reliability of a 16mm stroker?

[#ZERO]

...and just how do you base your statement?

Brian

I've had some back luck with throwing the rods of cranks in the past.

If the rods are stronger and the correct length for the +16 mil stroker; it might last a little longer.

Are the crank pins and lower rod bearings any larger on the 16mm stroker?

 

[wsuwrhr]

I would still like to hear your take on this if you ever get time. Thanks

Sorry, forgot all about this.

DASA recommends all of our rec engines to have the top ends INSPECTED every 50 hours and the bottom ends every 100 hours.

Race engines about 35 on the top and 75 on the bottom.

Now I want to stress this is for INSPECTION only.

Dan says 7500 RPM is safe for the 16MM engine in short bursts and 6500 RPMS will still be OK for WOT runs. WOT is not really applicable for freestyle, but nonetheless.

I love some of the threads and replies in threads about people who don't take care of their stuff and blame parts for failures due to their lack of maintainance. "Stroker crank reliability" threads and such. Almost laughable threads sometimes, the people with bad "experience" ruin it for the other guys looking to step up to a bigger motor, or worse, in my opinion, get talked into the stock stroke/90MM big-bore deal thinking it is a good idea.

I mean you are using an engine design that was designed for what, 60-65 HP and we are cranking 160-180 on the smaller setups to 200HP on the larger engines and you are complaining about reliability? Come on.

The GP engine design is a lightweight compact design, not like the GPR, complex Seadoo, or Polaris/ snowmobile hybrids. There is a simple reason why the design has lasted so long and why it is still the most popular.

The full billet 16MM engine(shortblock/long block whatever) is only 65lbs. A cast case billet cylinder 10-12MM stroker would be at least 5-7, maybe even 10 lbs less than that. Making at minimium 150HP.

I have 5 HARD seasons on a 10MM stroker 525 Banshee, with regular teardowns and keeping up on maintainance, it is still going.

Some of it is kinda got off the subject, but there is our answer....

Brian

 

[wsuwrhr]

I've had some back luck with throwing the rods of cranks in the past.

If the rods are stronger and the correct length for the +16 mil stroker; it might last a little longer.

Are the crank pins and lower rod bearings any larger on the 16mm stroker?

By letting the engine rev to the moon and bang off the rev limiter when it comes out of the water during your backflips and barrel rolls?

Whose crank, who setup the cylinder, who assembled the motor, sir?

Crank pins are factory sizes, rods are factory CR500. We use Crankworks exclusively and we stand behind CW's work.

Brian

 

[wsuwrhr]

Keep in mind a larger engine, by design, doesn't necessarily need to be "leaned on" quite as hard as a lower HP smaller engine.

Make sense?

Brian

 

[wsuwrhr]

.....but the crank/big end/small end bearings are the same size

Not true

 

[kevbo]

There is always lots of talk about the size of engines, carbs, and horsepower. I would like to know how all this extra torque at lower rpm is making more thrust with a 144 pump.

 

[freestylegeek]

There is always lots of talk about the size of engines, carbs, and horsepower. I would like to know how all this extra torque at lower rpm is making more thrust with a 144 pump.

The pump is basically just converting the mechanical energy (rotating shaft) into hydraulic energy (fluid flowing under a little pressure). Whatever power the the engine makes, the pump converts (ideally). Granted, there are mechanical and volumetric losses, yadda, yadda, but the basic idea is that the pump is just an energy converter.

The pumps I work with are positive displacement (unlike a jet pump), but hopefully this basically still applies. With a hydraulic pump, there are two things needed to do work - flow and pressure. Both of those require power. If you have 10 hp you can flow 21 gallons per minute at 500 psi, OR you can flow 1 gallon a minute at 3000 psi. In order to flow 21 gallons per minute at 3000 psi, you need 40 hp. The same pump can do both, it just depends on the engine.

This is just a generality, and obviously, big HP motors need a far more efficient pump than a stocker, but hopefully that cleared it up a little.

