FM stroker alternative?
07-03-2013, 04:53 PM
#21
FYI, you can't get the same pistons from Wiseco. All the pistons we sell are made for us to our specs, and the strokers in particular are unusual due to that low compression height.
Add up the same spec (ceramic tops, moly sides, uprated rings, oil ring support) and you'll discover there isn't an "FM tax". You guys have such a ridiculous view of our profit margins.
If someone comes up with a source for the crank that's as strong (they've been used in 800 hp engines) and less expensive, point me to it.
Add up the same spec (ceramic tops, moly sides, uprated rings, oil ring support) and you'll discover there isn't an "FM tax". You guys have such a ridiculous view of our profit margins.
If someone comes up with a source for the crank that's as strong (they've been used in 800 hp engines) and less expensive, point me to it.
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07-03-2013, 05:28 PM
#25
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I remember Jkav's article about a long rod BP conversion on Edmunds.com using Milspec rods and JE pistons. Basically longer rods and shorter slugs. Not a stoker but altering piston speed and reducing side loads in the bore.
Long Rod BP Conversion And Nerdery - 1997 Mazda MX-5 Miata Long-Term Road Test
Long Rod BP Conversion And Nerdery - 1997 Mazda MX-5 Miata Long-Term Road Test
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07-03-2013, 06:52 PM
#27
If the head would breathe, it would be fun 
We can do a long-rod engine without too much difficulty by matching stroker rods to custom pistons. We've had at least one set of pistons made up to do it in the past. I don't really know what happened to them though. If someone else wanted to give it a try, it could be arranged.
We can do a long-rod engine without too much difficulty by matching stroker rods to custom pistons. We've had at least one set of pistons made up to do it in the past. I don't really know what happened to them though. If someone else wanted to give it a try, it could be arranged.
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07-03-2013, 09:12 PM
#28
So your saying the Weisco doesnt offer custom pistons to the public, Well just about every piston manufacturer does. And if you know what you want, you can ask them for a specific compression height, or whats the lowest you can go. Not every one needs flying miata to think for them.
Sav, obviously there are people that will pay big bucks for a specific power curve. I mean i payed big buck for top end power. Then bought nitrous for low end. My opinions greatly differ from yours because i do not care about fitting into a specific class.
And as far as sleeving goes, its all the same process, and they all can sink. I have seen v8 iron block sleeves sink, And i have seen tons of honda sleeves sink. There is always the possibility. Its not fun to chase blown head gaskets and overheating and oil mixing with coolant because of a sunk sleeve that you paid big bucks for. I think anyone with have a brain would avoid that headache.
Sav, obviously there are people that will pay big bucks for a specific power curve. I mean i payed big buck for top end power. Then bought nitrous for low end. My opinions greatly differ from yours because i do not care about fitting into a specific class.
And as far as sleeving goes, its all the same process, and they all can sink. I have seen v8 iron block sleeves sink, And i have seen tons of honda sleeves sink. There is always the possibility. Its not fun to chase blown head gaskets and overheating and oil mixing with coolant because of a sunk sleeve that you paid big bucks for. I think anyone with have a brain would avoid that headache.
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07-03-2013, 09:21 PM
#29
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Just been wondering how much longer stroke you might be able to get with stock pistons and crank. My '95 1.8l Roadster has I believe 9.0 comp pistons or slightly under.
Would lengthening the stroke a little mean the piston rising too much and mash the valves?? or is there a small useable clearance? or will the rings jump out the sleeves.
Reading JKav's blog he gains 7mm with the Mil-spec rods but uses specific JE pistons
Would lengthening the stroke a little mean the piston rising too much and mash the valves?? or is there a small useable clearance? or will the rings jump out the sleeves.
Reading JKav's blog he gains 7mm with the Mil-spec rods but uses specific JE pistons
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07-03-2013, 09:58 PM
#31
Sure, design your own pistons and Wiseco will make them for you. Don't expect them to be any less expensive than ours though if you spec them out the same way. That's my point. And you can't just call up and ask for "Flyin' Miata stroker pistons", you will have to do some thinking.
It's interesting to note that Wiseco's off-the-shelf Miata pistons used to be quite a bit different than ours in small details such as the side profile of the piston. More piston rattle when cold. I think it's because they just stuck with their original design while we continued to evolve ours to improve. Even the stroker pistons have been through several running design changes over the years, from mild changes to increase valve clearance on VVT motors to fairly fundamental changes to the underside structure. When Wiseco went to the new castings, I think they updated a lot of their specs to match what we'd learned with ours. They're still decontented though.
Freaky, stroke comes from the crank. Unless you modify the stock crank by welding and grinding, the stroke won't change.
It's interesting to note that Wiseco's off-the-shelf Miata pistons used to be quite a bit different than ours in small details such as the side profile of the piston. More piston rattle when cold. I think it's because they just stuck with their original design while we continued to evolve ours to improve. Even the stroker pistons have been through several running design changes over the years, from mild changes to increase valve clearance on VVT motors to fairly fundamental changes to the underside structure. When Wiseco went to the new castings, I think they updated a lot of their specs to match what we'd learned with ours. They're still decontented though.
Freaky, stroke comes from the crank. Unless you modify the stock crank by welding and grinding, the stroke won't change.
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07-03-2013, 10:37 PM
#33
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You'd have to be a special kind of stupid to machine a full 8mm out of the rod journal diameter in order to gain 4mm of stroke. If you're having someone like Castillo grind you a stroker crank without adding 4mm of material to the outer edge of the pin first, you're doing it very, very wrong.
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07-03-2013, 10:47 PM
#36
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I wouldnt try that at all Id give it to my machine shop to do, it sure wouldnt go to my grinder shop however.
The point of the post was that keiths post made it sound like a backyard operation with hand tools, where as it isnt, it was for the benefit of the poeple above me who clearly dont understand the process.
Offset crank grinding is a common practice, however taking 8mm out without doing anything else would not be recommended.
Last sentence again for the above people.
Dann
The point of the post was that keiths post made it sound like a backyard operation with hand tools, where as it isnt, it was for the benefit of the poeple above me who clearly dont understand the process.
Offset crank grinding is a common practice, however taking 8mm out without doing anything else would not be recommended.
Last sentence again for the above people.
Dann
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07-03-2013, 11:41 PM
#40
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Ah, gotcha. In the US, pretty much any machining process that refers to the crankshaft is colloquially known as "grinding", no matter how elaborate the process. Rewelded, re-machined with an offset centerline, added 3mm to the pin diameter in the process? It's referred to as a "Crank regrind".
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