Most power for the money?

[Kartin’ kid]

Hey y’all, it’s been a while. I’ve been busy with school and such and haven’t had time to work on much of anything. Anyways, I’m looking to finally build my first engine. I’m opting for Preddy 212. Yes, I know that I could spend my money other places to get more power for the same price instead of modeling a predator but that’s not necessarily the point of this. I’m really doing it for the skills and experience. Anyways, with that said I’m giving myself a budget of about $300. The task is simple, how much power can I get for this money and what mods do I need to get there. Open to any and all advice!

 

[panchothedog]

To make horse power you need to turn rpm's. To do that with out destroying the engine you need replace the rod and flywheel. There goes at least half of your budget. After that it needs to breathe. A camshaft with lots of duration and more lift than stock. F-275 or a 308. That's another $100. A milled and ported head. That's up in the air. Do you have a IN or know anyone who does with a machine shop, or a cylinder head shop. It's all just labor so it is very difficult to put a price on that. Stainless steel valves and stiffer valve springs are also needed. If you don't run stiffer springs the valves will float and potentially hit the piston. If you don't run the stainless steel valves the increased pressure from the stiffer springs along with the higher RPM will eventually and maybe quite quickly tear the heads off of the stock valves, which will ruin the engine instantly. NOTHING in these engines is very high quality as built from the factory. The only parts you won't replace on your way to building 16 to 20 horse power is the engine block, the crank shaft, the cylinder head casting, and maybe the piston. I would assume you already know about a header exhaust pipe , free flowing air filter and a larger jet in the carburetor. That is what is typically called a stage one kit. That along with the govoner removed will get you around 2 1/2 hp. over stock and is pretty cheap, around $80 to $100.
ANYTHING after that needs to be the aftermarket rod and flywheel. The question is almost as old as the automobile it's self. How fast do you want to go? How thick is your wallet?

 

[Kartin’ kid]

To make horse power you need to turn rpm's. To do that with out destroying the engine you need replace the rod and flywheel. There goes at least half of your budget. After that it needs to breathe. A camshaft with lots of duration and more lift than stock. F-275 or a 308. That's another $100. A milled and ported head. That's up in the air. Do you have a IN or know anyone who does with a machine shop, or a cylinder head shop. It's all just labor so it is very difficult to put a price on that. Stainless steel valves and stiffer valve springs are also needed. If you don't run stiffer springs the valves will float and potentially hit the piston. If you don't run the stainless steel valves the increased pressure from the stiffer springs along with the higher RPM will eventually and maybe quite quickly tear the heads off of the stock valves, which will ruin the engine instantly. NOTHING in these engines is very high quality as built from the factory. The only parts you won't replace on your way to building 16 to 20 horse power is the engine block, the crank shaft, the cylinder head casting, and maybe the piston. I would assume you already know about a header exhaust pipe , free flowing air filter and a larger jet in the carburetor. That is what is typically called a stage one kit. That along with the govoner removed will get you around 2 1/2 hp. over stock and is pretty cheap, around $80 to $100.
ANYTHING after that needs to be the aftermarket rod and flywheel. The question is almost as old as the automobile it's self. How fast do you want to go? How thick is your wallet?

Thanks for the input! I’m considering giving myself another 100 to play with on top of the 300. Worth it? That just means less money for other parts. Anyways, I unfortunately do not have access to a machine or someone who does for the head. Is that truly necessary or is there ways to (safely of course) get around that? Could you recommend specific springs to use aswell as jet size?

 

[Kartin’ kid]

Also, what’s the difference between a 265 and 275 cam, and is it important? I’m just noticing that 265s are decently cheaper

 

[madprofessor]

Maybe Pancho didn't mention it because they're all flat, but I think I recall that non-hemi Predator 212's don't have flattop pistons like the hemi's do. My understanding is that a flattop piston is a desirable upgrade for compression, as is a .010" - .012" head gasket.
If my memory serves correctly, then you could get the flattop for free by just choosing to start with the hemi version, and the head gasket is likely the most inexpensive mod you could do.
6.5 HP (212cc) OHV Horizontal Shaft Gas Engine, EPA (harborfreight.com)......NOTE: The hemi version is model # 60363, non-hemi is #69730.
Predator 212cc Performance Gasket Set,Fits Hem 60363 Engines(Best on the Market) | eBay.........This is what I use.

 

[Kartin’ kid]

Maybe Pancho didn't mention it because they're all flat, but I think I recall that non-hemi Predator 212's don't have flattop pistons like the hemi's do. My understanding is that a flattop piston is a desirable upgrade for compression, as is a .010" - .012" head gasket.
If my memory serves correctly, then you could get the flattop for free by just choosing to start with the hemi version, and the head gasket is likely the most inexpensive mod you could do.
6.5 HP (212cc) OHV Horizontal Shaft Gas Engine, EPA (harborfreight.com)......NOTE: The hemi version is model # 60363, non-hemi is #69730.
Predator 212cc Performance Gasket Set,Fits Hem 60363 Engines(Best on the Market) | eBay.........This is what I use.

That would be great, the only problem is I’m in California. Do you know if harbor freight still sells them? When I’ve been there in the past I haven’t seen them but then again I haven’t looked

 

[Kartin’ kid]

Or would it be possible to buy the hemi head online somewhere and swap it out?

 

[madprofessor]

Other folks here could tell you if you would be better off changing out a head than a piston.

