So I have spoken with someone over on the Nissanminis forum which is where I primarily hang out and they have built a KA twice with the ford 5.4l rods. now my understanding is the only advantage to these rods is lighter rotating assembly, and improved strength. He didnt unfortunately use the ford pistons for which i dont know why but maybe because he didnt want to offset grind the crank. He told me total crank work for just enlarging the rod journals was somewhere around 325 bucks and then another hundred for some re-work. I dont know if you guys have priced these parts out or not but you could almost build two of them for the cost of one ka built with ka specific parts. I found a set of these rods for like 300 bucks! Thats 8 rods that are just as strong but lighter than the ka's, thats just crazy! If the pistons can work, assuming the crank pin height can be lowered enough. then this setup can make for a real screaming ka and pistons can be forged for 70bucks a piece in pretty much any configuration you want from JE. I beleive they have three standard styles for the ford flat, dished,and flat with valve reliefs for the 3 valve model. Im really kind of dreaming right now because theres a real big proboem with this setup apparently. The ford rods are not as thick as the KA's(hence the lighter weight) at the big end, so oil is allowed to escape when spinning around. This causes massive premature bearing wear and i have no idea how you would solve it without putting even more stress on the crank by having that area built up. Maybe even have eagle make some custom width forged rods so that this isnt a problem, im not sure?
Any ideas folks?
5.4l rods and other crazy KA ideas
Re: (S13 240SX)
He didn't say 5.4l ka. he said use rods from a ford 5.4l motor(i wouldnt know what car it's in) because they're lighter... but the post was kinda rambling, so i couldnt make much of it.S13 240SX wrote:omg bull crap 5.4 liter ka motor.. bull crap! let me see this forum website thingy.
the point is reading comprehension>you
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H.D.HUMPERDINK
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acrazyjohnny
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Re: 5.4l rods and other crazy KA ideas (nismopu)
talk to devious i remember seeing a thread on here that a guy from aus used a piston and rod combo from a ford i forget how long ago but i know for sure i saw it on here a while back devious knows wat to use hopefully he will spread his inteligence on this thread o btw he is the man when it comes to hybrids like this and other nissan hybrids
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deviousKA
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Re: 5.4l rods and other crazy KA ideas (acrazyjohnny)
It all depends on how much welding you want to do to your crank, if you want to actually build up the journal diameter well be my guest
Your looking at a lot more than 325, your going to need an expert machinist that is very familiar with his tools and equipment. The most tedious portions of the job will be aligning all of the journals, sounds easy right, they have a machine for that? Like I said, if you want to get it done you need the best machinist/shop you can find, it will cost.
This is done often for stroking of oem cranks, but even in that situation you are working with equal or smaller rod journal dimensions, so a lot less welding in general. You want to avoid any welding you have to do to a crankshaft, and building up the journal diameter is going to take a lot.
If your looking for some interesting affordable domestic alternatives, you could look into getting unfinished sbc parts from an aftermarket manufacture. You will need unfinished journals so that they can be fit to your application without crank welding. The same thing would go for those ford modular rods, find them in semi-finished form. I can tell you it is easier to find these this way in cnc aluminum and titanium than it is to find forged H beam.
Btw, with that 5.4l rod length the ford modular 4.6/5.4l/6.8l pistons would suit appropriately in the ka24, 90.2mm bore. These pistons were the "big secret" like a year and a half ago than no one told anyone about. That was untill it was found that various aftermarket manufactures had listed these parts with 33.5mm compression ht. vs. the 31mm that they actually are, good for strokers and hybrids.
Your looking at a lot more than 325, your going to need an expert machinist that is very familiar with his tools and equipment. The most tedious portions of the job will be aligning all of the journals, sounds easy right, they have a machine for that? Like I said, if you want to get it done you need the best machinist/shop you can find, it will cost.
This is done often for stroking of oem cranks, but even in that situation you are working with equal or smaller rod journal dimensions, so a lot less welding in general. You want to avoid any welding you have to do to a crankshaft, and building up the journal diameter is going to take a lot.
If your looking for some interesting affordable domestic alternatives, you could look into getting unfinished sbc parts from an aftermarket manufacture. You will need unfinished journals so that they can be fit to your application without crank welding. The same thing would go for those ford modular rods, find them in semi-finished form. I can tell you it is easier to find these this way in cnc aluminum and titanium than it is to find forged H beam.
Btw, with that 5.4l rod length the ford modular 4.6/5.4l/6.8l pistons would suit appropriately in the ka24, 90.2mm bore. These pistons were the "big secret" like a year and a half ago than no one told anyone about. That was untill it was found that various aftermarket manufactures had listed these parts with 33.5mm compression ht. vs. the 31mm that they actually are, good for strokers and hybrids.
