STROKER MOTOR
- Thread starter stick
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Silverback answers this best, if he dont chime in pm him:rock:
OCBob
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Short answer is that you increase displacement by increasing the length of stroke (up and down motion of the pistons in the cylinder) rather than boring out the cylinder to make it larger. I know that you do this on a bike by swapping out the flywheel and rods. This has always been an effective and relatively easy way of increasing displacement, and most people have heard of a stroker harley. You can bump a harley up from 88 inches to 95 pretty cheaply with this method, I think they are running our trucks up to 522's doing this.
mopower1958
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An engine that has a different crankshaft throw other than stock. In other words on a 440 cubic inch Chrysler the crank has a 3.75 stoke. A "STROKER CRANK" that is common for this engine is a 4.15 stroke meaning the piston travels more distance in the cylinder every revolution of crank rotation. It requires a different piston with the wrist pin relocated. A 4.15 crank will make a 440 a 493 cubic inch with same bore size. Some competition eliminator cars in drag racing "DESTROKE" an engine in order to change class to be more competitive. They turn some of these destroked small blocks over 10,500 rpm. The longer the crankshaft stroke the more torque an engine has, so the destroked engines have to turn more rpm to make power.
thankyou,,,I have been talking to Larry at manceto motorsports and told him I want the most horsepower and tourge out of my engine without forced induction. And he keeps saying "stroker". I did not want to seem like a dumbass,,,,,,,,,,,,Yall already know im a dumbass lol
It's been pretty well covered by those that have responded so far, so I will go into some other related information.
As MP1958 stated, the piston has to travel a greater distance per stroke. This therefore increases the piston speed in the cylinder. This in turn increases the loads on the crank and rod as the piston reaches the end of the stroke and has to reverse direction. While stroking an engine does increase the displacement and to a small effect the HP, it does not increase the ability of the engine to breath, hence to make more HP. Remember, that is where the HP is at. Getting more of the Air/Fuel mixture into the motor is what really increases HP.
Here is an example that I hope helps you understand.
Let take a V8 engine with a 4.00 bore and 3.00 stroke. This comes out to be 301 CI. Now if that same size engine, 301 CI had a 3.00 bore it would then have a 5.33 inch stroke. Same size engines, same HP? Nope.
The first engine with the 4.00 bore allows the head to have larger intake and exhaust valves. It will breath much better than the 3.00 bore engine that will have to have smaller valves to fit in the smaller cylinder. Since each engine has 37.6 CI per cylinder the 3.00 bore engine will not be as efficent filling that cylinder with the smaller valves so it will not receive the same amount of Air/Fuel mixture as that 4.00 bore engine.
Make sense?
As MP1958 stated, the piston has to travel a greater distance per stroke. This therefore increases the piston speed in the cylinder. This in turn increases the loads on the crank and rod as the piston reaches the end of the stroke and has to reverse direction. While stroking an engine does increase the displacement and to a small effect the HP, it does not increase the ability of the engine to breath, hence to make more HP. Remember, that is where the HP is at. Getting more of the Air/Fuel mixture into the motor is what really increases HP.
Here is an example that I hope helps you understand.
Let take a V8 engine with a 4.00 bore and 3.00 stroke. This comes out to be 301 CI. Now if that same size engine, 301 CI had a 3.00 bore it would then have a 5.33 inch stroke. Same size engines, same HP? Nope.
The first engine with the 4.00 bore allows the head to have larger intake and exhaust valves. It will breath much better than the 3.00 bore engine that will have to have smaller valves to fit in the smaller cylinder. Since each engine has 37.6 CI per cylinder the 3.00 bore engine will not be as efficent filling that cylinder with the smaller valves so it will not receive the same amount of Air/Fuel mixture as that 4.00 bore engine.
Make sense?
