Nissan Off Road & 4x4 Forum

so i've got some random SAS questions that i don't really see covered (on here and other boards) most of the questions are welding-related and pertain mostly to the SOA SAS i wanna do on my WD21.

i've only seen a few nissan guys add frame plating when they SAS, but i see it on most toyota SASs. i know the tacomas need it so that they have something to mount their steering boxes to. do you guys think it's unnecessary on my pathy?

i'm pretty sure i haven't ready anything about people pre or postheating their frames before welding on them. is this unnecessary? does anybody know the carbon content of nissan frames? i guess if no one knows i can do a clip test on parts pathfinder.

i've read in a few places that you should weld vertically to your frame. any specific reason besides spreading out the area over which you weld?

anybody think it's bad to use these kinda shackle hangers(link below) versus going through the frame? i'd assume that through-frame shackle hangers would be stronger, but i'm sure that drilling through the frame would be a PITA. i don't want my PF to be too tall. i only want 35s or so and i'll be using the waggy leaf pack that i got with the d44.
http://polyperformance.com/shop/Chevy-Shackle-Hangers-p-19168.html

i know these are somewhat complicated questions but this is stuff i don't really see discussed on boards. i'm just wondering if anybody knows something i don't. any advice helps. thanks!   :thumbup:

hopefully some more people can jump in on this but first off...
What frame plating are you talking about? just the small plate at the steering box on the yotas?

if so. it's because they relocate their box up and forward.

You don't need frame plates for leaf springs.  Over time, coil buckets and shock mounts can sometimes tear out the frame.  I can see hairline cracks staring to form on the bottom of my buckets, so i'm gonna add some flat bar.  But, for leafsprings I don't see a need for plating.

Don't worry about carbon content.  It's mild steel (non alloy).  It really don't matter what % carbon it has for welding.  I doubt the frame is heat treated, either.  Truck frames are pretty mundane hunks of steel. 



       

you talking about something like this?
(http://i190.photobucket.com/albums/z219/penski61/sas/P2260327.jpg)
(http://i190.photobucket.com/albums/z219/penski61/sas/P2260328.jpg)
(http://i190.photobucket.com/albums/z219/penski61/sas/P3060018.jpg)

This is not entirely true. If it it a tool steel, such as A-2, or D-2, that has NO carbon, it cannot be welded.

And if you go through the frame vs. under it, the overall height can be lower.

I think you've been misinformed yotah8r.  Steel by definition has carbon in it, between 0.2-2%, otherwise it is just iron.  It is the addition of carbon that gives steel it's amazing properties.  And, tool steels need to have a relatively high percent of Carbon to be heat treated to a higher hardness.  
A quick search says A2 has .95-1.05% C.  http://www.efunda.com/materials/alloys/tool_steels/show_tool.cfm?ID=AISI_A2&prop=all&Page_Title=AISI%20A2 (http://www.efunda.com/materials/alloys/tool_steels/show_tool.cfm?ID=AISI_A2&prop=all&Page_Title=AISI%20A2)

and D2 has 1.4-1.6 %C
http://www.efunda.com/materials/alloys/tool_steels/show_tool.cfm?ID=AISI_D2&prop=all&Page_Title=AISI+D2

yep. still weldable, but more difficult to get right since you gotta deal with preheating and such, and sometimes you have to get the temperature just right...kinda like how you have to be a little more careful welding 4130, than with mild steel...except more extreme. haha

Using those under frame mounts will result in two things:

1.  Your truck will be very tall.
2.  Unless you cut and turn the Cs and axle perches, your caster angle will be phucked.

A lot of people plate the frame where the shock/coilover mounts will be welded.  A good idea, IMHO, as it adds surface area and reduces potential stress risers.  You can further add welded suface area by cutting a large circle in the plate and welding that in addition to the outside (see previous pic) or (and I forget the name for this) cutting the plates in such a way that they aren't square but have a >< shape to the sides.

cracks are exactly what i don't want to have happen. i think it's possible to have it not crack. where are the cracks? at the toe of the weld the throat or what?

and i disagree with the second statement. here's an article that says how to weld higher carbon content steels.
http://steel.keytometals.com/Articles/Art68.htm

i guess what really matters tho is the carbon content (which i know you already answered) i just remembered a fairly easy test to check, so i guess it helped that i talked all this out with you guys to get to my answer.




