rebuild manual I came across the lube system that we have. It's a Scavenging oil system. It all makes sense now!15657966376191634091933.jpg
 

WillWagner

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Today, I re installed the main I removed, with the shims, the book I found indeed mentioned shims, measuring end play and rotation force. Since the rotation force cannot be measured as is, I just put the shims back into their original spots, kind of funky to me, .010 on one side and. 015 on the other side. The upper had no protrusion and the lower did have .020 on one side if I pushed the bearing shell flush with the tab side of the bearing/cap. Made a gasket for the lube pump mount and the actual suction tube, checked end play again after installing the lube pump mounts that are the main bearing cap bolts. Still have the same end play and it feels like it turns a bit better with oil actually on the bearing. Looked on McMaster and found some felt for the joints of the scavenger discharge and the main pick up at the screen.

I will update this in a couple of weeks when I get back from "vacation". :p

http://www.parks.ca.gov/?page_id=601
 

cucvmule

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Perfectly normal to have different shims or bearings to get best clearances. On any equipment that will see severe angles while in operation will have several pickup points to keep oil at the pickup. Also later on baffles or directional oil pan doorways are used to keep oil going to the pump also.

Motorsports engines use the same type systems, and even today ordinary production cars and trucks are also.
 

WillWagner

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It is basically 2 separate pumps. The main P/U in the sump pulls the lube oil and supplies the engine oil pressure. The scavenging system, when in high angular operation, pulls the oil from what is the front, but would be the rear of the vehicle and discharges it into the sump. The scavenging part is what had me going because it was unknown to me at first what it was. After boning up, it is clear as day how it works. I THOUGHT the pump pulled from all 3 ports and was unable to reason WHY/HOW it work like that because all that would happen would be that the pump would only pull air. I know the engine had OP, I dove it 15 or so years ago after getting it running, and stopping.

As for the shims, the parts and engine manuals indeed show shims on both rods and mains, but, it calls for 2, .003 in shims per side. The shims are hand made on this engine, .010 on one side, .015 on the other. I put it back together using the shims that came out of it and but them back in the same spot. It has end play, so I am not worried about that part. I know babbit bearing engines needed shims, I had never seen shims used on a modern tabbed type bearing, but, since this was made in the 40's, maybe it is a transition thing?
 

NDT

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Yes, the Hercules engines are 1920’s designs, and precision bearing halves were not yet invented. Rebuilding a Hercules engine, specifically setting up the crankshaft clearances, is an all day thing using trial and error with shims and lots of plastigauge.
 

WillWagner

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Here's a little update. The pig system came in a couple of days after it was ordered.

This, but not a Melling, https://www.jegs.com/p/Melling/Melling-Pre-Lube-Engine-Oiler/1398393/10002/-1

I pulled the oil filter can. Funny thing, the filtration is a scavenging or bypass type, meaning it pulls oil from an oil rifle and dumps back to the sump. There were no holes in the center pipe for the oil to be returned to the sump, so, this has had no filtration.

I verified the passages in the filter head, center was return to sump and outer was supply from the rifle. I used a greased tap and tapped the inlet hole to 1/8 pipe and installed the luber into that port, dropped the pan, pulled the plugs and oiled the cylinders. I also installed a gauge in line with the OP sender. Filled and pressurized the luber. Opened the valve quickly, nothing, opened again, pressure on the gauge. I rolled under it and had a volunteer operate the luber, had him open the valve and I watched, after 10 seconds or so, we had oil coming between main and rod journals and bearings! Stopped the luber, installed the starter and cranked the engine with oil pressure on it, it turned MUCH faster and sounded better, the cylinders were actually hissing as the pistons came to TDC compression. We put the plugs back in to see how it cranked with a load and it turned over as I remember it did, those of you that have heard the sound of a Herc in a scout car or half track will know the sound /speed of the engine while cranking. Checked spark, we now have spark too, (it didn't before due to the high amperage during cranking, it took 400 amps to turn before, less than 100 now)!
With that done, we have no pan set yet, it is on the way, I moved on to the carb. As suspected, nasty in there. It was not drained when it was parked. The vehicle has an electric pump on it, but it is wired directly to the ign switch, I will do to this as I have done to all the other things with electric pumps, wire the pump through a switch so that when it is time to park it, the pump can be turned off and let the engine run out of gas, hopefully this will stop having to clean carbs as frequently. Parts are getting hard to find for all these old things.

