You guys W/Strokers

[Natural1]

..But again as most have mentioned you don't build a motor for its 250k mile longevity, if that was your concern than leave your engine stock.

Exactly!

 

[Sinner]

what makes that comment stupid?

id never put a stroker in a 4.6...the gains just arent worth the cost. one could build a solid .020 over motor and make plenty of power.

"if you can't afford to rebuild it don't do it.", no one plans to rebuild a built motor unless they race only. most of us here don't have money to throw away on countless motor builds and i think it's a stupid comment to say that. unless i understood him wrong, but this thread is about stroked motors and them lasting, not about the money people have to build motor after motor. in fact, the OP asked this question to see what is the most reliable choice.

 

[EagleStroker]

I can't speak for a lot but I have 20k miles on mine without any issue, and it sees 6500 every time I drive it for reference 3.75" stroke with a 5.950 rod.

Some of the posts in this thread are plain ignorant......

 

[pacettr]

It is not bullshit at all. Stroking an engine changes the rod ratio and increases the load the piston exerts on the cylinder (yes, even with offset pins), usually in mid travel. If you've ever built a 347SBF, you know why it doesn't last like a 331. Also, a 5.4L is not a stroked 4.6L. Though, as you said, the 5.4L has a block with a totally different deck height but that's completely different when doing a rod ratio comparison.

Not entirely true. Read this:

Chris.......on page #1 I asked a few questions on the subject that got over looked or got ignored. Remember, I asked think about about EVERYTHING that would be affected. For instance, a 331 v 347. Sure a 347 has more side load, no question about it. But it is insignificant. Plus, the smaller engine with a taller R:S ratio will turn more RPM to do ANY job that the lower numerically R:S engine will do.

On the corral one of the village idiots over there (5spdGT) wanted to argue this point everytime it came up. He wanted to argue that the 331 would last FAR longer due to the less side load. Okay, go with that. If your 347 is turning 6500 RPM to get a certain job done, the 331 will have to turn 6814 RPM (or 4.83%) to get the same job accomplished. RPM will kill parts at a greater rate than side load. Even cruising down the road in 5th gear, the 331 needs more RPM to do what the 347 is doing at a lower RPM.

The 454 BBC has been brought up. 4.00" stroke with a 6.135" rod. 1.534 R:S. A 400 SBC from the factory is a 3.76" stroke on a 5.565" rod. That is 1.484 R:S ratio. Both are great examples of engines that were built when pistons were junk and both engines would last well over 100K miles. Today, the 4 cyl Hondas and Toyotas are taking medium stroke engines with relatively short rods and making them work. 3.50" strokes with 5.45" rods (1.557 R:S) and they turn 8000 RPM and up. How is this possible? Large heads (no velocity I guess ) and well designed pistons that utilize off set pins. This lessens the side load and makes for a long lasting piece.

being said, a stock 4.6L/5.4L can see 250K miles of fair driving. A built engine with a power adder (or even without) should be freshened every so often, so what are you guys worried about 100K+ mile longevity for? I'm not saying that you won't get that, because you could but I'd have mine apart every couple of years for inspection and maintenance. Built engines are a big investment and I'd like to protect that investment with preventative maintenance, the alternative is much more expensive. Also, I keep hearing these guys that say, "I want to spin my stroker engine to 7000+RPM.." and I'm like what the eff?! Why on earth would you want to do that? If you wanted to spin the crap out of it, big bore it and ditch the stroke, this will help engine airflow as well. Really, the beauty part of the stroker, is that you can spin it fairly high but it makes great torque and horsepower, down low, so you don't really have to. I personally see the big bore/stroker 327 being my next engine.

Much better.

Tiger, I forgot about the Saleen coming stock with one, darn good point.

I was going to bring this up about my car.

It is not the 8 cylinder spread or the 21 extra cubes, there's more to it than that.. Look, when you already have a rod ratio of 1.67 and you are adding .200"-.250" of additional stroke it breaks down like this:

Stock 4.6L(5.933) - 1.67
3.750 4.6L(5.850) - 1.56
3.800 4.6L(5.850) - 1.53
Stock 5.4L(6.658) - 1.59

* I didn't cut and paste the crap above, though the math is easy.. Rod length/stroke = rod ratio

The added stroke will increase piston speed, increase side loading on the cylinders (even more under boost) and create additional piston instability if the rings had to be moved farther upward for pin clearance and the skirt shortened for counterweight clearance. This information can apply to any engine. I'm also, not saying that the strokers are bad or unreliable or anything of the sort. What I am saying, is that the longevity will be slightly decreased because of the rod ratio and decreased even further by the engine's intended use, performance/hard service.

