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240z SCCA vintage race car, restoration


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thanks! Gosh I’m not sure how to adjust the res of the photo’s uploaded here. I can try e-mailing them to myself and uploaded from a computer instead of from my phone. The pictures themselves are huge

Hi all!   Restoring a rusted 240z series 1, SCCA vintage race car. Car last raced in 02'. Currently rebuilding to group EP spec's. I figured id start a new thread summarize my plans and prog

That is where it should go. Everyone usually mounts the cell at deck height which never made sense to me. Then you have to separate it from passenger with a big ass box or bulkhead design. Drop it dow

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Other things I’m working on, and a few questions for the team:

 

1) bought all the electric gauges I need, and working on gathering the sending units and wiring leads. Settled on:

 

tach w/ light. 
fuel pressure 0-12psi

oil pressure

oil temp

Water temp 

fuel level 

Volts

 

2) looking at oil coolers. Setrab most likely. Struggling to determine if an “oversized” unit would be bad in any way. The oil can’t get too cool when racing since water temp is thermostatically regulated and a cooler oil will just warm to the block/water temp. 🤷🏽‍♂️


3) looking for an affordable Lexan front windshield, but struggling to find one. Rear hatch is easy since it is flat.

 

4) just got the FRP hood ordered and already have the FRP ear hatch. Looking at the 280z FRP bumper as it is touted for having a positive aero effect. 

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46 minutes ago, calZ said:

I'll be very interested to see how much this car weighs once you're done with it. 


I have been weighing OEM components (albeit rusted) as I remove them, and weighing the replaced metal. Here is what I found:

 

1) the OEM pedal assembly & steering column mount. Going to Tilton assembly net 3lbs savings (including the independent rear brake MC). 
 

2) cowl being replaced with 20-gauge single layer of steel saved about 4lbs. 

 

3) engine bay unibody frame stiffener: this was a wash. The stainless tube is pretty heavy, but is a more efficient cross-section and I stronger. 
 

4) my reinforced rockers added about 3lbs per side.
 

5) little floor pan support extension is about 1.5lbs per side.
 

since the front end isn’t supporting much weight, this will be a thinner gauge of tube. 


Net, I think I’m up maybe 10-15lbs with the strut tower reinforcements.

 

I have gone back and ground down all my welds to reduce as much unnecessary steel as possible. I’m also concerned about the additional weight I have added, but there is also quite a bit of unnecessary stuff I have removed (mounting tabs, weld-nuts, lap-joints etc.) 

 

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Yea, weight is a struggle for me as well. It's hard to tell what is added vs. Subtracted on my hack job. My shell with cage weighed 500lb before I started. When I take it off the stand I will weigh again.

 

I can comment on the Lexan. I always do mine myself. I buy 1/8 generic polycarbonate, I think SCCA requires thicker. Cut it to a pattern little oversize of an old windshield makes it little easier. I trim the edges down until the face is just flush with metal. Spray paint a 2" flat black ring around the inside perimeter. My new process is to drill the mount screws and mount with a little spacer out of vacuum hose to get the right height. Use lock nuts.. Tape up the outside very well to seal to the window frame and tape 3 or 4 inches on the inside. Spray foam insulation around the inside. Trim it along with the inside tape. 1/4 to 1/2 turn on the screws to lock solid. If done correct you can't see anything from outside and about a 1/2 foam filled gap on inside. Polycarbonate is very easy to work with, you can't crack it. I don't think mine has any fancy coatings. As long as you are careful cleaning it with right products and don't get any chemicals on ti, it will last a long time. Not like you are dirt track racing or something. And if you need to bend it 45 or 90 degrees just heat it up carefully. Too hot and it will bubble.

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I just looked for a local plastic and composite retailer. 4x4 will not work, must be 4x8 for the front. Most people that sell that kind of stuff can order any thickness. Start with little oversize on the cut out and slowly work your way down by fitting and sharpie marks. You can trim with a sander, die grinder, or skill saw or all 3. Once you work with it you will want to use the stuff everywhere. Trick with windshield is try to get perfectly smooth transition to metal for least wind resistance. 

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Jigsaw cuts Lexan like butter. Just don't peel the protective film off, and think about adding some masking tape around the lines too. It scratches so easily and that shoe on the jigsaw has to drag all over it.

I buy my Lexan at tapplastics.com. Not sure if they have locations in SoCal, but there has to be someone in that area that sells 4x8 sheets. If you need smaller pieces it's cheaper on ebay than at TAP, FWIW.

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1 hour ago, JMortensen said:

Another tip is to make the holes for the screws oversized a little bit. Apparently if they're tight you can crack it when it heats and cools. I used plastic spacers from mcmaster.com to get my hatch glass to sit flush.

Yes all Jon said above. I normally use black button head Allen screws with lock nuts and washer under nut. 10-32 I think or 8's I can't remember. Whatever you do don't tighten too much. Just snug.

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@JMortensen @clarkspeed thanks for all the help Jon, Clark! Yep his will definitely help me once I get to the windshield. I may not be that far away! 
 

updates: 

 

1) got a push/pull remote actuator for my Accusump. I don’t want to have that much warm oil in my cab, and it’s time to start mock-fitting all the components so I can make brackets and drill holes before primer.

 

2) settled on an oil cooler. Setrab series 6 34-row. Good balance of performance, price ($300) and pressure-drop (2psi). Needed it in-hand to lock-up the front and get brackets in.

 

3) Front-end chassis is coming along. Got the radiator lower mount welded so I can remove the top rad crossmember. Braced in 2-places to avoid warping. Almost done with inner wheel-well skin. 

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  • 2 weeks later...

Some updates, and a few questions for the phenomenal team here! 
 

