What do these Weird markings mean on a WW2 jeep Engine???

Surprising they went to these lengths in WW2!
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[@conrod7]

Matched pistons were a fairly usual thing in Engineering at the time - Jaguar used the same system right up until the late 60's

[@michaelovitch]

The baffle is to separate PCV gases from liquid oil, in case of bumpy ride,so liquid oil is not sucked in the engine,hydrolock it,or foul and kill it. The pcv system is connected just above the baffle,and directed to the intake hose. All PCV systems have oil/gas separators like that,even today. They are grilles,meshes,sheet plates to condensate vapors and separate gas from liquid. As you see,you have to aim the baffle in the pipe when reinserting the dipstick,it's adjusted to not allow easy fluid circulation.

[@benjohnson1082]

The dipstick baffle is to keep the stick from flexing/rattling and eventually breaking off the cap from flex fatigue. Imagine pulling your cap and not getting the dipstick!

[@martyzielinski1442]

I don’t believe that...

[@benjohnson1082]

@@martyzielinski1442 great!

[@davebaker9128]

Excessive head skimming can be accommodated by using copper head gaskets of oversized thickness

[@gjs9871]

Nice video. you could consider restoring one of the welders or generators that the military puts the engine in and using that as a “spare engine” to test components on.

[@Greendot319]

yes: kzbin.info/www/bejne/bqaupJiQjJtsZ9U

[@tobiashoffiversen]

Matt is like the uncle who is letting his nephews and niece join the garage and teach them how to fix a vehicle and the history of it. By the way, it was interesting to see and learn about the ABCD markings. Now I want to pull off the head of my Engine to see if the Jimmy straight 6 has the same

[@Greendot319]

Ha ha!

[@theezeelife292]

Great info. And thank you for pronouncing, "Willys," correctly. I find it amazing how many Jeep people can't pronounce it right.

[@blacksquirrel4008]

I know, once you know the whole story it really grates, doesn’t it. And if you do use it they look at you like you’re from another planet.

[@theezeelife292]

@@blacksquirrel4008 I know it's a minor thing, but yeah, JEEP people, people who know and love Jeeps and run nothing but Jeeps, should damn well know how to pronounce Willys correctly.

[@blacksquirrel4008]

@@theezeelife292 these guys know www.southeastwillysjeepgettogether.com I was going to drive my Jeep over the mountains to attend 2 years ago but weather. Now, I’ve sold it.

[@greywolfwalking6359]

Great Intel, n history... Thanks!

[@andrewgillis3073]

My Army National Guard unit had some old jeeps when I joined in 1983 (I think). Not only were the cylinders marked, but the didn't always match. You might have a block that was B,B,D,B. Ours were made much later than WWII, possible in the late 1950s or early 1960s. Some of the cylinders had no markings, however. We had one jeep that was made during the Vietnam War. They run forever if you keep them up.

[@briang.7206]

What model were they ? I thought WW2 jeeps were discarded in the 1970's. Our local jeep dealer have lots of them back then they were surplus.

[@andrewgillis3073]

@@briang.7206 You are correct, but some jeeps remained in the Army National Guard for many years after. I don't know the exact models, but they were a hodgepodge of different ones. Fortunately, most of the parts needed to fix them could be bought at the local car parts store. I believe most of them were the M-38 model. The Army National Guard is the last to field any new equipment, and so has a lot of obsolete equipment. Air National Guard units do pretty well as far as equipment goes.

[@briang.7206]

@Daniel Pearce The M-151s were cut in half deemed unsafe to drive on the highway .

[@robertmoulton2656]

The collar on the dipstick it to keep the stick from thrashing about in the tube so much . Metal fatigue and such 🤦🏻‍♂️

[@larryashmore489]

Stumbled onto this. Very knowledgeable. Subscribed.

[@jstutzman1301]

Wonderful video, learned a lot about jeeps. Thanks.

[@Greendot319]

You're welcome!

