2005 Z51 LS2 6 speed. It had a squeak/knock/banging that sounded really bad. Turned out it is really bad. The oil filter was full of metal and there were other issues so it is time to rebuild if the block isn't trash. I know basically nothing about stoker engines, but I am thinking about it. I want a reliable engine with as much HP that I can get without causing other issues. What would the advantages and disadvantages be too putting in a stroker engine? Please don't give me a long dissertation on how they work just a quick opinion. Thanks.

 

Only down side I see is the cost. You'll need new pistons, connecting rods, and crankshaft. You may need that anyway, only thing more expensive is the forged 4" stroke crankshaft. If you're starting with an LS2, you'll also need cylinder head upgrades and a better intake manifold. LS2 heads are marginal for performance use in stock form even with just stock cubes. The LS2 intake manifold is a POS.

The upside is that it's easier to upgrade your power level if you're starting with more cubic inches.

 

Pro's

More Displacement = More Torque


Con's

Higher Piston Speeds at any Given RPM
Higher Rod / Piston Acceleration at any Given RPM = Higher Loads on Components
Increase in Compression Ratio (may be a Good Thing or a Bad Thing - depending)
Components (Crank, Rods & Pistons) Will Probably be More Expensive than Comparable Components for Stock Displacement
Machine Work May be Required on Block (to provide clearance for stroker crank / rods.

So - if you go that route - make sure not to skimp on the Rotating Assembly components (Crank, Rods & Pistons), and especially not on the Rod Bolts.

And old motorhead is correct - to take full advantage of the longer stroke - the heads need to be able to flow enough to support the extra displacement.

 

A 4" stroke would really put the torque into OD. If trying to stay on a budget, LS3 heads and intake would be a great addition. If staying cathedral, you can make decent power, but it will be more of a torque engine, than a higher rpm, high horsepower engine. But if you go cathedral, pitch the LS2 intake. I never really got into the reasons why, but GM really dropped the ball on the LS2 intake. The LS6 is far better. But if it were me, I'd go with LS3 top end stuff. I believe this will work out to a 402 cubic inch, which could easily reach 550hp. Best of luck to you........

 

Do not use a stroker. Reliability is use a stock engine with some mileage. Get a motor with known good historical evidence and between 50k to 150k miles and modify it as little as possible and WHAM reliability. If you seek power add forced induction, don't modify the engine. If you use a cam/spring use a very slow ramp rate cam with low lift and the weakest spring possible, and do not touch any internal engine parts with bare hands- always use new disposable gloves, it is akin to surgery, blood is like oil. For example I used TFS-30602001 and PAC1218 for 150k miles of reliability 800rwhp forced induction on a stock 5.3L engine. Use a high quality air filter to maintain reliability, the most important part on a reliable engine is the air filter. Use double air filtration if you can, a filter within a filter. The engine will last two to ten times longer if you keep it clean inside and quality synthetic oil with all original parts.

 

I respectfully disagree with you regarding reliability and rebuilt strokers. You can have reliability with more power in a stroker. Valve train issues are most important in my opinion. For instance, steep ramp rates can cause damaged cams and resultant damage. The blocks are reliable if machined properly. A milder cam (.600" and under) with Ls3 top end is eating your cake and having it
too.

 

Not really what I meant. Nothing wrong with the right 'stroker'. For example 5.3L in my car is a stroker, technically. 5.3L and 4.8L share the same exact bore so the 5.3 is the stroker version. It is capable in terms of piston velocity maximum nearly 7,000rpm and factory intended for reliability application for 200k 400k 800k miles and so forth depending how it is maintained and treated. And still, supports 600 to 800rwhp reliably as any forged bottom end if tuned properly, as evinced by my and similar setups. I have 50,000 miles on mine so far, 5 years of daily driving with this 5.3 "stroker" version of the 4.8L chevrolet 2002 engine.

