'90 K5 - Project Betty - LS3 Swap for a DD/Offroad/Utility Build

[cliles]

Spring Perch Math

This guy has a decent write up about how the center pin in the spring back moves.

http://coloradok5.com/forums/showpost.php?p=2711679&postcount=138

I am going to copy and paste some below so people dont have to reroute

"You can calculate how much the centerpins moves, so you don't have to guess about how much to mill.
Just to show of my wicked MS-paint skills, I made a couple of drawings

Driver-side:

The centerpin moves forward according to this formula:
D=R*sin a
R=the radius of the axletube plus the height of the spring perch (11cm),
and the angle "a" is the same as the shim angle (6 degree)
So, D=11,5mm

And the passenger-side:

Here the centerpin moves BACKWARDS instead
D=L*sin a
L= The thickness of the spring-pack measured along the centerpin (in my case 8cm),
and the angle "a" is still the same as the angle-shim.
So, D=8,4mm"

I havent check his math, but it looks pretty sound outside of maybe needing an angle to radians conversion

 

[cliles]

It's a D60 guys. The pass side spring perch is cast into the housing as well as uses 2 bolts and 1 u-bolt on that side instead of 2 u-bolts.
He's gonna have to find something like this (from previous page, already discussed).

The shock mounts may be fine as they will just be rotated up slightly, as said. They can always be cut off and replaced if needed after you get the Cs turned and the axle back under the truck.

I am going to get a quote for something like this, because I am not going to cheap out at this point if it is reasonable.

However this example (the only one I found) doesn't have any shim/angle under the springs, just the top plate.

Does that seem incorrect to anybody else? I am far from an expert, but I don't understand why they would go to the trouble and not shim the bottom of the spring pack.

 

[y5mgisi]

Youggot it backwards man. There is no shim under the spring plate, there is only a shim under the spring using that method.

 

[cliles]

Youggot it backwards man. There is no shim under the spring plate, there is only a shim under the spring using that method.

Yeah, I guess that is just a typo and I meant to say pack instead of plate. I would assume you would need a shim (taller at the front of the vehicle, narrowing towards the rear) under the springs on the passenger side to replicate the original flat surface. *edit* not just flat, horizontal surface, being flat is only half the battle. Man, I am really struggling with my words lately.

 

[cliles]

Quick update such that anybody who may be interested in this thread doesn't think I flaked out or gave up.

I have started disassembling the front end, and I am a couple of bolts away from doing the rotation and mock up.

I had a horror story experience trying to remove the dust cover off the hub locks. Little T15 bolts, broke no less than 20 bits, 15 of which were impact rated. Tried everything I knew, wd40, inward pressure, tapping with hammer, still had to use a screw extractor for about half and at the end got frustrated and broke the a bolt off in both sides after hours of reaming and failure to extract.

Once I finish the mock up, I will clean and reinforce the knuckles and C's and send it off to be rotated.

 

[y5mgisi]

What a pain in the ass!

 

[Teck]

Who's rotating the end for you?

 

[cliles]

It's a long story but I called around to about 30 shops trying to see how much it would costs in order to decide whether it was worth attempting myself. The owner of Fort Worth gear and axle, told me of a shop that he was certain could do it called Arlington 4 Wheel Drive or something. Long story short, it has been closed for a while now but I got the previous owners cell phone number. He said he has mille/lathe jigs set up to cut the weld on the c's, jig for a press, etc.

I decided to go with him bc of his knowledge and confidence, combined with the fact I could only find one person to do it who had never done it before.

I figure I will just do my best to get the correct markings for the rotation and trust he can do the rest.

 

[Teck]

He does know his stuff.

 

[rksjd8420]

Bill does very good work, especially axle work. I had a problem setting up a 14 bolt ring and pinion up right. Only way I could get it set up with a good pattern was to completely leave out the pinion shim. Took it to him thinking something was wrong. He looked at it and quickly told me it was right and the Zoom gears that I had bought cheap were POS's. Had so much trouble setting up an easy 14 bolt that I just let him set up my dana 60 since I bought the same gears for it too. Did a very good job and was very reasonable.

