GasketCase's SEARS Swamper LT [2018 Build-Off Entry]

IDK about swapping longer axles into that 600.  I would put in some axle support bearings if you did that.  I doubt the axles would swap over from a different axle.  Guys usually do something like a Doc Locker and then they have a long solid axle to work with to get the rear track width right where they want it.

@Crazy_Carl hmm OK back to plan A, try my best to stay same width haha. WAIT! I'm using the four lug rims for the front. I'll be able to just turn the rim around and bolt them on. They do have a decent negative offset to them. Hoping. Just gotta be mindful while building the front suspension on how much room the offset rims give me

So today I decided I need the engine mounted also, so I can continue figuring out the dimensions for the ifs and shock tower configuration. I covered the air box with a thick trash bag and then Pressure washed it.

Why is the engine block gold in certain parts? Over heating or not cooling properly?

That’s just discoloring of the cast aluminum from getting so hot with oil crud on it

@CraftsmanQuad19 yeah there was Alot so I used pressure washer to clean It more efficientky lol. Is there any precautions for the twin opposed that I should be aware of?

I already have separate vacuum fuel pump to replace the one on the carb uses.

I'm going to be making a new exhaust system as well.
Anything else?

So engine Is on tractor but not bolted yet and boy I ssay boy it looks sweet.  I am having to add Shims because of two reasons #1 being thecrankshaft hole on frame is too big so it doesn't align with them and #2 the oil drain pipe was interfering The deck designs. Swapped out pipe for exhaust.  The Tecumseh 10 HP on it originally looked to have one offset engine mounting bolt then the other three . So since its too big and the twin fall in the hole.  I decided to install 4 1/4 inch steel plate that will be welded to frame and then oil drain will be able to clear.

I also have to cut the hood where the tape is placed sloppy so that the engine head can come through and center the motor evevenly

looking good! I love my oppys, cant get that torque from singles! with that small frame it should have pretty rapid speed increase.

The hood might have to be cut more to allow for room the the head tins.

Would you consider raising up the grill and hood?  You might have to anyway for the IFS.

@biggasmowers thank you! Any ideas for some performance other than port & polish brows,  intake,  exhaust? Also I heard of their being a better carb found on these according to how many bolts? Which bolts am I suppose to be looking for?  

@Crazy_Carl I posted earlier about the hood and I do agree I have to cut the hood a little.  Im trying my best not to move the hood but I may try it cause the mounts for the hood and grill assembly are welded onto the front axle plate and I may be able to shim the plate up and make the hood clear. Just don't want it to look funny with a bunch of open space in that area.

Update : 18hp oppy is bolt up with the shims I made.

Looks like just the right amount of clearance.

Just wanted to give an update . I'm trying my best to get out there and get some progress done these past two weeks.

I've modified my 3 screw body and removed the original stock carb fuel pump and added a separate fuel pump to the system.  Drilled a hole and tapped the smaller hole found on the pump mating surface and inserted a set screw to prevent leaks and then the same with large hole but install a 90 degree for the fuel line inlet to attach.


Then I drilled and tapped a new vacuum port into intake manifold instead of the stock vacuum port that was directly to the crankcase. Blocked the original  vacuum
Source as well.  You can see the original vacuum port just behind the governor assembly in the last photo.

so now you have an external pulse fuel pump.  Nice work.

Nice work here. On the 600 transaxle, They have a short axle and a long axle in them because the actual gearing section in them is off to one side from the center of the whole transaxle and put the pinion gearing way off to the other side. It would be possible to switch over the short axle with a long axle to extend the overall width, with another 600 axle. The extended side would be sticking out of the case longer without support with the short axle support housing on. I don't know if the long axle support housing would work right or if it would cover the key way some to where you couldn't put on a hub or a tire. Which means you need a spare 600 transaxle to rob the parts off. And extending the transaxle width on one side this way means you would have to recenter the transaxle in the frame which would probably be a whole other can of worms. Oh, and the axle shafts for this trans are hardened steel shafts. I was going to do the opposite of this to my transaxle and shorten the overall width so this transaxle would fit inbetween my tank chassis frame rails, but decided against it since I wanted a whole spare trans to just throw in and not to have to do much to it to get it to work.

To improve the oppey, the porting part you can do all that was mentioned, the best place to port though on any flattie is the short radius side of intake/exhaust runner, mainly in the engine block part. The idea is to get as straight of a path through the runner as possible, mainly where the valves are. The short radius of the runner is just how it sounds to ID the spot. The inside of the turn, in other words. You trace the path from the carb to the valve and can ID all these spots to improve performance. Plus removing casting flash too, (speed bumps). I would suggest to keep from grinding the ports to big, by opening them up to a bigger diameter to much since these ports casting walls are soo thin to begin with, opening them up will weaken things and cause cracks in the long run. Just be weary on what you remove, confirming that there is the metal there to be removes.