[@tsmith578]

Another reason that the engine blocks were stamped with lettering during production, Was to mark the cylinders for being true to round. And these markings are often found on the oil pan rail of engines of many different manufacturers. Have you ever noticed these. And seen a lot of A and B marks ? If so that is likely to be a engine that has lasted for a exceptionally long time without having blow by through the piston rings. As compared to a engine that might have a lot of C D or E stampings.

[@Grahame59]

Re the ABCD bore and piston matching, I have a Hillman Imp and Rootes did exactly the same. ABC or D is stamped on the block (in the Imp's case, visible externally. Mine's a C). I imagine many manufacturers did this but it is interesting in a wartime vehicle with a limited life expectancy how much care was given to getting it 'just so' in the factory. Btw, love your channel and videos. I have an ex-military Series 3 Land Rover and it is amazing how many features of the Jeep were copied for the Landy. I'd love a Jeep but sadly they are not available in my size - if only they did them in ABC and D like the pistons!

[@timblack6422]

Nice shout out to G503!

[@dmcarpenter2470]

Enjoyed the vid. Nice collection of information.

[@Greendot319]

Cheers Dave!

[@markingram2826]

The Colour Tune is a nice piece of gear, Got my jeeps sorted in a few minutes!

[@Greendot319]

Good to hear (or see in this case)

[@thomaslemay8817]

A lot of American engines had the piston A through D marked on the deck and piston crowns, it is not uncommon to see different cylinders in the same block to be different bore size within that range. It was not unique to any single brand.

[@-oiiio-3993]

Excellent content.

[@rockcrusher4636]

Excellent, thank you.

[@brianyoung9014]

Bore std oversize markings are common on many engines.

[@blacksquirrel4008]

Like Ben Johnson said, the disk is a baffle to prevent rattling and fatigue. Be sure to check the weld on the baffle though, as mine actually came off from the stick when I went to check the oil. Luckily, I saw it just in time and could wedge it in the tube and it didn’t fall all the way down.

[@arjenboeijenga117]

Half a thousands of an inch...?? I love the metric system! Great video by the way!!!

[@haggis525]

I am a machinist and I live in metric but almost always worked with drawings in Imperial. It was quite rare to see drawings in metric.

[@arjenboeijenga117]

@@haggis525 Hi Chris, I think Metric and Imperial are 2 different worlds. Are you UK or USA?) Altough... last time I was in UK they sold fuel by the liter, not gallon. And I have heard that UK automobile industry uses the metric already (I myself am a Peugeot-guy)

[@haggis525]

@@arjenboeijenga117 I'm from Canada 🇨🇦. We use metric but virtually all my machining was done in Imperial. Canada is funny, though, we are 50 kilometers from a destination, will need 4 litres of milk, 2 kilos of beef but I am 5'8" tall and weigh 171 pounds. Temperature is expressed in °C but TV's have, say, a 50 inch screen. I'm also the last generation who became teenagers when the change over from Imperial to Metric took place - pretty much everyone my age +/- 5 years knows both systems equally well.

[@michaelkienhofer6394]

Great channel!

[@Greendot319]

Cheers!

[@aboyandhisdog]

Very cool, Matt. I had no idea about the 'a, b, c, d' stamps. I know a lot of guys will shave the heads to try to increase the compression ratio from 6.8 to as much as 7.1 I believe. Thus making an engine that produces better at altitude. I did this too - wish I could say that I can feel the difference, but alas...I'm not that good!

[@Greendot319]

Yes I doubt you'd notice any difference Tom!

[@GPW96226]

Very interesting indeed! Never seen or read before.

[@Greendot319]

No I was surprised!

[@klrmoto]

My 87 Nissan pathfinder explained that in the shop manual. They match the letters on the bearings. The technique has been carried on.

[@jamesziegler4383]

Good reporting

[@joecrachemontange4613]

I like to go to the gas station and trick the attendants into finding the dip stick when they ask to check the oil.

[@pcmmulders]

Interesting Matt, made some screen shots of your table for my dbase.

[@Greendot319]

Not a bad little bit of info, no use to us nowadays but interesting all the same!

[@rahtorenripcore1699]

Would love have old military jeep. Wanted one but never owned out.