The 5.4L is also available as a stroker with 4.35" and 4.415" strokes. These cranks are from Paschal and are billet. I added the 5.4L, simply for additional information. I like to keep my posts detailed for reference use.

If it decreases longevity at all, it's insignifigant.





Get the stroker.

 

[Natural1]

Nothing I ever said was to deter him from getting the stroker. I believe I even commented that my next engine was going to be a big bore with a 3.80 stroke or 327. Remember that rod ratio isn't the only factor. The ring location and distance from the pin to the top of the piston, plays an important role in piston stability and the prevention of wear, as well. The compression height in any stroker, is obviously determined by the available deck height and available rod length(s). While we are on the subject of Chevrolet engines, the 400SB may have a bad rod ratio (increased dwell) but it also had a compression height that is about .300" greater than a stock 4.6L, which would then allow the rings to be spaced farther for stability.

 

[pacettr]

Nothing I ever said was to deter him from getting the stroker. I believe I even commented that my next engine was going to be a big bore with a 3.80 stroke or 327. Remember that rod ratio isn't the only factor. The ring location and distance from the pin to the top of the piston, plays an important role in piston stability and the prevention of wear, as well. The compression height in any stroker, is obviously determined by the available deck height and available rod length(s). While we are on the subject of Chevrolet engines, the 400SB may have a bad rod ratio (increased dwell) but it also had a compression height that is about .300" greater than a stock 4.6L, which would then allow the rings to be spaced farther for stability.

 

[Germeezy3]

Another thing not mentioned is the power increases a big bore setup will pickup due to the increased airflow from unshrouding the valves. But I agree with you guys in the fact that a lot of the things that used to be true about bore to stroke ratio and piston speed are not as set in stone as they once were.

Case in point is the undersquare 1ZZ-FE in the Lotus Elise with a transient 8,500 rpm redline or the Audi/ Lambo V10 which is undersquare but still has no problem having a 50k warranty and an 8700 rpm redline.

 

[Natural1]

Another thing not mentioned is the power increases a big bore setup will pickup due to the increased airflow from unshrouding the valves.

On page 2, I mentioned it. "improved airflow..."



Being under square is ok, as long as you aren't stuffing a ridiculous stroke in a block with a short deck.

 

[KungFuHamster]

the new 5.0 is slightly undersquare too.

 

[Natural1]

We do know that oversquare means a larger bore than stroke, right?

 

[Fast64ranchero]

Thanks for the good info, I'm going to do the 3.8 stroke, Boss 3.7 block

Eaglestroker you stated you have 3.95 rods with 3.75 crank, is the pin in the oil ring land? 20K that's good news.

Natural1 I was talking about how fast the piston goes from a dead stop to it's fastest piston speed, then back to a dead stop (TDC/BDC) a shorter rods increase acceleration, and even worse deceleration, which is where most rods and or piston pin bosses fail. It also affects dewel as you stated or am I wrong??

 

[Natural1]

That's a badass combo! If you are going that route, do the L&M Engines pistons. Also, I believe it's 5.850 rods with the 3.80 stroke.

As far as the other stuff, it's not really referred to as accel or decel, it's usually referred to as dwell (measured in thousands of piston travel) over so many degrees of crankshaft rotation. For instance on a hypothetical engine, at TDC you may have .000", at 5deg ATDC you may have .008", and at 10deg ATDC it may be at .028" and so on. The interesting thing is that the piston never travels the same distance in any given degree of rotation.

Hemmings gives the best summary in this excerpt:

"When Detroit designs an engine, any increased octane tolerance is always welcome, because it allows a higher compression ratio that will result in greater thermal efficiency and better throttle response. If brute power, fuel octane and longevity are minimal concerns, an engine with a short connecting rod is desirable. If you're aiming for low-speed torque, balancing octane tolerance with compression ratio and longevity, any ratio over 1.6 will suffice; there's no real-world gain beyond that."

I understood what you were making reference to, though and you are correct about the stress this causes.

 

[Sinner]

wow, this thread is so far over my head... i need to study! sounds like some great info though.

 

[EagleStroker]

Thanks for the good info, I'm going to do the 3.8 stroke, Boss 3.7 block

Eaglestroker you stated you have 3.95 rods with 3.75 crank, is the pin in the oil ring land? 20K that's good news.

Natural1 I was talking about how fast the piston goes from a dead stop to it's fastest piston speed, then back to a dead stop (TDC/BDC) a shorter rods increase acceleration, and even worse deceleration, which is where most rods and or piston pin bosses fail. It also affects dewel as you stated or am I wrong??

