Predator 212 Engine build. Tell me everything I need to know

[adsum]

I'm apologizing aware of some of the threads out there in regards to other Predator builds but I'd like to try and condense the information into one. This post will more than likely only suit my build, but may be a reference for others in the future. With everyone's help we could construct a thread written in the style of "Explain it to me like I'm five" to maybe help others with their future builds.
Without further adieu,

My Goals:

1. Build a Predator motor capable of 50mph or greater
2. Have a reasonable amount of low end torque, without suffering completely at the top end
3. Reliability and longevity being a key factor (This should have been first)
4. Learn as much as I can about "building" these motors

Things I know nothing about:

• Valve lash. How to set it. The importance of it.
  Google's definition of Valve lash-This is the clearance between the base circle of the camshaft lobe and the camshaft follower or tappet.
• Jackshafts (What they look like and how they work)
• Will my Comet Tav 2 Torque Converter be interchangeable with the new Predator 212 set up? If not, what else would I need
• Determining the length/type of the chain I might need if the motor doesn't mount in the exact same position as my original.
• Belts (How much play is too much play? What is the proper amount of play on a belt)
• Would removing the governor be detrimental to my engine if I plan to be wide open throttle 3/4 of the time. (This Kart will be built as a toy and mostly pavement driven)
• Will my current brakes set up be sufficient enough to stop the kart with this new motor? (I'm currently using a manual caliper/disc set up)
• How to choose which cam is the RIGHT camshaft for the performance increases Im looking for.

Resources:

1. www.harborfreight.com
2. http://www.kartpartsdepot.com/
3. http://www.ombwarehouse.com/
4. http://www.smallenginecams.com/
5. http://www.gokartsupply.com/tcbelts.htm
6. How to Clean your Torque Converter (will add link later)
   

More to be added at a later date. I'm sure there may be better prices if you shop around but these are the websites I've collected so far with my limited knowledge.
For now, that's all I can think of. I'm sure if more comes to mind tomorrow, I'll edit this post

I'm *one* click away from purchasing my engine. I found a discount code online that offers me $24 off! Grand totaling $95.99 for the 6.5hp 212cc.
http://www.harborfreight.com/65-hp-212cc-ohv-horizontal-shaft-gas-engine-epa-69730.html

 

[KartFab]

To answer your belt question, just have the right center to center distance and driven unit for the belt. Reference here http://www.gokartsupply.com/tcbelts.htm

You have a Jackshaft on your torque converter. It's just the rod in the driven unit.

Your comet 30 series TAV will be 100% interchangeable. The Tecumseh engine shaft is longer though.

I just took the easy ones. Everyone else can answer the harder questions.

 

[adsum]

To answer your belt question, just have the right center to center distance and driven unit for the belt. Reference here http://www.gokartsupply.com/tcbelts.htm

You have a Jackshaft on your torque converter. It's just the rod in the driven unit.

Your comet 30 series TAV will be 100% interchangeable. The Tecumseh engine shaft is longer though.

I just took the easy ones. Everyone else can answer the harder questions.

That's a great source website!
I'm happy to hear it'll swap over!!

By the way, you're only one post away from 1k!

 

[Half-breeder]

Repost link... http://www.diygokarts.com/vb/showpost.php?p=339590&postcount=34

 

[tuneman]

The stock predator engine with that tav should hit 50 with the governor removed maybe without it. I purchased a predator hemi and broke it in. It surprised me with the torque it had. Very worth the money

 

[adsum]

The stock predator engine with that tav should hit 50 with the governor removed maybe without it. I purchased a predator hemi and broke it in. It surprised me with the torque it had. Very worth the money

Really? Maybe I'm misinformed but I assumed that the motor would need some tweaking in order to reach that speed.

 

[firemanjim]

I can hit 100mph with just 3hp!...... I can...... It will just take forever to get there.....
HP only plays a role in top speed, by, how fast you GET to that top speed. It's you're gear ratio, coinciding with your engines RPM max, combined with your tire size, dictate your top speed.
My personal kart had a top speed of like 26mph. I modded the engine and removed governor. Wow, I got it to like 29..... Changed gear ratio, then it was getting 36-37..... If I go one up in tire size, it changes to 42...... Same engine, different gear ratios....... Different speeds.
A stock 212, geared right , with a TC, can easily hit 50mph and not take forever to get there..... Half-breeders kart is proof......
The popular misconception with hp is that if it has a lot of it, it has to be fast. No true..... My last toy car put out 400+hp and I could do a quarter mile in the low 12's.... @111-122mph (iirc). A big monster truck has on average, 1500hp!! So, does that mean it can go 350+ mph because he has 3.5 times more hp? Uhhh, NO....
Gearing get you top speed..... HP/torque is how fast you GET to that top speed.......

