Updated photos

[idiocrates]

If anyone is interested I've added some new pics of my m38a-1 taken while in the "discovery" phase of removing the the tub and preparing the power plant for removal. The photos can be viewed at:

http://www.flickr.com/photos/22032113@N ... 6764/show/

couple of questions......Has anyone ever tried to find a double grooved pulley for their alternator to match the double groove in the water pump and crankshaft? Also, my T-90 transmission has "10-16-53" cast into the case on the drivers side. Is this a casting date or just a coincidence since I believe this to be a 1953 model? In the rear....does the floor panel rest on the machine gun mount or was it supposed to clear the plate? Finally, the two diagonal braces that reinforce the pintal hook mount were apparently cut off to allow the installation of a gas tank. I have no plans to use the pintal mount but did these braces also supoort the rear floor at all or was there a space between them and the floor? Thanks in advance for any and all help provided.

Jim

[Ryan_Miller]

That sounds like a casting date. Sometimes it was a day / month and other times it would not.

For the alternator pulley, are you looking an original style? I think there are some parts suppliers that would have those.

The reinforcing around the pintle was there for a reason.

I am not sure, but I though the A1 machine gun mount plate on the frame came close and touched the rear floor.

[idiocrates]

Were alternators ever "original" on these vehicles? This one has been civilized and all its 24V equipment removed. When they went back with the 12V equipment they installed an alternator that only has a single groove pulley. This meant they were only able to put one v belt on the motor. My only real interest is to get the engine back right and put two belts back where two belts were originally......while probably not to mil spec......simply because of cost. I have since located several sources for both alternators with double groove pulleys and retrofit double groove pulleys for my existing alternator so this issue has been resolved.

As for the rear floor and the gun mount and the pintle hook bracing....my rear floor was so badly collapsed everything under the floor was touching and holding it up. When I go back in with new I was just curious if I was going to need rubber isolators for these points. It'll be a awhile before I get that far along anyway. Monday the machine shop gets the engine and I get to start on the transmission and transfer case.

Jim

[wesk]

1-A couple of military 24 volt alternator systems were used and installed in the field. They are quite expensive today. For a stock M38A1 not running a large set of old 60's vintage radios the original 25 amp 24 volt generator is more than adequate. Any reputable electrical overhaul shop will be able to supply you a double narrow groove pulley in the correct diameter for your set-up.

2-The body mount points used rubber isolators and shims in specific thicknesses. They are all listed in the parts manual. These will insure the tub starts in a position reasonably close to where it needs to be. Final fitting with front sheet metal will usually reguire adding or substracting some thickness here and there. In the end all fenders, hood, grill and tub should line up correctly and steering column, pedals and shifters should all be reasonably centered. The rear edge of the tub is your starting point and if you cannot get it aligned then your tub or frame is twisted or bent. Once the rear edge os aligned you then work on adding and removing to center up close as possible the controls in their openings. Then it's on to adding the front sheet metal and adjusting more. This is a long and tedious task but very rewarding in the end when all lines up. The tub is simple to check for squareness and the frame measurement for alignment check are in the service manual. Do not tighten up any fasteners until all alignment is complete.

3-In an ideal fit the frame machine gun support pad will just touch the floor of the tub or be withing an 1/8" of it. Rubber is not used between it and the tub. If you install a gun pedestal and you are starting with a gap between the plate and the tub then do shim the gap closed with steel plate before bolting in the pedestal.

4-As you can see in your photos the stub of the drawbar angles that remain have the two bolt holes for the tub mounting that align with the holes in the rear floor. These are two of the numbered tub mounting points and get rubber isolators. The rest of the angles that went to the rear crossmember at the pintle mount were only there to provide additional strength to the pintle.

5-Yes the 10-53 is the casting date for the tranny.