Got it pulled apart, Evap-o-Rust to the rescue again! I put that stuff in an ultrasonic cleaner and cleaned the carb and parts in it. 480 seconds in the heated solution and the cast iron of the Zenith 29 was clean bare cast iron! Cleaned out all the passages and gave the body a good painting. Brent Mullins has major rebuild kits for the Zenith 29 M8 version, so I called him and have one on the way. Hopefully, next work day, we will have a running M8 again! Then I can start on the stopping part. Hope it is just a no fluid issue, We did the complete brake system a while back, well, probably 15 years ago, i'm getting old, seems like a year ago. Pics to follow.
 

WillWagner

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It has been a productive couple of week at the Museum. No pics before of the crankcase in a dry condition, but here are some of it after using the pre lube system.

The "washers" are the felts that go on the pick up tube/screen filter and the scavenging pump discharge on the windage tray. The pan is back up using a new pan set, had to trim the buttress gasket and piece it in because the flywheel housing is on and the engine is still in chassis. The front seal band at the front seal was still soft, so that stayed, wasn't about to remove the front cover to replace it. The pan set did not come with a gasket for the screen filter, so I made that and the drain plugs had no seal washers on them, Mc Master has them so we ordered a package from them.
 

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WillWagner

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After the pan was back up, the engine spinning freely and spark again...amazing that, when it takes 400 amps to spin an engine, you can loose spark!....on to the carb issues. The vehicle has an electric fuel pump on it, but we think it was putting out too much pressure, so a 1.5 to 4 was installed and wired to a switch so the pump can be turned off and the carb run out of fuel so the nasty yellow mold doesn't happen again. When I took the carb apart and inspected things, the needle was worn badly. Between the fuel pump and the worn needle, I think the root cause of the gas in the oil which led to the engine issue has been found and repaired.

I found a carb kit, BIG thanks to Brent Mullins for getting it out to us. A nos unit. In the pic, notice the rust hole in the small bag. That is from a lock washer in the kit that rusted. The rust ate through the bag and a part of the top cover gasket, but it was in a spot that just joins the outer cover to the air bleeds, no sealing in the area of the damage.

It helps to have the correct books when working on this stuff and the proper tools!

You can just mak out the packing date, May 1951 and it is a Ford part!
 

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WillWagner

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Since the packing date was way before I was born and 2 years after my father was born, I wasn't surprised to find the gaskets hard as nails, that is an easy fix and I could have made new gaskets if they were destroyed, so they were re hydrated in boiling water. This will make the gasket pliable and regain it's original size. The only gasket I was worried about having to make was the the one between the bowl and venturi. All of the gaskets came back to life.
 

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WillWagner

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Rebuilding the carb, again, nice to have the proper tools and books. After the carb was installed, I put new oil and filter in the engine, had to re mark the stick, it was marked 3 qts too low. The engine fired with little cranking....would have lit faster if I remembered to take the cap off of the exh pipe! Good oil pressure, pegged a 40 psi gauge when cold and hot idle held steady at 16 psi. I have a video of it running, just need to put it on my YouTube channel.

The gasket I was not looking forward to making is the white, square one with all the little holes in it!
 

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WillWagner

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Last of them....The floats needed adjustment, the book had a picture of the tool used to bend/adjust the floats, it wasn't in the kit, so I made one. Now, onto the clutch and brakes. Thankfully the throttle has been converted form hydraulic to a Morse cable!
 

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DaninNM

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Have you tried Rod Shaver (Scout Car Rod) in Phoenix.....he's not only a wealth of knowledge but he has a lot of parts for scout cars....602-421-0858
 
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