 

[Half-breeder]

Really? Maybe I'm misinformed but I assumed that the motor would need some tweaking in order to reach that speed.

He is sayin 'maybe'... probably cause it is possible but at a cost of the gearing, straining too much on either the clutch or belt... "bad setup" IMO.

So it is wiser to mod the engine vs up gear at a cost to great wear to the TAV....

EDIT: ... or what Jim said above...

This is just my opinion.

 

[Badot]

Jim, don't forget air resistance

 

[firemanjim]

Jim, don't forget air resistance

Ah yes! Not to mention the earth's gravitational effects on acceleration and momentum. Drag coefficient is just, well, a drag......
Traction is going great to be another thing to deal with as a live axle kart will scrub more speed than a one wheel peel.... And the tires them selves pose a dilemma.... Do you go low and wide or tall and skinny? One uses more power to get going than the other..... Hmmmm

 

[tuneman]

To op. I'd modify it just for the heck of it u can never have too much.

 

[Half-breeder]

To op. I'd modify it just for the heck of it u can never have too much.

... says the man that wont be buyin him a new TC...

 

[adsum]

I can hit 100mph with just 3hp!...... I can...... It will just take forever to get there.....
HP only plays a role in top speed, by, how fast you GET to that top speed. It's you're gear ratio, coinciding with your engines RPM max, combined with your tire size, dictate your top speed.
My personal kart had a top speed of like 26mph. I modded the engine and removed governor. Wow, I got it to like 29..... Changed gear ratio, then it was getting 36-37..... If I go one up in tire size, it changes to 42...... Same engine, different gear ratios....... Different speeds.
A stock 212, geared right , with a TC, can easily hit 50mph and not take forever to get there..... Half-breeders kart is proof......
The popular misconception with hp is that if it has a lot of it, it has to be fast. No true..... My last toy car put out 400+hp and I could do a quarter mile in the low 12's.... @111-122mph (iirc). A big monster truck has on average, 1500hp!! So, does that mean it can go 350+ mph because he has 3.5 times more hp? Uhhh, NO....
Gearing get you top speed..... HP/torque is how fast you GET to that top speed.......

I swear, whenever I'm clueless about something I literally shut my brain off. I should probably hit the "ON" switch before getting into this build. Jim, you're absolutely right. Gearing is going to be a critical factor in reaching 50mph.
I think the reason I prefer "toys" over actual cars and motorcycles is the price. It's much easier to budget $1,000 vs $10,000.


My question to you is, what sprocket could I use to reach that goal while not sacrificing my low end torque entirely?

 

[adsum]

He is sayin 'maybe'... probably cause it is possible but at a cost of the gearing, straining too much on either the clutch or belt... "bad setup" IMO.

So it is wiser to mod the engine vs up gear at a cost to great wear to the TAV....

EDIT: ... or what Jim said above...

This is just my opinion.

I'd actually prefer to rip apart the motor and build a monster over tweaking a stock motor. I enjoy tinkering with things too much to pass over this opportunity.

 

[adsum]

Ah yes! Not to mention the earth's gravitational effects on acceleration and momentum. Drag coefficient is just, well, a drag......
Traction is going great to be another thing to deal with as a live axle kart will scrub more speed than a one wheel peel.... And the tires them selves pose a dilemma.... Do you go low and wide or tall and skinny? One uses more power to get going than the other..... Hmmmm

I posted a picture over herehttp://www.diygokarts.com/vb/showthread.php?t=27242&page=2 of the tires I'm currently running. Which appear to be low/wide. I really like the responsiveness of the tires but I wouldn't dare touch that steering wheel at 30mph....let alone 60.

 

[Half-breeder]

I'd actually prefer to rip apart the motor and build a monster over tweaking a stock motor. I enjoy tinkering with things too much to pass over this opportunity.

