Engine Upgrade for 70's Argo 8x8

[jchiotti]

Hello,
I am thinking about upgrading engines in my 1970's Argo 8x8. The current engine is a kohler 399-2st.

I was thinking about upgrading to a 18-HP Vanguard B&S. Does anyone have any advice and whether this would be sufficient horsepower for this machine. I may use tracks in the future and will commonly have three people in the machine going through long stretches of mud. Don't need to go fast, just get through mud/water with 750-900lbs of weight and reliable.

If I have to get a new clutch, how much will this cost?

Thanks for your help. This website has been very helpful so far and just want to consider how much this will cost before I jump into it.

[thebuggyman1]

Search hard for a good deal on a motor.....Last time I looked a 16 briggs was about $1k, 18hp $1200, and a 23 was aboout another $100. I'd buy the 23, or even better, spend $1600 and get a bandolero (28-30hp) and have a wider rpm range.
A 1" straight shaft clutch will cost about $250. You may also need to modify/replace your secondary, but I'd wait and see what it drives like first.

[outsource_mech]

Buggy...would you think that swapping in one of these bandeleros would be a good option for the 2 stroke Kohler that I am about to be done with? I am looking for longevity and need this machine to be a work horse for the guy who has it.

Thanks,

[jchiotti]

Thanks for the advice. Do you think the frame, axles, etc on the 1970's 8x8 will hold up when converting to the 23 hp briggs? The frame and body are in good shape and the 399 kohler still runs. I replaced the condensers and did a couple of maintnance items to the motor last year.
I basically don't want to buy a new motor just to put into a machine that might not be able to handle it. Also....what shaft size should I get? I see the 1" and 1 1/8" are common.

Thanks!

[thebuggyman1]

I can break anything...here, hold my beer and watch this.

It won't be the motor breaking things, it will be the driver. If you put a 100 hp motor in, but drove like grandma, it would hold up. With more ponies, you will want to use them. That kohler 2 stroke is probably much harder on the machine than a 23 briggs though. My thought is: Is the machine worth dumping about $2k into it? Or would you be better off selling it and buying a newer machine with a 4 stroke already?

A 1" shaft clutch is cheaper than one for a 1 1/8" shaft.

[jchiotti]

Yep that is what I am struggling with....if I put 2K into I want to be able to use it for a while. I bought it for $2900 kohler ran fine. How much do you think I could sell it for with the kohler running. The body and everything else is in good shape and functions fine.

[thebuggyman1]

Well,......you paid $2900 for it. A machine is worth exactly what someone else is willing to pay for it. Low end machines seem to be in much higher demand, at least in my area. People want "cheap". The question is: Can you find a nice machine for the $2900 plus the $2000?

[seantoni]

I put a 20hp honda in my 81 8x8 and had no problems lot of power.

[spookum]

just for fun.... put polaris snow go clutches in it. Gives you DOUBLE the low end and 25% more top end.... gear ratio wise.... Have you considered a geo metro 3 cylinder mod??? http://www.6x6world.com/forums/argo-...ll-others.html

and my insperation:

http://www.6x6world.com/forums/argo-atvs/16016-99-conquest-chevy-sprint-engine-swap.html

At the very least, extend out your inner frame rail and put splined shafts in the front... that is the most bang for your buck and should not be too bad if you already have the power pack out

[JGrund85]

Do you have to extend your inner frame rail to put splined shafts in the front?

[spookum]

In that vintage of a machine I would assume yes.... Maybe look at keying the current axles?

One thought I have is to build bearing cages out of 4x4 tubing. Run dual out board bearings (just on the front ) then take a six spline coupler (off the shelf parts here nothing fancy) and weld an appropriate length 1 1/4 shaft in it. Couple this extension to the short new splined axles and eliminate the need for frame extensions? It could even make a dude so e money