RedRamRules
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Would increasing the bore size ONLY be a recommended path to increasing displacement, or would you also have to increase stroke or reduce stroke length as well?
mopower1958
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I would do just the stroker. I would leave the bore size alone if the cylinders are ok. The thicker the cylinder walls the better, less cylinder distortion under load and better heat transfer to the water jackets.
mopower1958
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Horsepower is made more through cylinder heads and lightweight reciprocating pieces more than cubic inches. Look at Pro Stock cars in the NHRA. They have a 500 cubic inch limit and with 2 dominator carburetors make in excess of 1100 horsepower, no nitrous or superchargers. NASCAR engines have a 355 cubic inch limit and make over 800 horsepower. Cars like the one in my avatar have from 426 to 450 cubic inch HEMIS. The cylinder heads have huge valves and ports,the pistons are ultra light weight and run with 2 factory 4 barrel Holleys.Charlie Wescott runs the Warfish Cuda and turns it 9500 rpm. Runs 8.50's at 154 mph. All done with light weight internals and large high flow HEMI cylinder heads.
RedRamRules said:
Now the following is only my opinion. So please treat it as such.
With a 522 stroker you are only picking up 17 CI, or 1.7 CI per cylinder. These motors already produce a ton of torque so to me it's not worth the cost for a naturally aspirated engine.
If you are going to the trouble of building an engine for turbos or a S/C, then I would go for it. If you are going this way, remember one thing. You are better off going with a low compression / high boost combination than a high compression / low boost set up. For the same cylinder pressures you will have more A/F mixture in the cylinder.
Also MP1958 is right. Stay with the stock liners. The thicker the better.
mopower1958
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Has anyone swapped to the Striker heads with a good cam and left the bottom end alone? Curious as to the HP gains with just heads and cam. Seems like that would be the more dependable/economical power increase.
Blakewilder
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BRO...its Macedo....not Manceto. Dont wanna insult Larry 
mopower1958 said:
Eric (Ram From Hell) was going this route on his rebuild I believe. He has not posted lately on what is happening with his truck. I know he has been busy with the new house and such, so that may be taking all his time.
Blakewilder said:BRO...its Macedo....not Manceto. Dont wanna insult Larry
sorry no disrespect intended,
So I guess tis is not what I want to do to my truck, I am looking to get around 600 or more HP . I want something thats all motor for when I punch it , my wifes car will see nothing but a yellow streak.
And I want it to have a lope to it
stick said:
Cam, Headers, High Flow Cats, Heads, and a PCM upgrade. On the heads, at a minimum have the ports matched to the intake. If you can afford it go for a full port job.
Once again as MP1958 said. HP is in getting the Air/Fuel mixture into the engine.
Nowwhat
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mopower1958 said:
If you go Strikers + Cam + the needed match port to the intake + headers (needed) + valve cover spacers + tune + labor.....you will spend more than just adding a paxton...and get only a 150ish rwhp jump....
Texas Yellow Fever
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Nowwhat said:
Ah, but if you do all the above AND add a paxton...:rock: :rock: :rock:
Nowwhat
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Texas Yellow Fever said:
then you are 900rwhp like Blake.....
:rock:
FSTJACK
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John (Silverback) is correct in what he said. I have talked with a man who has built many of these motors both forced induction and normally asperated. The "stroker" is not worth the cost in relation to the benefit. This has shown up many times on the engine dyno. Spend the money on the heads, and manifold porting. You will be much happier with the result.
Striker heads, custom camshaft, Long tube headers, freeflowing enhaust, should get you 575-600 RWHP on an Regular cab. It does take the right combination to get these #'s, but EED (Exotic Engine Development)
Contact Kevin Singleton at Exotic Engine Development (EED), he builds many exotic engines and has customers from all over the world . He is one of our vendors here and the motor builder for my Drag SRT-10 truck. He has more experiance in building these motors than most and worked on the development of the Striker Head with the Mfgr. He can build you a very reliable combination at a fair price.
http://www.exoticengine.net
Striker heads, custom camshaft, Long tube headers, freeflowing enhaust, should get you 575-600 RWHP on an Regular cab. It does take the right combination to get these #'s, but EED (Exotic Engine Development)
Contact Kevin Singleton at Exotic Engine Development (EED), he builds many exotic engines and has customers from all over the world . He is one of our vendors here and the motor builder for my Drag SRT-10 truck. He has more experiance in building these motors than most and worked on the development of the Striker Head with the Mfgr. He can build you a very reliable combination at a fair price.
http://www.exoticengine.net
Nowwhat
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FSTJACK said:
2nd that.....EED is building my new motor and doing some favors......:rock:
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