Zink Formula Vee

Thanks for the detailed posts, it's all super interesting to see. Good luck at Grattan!

Following this topic with great interest.  I had a Vee for a couple of years back in th mid-80s.  It was a race legal car, but because of where I lived and my job at the time I only ran it in autocrosses (although some were pretty fast autocrosses on an abandoned airport).  It was an interesting homebuilt called a Comet with a zero-roll rear suspension and very long rear trailing arms and handled great,  After I sold it a later owner converted it to a solo Vee, and as far as I know it's still out there somewhere being used.  I've always loved Vees, especially Zinks and Autodynamics cars.  Good luck and keep us posted.

I can't quite wrap my brain around the condensation on the intake on a Dyno. The expansion in the intake is dropping the temp enough to cause cooling? I would have thought that running on the Dyno would be mostly WOT so the pressure differential would be minimal. 

In reply to DrMikeCSI :

Latent heat of vaporization.

Basically the evaporation of the fuel sucks the heat. That's many times greater effect than the simple pressure differential of the air. Similar to how evaporating sweat cools you.

In reply to DrMikeCSI :

Like Apexcarver said. It's how air conditioning works, too.  It's also why you'll get carb icing on cooler days with some cars, even if it's above freezing.

And it's also why most intake manifolds have water or exhaust heat running through them. The stock VW manifold used exhaust heat, but that all gets removed for FVs.

We ran the car on the DynoJet 248 at Capizzi Automotive this afternoon.  Jon Capizzi normally does big turbo V8s making 1000+ WHP, but still gets a kick out of our little sportscars.

We were hoping to move the powerband up and get a little more HP at the top, and that is what happened.

Jack is way more competitive than me and doesn't want me posting the numbers, hence the blurry graph with no numbers except RPM. The red lines are Torque and HP before the rebuild and the blue lines are after. The lines that start high and go down are Torque, the ones than climb, peak, and drop are HP.  We moved the power band up about 500RPM and that's really going to help above 4500 RPM.  The new heads are clearly breathing better so we have much better power at 5800, where we plan to redline. We only lost a tiny bit of HP and Torque in the midrange.  Ignore the length of the lines--we wanted a larger sweep today so we started at lower RPMs and ran higher than our last visit.  Also ignore the peak and dip near tip in on the blue line--that happens a lot at tip in and it's just noise.

*pulls out notebook and makes tiny coded marks* I see jack I see...

Nah this is awesome and totally makes me want to try a FV instead of spec miata. Seems like there's a decent presence in the mid Atlantic. 

It's a beautiful Friday morning at Grattan. 

Won't share dyno numbers, really?  Seems like if you're not cheating, you don't have anything to hide!  Also, at least out in Colorado, us vintage Vee folks share all the tips.  Since it's about a good race, not about winning, we're all better off if we're closer together.  Just recently a fellow racer that was consistently behind me mentioned that he runs 20W-50 oil.  I pointed out he was giving up noticeable power with such thick oil--he switched to a lighter weight and knocked a second off his laptimes and finished in front me last weekend.

Here's my dyno plot, though with a Rocky Mountain 1385 car, it's not apples to apples.  Also, it's an engine dyno, not chassis dyno.  We tend to make less peak power with a 1385 because the 1200s have better volumetric efficiency.  Everything else is the same, so we're still intake limited, but have a flatter torque curve and more grunt down low.  We shift around 5500rpm.

Berck said:

Won't share dyno numbers, really?  Seems like if you're not cheating, you don't have anything to hide!  Also, at least out in Colorado, us vintage Vee folks share all the tips.  Since it's about a good race, not about winning, we're all better off if we're closer together.

I'm with you and all about sharing.  That's why I made this build thread. But I promised Jack I wouldn't post his numbers. You may have noticed that I did post the tick marks, so anyone can count them to get the numbers...and I'm sticking to my promise to Jack--no numbers posted.

Thanks for all of your tips and posting your numbers!

Not a beautiful Saturday morning at Grattan. 

This was last Saturday at NHMS for about thirty minutes.

I turned wrenches for a friend renting a Citation.

Saturday was wet!  We were chasing a misfire Friday, which went away when I changed the condenser. But we weren't sure it was fixed because Jack couldn't push the car very hard in the rain.

Today, it was cloudy and mid-60s, so a very nice day to be at a racetrack. 

There were two races today.  The car ran well (no misfire), handled well, and everyone had fun.

Our next event will be at Road America in September.  We'll be doing some minor changes but are pretty happy with everything now.