That said, displacement is meaningless with the right forced induction. How much power does a 2L engine make with a 500hp turbo? 500hp. How much power does a 7L engine make with a 500hp turbo? 500hp. Displacement is not a factor with the correct drivetrain setup per application details. In other words adding displacement to gain power is an potentially extremely unreliable means of gaining power. But I digress

What I am saying is beware of rebuilding any engine. Statistical analysis t-test may show a P value much less than .005 (<< .05) for population distribution > 1,000,000 sample size, that for factory Chevrolet engines made between 2002 and 2012, and Toyota/Nissan engines made between 1992-2002, it is extremely rare (P << .05) for a rebuilt engine to reach 200,000 miles whereas it is extremely common for factory versions of those engines to reach 200k and beyond.

 

The issue you have with going to a 4-inch stroke on an LS2 is the sleeves are too short at like 5.45 or so inches long. You need a sleeve of like 5.80 inches or so just like the OEM LS7 which also has a 4-inch stroke. Can it be done with the LS2 sure will it last long without piston rock probably not. Or you can get a custom piston but the longer sleeve is nice to have. They sell blocks with the longer 5.80 inch sleeves or you can have yours done up by RED on west coast they specialize in sleeving.

 

Not until you upgrade the diff

 

Diff is OK, until you upgrade the tires!!! And then.......

 

Are you suggesting that spinning a smaller motor up higher in rpm range and or running higher compression or more boost in an FI application is more reliable than a larger NA motor with less cr that doesn't need to turn higher rpms?
Doesn't matter imo which motor "lasts" longer-the OP's motor is shot lol despite it not being rebuilt, it happens.

If it were me I'd look for a reputable builder to build something or look to get a new shortblock and have upgraded heads and cam-turn a negative into a positive. jmo

 

1. Im suggesting to use an engine from the Factory which already has 50k 100k 150k miles on it, to ensure reliability for the next 150k to 300k miles.
2. Longer stroke has some issues in and of itself which have been mentioned I think. From engineering perspective, the forces and stresses involves with longer stroke can become significant at high RPM making it undesirable in performance applications. It isn't about displacement it is about stress and details associated with the angles made which may have long term consequences, such as piston 'side loading' or piston rocking, and the depth of piston in the bore, and some things we don't even realize by inspection, it may take a computer model of the exact engine and stroke to see all of the potential abuse.

You can skip all this issues by simply using a previously reliable engine with 100k miles or whatever and just taking it another 10-20 years. They are low cost, generally, my 5.3L for example was free. And there is no down time, no waiting for machine work. You can swap in a day. Be driving tomorrow.

 

I get what you're saying, I just don't agree that someone can find a motor with the kind of mileage you're suggesting and call it reliable. You can buy 10 motors used and get 10 that weren't taken care of properly. Plus it sounds (to me) like the OP is looking for more power, albeit reliable power.
Taking into consideration what you're saying-perhaps going to a 3.9 stroke instead of 4.0 would be a better choice for an LS2.
If it were me and I had to pay for tear down and install etc-I'd prefer to put in something with more punch.
Your way of thinking, the OP would have to pay good amount of money to get exactly what he had before.
My thinking is the OP, having to spend the labor/parts money already, may as well pay little more and get more horses and torque.

 

OP-how much mileage is on your current motor?

 

And this is probably why my advice is useless on these type of forums. It takes a true expert- experienced mechanic and with diagnostic ability to select a well cared for engine. It isn't HARD but it does require blood and headache which few people have patience and life experience for. I've inspected a thousand imported engines and become quite good at being able to single out the quality specimen among many. It is basic knowledge that has been lost among the performance crowd for some reason.
Its not some secret, I will tell you now: The primary character of well cared for engines with high mileage is
1. Intact OEM pcv hardware, no catch can or modded hoses/breathers
2. Original air filter and air tracts, no cold air intakes or aftermarket filters
3. Crankcase staining features of quality synthetic routine maintenance "light gold brown" with no texture from deposits/conglomerates
4. Under valve cover reservoirs of oil are dark but not sludged or sticky
5. No crust formation around fringes of operating oil level washing areas which indicates contaminated oil flow through for extended periods
6. Even compression test across all cylinders, doesn't have to be high, just even
7. Color of gaskets, silicone if any, is OEM indicating never-before-removed covers and seals
8. Factory harness, OEM tapes & ties, look for unripped plastic insert 'buttons' that hold wiring down which has never been removed
9. Absolutely no modification to the engine
10. No evidence of pressure washing or heavy degreasing on behalf of the salvage yard or engine sales
11. Never buy from a personal seller, only seek used engines from salvage yards which have hundreds of engines to sell of all kinds
Its also good if the Engine is from a crashed vehicle (or some evidence of a wreck) with a bit of broken glass or smashed plastics (reason for removal)

