Designing my first build... Help!

[bread]

Thank you for the links. Do you recommend using a torque converter for a vehicle of this size and weight?

I don't understand why I can't just put that clutch on the crankshaft...

I might just end up building my own jackshaft with pillow blocks; this way I can get exactly the gear ratio I want/need.

 

[OzFab]

Thank you for the links. Do you recommend using a torque converter for a vehicle of this size and weight?

Absolutely!

I don't understand why I can't just put that clutch on the crankshaft...

With a centrifugal clutch, you get one ratio, which usually means you have to sacrifice speed for torque... meaning, to be able to move at all, you need to increase the gear ratio which, in turn, will reduce the top speed.

With a torque converter, you get the best of both worlds, top speed & torque because a torque converter is variable, it has a low ratio of around 2.5:1 & a high ratio of around 0.9:1

I might just end up building my own jackshaft with pillow blocks; this way I can get exactly the gear ratio I want/need.

You wil still need to set a specific final gear ratio but, as stated above, with a torque converter, you will have a little more freedom & a lot more fun...

 

[bread]

Ok now I understand; there still lies the issue of the crankshaft on my tecumseh being 7/8". There are no clutches that I know of that have a 7/8" bore. There also don't appear to be any 7/8" drivers on any torque converters. I also don't have a lathe, so shaving down the crankshaft isn't an option.

When you google "7/8" go kart clutch" up comes pics and websites for the attached pic, and apparently I cannot put that right on the crankshaft.

What do I do? Do I just need a new engine?

 

[jeeperjoel]

concerning the power it's going to depend on how fast you want to go, you could gear the cart really low and have plenty of power, but you'll lose top speed, as for the engine you could probably find a different crankshaft that'll fit it alot easier than making an adaptor, but now you're spending $ on it... not just the crank, but matching torque converter, as the crank you'll find will be most likely 3/4" output, the engine you were planning on has a 1" shaft so when you do decide on more power that's a part you'll have to buy again, a 3/4" bore comet clutch is generally found on a 30 series TC, you can get a 1" bore clutch for a 30 series TC, but it won't be able to take the power of the larger engine should you decide to step up later, for that you'll need a 40 series unit... for 1 person a 5 hp range engine works good, for 2 people not as much fun, i'd stick to original plan, the build will take time, get metal for the chassis, wheels, everything you need to make a roller first, probably still will have enough for the engine, that'll get you started, as you build buy a part here and there, rome was not built in a day lol my buddies jeep build took 4 years, not driving it at all, of course it's not a go cart, but same applies

what i was saying, if you want to run that engine your best bet is to swap out crankshaft to a 3/4 output, probably can get a crankshaft from small engine supply, or ebay that's where i got the crank for my gx390, it had a tapered shaft off generator when i got it

 

[bread]

Could I just buy one of these

http://www.ebay.com/itm/7-8-to-1-in...k-Shaft-Sleeve-adapter-Predator-/380843550721

... and get a 1" torque converter?

 

[mckutzy]

The 1" TC is going to expensive, more so than the 3/4" thats for sure.

 

[bread]

I have drawn a diagram of my final frame design. I added another level of framing for arm rest and to keep people from falling out. The rails hook into the shock towers. I am wondering how far the foot rest should be from the edge of the seat for about 6' passengers.

 

[tiremikejr]

just wondering if that upper rail will tie in to the main beam at the front of the cart in the picture it looks as if it does not and you will need to for structural integrity. just an idea you could stack the main beam just in the front and weld together then tie the top to that and also would allow for a mounting place for your upper shock towers. only double the height on on the length that you will mount the control arms. so the full length of the kart will be 3x6 and the front where the suspension connects would in theory be 3x12 12 being the height. just a thought and maybe I missed something but my $.02

 

[bread]

The shock towers extrude from the main frame beam; they come up looking like a "T". The upper frame rails connect right to the shock towers. The shock towers and the upper rails will all be 1" square steel tubing.

 

[tiremikejr]

ok I see what you have planned. I still do not think that this T setup will be sufficient structurally. what is to keep the t support from getting bent side to side if you are on uneven terrain. ie pulling into an uneven driveway or something. there are many ways to achieve what you desire. if you do what I said you can tie side rails into the rear of the upper frame section to reduce flex and you would have a very stable mount for your shocks

 

[tiremikejr]

Please forgive the cave man sketch but I had to show not tell

 

[bread]

Thank you for the advice, I was thinking that a shock tower made of 1" tubing like that would problem not hold under stress.

I think this what you are saying; there is another piece of 3x5" over the main frame of 3x5" making the frame a tall 10".

 

[tiremikejr]

yes you have it now! this is exactly what I was describing. the upper frame ties into the ten inch tall piece for frame strength and the shocks mount exactly where you have them with two small brackets off of each side. this will work perfect.

 

[bread]

Excellent, thank you for the improvement!

Do you think it will be a problem having no suspension in the back?

I'm planning on doing mostly on-road driving and very light and rare off-road driving.

 

[OzFab]

Please forgive the cave man sketch

The sketch itself is ok... if it wasn't upside down

 

[bread]

 

[bread]

Can I get away with a suspensionless rear end?

 

[bread]

Can I not have suspension in the back?

The 16hp duromax will be sufficient, or will the 5.5hp tecumseh work?

Thanks and sorry for the amount of questions; I am normally working with farm equipment and this is mostly new to me.

 

[OzFab]

Can I not have suspension in the back?

Of course you can; you're building it, you can do whatever you want...

The 16hp duromax will be sufficient, or will the 5.5hp tecumseh work?

Until you build it, there's not really a guaranteed way to say whether the smaller engine will be sufficient or not; I mean, with the proper gearing, it will move the kart but, how well is another question...

Thanks and sorry for the amount of questions; I am normally working with farm equipment and this is mostly new to me.

We all learn by asking questions & we all had to start somewhere

We'd rather you ask questions & build it correctly than not ask & build a death trap

 

[bread]

Thanks man; I am going to start this build in late January.

You have a happy holiday!