1/12th scale 68 Gerhardt Traco Chev F/A (F5000)

[arcticwolf]

At least that's what I'm hoping it will be (it might end up as a Lotus 70, we'll see as we go). This is a stretch for me, I've never attempted half of what's needed, so this might be a two year thread . Using bits from two Lotus kits Patrick kindly donated, and a lot of clones from other kits, and some resin from scratch. I'm going about it a very odd way, I'm building the back end of the car, and then I'll figure out what to attach it to. I hope.

Problem 1, a 1/12th Chev small block? I had some very basic parts, so I decided to make my own, from resin.

Step 1, all parts must have one flat surface - so place flat side down on a sheet of melamine, and brush one coat of liquid latex over. Do not touch until it turns this horrible colour:

Step 2, 3, 4: More coats of latex - this is how it looks wet:

Let it cure for about a week at least.

[arcticwolf]

I cut the bottom out of a chicken wing tray and taped it to the melamine. Then I filled it with Plaster of Paris (the latex by itself will flop around):

When it sets, peel it off the melamine (it won't stick) and flip it over, and carefully remove the original parts:

We now have a re-usable mold, good for ?? copies - varies a lot and quality degrades each use, but I get a few usually.

Next is to fill with resin. For this I used EasyCast 2 part, 2 gelled resins mixed 50/50 by volume so no weighing required, and very little off gassing as it's winter and I'm indoors!

In the summer I just use regular auto repair resin with a liquid catalyst outdoors in the sunshine, it's cheaper:

Cure time varies, but 2 days at room temperature is usually enough with this stuff.

All of this took about a month at least (not counting a year of getting prepared, lol), but now I have something to work with.

[arcticwolf]

Next is to carefully remove the resin parts - I got this mess:

It's actually easier to remove the bits if you overfill the mold slightly.

Next trim the flash off (the resin is still a bit soft so it's easy to do - don't wait).

And start machining the mating surfaces flat. I use a random orbit sander, 100 grit, lowest speed. Accuracy counts from now on:

When you're happy with the fit, CA it together. I used the purple stuff from BSI:

And just keep going. I have no idea what kit the finned valve covers came from, but I like them, and anything can be modified after:

Starting to look a little bit like an engine?

Cheers

Paul

[arcticwolf]

I started some assembly work. The oil pan was missing the bolt flange, so some styrene added, also the bottom extension (on the 1:1 car its welded on) and oil filter adapters.

Almost time for a coat of primer.

[arcticwolf]

A coat of primer always helps - and shows up all the flaws. Nothing a little filler won't cure.

The two holes in the back are for alignment to the bell housing. Last shot is a test fit of a 4 Weber setup I have, I may not use it on this one as I really want to give it Hilborn injection, but at least I know it will fit.

The plan is to build at least 3 engines, one is for display and the others for kit projects down the road. With luck I can get them from my molds, but might be pushing it.

[tatocorvette]

Very nice! Love finned valve covers.
When the resin hype wave was at full swing (late 90's early 2000s) I tried it and even sold copies of my scratchbuilt C5 Corvette T56 manual transaxle. But resin casting was not cheap. Yield and shelf life were also sub-par and I lost interest. I've been fooling around with the idea again on and off for years.

Thanks,
Ismael

[arcticwolf]

After a long delay, acquiring bits and pieces, a couple of used kits etc I've decided there will be several of these creations.

The first one is kind of a fantasy car. Some background:

Back in 1969, the CASC decided in their infinite wisdom that the Canadian Drivers Championship should switch from sports cars to Formula A cars. So, in that vein, I'm going to build my own F/A car. (Formula A = F5000, same thing). So how would you build a F/A back then?

I'm taking a Gerhardt indycar chassis because they were quite good and readily available, and modifying it to take a 5 litre Chevy. Others did this with Eagle and McLaren chassis, so why not?

Basically making this

into this:

Since there are no 1/12th indycar chassis kits of any description in existence, I'm going to build one out of whatever I can find. Plus a fair bit of artistic license!!

The engine will be the one shown above.

I'll try to update regularly if there is any interest.