We're starting the next round of e prep and modifications before we head to Road America for the VSCDA Fall Vintage Weekend September 16-18.  We haven't been running rear bodywork because the pieces we have aren't very nice and we wanted easy access to the engine as we were sorting the car out. So far, nobody has complained, but Jack did pretty well at Grattan, so we figure we should get the rear bodywork on.

You'll remember Jack is pretty competitive. He also hopes that the rear bodywork will give us a little better aero and be a good advantage at a long track like Road America. And of course, he wants it super lightweight (because competitive).  

So we've enlisted my other son Chris, who did an internship at a composites company this summer, to pull molds and make us some lightweight pieces.

He started with the used engine cover that came with our parts stash. In addition to being heavy and fairly beat up, it fit very poorly, especially at the lower flanges. Our plan is to make the mold weak at those flanges, then reshape them a bit with some aluminum bent to the correct angle and glass that aluminum into the mold. Chris did a little bodywork on the used cover, primed it, and got it ready to be the plug for the mold.

He sprayed mold release, then orange gelcoat on the piece, then laid up a few layers of cloth and I think one layer of chopped 'glass.

He ran the wire at the bottom because the used piece was too wide and flat and that was a quick way to get closer to the final shape we're going to need.

After things cured, he popped the plug out of the mold and we think we'll have a decent chance at making a nice new engine cover. I want to use a different color gelcoat for the new piece--probably white.

My younger son, Chris, and I are heading to the Solo Nats to run in GS later this week and Jack is running the Enduro Kart at Gingerman this weekend, so we're feeling pretty spoiled, racing-wise. And we head to Road America next week and we don't believe in last-minute thrashes, but we're not quite ready yet. 

We put the car up on the table again and checked everything over. I went through the valves and will check the tune.  We also have some minor oil leaks to address. 

The right rear seal was just starting to leak, so I replaced it. 

We want to go from this collector and megaphone to a 4-2-1 setup with a smaller and shorter tip, but won't get to it until after the race. In the meantime, we decided it would be nice to have wideband logged to the dash, so Jack welded in a bung and we'll wire it all in. 

Chris and Jack pulled the first test piece out of the mold and we're going to run it. It has quite a few flaws that we can live with. We'll make another one that's better before the winter painting commences. 

Jack mounted the rearmost piece of bodywork, which also needs some work. It's just resting there in this picture and won't be touching the exhaust once mounted. Our plan was to make a mold for that and make a new one, but again, we won't be doing that until after the race. I'll be painting both pieces this weekend, after we're back from Lincoln. 

So we're not quite as far as we'd like to be, but we're in good shape. And spoiled (and thankful) for how much racing we're getting in the next few weeks. 

Nice.  Do you run leaded fuel?  Curious how long the wideband will last if you do:)

There's quite a few styles of Zink tails available.  My club had molds for a least one of them--we're a long way off in Colorado but I can ask around if anyone knows where they are and figure out which style if you're interested.  The bigger difference in aero between them seems to be related to how easy it is for the person behind you to draft.  The most desirable versions, as I understand it, attempt to deflect as much air as possible downwards.  Still, compared to something like a Mysterian, a Zink is a brick...

In reply to Berck :

We run unleaded ethanol-free fuel (they call it "Recreation Fuel" in Michigan) that's usually 89-91 octane.  We haven't found the need for 110 or AV gas like other FV guys run. So our wideband should last.

We have the tail shown plus one of the "Daytona Tails" that are supposedly good for big tracks. The Daytona Tail is rough and we'll fix it this winter and try it next season. We have a lot to learn about aero, especially Zink aero!

Chris and I roadtripped to the Solo Nats.

We co-drove my black 2020 Civic Si, which was probably the least prepped car in GS. All we had was wheels and three-year old Falkens. But we didn't lose so that was fun.

Jack ran the kart at Gingerman Friday and Saturday.  Sunday rained him out so he was back at the shop finishing up the FV with me...photo dump to follow.

Jack went through some minor things on the car while I repaired and painted the rear bodywork. I've done a ton of body and paintwork over the years, but very little with fiberglass. I love to learn new things, so it's been fun working with repairing the old parts as much as making the new ones. Except for the itchiness. I'll put all my repair steps in this post so that those who also want to learn can see what I did and so those who know more than me can tell me how to do it better next time (thanks!).

This piece had a big crack and the paint was flaking off.  Jack and Chris had previously laid some new 'glass over the backside of the crack, but left the top for me. 

I used a 36 grit disk on a 2" grinder to make a pretty big gouge and get rid of as much of the crack as possible.  I made it sort-of "V" shaped so that I could put progressively larger layers of cloth in there.