6-When taking a classic 58 year old engine to a modern engine shop always be sure to ask some questions:

A-How many of these classic Willys engines has your shop overhauled?
B-Can you give me the names and phone numbers of several satisfied customers?
C-Show me the manuals you have that cover this make/model engine.
D-Will you test run this engine before I pick it up? If not shall I deliver my rolling frame to you so you can mount and test run the engine?

Be sure to have a written agreement and estimate for desired work. Now-a-days the handshake and smile are the trademark of politicians and attorneys.

7-Be sure to use these web sites for your tranny and transfer rebuilds:
http://www.willystech.com/wt/T90Rebuild ... ebuild.htm
http://www.willystech.com/wt/Model18TCa ... rCase.html











Frame alignment check is done as follows:







The instructions and drawings for the 100 amp alternator (AC/DC generator) installation can be found in Change 3 to TM 9-8015-2. Page one shown below.



This set-up used 4 fan belts, a seperate rectifier mounted in front of the radiator and can be found but will run about $1500 or more. There is also a 60 amp 3 fan belt set-up introduced with the M151 that can be adapted and this system has the regulator built in at the rear of the AC generator.

[idiocrates]

Thanks for a LOT of great information. I think I got it all printed out. When I stated this little project I was just going to try to get things back to operational. The more I work on it though the more it seems I'm doing a restoration as opposed to a simple repair. Somebody else on here said.....its amazing how things jump on to the "things to be fixed" list. I KNOW now what he was talking about. We'll end up with a thermostat where none existed before.....below a new head water inlet to replace the rotten old one. We'll still be 12V on an alternator.....but it'll have a double groove pulley and we'll have two v-belts on the engine. New speedometer......new oil pressure switch.......and all new gauges. etc, etc, etc......I'm sure you know how it goes. Any way.....here's what I'm going to the machine shop with.....so we'll see how it goes. Hope you don;t mind that I stole some of your words...........

1-The vehicle this engine comes out of is a classic 1953 Willys M38A-1 jeep. The engine is a Willys F-134. Please do not alter the engine from stock without my approval. This includes doing any machining that physically changes the identity or exterior appearance of the engine. Allowable machining not requiring my approval includes:

a. Over-boring and sleeving of cylinders. If this procedure is required the maximum permissible over-bore that will be allowed is that necessary to accept 0.040 oversized pistons. If measurements indicate that this is not possible then the cylinder will be over-bored and sleeved to standard size pistons. If sleeving is necessary a minimum ¼” deep landing will be left at the bottom of the cylinder for the sleeve to sit upon.
b. Machining for the installation of hardened exhaust valve seats.
c. Replacement of square-drive and square-head internal gallery plugs with hex-head plugs.
d. Sizing and polishing of crankshaft main and connecting rod bearing surfaces.
e. Repair of the broken studs and bolts (one on the exhaust manifold and one on the cylinder head water inlet fixture)


2- The cam shaft originally only had one bearing on the front journal and the middle and rear journals ride in the block. If the clearance checks of the center and rear holes in the block show excess wear then it may be necessary to slightly modify Ford 260/289/302 cam bearings to make these clearance acceptable.

3- On this engine excessively worn tappet bores can cause noise and low oil pressure. Oversize lifters are available and should be installed if this is the case.

4- During reassembly it should be noted that there are two different types of piston connecting rods. One type is used for cylinders 1 and 3 and the other type is used for cylinders 2 and 4. Extreme care should be taken to ensure that the piston and the connecting rod are properly oriented to each other with respect to piston “T” slot and rod oil spray hole and that the rod is properly oriented to the crankshaft main bearings with the wide side of the rod located away from the nearest main bearing. Improper side loading and premature wearing of the pistons and crankshaft journals will result if this step is not followed exactly.

5-During the engine reassembly, prior to placement of the crankshaft rear main bearing cap the bolts for the flywheel must be installed in the crank flange front to rear.

6-It is imperative that the oil pump be correctly indexed during installation to insure that the distributor gets indexed correctly. This is best done while the cam gear cover is NOT installed so that the gear timing marks can be used.

