[DNF][2020 Build-Off Entry] Murrraymountain's "Ole Blue" Murray

Woah, that's some serious piston slap. I don't know what even....it shouldn't have ran at anywhere near that state. That's gotta be an undersized piston. You better hope it's one. As for the cam? Probably ok. Bearings operate in pairs, especially ones like those. You can't tell if they're actually bad without it assembled.

The cylinder is probably egg shaped in that engine, that's why there's so much movement. It'd run, but man she'd have some blow by, haha. That thing needs 0.010" over for sure, but I don't know if anyone makes oversized pistons for these engines. Even if so, it probably wouldn't be worth putting all the money into having it bored out.

About the rod and crank machining.. when you get a damaged crank machined they take the journal down to a smaller diameter, and an undersized connecting rod is required. Like 0.010" under or 0.020", depends on how bad the crank was. But much like oversized pistons, I don't know if anyone makes undersized rods for these engines. From what I saw in the picture though, your crank journal wasn't actually grooved, and could probably be polished up. First you could mic it to see if it's still usable.

I could be wrong about those parts, maybe someome does make them aftermarket or something. But from what I see there especially with the loose bore, I'd probably junk that tired engine and find a replacement.

darkside0914 wrote:

to my knowledge the piston is not supposed to move like that unless the rings are off of it, i've never seen one move like that in the bore with good rings, the cam will not have that movement once the cover is in place and it's seated in it's bearing, so that movement while the cover is off should be normal

Actually, I'd be willing to bet the rings are bad. I replaced the head gasket in 2018, but I could still smell the burning oil.

I should've thought about that with the cam. Makes a lot more sense now.

RichieRichOverdrive wrote:

Woah, that's some serious piston slap. I don't know what even....it shouldn't have ran at anywhere near that state. That's gotta be an undersized piston. You better hope it's one.

Believe it or not, this is one of the best running motors out of all 15. It never EVER let me down aside from a clogged fuel filter. This is basically ol' trusty next to a little oil burn (which is probably coming from the piston slap.) But still, comparing this to the rest of our motors... Something's not adding up.

AllisKidD21 wrote:

The cylinder is probably egg shaped in that engine, that's why there's so much movement. It'd run, but man she'd have some blow by, haha. That thing needs 0.010" over for sure, but I don't know if anyone makes oversized pistons for these engines. Even if so, it probably wouldn't be worth putting all the money into having it bored out.

About the rod and crank machining.. when you get a damaged crank machined they take the journal down to a smaller diameter, and an undersized connecting rod is required. Like 0.010" under or 0.020", depends on how bad the crank was. But much like oversized pistons, I don't know if anyone makes undersized rods for these engines. From what I saw in the picture though, your crank journal wasn't actually grooved, and could probably be polished up. First you could mic it to see if it's still usable.

I could be wrong about those parts, maybe someome does make them aftermarket or something. But from what I see there especially with the loose bore, I'd probably junk that tired engine and find a replacement.

They do make oversized pistons a "decent" price. Rings are about $50 and a piston with rings is about $80 I think. Since it looks like I'm getting another piston I'll probably see if I can order one from ARC. Not sure about an over sized rod though. The crank doesn't need to be "machined", but it does need to be polished. I can maybe do that with some SUPER fine grit sand paper. But what about the rod? It is somewhat grooved.

I'm gonna rule out a new motor. 1), I could guarantee you it's just the same internally and worse externally, and 2), I love this little motor.

AllisKidD21 wrote:

If it's not knocking, there's no piston slap yet.

This was when we were talking about the Husky... Neither one of these motors have the slightest bit of knock. They just  drink a lot of oil. But from what I see, they do have piston slap and a lot of it even though they are not knocking. And the Husky has more slap than this motor and it doesn't bog AT ALL. It runs great.

Now just for fun, when you guys have time, I STRONGLY suggest taking the heads off some of your motors to see if the piston moves. I guarantee you they do. Let me make a list of the ones here that do.

-This motor.
-The Husky's 21 V-twin
-The Craftsman's Teccy 12 horse (didn't have very much though)
-The JD's 20 horse V-twin
-The 16 horse oppy
-The 19 horse oppy (was missing the compression ring though)

I think it would be kind of interesting to see what some of y'alls look like.


Anyway, looks like I have some work to do. @AllisKidD21, what type of shops would check the crank for roundness? And is there any way to save the con rod?

Nah man your good. My John Deere is worse than that and it runs like a champ just gotta keep the oil topped off cause it'll burn it LOL! But I can assure you my JD is the only one with that much slop because it mowed grass for 40 plus years. Your engine definitely has a lot of run time. Id be looking for an engine if I was you.

Yeah they do burn!

Okay, I got everything tested today! This video has the results in it.

So yeah. We're running stock parts until it develops a rod knock. Then I'll end up building it. So honestly, no plans have changed. I am proceeding with all the original plans as if everything was fine because everything will be fine for a while. Just gotta watch the oil level.

Anyway, this project is not going to get any finances from the Craftsman when it sells. That is for other projects. But this one will get all of the $600 from the Yard Machine, so we're in good shape. Much MUCH better shape than the MM was at this point last year.

Just get an a-dapter kit and put a sbc in it. That'll fix all yer problems right there. lol!

Alright, workin on da watch list again. Is normal mower wiring 12 gauge or 16 gauge?


And can someone tell me how to tune my carb for better performance?... Like jet specs and stuff. Something to make it more responsive.

Depends... never go wrong on 12 guage.

I'd go with 14 awg or 16 awg. In open air in short lengths it can handle the low amperage in these charging systems. Plus the wires slide right into blue connectors which seem to be the easiest ones to buy in stores.

