Weight reduction: Running out of ideas.

[69427]

Ounces here, ounces there.

Swapped out my intake manifold (an antique, but stock appearing Edelbrock C396 model) for a spare one I had gathering dust on the shelf. On this replacement manifold I cut down the plenum divider (for hopefully a couple more upper RPM horses) and cut out the exhaust crossover casting under the manifold to get rid of a few more ounces of material. Had to weld up the crossover ports, but ended up with a little over 3/4 pound off the manifold (up front and up high!).

While bolting everything back on the manifold, for amusement I weighed the stock ignition coil (still working great after fifty years) and an 80's HEI/EST remote coil. The "newer" coil is about 5 ounces lighter, and when coupled to the HEI module hidden under the shielding, should provide a touch more high RPM energy to the plugs. I have to modify/replace the coil bracket, as GM in their infinite wisdom changed the bolt spacing by about a half inch on the bracket.

Not great leaps in weight reduction, but it's progress until I can get working on the aluminum LCA crossmember this winter.

 

[BBShark]

Is this the kind of coil you are describing?

 

[69427]

Is this the kind of coil you are describing?

Yeah. I've got a assortment of used OEM coils, including those types, that I've accumulated over the years. The "newer" EST coils generally have lower resistance and inductance, which makes it easier to get energy into them at upper RPMs.

I'm putting the distributor and the stock coil back in this week, hoping to get the engine running again after being apart the past while. I've got three new variables (the modified intake plenum, different carb jetting, and a shortened advance curve in the distributor), and I'll add the fourth variable later once I've got the first three items run in and tweaked.

 

[BBShark]

I'm using the same coil. Is the wiring this easy? I did find that the coil + & - are not accurate.

 

[69427]

I'm using the same coil. Is the wiring this easy? I did find that the coil + & - are not accurate.

The coil wiring is pretty simple. On my coil the two inner connector pins (closest to the laminations) are shorted together, and the two outer pins are also shorted together. The inner red wire is the high current 12v supply to the coil, and the smaller pink wire is the tapoff/feed to the ignition module. The outer two pins are the coil C- leads (one leads to the module switching transistor, and this internal connection is also the flyback voltage that is used in traditional tachometer circuits).

The coil secondary winding connections are at the coil large terminal (obviously), and the other end of the secondary winding is tied internally to the coil C+/12v pin (like most coils traditionally).

That's what I've gleaned looking at some online diagrams and using my ohmmeter.

As I mention before IIRC, I'll have to modify the current bracket or fabricate one to get the coil to position correctly under the ignition shielding (for the stock look).

 

[BBShark]

Thanks, the Holley diagram was confusing me because there is no + & - side to the coil and I found the terminals tied together as you describe.

 

[69427]

A couple more ounces

While searching around for some parts/options, trying to get the engine back to running condition, I used some otherwise non-productive time to shave a couple more ounces off the engine. I'm replacing the stamped steel brackets under the ignition shielding with aluminum pieces. Not much weight available to remove obviously, but the slight reshaping of the bracketry will free up some room under the shielding for the eventual replacement ignition coil, and give a touch more adjustment room for the vacuum advance canister.

 

[vette427sbc]

Small but easy... The seat position lever could be reproduced in aluminum with a plastic ball at the end to mimic the factory steel ball.

 

[BBShark]

Large and not so easy.... getting parts out for my car and was surprised at how heavy the wiper door (5lbs) and lift mechanism (5lbs) is. Maybe you could make a flip up fiberglass replacement for the door or, if you could live without wipers, a fixed door and remove the wipers arms and transmission.

 

[69427]

Small but easy... The seat position lever could be reproduced in aluminum with a plastic ball at the end to mimic the factory steel ball.

I welded up some replacement seat mounts a while back. I got an offer I couldn't refuse on some lightweight '79 seats (Thanks again, Karsten), and made some lightweight non-adjustable mounts, as I just needed to put the seats as far back and low as possible.

I appreciate the suggestion, and please keep them coming. :thumbs:

 

[69427]

Large and not so easy.... getting parts out for my car and was surprised at how heavy the wiper door (5lbs) and lift mechanism (5lbs) is. Maybe you could make a flip up fiberglass replacement for the door or, if you could live without wipers, a fixed door and remove the wipers arms and transmission.

I have kicked around trying to pull some weight out of that area, but haven't made much progress so far. I'll take another look at that.

You have reminded me with that, that I've always been interested in a lighter wiper motor setup. I've still got the distributor and shielding stuff off the engine, so this is a good time to do a bit more measuring of the wiper motor. I'll confess I'm still very unclear/unsure what details I have to work out to deal with the wiper door operation with a non-C3 wiper motor.