Re: 5.4l rods and other crazy KA ideas (deviousKA)
Does that mean the aftermarket manufacturers had listed them wrong, or that they had higher compression models? What's the "compression ht." on the KA piston (8.6:1, 90mm)? Would the 0.2mm difference be significant? Would you bore out your cylender slightly more?deviousKA wrote:Btw, with that 5.4l rod length the ford modular 4.6/5.4l/6.8l pistons would suit appropriately in the ka24, 90.2mm bore. These pistons were the "big secret" like a year and a half ago than no one told anyone about. That was untill it was found that various aftermarket manufactures had listed these parts with 33.5mm compression ht. vs. the 31mm that they actually are, good for strokers and hybrids.
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deviousKA
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Re: 5.4l rods and other crazy KA ideas (Nanaimo)
ka24 piston compression height, or compression distance (center of pin to top of piston crown, edge)= 34mm
The modular piston is 3mm shorter and will have a tendency to cause pre ignition much sooner in comparison to a piston that is in proper proximity to quench area. I say this because one might look at the specs and see that a modular piston in flat top design would give them about 8.5:1 compression ratio with a ka24de combustion chamber and stock rod/crank. While an aftermarket modular piston can be obtained in forged material, this situation is still very undesirable.
A 33.5mm compression distance would be much more realistic and one could say, usable. I am only speaking of the main piston profile here and not dish volume changes which have nothing to do with the point, a variety of dish volumes are available for these pistons.
So basically, compression ratio is far from everything, a flat top piston that is 3mm (~.120") below the deck surface is inferior to a piston that comes to deck surface with ~13-15cc of dish volume. All advantages of quench would be lost and the now defunct chamber shape would work basically opposite of the way it was intended. It would be a slightly different story if the quench area/volume was absent from the combustion chamber, but that would put these pistons into the realm of non-usuable compression ratio, like they would be in the ka24e.
About what I said before, yes a few manufactures had marked their stock wrong. And about the 90.2mm bore, that will be fine for any NA or turbo application.
The modular piston is 3mm shorter and will have a tendency to cause pre ignition much sooner in comparison to a piston that is in proper proximity to quench area. I say this because one might look at the specs and see that a modular piston in flat top design would give them about 8.5:1 compression ratio with a ka24de combustion chamber and stock rod/crank. While an aftermarket modular piston can be obtained in forged material, this situation is still very undesirable.
A 33.5mm compression distance would be much more realistic and one could say, usable. I am only speaking of the main piston profile here and not dish volume changes which have nothing to do with the point, a variety of dish volumes are available for these pistons.
So basically, compression ratio is far from everything, a flat top piston that is 3mm (~.120") below the deck surface is inferior to a piston that comes to deck surface with ~13-15cc of dish volume. All advantages of quench would be lost and the now defunct chamber shape would work basically opposite of the way it was intended. It would be a slightly different story if the quench area/volume was absent from the combustion chamber, but that would put these pistons into the realm of non-usuable compression ratio, like they would be in the ka24e.
About what I said before, yes a few manufactures had marked their stock wrong. And about the 90.2mm bore, that will be fine for any NA or turbo application.
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nismopu
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Sorry about the first post being hard to follow and I know I am no english major. lol
I know your not saying this is impossible and I know you dont like to give out any secrets but I have been told by machinist supervisor that this amount of work can be done. It is alot of work! I think it can be done for the price I was told cause I went to a local shop down the road and they said it was about right. this shop also built my turbo l28 so they do know nissan engines too.
Also from what I am getting about the pistons is I should go custom anyway and along with the rods. I just thought it would be cool to be able to purchase internals that were fairly inexpensive and worth while.
Thanks for the input guys. Now i got a better understanding where i should start with this project. peace.
BTW I noticed you spoke of the E alot and not much of the DE, is the CC that much different?
I know your not saying this is impossible and I know you dont like to give out any secrets but I have been told by machinist supervisor that this amount of work can be done. It is alot of work! I think it can be done for the price I was told cause I went to a local shop down the road and they said it was about right. this shop also built my turbo l28 so they do know nissan engines too.
Also from what I am getting about the pistons is I should go custom anyway and along with the rods. I just thought it would be cool to be able to purchase internals that were fairly inexpensive and worth while.
Thanks for the input guys. Now i got a better understanding where i should start with this project. peace.
BTW I noticed you spoke of the E alot and not much of the DE, is the CC that much different?