yeah, that's what i'm talking about. you're one of the few nissans that i've seen with that extra frame plating, and you're leaf sprung. the other nissan i've seen it on is yoszi's 3 link. what made you put those extra plates on? to strengthen the frame, i assume?


yeah, i'll probably cut and turn my Cs (if necessary) and mount my spring perches for good pinion angle.

yeah, cutting the plates like > or < not only adds weld metal, but it spreads out the stress as well.

even with extra plating on there, the shock/coilover hoop would still rip out at the base of the hoop. it's the weaker link, compared to the extra plating, cuz there will be less weld metal at the base of the hoop than at the plates, ya know what i mean?
i'm still guessing the extra plates are on there to strengthen the frame.

yeah some people plate it to strengthen the frame a little more after grinding off the IFS. I can't tell ya from experience, but I've read up on a few swaps done where they plate the frame. Here's an example on pages 9 & 10 where they talk about it...

http://www.4x4parts.com/ubbthreads/showflat.php?Cat=0&Number=540993&page=0&fpart=10&vc=1

I think in the photo above, he's just running a shock off that.  Not a coilover.

Coilover mounts need a bit more bracing and support.

So, what's the easy test for % carbon?

You can never go wrong with more beef.  I admit I should have added some 1/4" plate for my buckets.  ::)  I'm a little embarrassed about the cracks.  So, I'll post pics after the retrofit. lol







    

it's not necessarily a test for % carbon per se. i was told it's called a clip test (from my welding professor) but i can't find it through google or anything. it's a test to see if the material that you're welding on is crack sensitive (medium to high carbon steel can be sensitive to cracking. i can talk more about the metallurgy if you guys want, but right now i'm just gonna talk about the test)

one of the last links that i posted on welding on different carbon content steels gives directions on how to weld on different carbon content steels. it gives these directions so that you don't develop cracks or other weld failures. the directions tell you to preheat, use a low hydrogen electrode like 7018, and to postheat in order to control the rate of heating and cooling and to prevent cracking. peening also helps relieve stresses in the weld, which also helps prevent cracking.

to do the test you basically do the opposite. don't preheat, pick a non-low hydrogen electrode, and don't postheat or peen the welds. you can even speed up the cooling by throwing some water on the weld. fast cooling rate one thing that makes it crack.

so you weld a piece of metal that you know is of low carbon content (which isn't sensitive to cracking) to a piece of metal (in this case, the frame) that you wanna check the crack sensitivity (again, higher carbon content=more sensitive to cracking) make sure you follow the opposite of the directions. then you beat the low carbon steel piece with a BFH til it breaks off. make sure the side that you hit with the BFH is the same side that you welded on.

if the weld fails at the throat (right down the middle of weld) the steel with the unknown carbon content is now known not to be crack sensitive, and not a medium to high carbon content.

if it fails at the base metal (the unknown metal) or somewhere in the heat affected zone of the weld, that proves that the unknown metal has a medium to high carbon content since it was sensitive to cracking. here's a pic of what i'm talking about.

(http://i35.photobucket.com/albums/d185/lbz134/BrokenHoop002.jpg)

either the frame has a higher carbon content or the weld AND the shock hoop are stronger than the frame. otherwise it would've broken at the weld or at the shock hoop (instead of the frame)

damn, that was more typing than i wanted to do  :hit:

Just to clarify on the earlier post, because pinion angle and caster are two different things. 

I'd get the axle in there, set the pinion angle and perches first, then locate the Cs so that you can get the caster where you want it.  If you're going spring over, and it sounds like you are, this will be something you'll probably want to do to get things done right.

Sure, you can drive it, but since you're taking the time, why not get things done right so it will drive well.

Hope this helps.

my earlier post or your earlier post? lol we both kinda messed up on that one by not being very precise. i think we both know what we're talking about tho  :thumbup:

oh yeah, one more question that i forgot.

i'm mainly doing this SAS for strength and reliability. i'm tired of breaking IFS parts and IFS in general.

so now that i'll have a strong axle and steering, what's the next weakest link? i think i've heard somewhere that d44 hubs are the weak point.

U can do a grind test for carbon content of metal too. Chip test is more involved. If thesparks are a more orangish yellowish then its a mild carbon steel.

ah that sounds easy. i never thought of that lol.