Theres more but this is most of it. If you follow these it is high chance of success.
In 2017 I went to a yard and looked at 10x 5.3L engines. I compression tested all of them and the best one was the most filthy, highest mileage engine they had. They gave it to me free, couldn't believe that was the one I wanted. Since then I put 50,000 miles on it 600rwhp over 5 years daily driving.

Not everybody can do what I know how to do. But it isn't impossible either. I am not here telling people what to do: Only revealing the possibility, adventure, ideology, ambition, affect to get what you want and not have to worry or pay a lot of money or spend a lot of downtime waiting on other people and trusting other people only to be let down.

We can use a stock 3L Engine to make 700rwhp. Or a stock 4.8L engine to make 700rwhp. Or a stock 6L engine to make 1000rwhp if you wanted. Those engines are very cheap. The key is forced induction, That will give reliability. for Reliability, it should use a slow camshaft rate, a low lift, very gentle valve train. Max RPM can be set near 6000rpm to preserve the engine as well. The point being- it doesn't matter what mods you make to an engine or how stock it is. The more aftermarket parts and more hands and people that touch it, makes it less reliable and more problems, and doesn't add any power or potential. Stroke or not stroke is negligible, not a component of power output with forced induction, and neither is displacement. Displacement can shift torque and area under the curve around, but that doesn't give more power and the true affect is imparted by the type of forced induction- and actually more friction and less power when things get larger and heavier despite being more difficult to slow down and easier to spin tires and snap axles. Again not necessarily an advantage when it comes to power and putting power to the Earth to good affect.

Not following me yet. Forget tear down. Install everything yourself. This is a car hobby not a pay to win game. The more you pay the less you win in this field. Its what we can do with the minimum investment. Use a free engine and make 800 horsepower is win. Learning curve is steep but not impossible. "PUNCH" is simply setting up the right combination of parts. I can easily use 3L to generate more 'punch' than a 6L Engine under the correct circumstances and with much higher output using a turbocharger than any engine with any displacement naturally aspirated.
You get more when you pay less by using knowledge because knowledge really is power.

 

You win.

Next time I need a motor I’m pm’ing you.

 

Here is the latest update on my engine/car. I decided to stay with what I had, but build it stronger. Everything in the engine that moves is bad and everything is being replaced. I mean everything, There were pieces of a lifter, brass sparkles, along with other metal stuff in the oil pan. The block is still good so far. Hopefully they don't find anything else. The work being done is at a very respected performance shop and the engine is also at a very respected performance engine shop. Everything being replaced is better than OEM in the motor and the rest of the car. Due to the metal in the engine the radiator is being replaced, stage II clutch, installing new shocks, brakes, and the shaft from the engine has splines that are screwed up. There are several other parts being replaced. When it's all done I will have hell of a stronger drive system and maybe a little more power after the dyno. I will have a hell of a stronger car and should enjoy it for many miles. Thanks for everyones responses and maybe I can let you all know how it runs when it is all done. It's a pain getting parts so it might be a while.

 

 

 

Not sure why radiator replacement has anything to do metal inside the engine, unless it's over 50% plugged, and caused an overheat condition. Can't hurt anything, for sure. I'll suggest DeWitts. I've had the same one for almost 17 years/70,000 miles now. Good as new! Just change coolant every 4 years (or 3, depending on preference), and they'll last longer than most will own the car! If running Dexcool, NEVER go over 5 years.......