I always hear the old muscle car guys talking about their "stroked 427" or whatever. I know the stroker kit is a power adder, but I have no clue what it actually does. Can someone please explain to this noob what a stroker kit does?

1. what parts are involved?
2. does it change displacement, bore, stroke, compression...what are its net effects on the engine?
3. Supporting mods involved
4. Can you do it to any engine or just V8's?

Thanks

 

well the ss s/c is essentially a destroked 2.2, it is possible to do a stoker, it would require some boring a new crank and rods and pistons, compression is up to u do u plan on running turbo s/c or nitrous then u would want low compression, if u plan on n/a then high compression. it would require alot of money as no aftermarket kit is avail.

 

Perfect
couldnt explain any better.
Its a lot of work

Im going to stroke my 350 LT1 to a 383 over the winter

 

1. Usually pistons and crankshaft.
2. Yeah it can it tends to wear out the pistons sooner. Additionally it tends to affect engines that run at high rpms and may lose performance. Think of this this way your banging some chick and you making 3" strokes but you decided f--- this I want to make 7" strokes in the time that it take to make a 3" stroke. Youre going to feel it.
3. ?
4. Generally this is done to obtain more torque. Although torque and power which then links hp, and torque sorta curves at a certain rpm. Which in some cases doesnt mean your going to travel at a faster speed. Mr. Ksaki was full of **** I DID pay attention in physics well sorta hahaha. Here at cobaltss were all tend to go for more speed but not necessarily through torque if I am explaining myself correctly.

Hope this helps.

 

2. Yeah it can it tends to wear out the pistons sooner. Additionally it tends to affect engines that run at high rpms and may lose performance. Think of this this way your banging some chick and you making 3" strokes but you decided f--- this I want to make 7" strokes in the time that it take to make a 3" stroke. Youre going to feel it.



Thats a great way to put it !!!

 

Wow, this could take a while.
Stroking a motor increases displacement. For example, you can buy a crank to make a 350 Chevy into a 383. The crank increases displacement by moving the rod journals farther from the crank centerline, so the piston goes farther down into the cylinder at the bottom of the stroke, hence, a longer stroke. Since the top of the piston now goes farther up than before it has to be shortened to keep from hitting the combustion chamber.

Stroker kits usually include a crank, rods and pistons. The block may have to be ground to provide clearance for the rods and crank, because they swing farther left and right than stock.

A short stroke engine will rev faster and higher than a longer stroke engine.
Stroking a motor generally gains more low/mid torque and limits how high the engine will spin. Conversly, de-stroking a motor will decrease torque and allow the engine to spin to a higher rpm, making more high rpm horsepower.

The best comparison of long-stroke and short-stroke engines are a Harley vs a jap 4 cylinder bike. The Harley revs low and slow while the 4 cylinder revs fast and screams at high rpm. The Harley pulls with low torque while the 4 cylinder has to rev to make power.
The Harley will only rev about half as high as the other before its' long-stroke design tries to come apart.

Since it takes so many custom components, it is not likely anyone will make a stroker kit for the ECO, but who knows?

 

at the end of the day, it is not worth stroking a cobalt....the money involved will NOT justify the small HP gains made from changing a 2.0l to a 2.5l or similar displacement.

its more common on V8's because stroking a 4.6l engine to a 5.4l engine will make a much bigger gain than stroking a 2.0l to a 2.4l, but the cost will still be similar (only price difference would be 8 rods instead of 4)

 

+1

+rep

 

Thanks Stedd, + back at cha!

To me, where this whole bore/stroke thing gets interesting is with a Chevy small-block V8.
The first-gen Z28 was a 302 with a 4" bore and 3" stroke. That is about the highest overbore ratio (1.33 to 1) that GM used. It was a competition engine developed for Trans-Am (pony car) series racing. With that large a difference between bore & stroke, the engine would rev almost instantly and wind to something like 8-9K+ rpm.
GM later made a 400ci SB that they installed in full-size cars and station wagons. One of the famous crankshaft companies made a crank that would de-stroke that engine to a 348 and give it the same b/s ratio as the Z28, 1.33 to 1. In a light car that was an amazing motor, revving superfast and high, it was a Z28 with 46 more cubic inches.

The stroker 383 SB is going toward the other side of the coin; slower revving, won't wind as high, with more torque because of a longer stroke compared to the bore. That engine is better suited to heavier vehicles like trucks that need more torque to get them moving.

My point in talking about the V8 is to point out that you can build an engine for exactly the type of performance that you need by juggling the bore/stroke ratio.