 

[vette427sbc]

Large and not so easy.... getting parts out for my car and was surprised at how heavy the wiper door (5lbs) and lift mechanism (5lbs) is. Maybe you could make a flip up fiberglass replacement for the door or, if you could live without wipers, a fixed door and remove the wipers arms and transmission.

Short of the vacuum actuator and door, the linkage/mechanism looks about as slim as it can be. Maybe a few speed holes in the cast pot metal parts. I have tossed around the idea of a composite door, but I think it needs to be pretty rigid to maintain reliable functionality. Perhaps a re-design of the linkage to simplify things could help. Dont forget the cowl grille in front of the door is also cast pot metal!

 

[BBShark]

The linkage for the wiper door weighs 5lbs (lots of steel rods). And the door itself is another 5lbs. Maybe the wipers could be changed to plastic beam style wipers which are lower profile (and lighter) and the wiper door could be a fixed piece (like the later cars)? With a modern wiper motor you could shave ~10lbs?

Edit: The grill is 2lbs 7oz. Maybe if the wiper door is fixed, the grill could be part of it.

 

[69427]

Lexan windows

I think your comment was that you have the early 69 windows that are not compatible with the 69L and later windows. Correct. However, you can buy for $25 per window an lower track assembly that will allow 69L windows to be installed in 68/69E windows. I've read that it's an easy conversion. That's what I'm planning on doing with my 68. The parts have been ordered.

I wish, and I'm sure you do too, and many others, that we were somehow one of those 100's of millions of dollars worth employees of Microsoft or Apple. Just think of the things that could be done to build a modern super C3!

I have a C6. But I like the intimate interior of the 68. For me, getting into the 68 is like putting on clothing..it's cramped getting and fitting into the car. I think it's something akin to a 4 wheel motorcycle. It's a head's up driving experience. It's a convertible, and I estimate that it's about 2800 pounds with all the aluminum stuff I've added, and stuff I've deleted. I think the factory AIM sheet had it pegged at 3050 pounds from the factory.

Just going back and looking at stuff I didn't get the chance to pursue earlier. I'll look around for the lower track assembly, as I've got the later lighter side windows gathering dust on the shelf.

Thanks!

 

[69427]

dynamic vettes has a one piece targa top right now. Their "carbon version" weighs 17.7lbs for $2,100 per their facebook post.

once Im done with these hoods doors and t tops are the next big projects, then a solid top :thumbs:

I've been thinking about trying to get some weight off the top of the car, but carbon fiber parts are probably out of my budget, due to the $/# of weight removal.

WTH, I might just see if I can make some replacements in aluminum.

 

[69427]

Front crossmember replacement

Got some material gathered up for the new crossmember, and the jig partially done. I need to pull the current (35#) steel crossmember off to finish all the alignment and attachment points on the jig. So far the material weight looks to be around 20#, but I'm trying not to be greedy, and will be adding a bit of extra material here and there for a bit of extra strength margin. I'm also trying to get more comfortable with all the force vectors on the crossmember during braking and cornering.

 

[phantomjock]

Don't take this wrong - please. But wouldn't a tube chassis save a lot of weight? You have certainly shown a lot of effort that might be a major jump with a tube chassis at one leap. Or - am I off base here? I keep looking at pics of some (over) drilled chassis members and think some more weight may be saved there - but-- oh the pain.

Best of luck. Do you have a running total of pounds and ounces saved thus far?

Cheers - Jim

 

[69427]

Don't take this wrong - please. But wouldn't a tube chassis save a lot of weight? You have certainly shown a lot of effort that might be a major jump with a tube chassis at one leap. Or - am I off base here? I keep looking at pics of some (over) drilled chassis members and think some more weight may be saved there - but-- oh the pain.

Best of luck. Do you have a running total of pounds and ounces saved thus far?

Cheers - Jim

No worries. My reason for this thread is to get feedback on this topic, not any attempt to get my ego fed.

Regarding a tube chassis, I've only seen two examples out in the aftermarket. One has a shitload of small tubing comprising it, and every inquiry by me to find out the weight of that has been ignored. Not a big deal though, as the frame looks rather heavy, and is damn expensive. The other frame is a "copy" of the frame used in the early C2 lightweight Grand Sport cars. I only asked once regarding the weight of that, but got nowhere regarding an answer there either. I suspect it isn't cheap either, and I suspect it would take some additional modifications to work with my narrowed C4 suspension.