Yes it is. With the kit I used stock stroke is 5.900, so I didn't see a reason not to 'pop' for it and I really like it. It's also using the 1.889 rod journal which I think is a pretty cool set up.

 

[Germeezy3]

On page 2, I mentioned it. "improved airflow..."



Being under square is ok, as long as you aren't stuffing a ridiculous stroke in a block with a short deck.

You did say that, I wish I could give you positive rep you are damn knowledgeable about engines!

We do know that oversquare means a larger bore than stroke, right?

I hope so

That's a badass combo! If you are going that route, do the L&M Engines pistons. Also, I believe it's 5.850 rods with the 3.80 stroke.

As far as the other stuff, it's not really referred to as accel or decel, it's usually referred to as dwell (measured in thousands of piston travel) over so many degrees of crankshaft rotation. For instance on a hypothetical engine, at TDC you may have .000", at 5deg ATDC you may have .008", and at 10deg ATDC it may be at .028" and so on. The interesting thing is that the piston never travels the same distance in any given degree of rotation.

Hemmings gives the best summary in this excerpt:

"When Detroit designs an engine, any increased octane tolerance is always welcome, because it allows a higher compression ratio that will result in greater thermal efficiency and better throttle response. If brute power, fuel octane and longevity are minimal concerns, an engine with a short connecting rod is desirable. If you're aiming for low-speed torque, balancing octane tolerance with compression ratio and longevity, any ratio over 1.6 will suffice; there's no real-world gain beyond that."

I understood what you were making reference to, though and you are correct about the stress this causes.

A few other things are mean piston speed and peak piston speed, which is something that will definitely affect longevity. So while the side loading in the cylinders may be close if you pull a stroker to the same revs as a stock motor or a big bore engine its mean and peak piston speed will be higher and in some cases considerably so.

Nothing wrong with a stroker so to speak, but a big bore engine has its advantages of course but in some cases the stroker way is cheaper.

 

[Anthony05GT]

From what I gather, a 302 stroker has a stroke only a fraction of an inch longer (around 1/3'') than a 4.6 standard stroke. Combine that with the new stroker rotating assembly being balanced and I don't think this is an issue worth worrying about.

 

[Fast64ranchero]

You did say that, I wish I could give you positive rep you are damn knowledgeable about engines!



I hope so



A few other things are mean piston speed and peak piston speed, which is something that will definitely affect longevity. So while the side loading in the cylinders may be close if you pull a stroker to the same revs as a stock motor or a big bore engine its mean and peak piston speed will be higher and in some cases considerably so.

Nothing wrong with a stroker so to speak, but a big bore engine has its advantages of course but in some cases the stroker way is cheaper.

I did the math, stock stroke piston speed @ 7,000rpm is 4,100fpm, the 3.8" stroker is 4,400fpm (rounded) if I remember right, not that big of a difference

Eaglestroker: so your using the large import/nascar journal size, what are you using for a crank and rods?
I don't want to look like an ass, so I'm going to research, but I'm thinking offset ground stock crank or re-sized aftermarket crank, no idea what rods you used, maybe 4G mitsu?

 

[EagleStroker]

Otherwise known as 'Honda journals' its a really neat set up offered direct from Eagle as a forged 4340 replacement, .125" radius on the journals, don't take it as a sales pitch just an explanation. If I'm not mistaken it is the same as a 4cyl Mitsu just twice as many. I also did the Armor process on it because it can only help especially in longevity and lower oil temps. I'll break the block before I break this crank and rod combo!

 

[BMWM3]

Original Poster
in my ebay horsepower1 stroker high compression engine build it has 23,440 miles on it the 302 stroked block with stuff in build sig , NO PROBLEMS , used nitrous a few times on it now my uncle drives the car EVERY DAY , EVERY WHERE. for what it cost if i could do it all over again, i'd buy a used c6 z06 vette and do heads, cam, tune, cai, exhuast and a little baby juice and be done with it.

and the gas mileage on car city was 14-17 and highway cruise control 22

 

[Germeezy3]

From what I gather, a 302 stroker has a stroke only a fraction of an inch longer (around 1/3'') than a 4.6 standard stroke. Combine that with the new stroker rotating assembly being balanced and I don't think this is an issue worth worrying about.

I did the math, stock stroke piston speed @ 7,000rpm is 4,100fpm, the 3.8" stroker is 4,400fpm (rounded) if I remember right, not that big of a difference

Eaglestroker: so your using the large import/nascar journal size, what are you using for a crank and rods?
I don't want to look like an ass, so I'm going to research, but I'm thinking offset ground stock crank or re-sized aftermarket crank, no idea what rods you used, maybe 4G mitsu?

I gathered that we were talking about all 4.6 based strokers and not just 302 strokers.