4.165 bore stroker
08-16-2017, 10:34 PM
#2
Why does it have to be 1.050 comp ht piston? * you must have a set* Also if you do the math you'd know the crank stroke and fill in rods and then Know the comp ht or work it out if you have pistons. I'm in a hotel tired from driving. Go do the calculations and you'll know the stroke you have the compression height...... fill in the rods that's needed.
08-16-2017, 11:30 PM
#3
TECH Fanatic
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9.240 deck height, 1.050 compression height, 6.200 rod length, 4.00 stroke =436c.i. Not short stroke.
6.300" rod, 3.78" stroke = 412ci.
6.350"rod 3.680" stroke = 401c.i.
6.400" rod 3.580" stroke = 390c.i.
6.300" rod, 3.78" stroke = 412ci.
6.350"rod 3.680" stroke = 401c.i.
6.400" rod 3.580" stroke = 390c.i.
Last edited by 64post; 08-16-2017 at 11:45 PM.
08-16-2017, 11:55 PM
#4
08-17-2017, 09:55 AM
#5
FormerVendor
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LS-447 = Crankshaft 4.1" stroke. Hi Last1, I have assembled LS engines with a 1.06" CD.
That bit of kit : My 4.1" crankshaft, My 6.125" forged "H" beam rods, RaceTech forged pistons with "short" tangs.
My guess is a piston designed for the 4.10" crankshaft ? (LS-447)
Lance
That bit of kit : My 4.1" crankshaft, My 6.125" forged "H" beam rods, RaceTech forged pistons with "short" tangs.
My guess is a piston designed for the 4.10" crankshaft ? (LS-447)
Lance
08-17-2017, 10:02 AM
#6
I wanted to do something like this awhile back but my grinder wouldn't do it. He said that going to a 2.00" journal removes too much of the rolled fillets and not enough to get a good radius, so it really just weakens the crankshaft too much. He would only do it if the journals were welded up before grinding, but it wasn't cost effective at that point.
08-17-2017, 10:39 AM
#7
You can use the 6.350 rod with 1.050 piston on a stock stroke 3.622 as long as you set the deck height. There is more than 1 way to build an engine as long as you are ok with cutting ~ .030 off the block. BUT honestly after assembly most lsx pistons are above deck so assemble first, check total height THEN cut deck and run it. Make SURE the rest of your calculations take that into consideration like pushrod length and such but also realize you are slinging around a much heavier rod. Youd be better off to go to a better CH.
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08-17-2017, 12:51 PM
#8
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I see a trend with more people building or wanting to build large bore short stroke motors, hp in the RPM is the thinking. Don't lose interest in those pistons, OP, there's lot's possibilities there.
08-17-2017, 12:54 PM
#9
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You can use the 6.350 rod with 1.050 piston on a stock stroke 3.622 as long as you set the deck height. There is more than 1 way to build an engine as long as you are ok with cutting ~ .030 off the block. BUT honestly after assembly most lsx pistons are above deck so assemble first, check total height THEN cut deck and run it. Make SURE the rest of your calculations take that into consideration like pushrod length and such but also realize you are slinging around a much heavier rod. Youd be better off to go to a better CH.
08-17-2017, 12:56 PM
#10
Its more old school thinking than anything though. Ive seen plenty of stock stroke, 4inch, 4.100 and even 4.125 strokes spinning above 7k and still making power. A big bore helps but like i said there is more than one way to build an engine.
08-17-2017, 03:17 PM
#11
08-17-2017, 07:02 PM
#13
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That 401" or 395" with 6.350" rods would be an awesome set up with some MMS LS7 Heads! 7500+ RPM for the Win.
I used 6.350" Rods in my Big Bore 396"
I used 6.350" Rods in my Big Bore 396"
08-17-2017, 11:02 PM
#14
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I wanted to do something like this awhile back but my grinder wouldn't do it. He said that going to a 2.00" journal removes too much of the rolled fillets and not enough to get a good radius, so it really just weakens the crankshaft too much. He would only do it if the journals were welded up before grinding, but it wasn't cost effective at that point.
08-17-2017, 11:07 PM
#15
Offset grinding (a steel crank) .100" is only removing .050" per side of the journal and it couldn't be any weaker than a 1.850" journal that gets used in a high rpm application. Just because your crank grinder couldn't do it doesn't mean that it can't be done. Fillet can be cut in. Go throw shade on someone else's comment. Don't you have a vendor to suck up to, shill.
So in that case you are clearly wrong.
Last edited by tech@WS6store; 08-17-2017 at 11:17 PM.
08-18-2017, 12:21 AM
#17
Offset grinding (a steel crank) .100" is only removing .050" per side of the journal and it couldn't be any weaker than a 1.850" journal that gets used in a high rpm application. Just because your crank grinder couldn't do it doesn't mean that it can't be done. Fillet can be cut in. Go throw shade on someone else's comment. Don't you have a vendor to suck up to, shill.
You are obviously thinking about merely turning a journal down not offset grinding.
Im sure we know that you dont like kcs from previous posts, but when you try to "throw shade" at him and even his crank grinder without knowing what offset grinding means, it really doesnt help.
Sending me a nasty pm on top for pointing it out shows even less class.
The other part....still not doable esp on a stock crank or non sj crank. The oil holes move ALOT And it does indeed weaken the crank. Depending on the pin geometry it could take quite a bit more off the inside and very little off the outside. It depends on what offset you are looking for. Without extra welding its a recipe for disaster and after all that extra work and cost where are you?
4.8 stroke cranks have std large pins and are commonly used as "short stroke cranks" and are hardly ever turned into a small journal even let alone a Honda journal. 3.622 cranks same way.
Last edited by tech@WS6store; 08-18-2017 at 12:30 AM.
08-18-2017, 07:38 AM
#18
It's a different story with small Honda/Aurora size journal. That can be stronger because when you grind that much or design it from scratch, you can cut a nice large radius in the cheeks which gives the journal a lot of it's strength back. If you don't understand why that is so important, you really don't belong in this conversation.
Judging by your comment, you obviously have so much knowledge and experience in the matter. How many years have you been grinding crankshafts, seeing what breaks and what doesn't? Forget what my crank grinder said, he obviously doesn't know as much as you do.
08-18-2017, 09:38 AM
#19
TECH Senior Member
LOL Good one KCS!