 

[cliles]

Axle Cut and Turn

First thing I did was build an adapter for my jack. I got sick and tired of using blocks and worrying about whether I would be crushed or not. Then the drama of the hub dust covers detailed above, then after removing various axle components I took zero'd my angle finder on the shock perch which was close to level.

Looks like my caster angle was +7.3 from the shock perch, and the spring perches were +2 so all rotated clockwise.

I then used a jack to rotate the pinion angle up, and about -14 degrees from the zero'd shock perch got the driveshaft pretty straight.

 

[cliles]

Cut and Turn

So the dilemma becomes what to do next. So if I get it cut and rotated, then I will know the exact angle I need to rotate the spring and shock perches, but I am assuming I will need to disassemble the axles again prior to welding on the tube.

I could rotate the perches now, but if the C's come back slightly off or I mess up then I am doing it all over again.

 

[y5mgisi]

Very interesting.

 

[cliles]

Axle Cut and Turn cont

Cleaning up the knuckles, etc for reinforcing and painting. I am sick and tired of grinding (wire brush, flap wheel, abrasive wheel, or otherwise) on this project. I need to hear a rumble or two to get my motivation up.

Taking a pulse here, is a home sandblasting cabinet a good idea? I have read a lot of stories about it being expensive to buy the media (being in the petroleum industry, I buy several million pounds of sand a month, so I figure I could work that out as a favor or a fall of the truck type of scenario, not sure about the moisture content comments, could even get some high strength ceramic media).

I have also read that it is really cheap to have it done professionally. I am assuming they are not factoring in the individual dropping off/picking up the parts time and effort. To me there is a difference in how cheap it is to have a professional vs individual sandblast a front clip for a 1968 camaro and simply blast grease and dust off old GM parts.

 

[y5mgisi]

I think it would be a great idea to have a home blast setup! IF you were going to use it more than a couple times. If you just need a hand full of parts blasted for this one project, i think you would be best off just bringing the stuff somewhere.

 

[cliles]

Knuckle Reinforcement

I decided to removed and replace the king pins because one had a vertical gouge, and also I wanted to be sure to get the correct angle.

Everybody has said that this is quite the beating, my job wasnt that hard. I bought a 7/8" hex wrench off amazon for $12-15, cheater pipe, and they came right out. I found out about the lug nut trick too late.

After a copious amount of time behind a wire wheel cleaning grime and rust off of all of the ancillary pieces of the front axle, I was ready for the DIY4X knuckle reinforcement kit.

The initial fit was about 80%, I called Kert to confirm this was by design, a little heat and a hammer and things came together pretty nicely. If I would have waited for his more detailed pictures, I might have fought with it a bit more.

My finish product doesnt look as pretty as his, because 1. Professional metal fab is not in my job description and 2. I only spent a minute or two with the grinder afterwards. With another 30 minutes you can make them just as pretty as his demo picture, but I figure why? It is going to be hidden, who gives a shlt.

 

[cliles]

DIY4X Steering Knuckle Reinforcement Kit

Since I mentioned that the additional pics for the DIY4X Steering Knuckle Reinforcement Kit would be helpful, I like their products, Kert has always been very helpful, etc ... I decided to post them to promote interest.

 

[cliles]

DIY4X Steering Knuckle Reinforcement Kit2

Second series of pictures

 

[cliles]

I cannot get a hold of Bill, his phone has been saying that he is not currently accepting calls for the past week or so.

Now that I got all of the perches cut off, I am thinking about attempting the cut and turn myself.

It will take me a least 3 hours for two round trips to his shop, assuming I can get a hold of him. I should be able to figure out if it is too difficult in less time than that.

Anybody think this is too daunting of a task, am I getting too cocky?

 

[y5mgisi]

I would certainly attempt it.