Cheers  Paul

[arcticwolf]

Having most of what I need scrounged up, step 1, make an engine bay that accepts a small block Chevy

This requires shortening the pontoons as shown and some mods to let the crossmember fit properly

crossmember will locate at the flywheel, so I made a filler piece that will nest into the crossmember later

and after doubling it up, CA'd it to the back of the engine

this should all make sense later

[arcticwolf]

Skipping many hours ahead, I have a reasonable facsimile of a Gerhardt USAC car monocoque. Some kit parts plus a lot of sheet styrene and CA gap filler

looks a bit like a scruffy old indycar. I'm engineering this beast so that everything can be added on later, as opposed to Tamiya's nasty habit of having 50 parts dangling around that you can break without noticing - or forget until it's too late.

And now a test fit to make sure the Chevy nests in like I want it to

I think it will work nicely.

So off to hit the tub with a coat of primer and see how bad it looks.

cheers

[arcticwolf]

I have a feeling I'm posting these for nobody's benefit, but......

Some touchups and a recoat of primer

I'm happy with that. It does look a bit like I'm building a U-Boat, but trust me, it's a race car. I did build a U-Boat for a friend once. Boring.

Now a couple of engine mounts and a test fit again

Now the tub can wait until some more goodies arrive from Shapeways. Meanwhile I can play with the engine. Or go back to the Ford GT - AAARGH!!

[Oldtimer]

I love your attention to detail and reliance on multiple materials.

I don’t do resins, and respect you for your utilization of it.

[arcticwolf]

Thank you for the kind words Jim. It seems I'm posting these for no one else's interests. Maybe some day somebody might stumble over them and say, Oh, look! 

Anyway, the tub and nose cone are now the correct shape at least

Since I'm waiting for some Shapeways bits that part is stalled out, but I did work on the motor. It's about ready to drop in the chassis

Many thanks to 3D ScaleParts for the beautiful 4 Weber setup, the rest is all resin cast of course. It's a Chevy so I just had to paint it orange. 

[Chris K. Hale]

Ok I know You may think not many are watching this build but there is a fair number that are including me, I just read back through and I have questions. Your engine; wouldnt it have been easier to just use the block and parts from a Monogram 63 Corvette 1/12 kit and modify accordingly? I know there are some small block kits out there. The Chassis; Where did the rear pontoons come from? The Transaxle: check my 1/16th GT40 scratch build I did scratch a proper transaxle link race-car-models.proboards.com/search/results?captcha_id=captcha_search&what_at_least_one=1%2F16+Ford+GT40+AMR&who_only_made_by=0&display_as=0&search=Search about 1/2 way down.
I really like your crossmembers, are they 3D printed or ? , I just drew them on styrene and then replicated them adjusting to the factory drawings along the way. Well more later, with my head hurting form the surgery I am using the slow and easy method of thinking so Carry On and keep us informed..I am truly enjoying this build and I hope more members are gaining some scratch building methods from this. Chris

[arcticwolf]

Thanks for looking in Chris, I hope you're feeling a bit better!

Engine?  Yes, it would have been much easier to assemble the plastic bits I have and use it. But I need a SBC for this build, my next is a Bill Brack Lotus 42, a Bill Brack Lotus 70 maybe, both Chevy engined, and I want a stand alone display engine eventually..........

So now I have my molds I can make resin SBC's instead of hunting the internet looking for old kits/bits that people seem to want a fortune for - it's just easier.

Plus if anybody else wants one I'd be happy to cast the pieces for them.

Chassis? Part Honda, part Matra, part styrene sheet, part epoxy, filler and lots of time. The front end is mostly Matra and the back is Honda and the floor is me from scratch. Both the kits I took the parts from were the old motorized ones with battery compartments etc so perfect fodder for a job like this - lots to modify. The rear crossmember is Honda with extra holes drilled in it for my suspension pickup points.

Transaxle? Good point, probably going to be a ZF for this one, some of the early F/A cars ran them. It's easy as the Tamiya Lotus 49 kits have ZF boxes (even the 49B, which is wrong!) so making some molds and cloning a couple won't be a problem. Or I have lots of Hewlands I could use, but that's more authentic for a later car.

I also want to build a Chinook MK12, so I need a 1/12th small block Ford. Any ideas? I have a big block but it'll just look wrong.

Thanks again Chris, I'll post as I go along.

Paul

[Chris K. Hale]

There is a Formula 5000 series that has continued running in Australia since the 70's and I find it when I Google F5000. Cant remember the name of the series but they run with the Super V8 cars usually. Some really interesting cars and combo's . If I find the link I will list it.
and Thank You, I am feeling a bit better , the Dr. says its healing well but will take about 3 months to heal all the way. Chris
www.supercars.com/videos/support-categories/massive-formula-5000-crash/