I've never had an issue with any size wire on mowers. The charging system doesn't put out more than 5amps, and that's only when you're running it wide open with a load on the battery. If you're buying, 14 is more than enough. Wire size doesn't matter as long as your connections are good, which is usually the problem on a mower. Bad grounds are notorious for no starts and things not working.

Yeah I'll use 14 gauge. 350ft in total, and 7 colors. $25. I say that's a deal!

Meantime, I pulled the front end off again... After seeing what has happened to the MM's, there's no way I can use this. So I'm gonna pull the axle, spindles, and brush guard and scrap the rest. I'm going to build a new front end based off the original design, but just stronger and better. So the frame work is at a stand still until I get the welder.

So for now, I want to get the motor and trans finished. Right now I'm waiting on ARC to restock they're billet dogbones so I can reassemble the motor. I am about to order all the motor and trans parts that are needed. Looks like it'll total up to about $200-$250 in the motor and trans.

EDIT: Make that $300. I just spent $200 on the ONLY THE TRANS... Jeeze! I'm only about $30 into the motor at the moment but I've still gotta order the pull start and dogbone... Those'r the kickers.

Okay, so all the motor/trans parts are coming in sometime within the next 2 weeks I hope. Getting ready to order the recoil pull start.

Only problem now is that ARC stopped making billet dogbones. I can get a piece of billet cheap enough but now I need to figure out how much it would be to make one out of a solid block and where to have it done.

Well, nothing much has happened lately except for a whole lotta parts comin in. One of which was the METALLIC MAROON spray paint. I think it looks killer, but the picture doesn't do it justice...



I think that's all that's going to get painted this color for now. I'm sure I'll think of something else that should match along the way. Only thing I'm worried about is that this was not high heat paint... So hopefully it doesn't burn off. If it does, well I guess I'll have to get some high heat paint. But in the meantime, it sure is nice to look at. LOL.

Also, I wen't ahead and pulled the front end since I'm gonna have to make an "aftermarket" one. Just about everything is getting changed/modded except for the axle since it's far from being a tin can like LT1000 axles are. This thing should be indestructible when it's done... At least that's what I'm going for.

Okay, pull start comes in tomorrow. Only thing I'm waiting on to put the motor back together is a dogbone. Not sure how I'm gonna get that done. If someone can tell me where I can get a dogbone made out of a billet block, I would really appreciate it.

And then I have one more question... If I clear coat the flywheel, (I'd cover the magnet of course.) will it effect the way it runs?

clear coating shouldn't do anything at all, i seriously doubt you could put enough clear on it to throw it off balance,

Good, cause I already did it... LOL.

Anyway, the pull start came in... It's just a tiny bit too small, so I've gotta figure somethin out there.



Now I just gotta figure out how to get my hands on that billet dogbone...

Well, I just don't see any way to get a dogbone. So we're stuck with stock one. So, I have done a lot of reassembling so far...




I ported and polished the head, and then I lapped the valves...




Nice and shiny



And here's where we are right now....





This thing looks FREAKIN GOOD...  The entire engine side of the fuel system is plumed, most of the parts are back on, the push rods have been converted to steel, and the head has had some decent port work done. I need to get the starter greased before I can put that on. I am going to do some jet work on the carb as well. I still need to work out a snorkel, pull start, and I need to get an OHV gasket, a spark plug, and work out my throttle situation.

Also, all $200 worth of parts for the tranny are in. So as soon as I finish the engine, trans work starts...

Alrighty, a little more progress on the engine. Starter is on! I took it apart, sprayed some WD40 on the two contact points (I guess you could call them bearings??), and it freed right up. The top "bearing" is a little worn so the gear pulls away from the flywheel every now and again but it'll be fine.



Also started on my snorkel...




Sadly I had to cut up my beautiful air box... It better work.


Anyway, here's the to do list... Once this list is completed, the engine is done.

- Mount/install pull start
- OHV gasket
- Spark plug
- Build/mount air box
- Air filter from a 5 horse Briggs
- Jet/rebuild the carb
- Install throttle cable
- Install choke linkage
- Install under-shroud LIGHT
- Install engine pulley
- Zip tie gas lines and wires out of the way
- Clear coat muffler
- Paint snorkel

How should I go about rejeting the carb? Just enlarge the holes a little?

- Mount/install pull start
- OHV gasket
- Spark plug
- Build/mount air box
- Air filter from a 5 horse Briggs
- Jet/rebuild the carb
- Install throttle cable
- Install choke linkage (Using a pretty much stock setup... More to come there)
- Install under-shroud LIGHT
- Install engine pulley
- Zip tie gas lines and wires out of the way
- Clear coat muffler
- Paint snorkel








Comin' along.... I think trans work is gonna start sooner than mid-June.

if you have a set of the tiny drills for jets then yeah, just go up one size bigger than the one that fits the jet, keep going until you're happy with it, just remember you can't put it back if you go to large without replacing the jet

Do I just do it on the main jet or all the jets?

You'd only gain power from opening the main jet I imagine, probably leave the idle jet alone.

Okay. I'll mess around with 'er tomorrow then. I have a spare carb from the Craps-man, so if I screw it up then I'll move over to that one. One more question.... What exactly am I looking for in performance? Better response time?

Anyway, hopefully I can get a first start in tomorrow!

I don't think you'll get better throttle reponse out of one of these carbs, being that they're expecting the engines to mostly be run at full throttle for long periods of time. But as long as you have some high flow intake setup planned, opening up the main jet a bit should give you some top end power in theory.

Oh okay so basically less bogging. I'll have to work on my airflow then. It is most definitely not high flow.

Well, the first run didn't go to plan as you saw. I picked up a new flywheel key today and a few other things. I was in Asheville all day today so no work got done. Hopefully I can get a bunch done tomorrow...  I expect this motor to be done very soon!