1) finally got my hands on a decent L28 short block core (N42). Need to decide on whether to use this with the V07 crank I have to make a 3.1L for vintage racing, or for a 3.0L L28et for the street Z. Open to suggestions! I already have the L28et (F54 block), but don’t have the time or space to pull that motor out the street Z. It is mechanically stock, and needs a rebuild.

 

2) I got my stahl header! She is a beauty. Any thoughts on the collector? She ends in 2X 2-1/4” tubes now. I can go single conventional flange, slip-on with clamp, or dual V-band. I feel the slip-on option will be the lightest option but certain to get some exhaust leak and into the cab. 
 

Made an intake for the fresh-air box which will straddle the top crossmember. 

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That header is gorgeous!  I think you would have a hard time doing 2 v-bands with it because of clearance.  I think slip on collector with v-band downstream.  Plus the collector needs to be a certain distance from the valves for max extraction, which is probably just after the 2 pipes terminate.  You can search for it.

 

The stroker for vintage depends on the rules which you will probably break with that crank.  If you race as an IMSA GTU, no problem, 3.0 is allowed. Otherwise, you will want an org that does not care about such trivial things. 

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Hey Aydin, I'd be interested to see your airbox if you don't mind posting some pics at your next update.  Tried downloading the movie clip you included, but my laptop didn't like it (possibly because it's an ancient POS, and I'm too cheap to buy a new one.)

 

You might be able to use V-band clamps on the header if you stagger them on the two pipes (i.e. one slightly fore or aft of the other)?  Just a thought for your consideration.

 

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Thanks @clarkspeed @jhm
 

For some reason I thought some of the vintage org’s were pretty lax on engine specs if it looks stock and still using carbs 🤷🏽‍♂️. For instance, I know Greg is running HSR next week and he has a crazy hot cam that would never fly in EP. I would never bother putting the 3L in SCCA. People know their stuff and I would look silly (unless like you said, I was classed right). It is pretty damn tempting to throw in a 3L though! 
 

john, I just finished the fresh-air intakes. Here are some pics with the radiator lower mount in as well. I need to bridge across now, and finish the rad upper mount. The two intakes are not identical/symmetrical but who cares. The drivers-side one is bigger, which is the one I need most. 

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For vintage you want to end up in CP (2.4) Or BP (2.8). 0.40 over max.. That is where they ran back in the day. Many organizations use 1972 scca rules. SVRA has one of the most complete rule books. Engines are fairly unlimited. An EP air dam would not be allowed. 

 

Rules enforcement depend on the org. Some are happy to have a lot of cars on track and no one complains, others want parity, and many complain.  And even they are welcoming as long as you are not podium. Some will do a displacement check. When I run with SVRA they are critical of obvious things like big brakes and super wide wheels. But I usually run around mid pack. I've even run EFI with no problems. Some groups will let you run with no points, some will bump up a class if you are way outside the rules. Greg's latest car it built to win in that 2.4 CP class I believe. So he is ready for any scrutiny.  

 

Vintage is full of cars running much faster than they ever ran in the 70's. I ran against a Jag with twin plug head and 400+ hp. And not unusual to to see 40k Porsche engines with titanium rods and more. And V8 stuff forget about it. Some swap tires before every race.. I think the best answer don't worry until you are running top 5. Then if you want to run at the sharp end, tighten it up. I am usually around top 10 and have a hell of a lot of fun.

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22 hours ago, clarkspeed said:

For vintage you want to end up in CP (2.4) Or BP (2.8). 0.40 over max.. That is where they ran back in the day. Many organizations use 1972 scca rules. SVRA has one of the most complete rule books. Engines are fairly unlimited. An EP air dam would not be allowed. 

 

Rules enforcement depend on the org. Some are happy to have a lot of cars on track and no one complains, others want parity, and many complain.  And even they are welcoming as long as you are not podium. Some will do a displacement check. When I run with SVRA they are critical of obvious things like big brakes and super wide wheels. But I usually run around mid pack. I've even run EFI with no problems. Some groups will let you run with no points, some will bump up a class if you are way outside the rules. Greg's latest car it built to win in that 2.4 CP class I believe. So he is ready for any scrutiny.  

 

Vintage is full of cars running much faster than they ever ran in the 70's. I ran against a Jag with twin plug head and 400+ hp. And not unusual to to see 40k Porsche engines with titanium rods and more. And V8 stuff forget about it. Some swap tires before every race.. I think the best answer don't worry until you are running top 5. Then if you want to run at the sharp end, tighten it up. I am usually around top 10 and have a hell of a lot of fun.


hey that is really helpful Clark! I’d love to run EFI on a 3.0L if I could! Be nice to have a reliable, consistent race engine. Carbs are such a pain.

 

the background you provided on the different groups and classes was helpful! Since EP has such a well-documented rule book, I gravitated to that class since it’s more on spec and less reliant of experience (dealing with judges). So far everything was purchased, built, and installed to meet EP (including the 2.4L and head mods). there are a few other things that are borderline, like my engine bay to cowl vent relief, or new circle cross section frame rails. Not a true tube frame since the skin material remains in the unibody, and the mounting locations for all components (subframe mounts, engine placement, rad placement etc) is all OEM. Strut towers are still OEM too. 
 

this sucker just had too much rust, it seemed silly to replace with OEM frame rails when they were heavy relative to their strength (designed to crush in an accident), and thin-wall box frame is hard to find in the right size. EP states you can remove/replace unibody structural components as long as the unibody does not require “additional support” as a result. I interpret this as putting in frame rails so thin they need to be stiffened with additional ribs, stringers, angled tubing etc. after I boxed off the frame rails, it actually looks pretty OEM. The upper rad support/crossmember is the most non-OEM looking thing in the engine bay. 

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