@prancstaman thanks for the heads up and solid advice brotha! On the exhaust port there is threads to what i assume would be for those mufflers that thread in there. Can remove those also ?

as of now , I'm building the dual exhaust and found out should of measured how much to raise the hood with the engine cover lol gotta fabricate another set of extension brackets today haha. I mounted the fuel pump and routed the fuel lines and vacuum hoses so they are secure and not rubbing . Will have some photos up by tonight .

For those threads on the exhaust port. I did a porting job on a 5hp flattie Briggs for my kids mini bike. I removed around half the threads to open up the exhaust some and made a flange for the header and kinda coned it to the valve for smooth flow. I did it this way (removing abouts half the threads) to keep the flow somewhat fast at off idle to mid rpm. It worked great for it. Very strong a motor and still has gov on it. Made a video of it on my channel explaining it with a couple other videos too. I haven't worked on an oppey yet so I can't give any details of doing the work but should be similar. I got 3 oppeys waiting for rebuilds when I get the time. My 18hp like yours will be going in my tank:)

@prancstaman OK awesome! again I thank you, I highly appreciate the advice and time you have put into your posts.

UPDATE :

So yesterday I built the longer brackets to raise the hood more cause I didn't measure with the engine cover and tins on the engine... Oops lol so now it's now where it should be.  I also installed the bumper but i still have to adjust slightly.  You'll see the bracket is crooked as hell but just for now since its getting late.  I got started on it later than I usual would have but hey progress is progress. Also the front rims still have to get painted and still deciding if I have time and materials to do a IFS or not. May save the idea for another build , I been feeling it would totally molest the look of this 74 Sears.  I'd like to keep it as original as possible with slight upgrades.  

I'm loving the piant job on this thing a lot.  I'm a big fan of slightly modified tractors that are mostly stock, but have a lot of upgrades where they count.  The bumper is a nice touch.

Looks nice!  Great job!

@Crazy_Carl @MightyRaze thanks guys I highly appreciate the support and advice .

Does anyone have a trick up their sleeve when I comes to bending tube for exhaust I just want to dual out but I can't seem to find a method that works well yet. I tried packing the pipe with sand and heating it up but failed I also only have two 1 inch inner diameter 3 ft to 4 ft sections to work with so leverage is a little tricky. I want the length of the finished product to be somewhere around 1 ft to 1.5 ft in length exhaust. If anyone knows a simple or easy method. Feel free to let a brotha in on the secrets haha.

I have a conduit bender, but the bends are pretty long.  I'd love to get something tighter.  That's why I end up resorting to black gas pipe. (Oppy's are threaded on exhaust) Yeah many will talk about how restrictive the joints are... we are talking about a modified mower here..... not a top fuel dragster or race car.  

Tip.. 1" EMT will fit snugly over 3/4 gas pipe.

You have to be resourceful here.  There is tubing with tight bends in exercise equipment and old metal chairs.  I think MisterModified bought some small exhaust bends for his haspin build.  You should check out that one in the build off section.  It's a short read.

Yeah I either use pre-bent tubing or do the ol' notch, bend, and weld trick. It leaves some welds behind obviously but I usually clean them up with a grinder if they will be visible.

If you turn the oppy 90 degrees will it fit under the hood? Like redline did on his tractor?

Be kinda cool seeing the air filter and carb hanging out the side of the hood

@Crazy_Carl thanks man,  I had some mufflers laying around with the S bend on them still And cut them off and welded the conduit to it.  

@MightyRaze conduit is exactly what I have , my dads work were adding in electrical to a new building and he found whole 1in diameter conduit at about 6 ft long in the dumpster and I been slowly using it for exhaust pipe.  

@AllisKidD21 haha takes some skill with that method,  I tried it when I saw your post and it looked like I created an awful science experiment  haha .

@Creepycrawler I already have the engine mounted,  I posted it in previous posts , and I could of went along and 90 degree the motor but it wouldnt be the right image I'm going after since with both exhaust would be coming out one side and then the carb could get caught or hit by branches. Me and branches didn't get along too well with my 17.5 ohv avs.

UPDATE:

exhaust system has been built and sounds nasty as hell for a small engine.  Just the sound I was looking for.  Drilled a few holes in the end to counter the raspy pitch it would put out when I snatch the throttle plate.  





Also welded bumper to frame. I think if I can jump on it then I can probably hit something hard with it too haha.  I wasn't expecting to install a bumper but i have to protect that grill the best I can haha.  Onto the next....

LOL, oppys sound awesome.... might get you some ear protection.  After a while it does make your head hurt.