I had some West Marine epoxy leftover from some boat repairs.  Since I had it, it doesn't smell like polyester does, and it's really easy to mix up (just one pump from each part's container), I used it. As mentioned I cut three progressively larger layers of chop cloth and laid them into the crevice.  I let it set up overnight, then rough sanded it with an 80 grit disk on a DA sander. That epoxy is tough stuff to sand, but it came down nicely and feather-edged well. 

A quick coat of body filler, some sanding with an 80 grit on a DA, a few touch-ups with a little more body filler, and I was done with the repair.

I sanded the entire part with the 80 grit on a DA, then 220, the 400.  I was careful to feather-edge any area where I broke through to a lower layer. 

There were a few pinholes and other issues in the part we pulled out of our mold, so I did similar repairs.

Both parts got 2 coats of high-build urethane primer.

I wanted to see how fast I could do this as we'll be making nicer pieces over the winter. So I did some things to see how much I could push the limits of sloppiness and speed. I didn't do any hand sanding like I normally would, just used the DA.  The primer said I could sand after 45 minutes of drying per coat, so I waited 60 minutes instead of 90 to push the envelope and then sanded the primer with 400 grit on DA. It seemed to go very well. We'll have to wait several days/weeks/months to see if it shrinks up funny or the feather-edged parts start to show, but for now it looks good.

I put down 3 coats of cheap catalyzed acrylic enamel and it came out better than I thought it would given the rush. We'll put them back on the car tomorrow.  We'll pull a mold off of the tail piece this winter and make a new, lighter one. We'll also be making a nicer top piece this winter as our fiberglass education continues.

In reply to Carl Heideman :

I hope I'm not being presumptuous here, though you said you're new to composite parts.  I just posted some stuff on my TVR build thread about making a new carbo fiber part.  I have mold making and vacuum bag info too, though it's all sort of randomly listed by when I did the work over the last year or so.  It might be useful info - there are definitely tips and tricks to this kind of work. 

In reply to TVR Scott :

Not presumptuous at all! I've been following your thread and really appreciate the detail you're putting in. I had a 2500M for about 10 years myself, all stock, low mileage.  I sold it to Bill @ Dominion Spares as he was looking for a very original car as a reference car. Plus he needed a TVR since he was selling TVR parts.

Anyway, we're starting with the basics of wet layup but want to get into vacuum bagging and all of that so your tips and information will be very helpful as we progress.

The car is prepped and ready for Road America. We're packing up Wednesday night and leaving Thursday afternoon. It's about a 4-1/2 hour trip if the traffic is okay in Chicago. Elkhart Lake is 80 miles from us as the crow flies, but that big lake gets in the way so it ends up being around 300 miles. And it's in a different time zone, so that confuses us when the sun goes down an hour earlier.

Anyway, here are the new body panels on the car. They look okay from a distance, but they're pretty rough as you'll see further below.

There is supposed to be a flange at the base of the engine cover, but it didn't fit at all, so we just cut it off. We'll make it right with the next version, I promise. In the meantime, this will look good enough at speed.

We're not big fans of Dzus fasteners for parts that come off and on a lot, so we like to use these spring/hook fasteners whenever possible. We get them from Pegasus.

Composite stuff that will bite you down the road on your first repair. The polyester filler will loose adhesion to the epoxy structural repair when it gets out in the sun. Your black paint will agravate, but it happens anyhow. The epoxy structure will remain strong in the bond zone to any polyester that has at least 90 days cure time. There is epoxy filler, Aeropoxy, but damn it is difficult to get a good enough mix with it. With that said, I put up with the smell to use polyester resin when I repair polyester parts. Cheaper too.

Your bonding zone technique is right on the money. 

I found I became immune to the itch during the process of replacing a Lotus Elite (type 14) front subframe. That I did with epoxy, as none needed top side final finishing, and a little hidden kevlar goes a long way toward protecting the rest of the bottom.

If you become proficient at itch avoidance/immunity, it becomes a lot of fun for the parts you are repairing. 

Oh! I just spotted something in the last pic, and I agree about Dzus!  

Get whoever did the clever brake hose tether to turn in his twist ends! It may be his own wrist that gets stabbed when reaching for something else. 

In reply to TurnerX19 :

So, could use some advice here myself.  I'm repairing my fiberglass nose after this (not my fault!):

Was planning on coating with polyester filler before paint.  If it's going to separate, am I better off painting the epoxy directly?  The top layer at this point is mostly glass bubbles mixed with epoxy.  I'd assumed paint wouldn't want to stick to it and that was the prime motivation to coat with something like featherfill for paint?  How long will it take to separate from the poly filler?  If it's in the range of years, I start to wonder how long the car's going to go between incidents anyway:)