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tygaboy Reader
9/20/21 5:00 p.m.

Today was going after the fitment of the rear suspension, this time for real. First was to see what clearances were/weren't. The assembled rear suspension was put as close to "in place" as possible and the wheels were fitted, just to see. Turns out the wheels clear everything just fine. Not too big a surprise, given the outside-to-outside tire measurement was virtually the same between the 'Vette and the Benz. And I think the 'Vette wheels look pretty good on the car! 

tygaboy Reader
9/20/21 5:13 p.m.

The other critical elements that needed validation with things in the car:

- PDK fitment in the stock cradle

- axle position and alignment with the 'Vette axle openings

- engine position, given the above items

The excellent news is: It all seems to fit! As suspected, I'll need to do some clearance work on the 'Vette frame rails, due to the width of the PDK at the axle flanges. It's close, so I won't need to remove much material.

Today also validates that removing the factory cross bar was a good idea. Yes, I probably could have gotten away with clearancing it but why not just have a bunch more room to service the engine? 

I'm feeling better about a few things that were worrying me so, in all, a really good day!


tygaboy Reader
9/20/21 5:33 p.m.

In the above pics, the entire set up still needs to be raised up about 2" to get the car to the target ride height: I'm shooting for ~5" of ground clearance. So if you look closely, you can see that the upper shock mounts on the 'Vette frame rails are contacting the inner fender/frame. I'll be raising that cut until things are where they need to be.

Then, it's "connect the dots" and tie the 'Vette frame rails into RacerBenz's chassis. It not the best angle in the pic but: Look at how the frame rail curves out and points almost perfectly at a similar curve in the Benz chassis structure. I'm always amazed when stuff like this happens. Maybe I shouldn't be? Both rear wheel drive cars with the same track width, designed and build about the same time. Both perimeter steel frame structures with non-ferrous material attached to it. Hmmmm. Who knows? But I'll take a happy coincidence anytime!

tygaboy Reader
9/20/21 5:38 p.m.

I look forward to watching the reaction when someone walks by, peeks in the side window expecting a back seat area and instead, sees this...


Sparkydog HalfDork
9/20/21 5:52 p.m.

I don't know if this will help you or not, but when I was grafting the engine bay of a Mustang into my 944, I used all thread and some low-tech fixtures to accurately position the big chunk-o-Mustang that I was welding into the 944 unibody. I even had all thread pulling both fore and aft so that it was captured rigidly. With about 6 stations of all thread in the corners and fore/aft - I could accurately control the level, yaw, pitch and roll of the subframe relative to the rest of the chassis. Once I had everything positioned and measured 6 or 8 times, I started welding and making gussets.

tygaboy Reader
9/20/21 6:20 p.m.

In reply to Sparkydog :

NICE! I may shamelessly steal your idea. Great thinking, my friend!

tygaboy Reader
9/22/21 5:49 p.m.

With the chassis-to-'Vette rails fitment clearance completed and target ride height verified, it's essentially time to weld in the 'Vette frame rails. With the assembled cradle in place, first up is taking a closer look at how to tie the rails to the Benz chassis. What looks like a good approach is:

- trim the ends of the 'Vette rails to shape

- add four 1.5" x .095 wall tubes placed essentially where the tape and straight edge sits. These will extend up into the rail and be plug welded to the rail

- cap the end of the rail with a plate that has a pass-through for the tubes in each corner

- skin all around the tubes with 18 - 16 ga sheet metal

You can sorta see in the 2nd pic where the outside tubes will be welded to the Benz chassis rails. In the end, this all creates a giant box that should easily pass the "That's not goin' anywhere!" test. Tubes will also be connected from this box's tube frame to other points on the cage and chassis. Still need to get a few other things in place to know where, exactly. 

artur1808 GRM+ Memberand HalfDork
9/23/21 9:30 a.m.

Wow, I just read through from the start and this is an incredible build. Keep up the great work and definitely share the details!

tygaboy Reader
9/25/21 9:42 a.m.

You want details? OK, more details:
Next up, I need to be sure I can accurately position the cradle and frame rails in space, since this assembly first has to "float" inside RacerBenz, then be tied permanently to the existing chassis. I found measurements for C5 'Vette frame alignment/collision repair and mocked up the assembly on the fixture table. Using the height gauge you see there, the values that locate the points where the cradle bolts up under the frame rails were set.

This approach also proved out that the 'Vette components are in spec, that 0 degrees side to side at the center of the A-arm bolts is also 0 degrees across the top of the frame rails, etc. Who-Ray, everything checks out!

Anyway, once everything was positioned as it would be if it were part of a straight C5 (!), the fore/aft angle of the frame rails was recorded. Once the assembly is positioned back in RacerBenz and that angle is duplicated, all I have to worry about is the up/down, the side-to-side and wheels-in-the-wheel wells look. Most of that should be fairly straight forward... Remind me I said that when I get frustrated that it isn't! frown

Oh, and that blocked out area in the pic? If you haven't been to the Red Barn to see RacerBenz in real life and you guess what's going on and what it means to the build, lunch is on me! Hey, I gotta do something to maintain viewership! devil

sobe_death Dork
9/27/21 10:06 a.m.

I like the diamond plate duct tape frame rails!

tygaboy Reader
9/27/21 6:50 p.m.

How can I be sure everything is accurately positioned front-to-back? What if I just wedge some suitably sized spacers between the body and tires? Same deal on both sides, of course. That has to be close enough, right? Awesome - let's weld!

tygaboy Reader
9/27/21 7:24 p.m.

OK, kidding that I'd go with jammed spacers for final location - but only sorta. They got things to within about a fat 1/16" of square, believe it or not.