I'm still fantasizing about making a replacement frame in aluminum, but I'm amazed at how much life keeps interrupting me when I'm just doing small projects. I've priced out the material costs (roughly $2500), but I'm pretty sure it would end up a multi-year project.

Regarding the total weight removed, I'm guessing about 700#. I believe my car's original configuration was in the 3400# range.

 

[BBShark]

Don't take this wrong - please. But wouldn't a tube chassis save a lot of weight? You have certainly shown a lot of effort that might be a major jump with a tube chassis at one leap. Or - am I off base here? I keep looking at pics of some (over) drilled chassis members and think some more weight may be saved there - but-- oh the pain.

Best of luck. Do you have a running total of pounds and ounces saved thus far?

Cheers - Jim

No worries. My reason for this thread is to get feedback on this topic, not any attempt to get my ego fed.

Regarding a tube chassis, I've only seen two examples out in the aftermarket. One has a shitload of small tubing comprising it, and every inquiry by me to find out the weight of that has been ignored. Not a big deal though, as the frame looks rather heavy, and is damn expensive. The other frame is a "copy" of the frame used in the early C2 lightweight Grand Sport cars. I only asked once regarding the weight of that, but got nowhere regarding an answer there either. I suspect it isn't cheap either, and I suspect it would take some additional modifications to work with my narrowed C4 suspension.

I'm still fantasizing about making a replacement frame in aluminum, but I'm amazed at how much life keeps interrupting me when I'm just doing small projects. I've priced out the material costs (roughly $2500), but I'm pretty sure it would end up a multi-year project.

Regarding the total weight removed, I'm guessing about 700#. I believe my car's original configuration was in the 3400# range.

The SRIII tube frame advertised that it was "stiffer" than the C3 frame and lighter. I asked them to put some numbers on this and got no response. I asked them if they could tell me the stiffness or the weight of a C3 frame only and again, no response. Something tells me they don't know.

Looking at your diagram on the aluminum pieces. The crossmember you are going to make has upper and lower A arm mounts and bolts onto the frame, correct? I would really like to see what you are doing there.

 

[69427]

...........................
The SRIII tube frame advertised that it was "stiffer" than the C3 frame and lighter. I asked them to put some numbers on this and got no response. I asked them if they could tell me the stiffness or the weight of a C3 frame only and again, no response. Something tells me they don't know.

Looking at your diagram on the aluminum pieces. The crossmember you are going to make has upper and lower A arm mounts and bolts onto the frame, correct? I would really like to see what you are doing there.

I suspect you're correct about the SRIII claims. If they had actual numbers regarding lighter weight or torsion stiffness I would think they would put that on their site for all to see.

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My UCA mounts and LCA crossmember are separate pieces. The left side UCA mount is pictured above. The aluminum pieces in the previous picture are strictly for the LCA crossmember (the steel stuff in the picture is material for the jig). I've got a picture of the present steel crossmember, but it's being held hostage by Photobucket. The new crossmember will be a similar design, but with different material and thicknesses.

 

[69427]

Door hinge weight?

One of the guys elsewhere with a C2 GS clone is running aluminum door hinges. I'm just curious what C3 hinges weigh, and then I can figure out the weight reduction/hassle ratio. (The upper hinge bolts look to be a PITA to get to.)

Anyone out there with some loose C3 hinges to throw on a scale?

Thanks.

Mike

 

[BBShark]

I'm still fantasizing about making a replacement frame in aluminum, but I'm amazed at how much life keeps interrupting me when I'm just doing small projects. I've priced out the material costs (roughly $2500), but I'm pretty sure it would end up a multi-year project.

I've thought about this. It seems like, the best/easiest way to do this might be to make a bolt on cross-member front and rear and a frame. The cross-member's seem pretty straightforward but a good torsionally rigid frame seems like a challenge (given the space you have to work in).

 

[69427]

Just finished getting the bottom pieces of the crossmember cut to length and slid together (no permanent welding yet), and the LCA centerlines set up to match the partial jig. I now have to unhook most of the front suspension and steering to unbolt the steel crossmember from the car so I can use it to finish the jig to locate the steering rack and the attachment flanges that match up to the bottom side of the frame. The 4" x 6" aluminum plates at 3 and 9 o'clock in the picture show the rough placement in space of the flanges. The steel crossmember is roughly 35#, and my present tally of expected material in the new crossmember is in the 23# range, but I anticipate probably adding a couple pounds in extra reinforcing material in some places, just to help me worry a bit less while on the track.

 

[69427]

Front bodywork support bracket weight?