 

[Kartin’ kid]

Stainless Steel Valve Kit: 212cc Predator (KDVALKIT27-25)

The Stainless Steel Valve Kit is a must-have for anyone looking to improve the performance and durability of their 212cc Predator engine. This kit includes a 27MM stainless steel intake valve, a 25MM stainless steel exhaust valve, billet aluminum spring retainers, split lock keepers, 26lb valve...

www.gopowersports.com

Found this. would it work with the other recommended mods?

 

[redflash]

probably won't give you any more power, but they're pretty

Da Redflash

 

[panchothedog]

Hey Kartin'kid
some of the info I posted last night was probably steering you towards a extremely high hp build you may never be able to afford. Starting over. The
265 cm grind cam is about the hottest one of the lesser prices cams. Use it
with the 22 lb valve springs. Not expensive, but much better than stock are the aluminum retainers and automotive style keepers. All of these parts are advertised at Go Power Sports for about $85. You should be able to run this with the stock valves. If you buy a stage one kit it will have the bigger jet in it,
but they are cheap and can be purchased individually. # 36, #37, or #38. If you just buy one, get the #37. I'm in California also and have never seen a hemi 212
for sale. Don't worry about it. If you notice all the modified aftermarket high compression and big valve heads for sale are NON hemi. That's because with high lift cams and or milled heads the valves in the hemi head sit on a angle and it causes clearance problems with the valves and piston. To raise compression get the flat top piston, about $21 same place, GPS. The non hemi
will come with a dished piston and the flat top ( rings included ) is a horse power increasing bargin at that price. For the rod you can buy longer than stock but then you must run a thicker head gasket to maintain .030" clearance
between piston and head so that sorta defeats the purpose, stay with stock length and use the thin head gasket. Buy the ARC flywheel. It is a little more than the PVL but it also has 32 degrees advance compared to 28, and helps turn more RPM, and you won't have to mess with an offset timing key. Do this and you will end up with somewhere around 12 horse power and well within your budget.

 

[panchothedog]

The valve -spring kit you show in post #9 is great. The problem is the valves have 5.5 mm stems and the new Predator engines come with 5 mm valves in them so that kit won't work. O. M. B. Warehouse sells a similar kit with 5 mm
stainless valves for about the same price. E C Carburetor also has the same kit.
In fact the one I bought from OMB I think it came from E C. If you don't go past the 22 lb springs you should be able to keep the stock valves that are in the engine now. I have a mini bike built very much like described above and did
not change valves. I have lots of hours on that engine and I weigh 225 pounds.

 

[Kartin’ kid]

Thank you panch! That’s definitely what I was looking for. Much appreciated. I was wondering about Rod lengthbut you’ve cleared that up as well

 

[redflash]

Remember kid, you already have 22 lb valve springs, and a 265 cam. Unless you;ve already blown it up they're still good.

Da Redflash

 

[Kartin’ kid]

Remember kid, you already have 22 lb valve springs, and a 265 cam. Unless you;ve already blown it up they're still good.

Da Redflash

Different engine! Yours will still be put to good use, don’t worry

 

[Kartin’ kid]

Does anyone know where I can find a 265? GPS seems to be out of them

 

[Kartin’ kid]

If you just buy one, get the #37.

I can’t seem to find the 37s. Only 38. I assume that’s all right?

 

[Kartin’ kid]

Does anyone know where I can find a 265? GPS seems to be out of them

Never mind!

 

[Kartin’ kid]

OK here’s what I’m getting, let me know if it all checks out:

flat top piston:

Flat-Top Piston for 212cc Predator (70mm, .570 Compression Height) (FTPISTON212)

The Flat-Top Piston for 212cc Predator (70mm, .570 Compression Height) is a high-quality engine component designed for superior performance. This piston is made from durable materials and is precision-engineered to provide smooth and efficient engine operation. The flat-top design of the piston...

www.gopowersports.com

Retainer kit:

Predator Performance HP Spring Retainer w/ Keepers

The Retainer Kit (18lb, 22lb, 26lb) is a set of three high-quality retainers designed to keep your valves firmly in place. The kit includes three different retainers with different weights - 18lb, 22lb, and 26lb - allowing you to choose the right retainer for your engine's specific needs. Made...

www.gopowersports.com

Stage one kit (air filter, adapter ect, 0.38 jet)

Stage 1 Performance Kit for 196cc/212cc Engines (STAGE1PK212-BLACK)

Introducing the Stage 1 Performance Kit, specially designed for 196cc and 212cc engines. This kit includes all the essential components to optimize the performance of your engine and take your ride to the next level. The kit contains an air filter, air filter adapter and air filter cover that...

www.gopowersports.com

Stage two kit:

Stage 2: 212cc Non-Hemi Predator Performance Kit "Cruiser" (P2K.S2NH-CRUISER)

The Stage 2: 212cc Non-Hemi Predator Performance Kit "Cruiser" is a comprehensive upgrade kit that includes several high-performance parts to take your engine's performance to the next level. The kit includes a 6625 Standard Fin Billet Flywheel that reduces the engine's weight and allows it to...

www.gopowersports.com

Exhaust pipe:
https://www.gopowersports.com/header-pipe-skinny-center-exit-196-212/

 

[panchothedog]

Have you already bought the engine? The stage 2 kit you show is for a hemi.
the cam and the flywheel are NOT interchangeable between the two engines.
Get the engine before you buy those parts.