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egoman
egoman Reader
3/28/21 7:13 p.m.

So the last progress post mentioned pride going before the fall. Good work doesn’t necessarily mean that it will be usable.

So we need to mount the pan-hard rocker mount on the rear housing. Naturally everything will go well and there will be no problems right?

SOOOO the drain plug is of course in the way and we will get that moved. ANNND the studs that welded into the brake retaining plate snapped of. Guess we are going to switch to a milder steel for those going forward. They were not cooled quickly or anything like that. Just a little brittle when welded with the mig.

We also got the brake plates mounted to the rear end. This was a simple matter of just holding the calipers in place and centering the plates for hub clearance.

egoman
egoman Reader
3/31/21 7:31 p.m.

Here you can start to see that the spacers and the spindle and the steel bracket are coming together to make a complete braking system. At this point I have made a huge miscalculation, but I don’t know it yet?

I also bolted the aluminum spacer to the original spindle to bore it out and then turned it again to face it smooth and parallel.

Certain things require small clearancing, like the E-brake adjuster and some other stuff.

I have also placed the suspension brackets on the rear end so I don’t forget them later. I actually don’t forget them later too. That’s kind of nice isn’t it?

egoman
egoman Reader
3/31/21 7:55 p.m.

33    This time the rear end is mostly complete except for the trailing link brackets.

We have fixed the emergency brake cables and the mounts for those cables. They only required a small amount of heat and a creative bend to make them OK! We also fixed the clamping plates by going to a lower grade of steel all thread rod and TIG welding them into place. It is kind of funny that you will need both metric and standard tools to work on much of this stuff.

egoman
egoman Reader
4/1/21 9:24 p.m.

34   So with the rear finished for now what are we going to do next? I would guess the geniuses in the crowd would think the front end is next. They would of course be right, you know, because they are geniuses!

Good old GM for some reason couldn’t make the bolt holes the same distance apart. I measured that crap so often before I realized that the stock mounts varied by fractions of an inch on purpose. I WASN’T MEASURING IT WRONG!

A member on another forum lent me some very good C5 C6 suspension details that I have also shared with others. His only requirement was to never post it online. He was alright with me privately sharing that info though. Very James Bond right there eh?

So I got to practice some old school drafting again based on those measurements and that is included here.

egoman
egoman Reader
4/2/21 7:58 p.m.

35      I am a huge fan of captured nuts so assembly is easier and faster. I use this technique frequently on this car.
Once again with GMs jerk face designers designing all this with 2 different centerlines, it makes you question everything you are working on. Oh well tape measures levels and strings can fix all that right?
This one has a lot more pictures that words. A LOT MORE!


 

egoman
egoman Reader
4/3/21 8:33 a.m.

The drawing here is the one that I take over to my friend Doug so he can plasma it all out. Even with a drawing we still talk each bracket out to make sure we don’t screw it up. That of course still happens though.
And yes that crappy old drafting table is all that I need to make me happy. I love welding and cutting steel but drawing is a close second favorite for me.
I have done something different here. I have added text boxes as I felt there were too many pics without an explanation. Tell me what you think in the comments?

egoman
egoman Reader
4/5/21 5:35 p.m.

A few posts ago I mentioned the pieces with the holes in them for supports and stiffeners. Here you start to see what I was getting at. I used that for boxing in those brackets.

I am also at this time locking the rear end in the car at ride height and proper centerline.

DAMN that looks good with those big tires there doesn’t it?

I also added the watts linkage frame brackets at this time. I have found over the years that a stack of washers and other junk will be very accurate to space everything just right.

twentyover
twentyover Dork
4/5/21 11:05 p.m.

 

OK, I'll ask why. I've never driven a car with either a frame or axle mounted propeller, but it seems to me that a frame mounted propeller has a constant distance between the CofG and the roll  center, while a axle mounted propeller will vary distance during suspension articulation. The varying distance will change the length of the lever arm between RC and CofG. Seems to me that will cause the rear of the car to wiggle as the rear suspension travels- but I don't KNOW if this is a problem or not....

egoman
egoman Reader
4/6/21 8:07 p.m.
twentyover said:

 

OK, I'll ask why. I've never driven a car with either a frame or axle mounted propeller, but it seems to me that a frame mounted propeller has a constant distance between the CofG and the roll  center, while a axle mounted propeller will vary distance during suspension articulation. The varying distance will change the length of the lever arm between RC and CofG. Seems to me that will cause the rear of the car to wiggle as the rear suspension travels- but I don't KNOW if this is a problem or not....

Actually other than tire squirm the roll center stays consistent with the rear end mounted rocker. Also in order to clear the rear end bulge the axle mounted attachment points in the frame mounted rocker style are more prone to flexing. You are probably correct in that it probably doesn't make much difference, but that is why I made this choice. 

Thank you for responding, I am getting lonely here.

demnted
demnted New Reader
4/7/21 7:11 a.m.

Lurking, not always commenting... Nice so far please carry on.

twentyover
twentyover Dork
4/7/21 2:10 p.m.
egoman said:
twentyover said:

 

OK, I'll ask why. I've never driven a car with either a frame or axle mounted propeller, but it seems to me that a frame mounted propeller has a constant distance between the CofG and the roll  center, while a axle mounted propeller will vary distance during suspension articulation. The varying distance will change the length of the lever arm between RC and CofG. Seems to me that will cause the rear of the car to wiggle as the rear suspension travels- but I don't KNOW if this is a problem or not....