[@LesSharp]

Interesting stuff. I wonder if there's a reference dimension, say from spark plug spot face to the face of the head?

[@Greendot319]

That would be useful, I'm unaware of it, seems to be you just have to check the clearance on your particular setup, takes a couple of minutes

[@BilgePump]

She’s a ripper! Nice heat up of those tires! Mickey Thompsons?

[@Greendot319]

I know about Mickey Finns but not Mickey Thompsons!

[@thecommentary21]

The reliefs in the head are an old school hotrodders modification. Back then there was NO aftermarket so you had to figure out how to improve what you had. Most of the american mechanics in WW2 were farm boys and kids who had hotrods prior to the war. Model A's most probably. Engines were very similar. The reliefs added a few extra HP so its clear why they would do this on the jeep motors. They more than likely did some mods on the carb as well, re jetting them, swapping for larger ones etc....

[@benjohnson1082]

The Russian army motorcycles of the war and up to modern production use the A, B, C piston/cylinder marking as well.

[@imdeplorable2241]

Very interesting and impressive. I now wonder if other manufacturers did the same thing. Did all of the services require this? I'm not a reenactor or own military vehicles. I own an El Camino and a Corvette but, I do find historical detective work fascinating. Keep up the good work and the videos.👍

[@andrewholdaway813]

Selective fit? Yes and probably still do, it allows the easing of manufacturing tolerances whilst maintaining a close assembly fit.

[@stjepankorotaj4382]

Sorry to ask here,but can you make a picture of top bow straps how are the mounted on bows.thnx.

[@skookapalooza2016]

If I had one that was machined too far I would consider using 2 head gaskets. While that wouldn't be ideal...it would probably work well enough.

[@thomaslemay8817]

It works better to have a copper gasket of the proper thickness made to gain the needed clearance .

[@Subgunman]

Does any company make oversize gaskets to compensate for an over machined head or block?

[@redactedlogic]

I couldn't finish your video with that loud ass Bird in the background.

[@jimrosesadventureinmanilap715]

stihl chainsaw do the same thing.. Is on subsizing piston with block bore..

[@stephencurtis9400]

a spacer washer to raise the plug height.

[@AFV85]

That must have been alot of extra work having to machine different pistons like that for the blocks! What's What's old saying " measure twice cut once" doesn't seem to apply to this at the time! Being in a war you would think they wanted to keep everything near the same eh! Could you imagine waiting on a B piston and non available but say 100 As !

[@2paulcoyle]

Huge shortages of machine tools. Castings and dies were used way beyond life spans. Huge out sourcing from many small shops. I imagine engines were final assembled by hand/old guys. They had to get the stuff out the door. None was expected to last.

[@-oiiio-3993]

Common practice at the time. The same was done for 'shoe' bearings.

[@usmc481]

Windshield pasteners are upside down.

[@SteamCrane]

Just good examples of American manufacturing know how. Working to half thousandths with new hires.

[@thecommentary21]

Do you have any way of proving the dipstick was designed for that purpose?

[@Mocking69]

サイドバルブエンジンに秀樹感激Goodです=3

[@luvr381]

Did WW2 Jeeps have open differentials?

[@rickster4455]

yes.

[@conceptalfa]

👍 👍 👍!!!

[@raymondj8768]

is thr mic rite nexto the bird or what ? dont know if i can make it till the end ! CHIRP CHIRP CHIRP !

[@nikolakardonsky9108]

Hello, great video! Do you have a Facebook page?

[@Greendot319]

Thanks, No I don't :(

[@incomingshell3268]

Still waiting for the episode with the 'experimental' WW2 Factory Turbo with blow off valve..........Could be hidden in the same place as Hunter Biden's laptop.....The aliens from Roswell or the Zapruder Film.....

[@Greendot319]

The truth is out there

[@KobirAhmed-rn6lv]

Rock .star Kobir..ahmed

[@Colin-Fenix]

Peeps?

[@-oiiio-3993]

George Patton always referred to the G503 (MB/GPW) as 'Peeps' and the Dodge WC as 'Jeeps'.