7-Remember to install the special timing gear oil gallery fitting to direct oil spray onto the timing gear set. Failure to install this fitting will result in low oil pressure and lead to premature timing gear failure.

8- One of the head retaining bolts is located under and accessed through the carburetor opening in the intake manifold. This bolt should not be overlooked either during the disassembly or reassembly.

9- The orientation of the rocker arm shaft is critical to ensure proper oil flow to the overhead rockers. This shaft should be installed using tapered screws to insure it is oriented properly and cannot rotate. Also insure that the oil gallery plugs are installed on each end of the rocker arm shaft.

10- There are two different types of rocker arms. Exercise care when installing the rocker arms and separation springs to insure that the proper arms are installed in the proper places. Proper operation can only be maintained if the rocker arm separation springs are correctly installed.

11- Intake and exhaust valve guides must be installed exactly as indicated in the March 1954 TM 9-8015-1 Ordnance Maintenance Manual to achieve maximum horsepower and engine efficiency.

12- During the rebuild process the following are required regardless of discovered condition:

a. new pistons, ring sets, and wrist pins
b. new crankshaft main bearings
c. new crankshaft connecting rod bearings
d. new stainless steel exhaust valves
e. new exhaust valve guides
f. new exhaust valve springs, spring retainers, valve locks, and valve rotators
g. new hardened exhaust valve seats
h. new intake valves
i. new intake valve guides
j. new intake valve springs, valve spring retainers, valve locks, and valve oil seal o-rings
k. new front camshaft bearing
l. new Welch plugs
m. new crankshaft and camshaft timing gears
n. new oil pump
o. complete new oil seals and gaskets. The rear main crankshaft oil seal shall be the wider neoprene type
p. new studs for the exhaust manifold
q. new head bolts

13- The machine shop will provide a detailed list of all parts replaced during the rebuild including the manufacturer’s name and part number.

14- Generous amounts of assembly lube will be applied to all internal surfaces and oil galleries during the rebuild. The shop is advised that the engine rebuild is but one task in a long list of items undergoing restoration and subsequent rebuilds of the transmission, transfer case, axle assemblies, and body work will all be performed before the engine is ultimately installed back into the vehicle.

15- Prior to rebuild all bolt holes in the block will be cleaned and dressed with a tap of the appropriate size.

16- Head bolts that penetrate the water jacket will be coated with Permatex #1 sealant. Any other bolts which thread into the water jacket will also be coated with Permatex #1 sealant prior to installation.

17- All fasteners will be installed per the torque tables contained in the Ordnance Maintenance Manual TM 9-8015-1 dated March 1954.

18- All of the major old items replaced during the rebuild will be returned including:

a. pistons, rings, and wrist pins
b. all bearings
c. all valves, valve guides, springs, retainers, locks, and rotators
d. timing gears
e. oil pump

19-The machine shop is responsible for completing the following items:

a. total cleaning and repair of any defects found in the block
b. installation of pistons
c. installation of crankshaft, timing gear, and flywheel
d. installation of camshaft and timing gear
e. installation of exhaust and intake valve trains
f. installation of the cylinder head
g. timing gear cover


20- I will be responsible for installing the following:

a. the fuel pump
b. the water pump
c. the alternator
d. the starter motor
e. the carburetor
f. the exhaust manifold
g. clutch and bell housing


21- Because of the separation of responsibilities indicated in Items 19 and 20 the machine shop will not be able to conduct a test run-in of this engine. If this is unacceptable or negates any warranties, arrangements can be made to deliver the engine back to the shop in a rolling frame for the purpose of a test run-in. Any items of the machine shop’s responsibility found to be deficient will be corrected by the machine shop at no additional cost.

Jim

[wesk]

Jim,
Try not to overlook the most common error made by shops not experienced with the Willys four cylinder engines.

I don't see the installation of the oil pump and distributor in the machinist's responsibility list or your responsibility list although I do see it mentioned above.