What really happened was:

- use a laser level (set to vertical) to locate the centerline of the chassis. This was made remarkably simple because RacerBenz actually has a couple odd stampings in its chassis that appear to be of no use... except they happen to be in the exact center of the car! Thank you, Mercedes engineers, I'll take it!

- using a long straight edge, standing up on end and verified at 90 degrees to the floor, determine the distance from the outside of the rear wheel to a known location on the body, repeat on the other side to be sure everything is centered.

- with the center line established, measurements were made that proved the cradle's fore/aft position was correct and square to the chassis. Same for fore/aft tilt, up/down, and side to side level locations that were set using those screw jacks you see under the cradle.

- a hole was drilled in a cross brace I added (more on that later) and a fixture was made that triangulates to bolts on the cradle and locks things in place to the specs measured earlier. Yes, it's true that things could rotate around that hole in the cross brace but with our trusty spacers crammed against the tires, the whole contraption was surprisingly immobile.  And yes, that fat 16" mentioned above was reduced to nothing. With the fixture and wheel spacers in place, the cradle measures dead equal to the chassis everywhere that matters.

tygaboy Reader
9/28/21 6:30 p.m.

Door bars nearly complete. Just tacked in to ensure the fit/alignment. These will likely be removed as there is much climbing in and out yet to go. A short gusset bar will be added from the upper, front X bar up to the A-pillar to add some strength and provide another grab handle.

JesseWolfe Reader
9/29/21 9:22 a.m.
tygaboy said:

Door bars nearly complete. Just tacked in to ensure the fit/alignment. These will likely be removed as there is much climbing in and out yet to go. A short gusset bar will be added from the upper, front X bar up to the A-pillar to add some strength and provide another grab handle.

I've always preferred sedan/wagon body styles, especially so in race cars.  It just seems so odd and quirky to me.  But with a coupe, especially one this size, you have a significantly larger door opening dimension to work with, facilitating getting in and out of the car more easily when caged.

golfduke Dork
9/29/21 9:41 a.m.

whoa...  following along with you on this, amazing build so far! 


buzzboy Dork
9/29/21 3:12 p.m.

In reply to JesseWolfe :

I daily drive a 3 door wagon. Extra long doors and wagon practicality!

Having owned/driven 2 and 4 door racecars it's really nice having rear doors that open. Makes working on the car and also getting in and out so much easier.

759NRNG UberDork
10/4/21 7:43 p.m.

The only thing you and I have in common are the yellow ramps. Your shop and your fabrication skills are worth the price of admission. This mash up(no disrespect)  is another reason I come here for detox from the chaos that permeates our daily lives. So this leads me to the burning question in my world...... what is your day job? Definitely along for the ride.....carry on

tygaboy Reader
10/5/21 1:30 p.m.

In reply to 759NRNG :

Thanks for the kind words. To answer your burning question: I'm fortunate enough to be retired. I was in tech sales for the first half of my career then in IT for a large health care organization for the 2nd half. Along the way, I fell victim to a dishonest hot rod shop and from that point on, decided I'd just learn to do (essentially) everything myself. I certainly have a ways to go but I'm getting there. 

Stay tuned for more silliness - I have one more sorta major "mash up" thing to come!

tygaboy Reader
10/8/21 7:15 p.m.

'Vette suspension temporarily tacked in place strongly enough to verify ride height, test wheel movement, etc. And wouldn't you know it? Tires foul on the underside/inside edge of the fenders... Good thing the fenders are aluminum! Plan A is to roll them but it may take Plan B, which would be to make up some AMG Black Series-type flares in aluminum and graft them on. 

GaryC83 New Reader
1/14/22 5:59 p.m.

Any updates? Hope you're still making good progress on this thing.  It's a cool project


tygaboy Reader
2/2/22 3:35 p.m.
GaryC83 said:

Any updates? Hope you're still making good progress on this thing.  It's a cool project

Not much for the past couple months as the focus shifted back to my 914 V8 build and a few things I wanted to change: Fabbed a new transmission mount that allowed me to remove the stock one, did up a new exhaust and swapped out the ITBs for the stock DBW intake. This necessitates a new ECU so I needed to redo the engine harness. I got WAY too far into the wiring / electronics stuff and added an ECU Master PMU to replace all the functions of an Ardunio that was running some of the wireless steering wheel button functionality... You get the picture. I hope to be back on RacerBenz in a few weeks. Some crazy stuff is possibly in the works so stay tuned!


tygaboy Reader
3/7/22 8:43 p.m.

Well, then this happened. I meet this guy through a Porsche 914 parts hunt. Total car guy. We have LOTS in common. No surprise we start communicating a few times a week, meeting up a few times a month and he's becoming a friend.  We're talking engine swaps and I just sorta accidentally say "wouldn't it be cool to get a Ferrari engine..." and before I finish the sentence, he says "I have one. And the trans. And the engine/chassis harness and ECUs..." After I changed my underpants (!), we went and looked. 

Let me rhetorically just say: Isn't the world a fascinating and wonderful place? Maybe "putting it out there" earlier in this thread created this serendipitous moment? Who cares why? It's happened! Ladies and gents, may I present what I'd hoped for all along: 

Benzo Ferrari!

360 Modena engine, 400 hp @8500 rpm, 6-speed manual trans. In the back seat of a CL 500. Because Why The FNot?! 

There are a few/many things that might prevent this from actually happening but at this point, we're moving forward. Wish me luck!

OHSCrifle GRM+ Memberand UltraDork
3/7/22 8:48 p.m.

Why the hell not!

birdmayne GRM+ Memberand Reader
3/7/22 10:11 p.m.

Oh berkeley yes. 

yupididit GRM+ Memberand PowerDork
3/7/22 11:04 p.m.

What in the grm holiness. I'm super excited for this! 

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