Just remember... a TAV2 is rated to 8hp... as is I know Im borderline too much hp for a TAV2... next stage is a 40 series... more $$$

 

[Badot]

I think the reason I prefer "toys" over actual cars and motorcycles is the price. It's much easier to budget $1,000 vs $10,000.

Hey, don't discredit bikes... My current (04 EX250) cost me $1000 (without even haggling) and a quick carb clean with only 10k on the clock

 

[JToTheIzzack]

My Kart at home has a bone stock predator 212, 12 tooth clutch, 72tooth sprocket and 15 inch tires, and I can hit 36 pretty dang fast, and all I had to do was back out the throttle limit screw. I did the math, and a 60 tooth would take it up almost another 10mph. I would bet with that torque converter you could easily get to 50 with similar size tires and sprocket as mine, with no modification besides throttle adjustment. I would strongly consider gearing up with a 60 tooth or smaller main axle sprocket, running regular old 35 chain. I also prefer top speed when it comes to low-dollar karts like this, since you're not going to get crazy burnouts or face-ripping acceleration out of a 6.5 horse predator.

 

[OzFab]

Valve lash. How to set it. The importance of it.
Google's definition of Valve lash-This is the clearance between the base circle of the camshaft lobe and the camshaft follower or tappet.

The importance of valve lash is to ensure the valves open & close at the correct time as determined by the camshaft lobes, to achieve the best possible performance:

Too big a gap & the valves will open late & close early, reducing duration (the amount of time a valve stays open) &, therefore, reducing the amount of fuel delivery...

Too small a gap & the valves may not close completely, reducing compression & severely reducing performance

There's a much more detailed explanation but, let's keep it simple for now...

Jackshafts (What they look like and how they work)

As explained, you already have a jackshaft, the driven clutch & drive sprocket are attached to it...

Will my Comet Tav 2 Torque Converter be interchangeable with the new Predator 212 set up? If not, what else would I need

Interchangable as in bolt straight on, yes; interchangable as in will it handle the amount of hp, probably not...

Determining the length/type of the chain I might need if the motor doesn't mount in the exact same position as my original.

The engine mounting position should be close but, for safety sake, I'd be using #40 chain; it has a working load of over 800lbs as opposed to #41 @ 500lbs & #35 @ 480lbs

Would removing the governor be detrimental to my engine if I plan to be wide open throttle 3/4 of the time. (This Kart will be built as a toy and mostly pavement driven)

Just about everyone removes the governor but, if you pull this off, I dare say you won't be at 3/4 throttle very much...

Will my current brakes set up be sufficient enough to stop the kart with this new motor? (I'm currently using a manual caliper/disc set up)

Well, a disc setup is better than a band setup so, at least you're half way there, the ultimate being a hydraulic disc setup; however, it remains to be seen as to whether the mechanical caliper will be strong enough...

How to choose which cam is the RIGHT camshaft for the performance increases Im looking for.

There's a number of way to look at this question:

If you use a high range cam, most of the power will be achieved at the top end of the RPM range (~5k-8k) but, you will need high end internals (billet conrod, billet flywheel + others) so that the engine can keep up with the cam...

Yes, you may easily achieving your desired top speed but, it will cost you a small fortune, both in the initial build & when it all goes horribly wrong...

A mid range cam will provide a "power band" at around 3k-6k; again, high range internals are highly recommended

Not the most desirable cam (IMO) as you still need a mid range gearing combo to get the kart moving so, it's not likely you will achieving your desired top speed as the torque will start to "dip off" before you get there...

A low range cam will deliver most of its power in the 2.5K-5.5k RPM range but, you will still have a nice power curve above that point...

The beauty of a low end cam is you can use a higher final drive ratio & still have enough usable low end torque to get you going at a decent rate then, as a result of the higher gearing, you're closer to achieving your desired top speed

 

[Half-breeder]

My question to you is, what sprocket could I use to reach that goal while not sacrificing my low end torque entirely?

Honestly the TC compensates greatly for any lack of lowend... and asfar as the gearing... thats an easy find... but my question is what kinda 'clearance' do you have for said gears and did you decide on the # chain your going w/...? The size chain'll determine the size sprocket/gear. I personally have 1/4" clearance between my drive (9T) and axle (45T) sprocket and run a #41 chain. I dont run a #40 for the reason that a #40 chain wont fit too well (if at all) between the driven pulley and JS plate, but a #41 has an 1/16" clearance on both sides.