Actually other than tire squirm the roll center stays consistent with the rear end mounted rocker. Also in order to clear the rear end bulge the axle mounted attachment points in the frame mounted rocker style are more prone to flexing. You are probably correct in that it probably doesn't make much difference, but that is why I made this choice. 

Thank you for responding, I am getting lonely here.

Agree with your statement. My question is, is it more important  to have a stable roll center height or have a more stable distance between the CofG and the roll center (which you would have w/  a frame mounted propeller.)

I visualize that, as the rear suspension bumps and rebounds, the distance between roll center vand CofG changest, so the back end of the car would be rotating around roll center as the suspension articulates. Seems this would cause some  unpredictability.

 

But as many axle mounted propellers as there are, I'm probably talking well above my pay grade. In fact, let's just make that assumption

egoman
egoman Reader
4/7/21 7:40 p.m.

Asking questions is how we all eventually get answers we can live with. 

egoman
egoman Reader
4/9/21 6:06 p.m.

38     It’s time for this assembly to head home. I teach at my union hall for the 7Oaks SD., and when I am off the clock I will use the shop occasionally. A big thank you to Local 254 Plumbers and Pipefitters hall. Remember Unions built our middle class and that’s why they try to destroy them. Buy union and support those workers.

I described this piece as a big clumsy wheelbarrow.

The sharp eyed amongst you will notice the dirt bikes at the front of the trailer. Another passion of mine. I call it the methadone that tempers my desire to race sprint cars.

You can also see that I have tacked the front lower link brackets to the rear cross member. That cross member of course is at random length to be cut down later. The future holds more mods to this assembly for stuff that I never anticipated. Let’s see if you catch that in the future, LOL.

egoman
egoman Reader
4/9/21 6:14 p.m.

While there is not a lot to see here it is quite important. The car was inspected and safetied. I also got it licensed so it is officially mine now. This car was actually a good candidate for an old man to drive it into retirement. Well seeing as I am also nearing 60 that seems appropriate doesn’t it?

egoman
egoman Reader
4/12/21 7:43 p.m.

Sometimes I just need a break.

The World of Outlaw sprint cars make their way up to North Dakota and it gives me a thrill to see them. While I have raced with them in the past I never made any sort of mark with them. Heck I didn’t make any sort of mark locally either!

egoman
egoman Reader
4/12/21 8:24 p.m.

This is a series of cars that I have raced in the past few decades. I raced sprints in the 80s and dirt mods in the 90s. I have built cars for myself and others for almost all classes of racing. I also race dirt bikes to cover some urges. At 300 plus (That’s being very generous) I don’t fit the mold of a standard MXer. Even when I raced sprinters in my early 20s I was still 6-4 and 225lbs. I tend to be quite self-deprecating about my racing results. With the internet there is no sense lying about how great I may have been anyways.

I wish that all the photos that I had 20-30-40 years ago were still around but that stuff isn’t forever like the digital stuff from now days.

egoman
egoman Reader
4/16/21 8:38 p.m.

After a little racing break we needed to get back at the front end. That measurement of 71-1/2 is 2 inches wider than the stock rear-end width. I had planned for the front to be slightly wider than the rear so I could mildly IMSA the front fenders for heat release. Of course I maybe can’t leave that alone and maybe I will see if I can run 325s on the front also?

The plates for the upper control arms are clamped in place and needed a small trim to fit.

I actually left some really nice welds behind on this frame section.

wvumtnbkr
wvumtnbkr PowerDork
4/16/21 10:05 p.m.

Cool build!

egoman
egoman Reader
4/17/21 7:34 p.m.

In reply to wvumtnbkr :

Thank you! Keep checking in, it gets better.

egoman
egoman Reader
4/18/21 6:16 p.m.

That little bubble on the level is everything to me. The frame kick ups are very precise fitting and I agonized about them for hours. The drawing doesn’t do them justice for the amount of time put into them.

And you know, I didn’t finish them because I wasn’t comfortable with what I had done. Don’t rush a project just so you can do it over. That’s the best advice I can give a builder right there.

egoman
egoman Reader
4/24/21 6:55 p.m.

With a new day I forged ahead with the welding when I felt it was perfect. I also heated and pulled the frame back to straight with a little water and a lot of straight edges and levels. Welding those upper brackets caused a lot of pulling.With a new day I forged ahead with the welding when I felt it was perfect. I also heated and pulled the frame back to straight with a little water and a lot of straight edges and levels. Welding those upper brackets caused a lot of pulling.

slowbird
slowbird UltraDork
4/24/21 7:53 p.m.

That's a beefy looking frame. Nice work.

egoman
egoman Reader
4/25/21 7:00 p.m.

This post is my first that I am writing where I didn’t already have a description made up. We are bridging the UCA mounts and developing a LCA coilover mount that is a temporary substitute. I will from now on write less here and insert more text into the pictures.

egoman
egoman Reader
4/25/21 7:09 p.m.

I have a ton of pictures for this segment. I am going to spread them out over a few posts. Normally when I put the photos together that is just one day of work. The previous post along with this one and maybe one or two more are that ONE day of work.

egoman
egoman Reader
4/25/21 7:15 p.m.

Remember the last 3 posts equate to a single day of work. Plus this one!

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