One more quick fact: an engine with a longer stroke produces more torque because the longer stroke has more leverage to turn the crank and torque is the rating of the turning (rotational) power of the crankshaft.

I'm not an expert and didn't intend to bore anyone, just throwing some info out there as I see it. Hope this helps make things a little clearer.

 

You're the man, DrPutts. Everything I wanted to know.

Main points I got out of this:

A stroker kit is basically a crankshaft with a larger diameter than the stock. This makes the piston fall farther from the combustion chamber, thus increasing displacement...low end torque...etc. I had a feeling this was it, but I didn't know you could actually go the other to improve performance in smaller, lighter cars depending on the application.

If you could de-stroke an engine, and cam it to make power in the high revs, you could esentially have an engine that was...well, a honda vtec style engine (without the vtec), high revs, low torque, high horsepower. You learn something every day.

 

keep in mind, you move more air with more cubic inches.
you also lose that nice 7k rpm rev zone as well.

there is a reason why a stock bore and stroke 302 can run to 6500, and the stock bore and stroke 454 pukes it's guts at anything over 5500. {stock bottom end for comparison}


or more modern terms for the honda gen kiddies.

a b16b1 {yea the b16b kids, i know what it is} vs the h22. sure the b16 has dick for torque, but it also zings to 10k rpms. where as the h22 has tons of torque {relativly speaking} compared to the b series. but the h22 will flat out destroy itself at 8k rpms, regardless of what internals are in it.

99% of the dsm drag cars are still 2.0 liters for a reason.

you just have to find out if boring, stroking, and balancing the short block will be worth it in the end. remember, these are not v8's

 

Well put, Area, seems like I'm following you tonight!

I've got a '68 Triumph TR-250 in storage. Two-seater british sports car, for you younger guys that haven't seen one.
It's got a straight 6-cylinder engine with 75mm bore and 95mm stroke! It literally is a tractor engine cause Triumph used them in sedans and the tractors they built. With that long a stroke (compared to the bore) that engine has tons of torque from idle to about 4-5K, then ain't got **** for power up top. Redline is at 5500 but it is useless to rev it that high. It is like the complete opposite of a honda.
But boy is it fun to drive! Lights the tires anytime, anywhere.

 

I have/had a 383 stroker in my 69 C/10. It was a lot of fun up until it went out on me. It would get up and move and suprised more then a few people. I always had people asking what I had under the hood. Oh it's just a small block, hehe.

Sweet, my buddy just picked up a 74 Spitfire for free. It needs a lot of work but it is gonna be really cool when we're done. Don't mean to highjack but where do you get any parts you may need?

 

Sorry to threadjack!
Send him to these two to start:
http://www.trregistry.com/start/registry/index.htm
http://www.vtr.org/

Pretty much everything is available for these cars, but expensive. Not too many junkyard cars left, but some used stuff still floating around. There are a couple of great catalogs available from companies that specialize in new parts for British cars. Ebay has a lot of cars and stuff too. G/L, the spitfire is a neat ride.

Back to original thread, sorry.

 

Cool, thanks.

 

If our LSJ was a 2.4L we would have about 20+ more pounds of torque.

 

if it still had the 86mm bore, and was just stroked to 2.4l, say bye bye to that nice 7krpm redline stgII gives....hell, maybe even lower than that

 

You don't know that. Would have to check piston speeds. I think people would prefer more torque and a 6500rpm redline then less torque and a 7000rpm redline.

 

just lookin at the ratios of bore x stroke, so no i dont know that for sure, but its a good assumption

 

stalker!

it's ok.

i had a 280z with a 3.1 stroker in it. 4 grand alone in the short block. balanced, blah blah blah. the motor in this car was limited by the stock head, and crappy excuse for a cam.

it started life as a 2.8. your normal L series z car motor. ld28 crank, aka diesel maxima crank. 240z/l24 rods. 240sx pistons. blamo. 3.1 liters of torquey fun! this car ran out of power at 6k. i shifted at 6300 or so. the motor was balanced to sustain 9k rpms. a race motor more or less. not all strokers are low rpms. just lays in the hand of the builder.

 

mmm... destroked big block

 

I have been wondering if a person could swap in the Chevy Colorado's 2.9L I4 ecotec:
LLV = 190 lb.-ft. @2800RPM. Bore x stroke is 95.5mm x 102mm
compared to the cobalts 2.4:
LE5 = 163 lb.-ft. @4800RPM. Bore x stroke is 88.0mm x 98mm

Pretty good jump in low end torque would be a lot of fun for a N/A! And that is before bolt on's! Does anyone know if the block castings are the same, just with different bores, and mabe deck height?