I also see no mention of pre-oiling the block which any quality engine shop has the equipment to do.

I also see no mention of proper clearance checks of bearings using Plastigauge.

I also see no mention of which type rear main oil seal to use and what minimum/maximum crank journal diameter is needed if the lip type garloc seal is used.

The tap should not be used to clean threads in the block. The proper tool to use is a thread chaser since it will not remove any additional metal when cleaning the threads as the taps do.

New head bolts are the best way to go and insure the lengths are correct for each position.

[idiocrates]

Good points.........I added the oil pump to the list of the shop's responsibility with a reference to the point in the 8015 manual where it describes how to align it with the camshaft to achieve proper timing. I also added a statement to the list requiring pre-oiling of the block (at least to the extent possible given their level of reassembly). With regard to the use of Plastigauge......is this something that is usually done when the crankshaft is ground and polished and new bearings installed? I was under the impression this insured proper clearance...but I can darn sure add the task if you think its worthwhile.

I'm a little confused about the statement regarding the rear main seal. I understand the original seal was a rope seal and I don't think I want to go back in with that. What I asked for in the list is "The rear main crankshaft oil seal shall be the wider neoprene type". Is it necessary for me to spec the crank journal diameter for this seal.....or does it come sized based on the finished size of the journal (which only the shop will know when they are done with the crankshaft)?

Understood about the difference between a thread cleaner and a tap. I've changed the wording in my document.

Without the lifting hook there are only two lengths of head bolts.....right? Given the difficulty getting the odd longer length bolts required for the hook I've opted not to install one. I have a 4 ton woven strap that works great for slinging this engine so I'll just stick with that.

One last question........what's the best way to transport this engine to the shop? Can it be laid over on one side or the other.....or is it best transported standing upright......sitting on the oil pan?

I really want to thank everyone on this board.....and especially Mr. Kneetles......for all the help and great advice.

Jim

[wesk]

Every bearing installation should be checked for proper clearance using a system similar to the plasti-gauge system. Mic'ing alone does not take into consideration crush and shift that occurs when torqueing the cap on.

The head bolts are short under the carb, taller with the lift bracket and medium for the rest. However check the fit of the two bolts that also retain the oil filter bracket adapter plate.

I usually lay it on it's side on a set of two or three old tires and strap it to keep it from sliding around.

The preformed lip type rear main seal will only seal properly on the correct diameter crank sealing surface. The tolerance is very narrow and was covered very recently in another thread. The rope type seal is more flexible and will work in a wider tolerance range.


http://www.g503.com/forums/viewtopic.ph ... 32&start=0

http://www.thecj2apage.com/forums/forum ... 1550#81550

[idiocrates]

Okay........well that whole rear main seal thing has suffciently scared the k-wrap out of me.......I'm going to ask for the rope seal.....period. Its not that I'm opposed to rope seals.....we've had them for years on our tractors......I just thought.....albeit incorrectly......that the wide lipped neoprene seal would be better. Man do I feel sorry for all those folks who learned the hard way that just isn't necessarily so. And I know I have rear main seal problems now......I practically took a bath in the oil that came out of the flywheel cover when I removed it. Last thing I want is a to go to all this effort and end up with an engine that leaks just like it did before.....or even worse.....spins a bearing and siezes up. So, the crankshaft seal area diameter I'm looking for for the rope seal is 2.302 - 2.312.......right? And what if the polished diameter is below this.....use the neoprene......replace the crank.....or is there an over-sized rope seal for this?

Jim

[wesk]

The shop can build that surface back up to spec and re-polish it. The rope seal is very forgiving but has always experienced a limited life. Today we expect our engines to last 150,000 miles before such problems show up and todays engines usually last at least that long. 1926 design engines can only be expected to last 50,000 to 75,000 on bottom end parts and seals. This can be considerably less if there are other major wear factors involved. Any auto-machine shop operator worth a salt should be able to get you set up correctly using the data you just reviewed.