 

[luker]

might be a bit off topic but couple of guys here in aus got the complete 10mm stroker, billet cases the works etc awesome motor goes really good but the biggest let down (i think) is that there isnt stainless bolt in it the whole motor was assembled with bolts etc that have corroded and rusted only after 3 rides every bolt in the cases and head have had to be replaced

 

[wsuwrhr]

might be a bit off topic but couple of guys here in aus got the complete 10mm stroker, billet cases the works etc awesome motor goes really good but the biggest let down (i think) is that there is not 1 stainless bolt in it the whole motor was assembled with bolts etc that have corroded and rusted only after 3 rides every bolt in the cases and head have had to be replaced with stainless !

Unfortunately.....

That has been a problem, in our opinion, stainless is not the answer and we don't recommend using them either.

Unless it is a high-end bolt like ARP, stainless as a critical fastener is just not worth a damn, either in elasticity or in it's service life by galling. That is exactly why you won't find any stainless hardware on our motors except for the PV attachment hardware.

We have tried to find a suitable, cost-effective alternative, as sh itty as it sounds, we decided having a rusted bolt is better than having a stainless bolt failure.

We weren't able to find anything, so now we are having the steel bolts stripped and zinc plated.

Brian

 

[wsuwrhr]

Very good explaination.

The pump is basically just converting the mechanical energy (rotating shaft) into hydraulic energy (fluid flowing under a little pressure). Whatever power the the engine makes, the pump converts (ideally). Granted, there are mechanical and volumetric losses, yadda, yadda, but the basic idea is that the pump is just an energy converter.

The pumps I work with are positive displacement (unlike a jet pump), but hopefully this basically still applies. With a hydraulic pump, there are two things needed to do work - flow and pressure. Both of those require power. If you have 10 hp you can flow 21 gallons per minute at 500 psi, OR you can flow 1 gallon a minute at 3000 psi. In order to flow 21 gallons per minute at 3000 psi, you need 40 hp. The same pump can do both, it just depends on the engine.

This is just a generality, and obviously, big HP motors need a far more efficient pump than a stocker, but hopefully that cleared it up a little.

 

[Flash-FX]

What do you think happened here?

 

[waterfreak]

What do you think happened here?

Is that a crankworks? :ugh:

 

[Flash-FX]

Hmmm...don't know. I had some similar failures on my old 550 reed motors, never got a good reason why they break like that.

 

[Matt_E]

Unfortunately.....

That has been a problem, in our opinion, stainless is not the answer and we don't recommend using them either.

Unless it is a high-end bolt like ARP, stainless as a critical fastener is just not worth a damn, either in elasticity or in it's service life by galling. That is exactly why you won't find any stainless hardware on our motors except for the PV attachment hardware.

We have tried to find a suitable, cost-effective alternative, as sh itty as it sounds, we decided having a rusted bolt is better than having a stainless bolt failure.

We weren't able to find anything, so now we are having the steel bolts stripped and zinc plated.

Brian

What about OEM Yamaha hardware? :dunno:

 

[WaveDemon]

What do you think happened here?

you didn't inspect it. oke:

 

[SuperJETT]

What do you think happened here?

Mismatched case halves possibly?

 

[Matt_E]

Bad gas

 

[wsuwrhr]

What about OEM Yamaha hardware? :dunno:

Some too short, some head is too big.

Not that simple.

 

[wsuwrhr]

Hard to say since the picture isn't very good.

Crank maker?

The rod on the broke rod side looks discolored like a lean condition. Better too see it with a good picture, what did the other rod look like since you really can't see it?

Front bearing and center bearing looks discolored as well.

Otherwise could be a few things. Loose cases, mismatched cases, bad line bore, bad center bearing, bad rod bearing, lack of oil, ect.

Like it was asked already, are you saying you never came up with a reason for the failure?

Brian

Hmmm...don't know. I had some similar failures on my old 550 reed motors, never got a good reason why they break like that.

you didn't inspect it. oke:

Mismatched case halves possibly?

Bad gas

 

[egbrig]

Brian, since you are building the top of the line stuff why not use ARP 300 stainless studs and bolts. Seems to me if someone is paying that much for an engine they should pay for the best parts to hold it together? I haven't bought ARP in awhile and I know they are not cheap. What was the price difference?