While I'm disinfecting my lungs of any Corona virus bits by inhaling argon and welded aluminum fumes, I've been curious what the weight is of the early C3 stamped steel support bracket that bolts between the radiator crossmember and the area right behind the center of the bumper. Anyone have one of those brackets gathering dust that you could take an accurate weight of?

Thanks.

 

[LAKEVET]

In you venture to go light in weight, have you paid attention to your cross weights or front to rear percentages? Just interested in your results.

Thanks

 

[69427]

In you venture to go light in weight, have you paid attention to your cross weights or front to rear percentages? Just interested in your results.

Thanks

I don't own any wheel scales, so I can't track the corner weights with high accuracy (I generally have to calculate them). When convenient, I've used the scales at the track, and occasionally I've stopped in at a truck stop and weighed the car there. The track scales are usually pretty busy, so all I've been able to get is F/R weights, and I occasionally get L/R weights at a track stop, but it's been a frustrating experience trying to explain to the gal at the scale controls why my car is sideways on their scales.

Without me in the car, the car weighs 2730#, and the front weight is about 100# more than the rear (roughly 52/48 % F/R), and the left side is IIRC about 50# more than the right side (I don't remember the ratio I calculated a while back).

I'd certainly prefer that the F/R weight ratio was just the opposite, but there's not an easy way of doing that with a front engine street/licensed car. Regarding corner weights, I can only try to get the car to sit at an even ride height, and then tweak the corner spring height adjusters if I find that the car likes to take left and right turns noticeably different.

I'm the "team" engineer, fabricator, driver, and all-around gofer. There's several detail items I'd love to fix/change/adjust/know, but there's only so many hours in a day.

 

[phantomjock]

I'm the "team" engineer, fabricator, driver, and all-around gofer. There's several detail items I'd love to fix/change/adjust/know, but there's only so many hours in a day.

Man I feel that! I have my pit boss/cfo/wife/girl friend/she who must be obeyed - and she really shines at the track but at home---reminds me to get back to work!

Have you considered building a set of the Ruggles Scales? Pretty cheap and "close enough" for most of our purposes. I was very lucky to score a set for shipping costs only. Could send some plans - or post in Download Section.

I've been trying to sort out the SR some -- and the weights/ride heights are where my focus has been too. Your cross weight looks pretty good from your post. I'm struggling with throttle off oversteer on it - Think it is combination of cross weight and in this case rear engine + different length half shafts on the Renault engine.

You mght try some ballast opposite on one side at F/R - just to check. May tell the story quicker than adjusting springs/ride height.shocks/ARBs. Tie them down well!

Stay safe and best of luck!

Cheers - Jim

 

[BBShark]

While I'm disinfecting my lungs of any Corona virus bits by inhaling argon and welded aluminum fumes, I've been curious what the weight is of the early C3 stamped steel support bracket that bolts between the radiator crossmember and the area right behind the center of the bumper. Anyone have one of those brackets gathering dust that you could take an accurate weight of?

Thanks.

Since my car is still mostly in pieces, I have access to one of those!

Weight is 6lbs 12oz

 

[69427]

While I'm disinfecting my lungs of any Corona virus bits by inhaling argon and welded aluminum fumes, I've been curious what the weight is of the early C3 stamped steel support bracket that bolts between the radiator crossmember and the area right behind the center of the bumper. Anyone have one of those brackets gathering dust that you could take an accurate weight of?

Thanks.

Since my car is still mostly in pieces, I have access to one of those!

Weight is 6lbs 12oz

Well, thank you, sir!

Once I finish the front cossmember, I think I'll look into swapping out that bracket. The weight amount removed will be small, but it's way the hell up front.

 

[69427]

I'm the "team" engineer, fabricator, driver, and all-around gofer. There's several detail items I'd love to fix/change/adjust/know, but there's only so many hours in a day.

Man I feel that! I have my pit boss/cfo/wife/girl friend/she who must be obeyed - and she really shines at the track but at home---reminds me to get back to work!

Have you considered building a set of the Ruggles Scales? Pretty cheap and "close enough" for most of our purposes. I was very lucky to score a set for shipping costs only. Could send some plans - or post in Download Section.

I've been trying to sort out the SR some -- and the weights/ride heights are where my focus has been too. Your cross weight looks pretty good from your post. I'm struggling with throttle off oversteer on it - Think it is combination of cross weight and in this case rear engine + different length half shafts on the Renault engine.

You mght try some ballast opposite on one side at F/R - just to check. May tell the story quicker than adjusting springs/ride height.shocks/ARBs. Tie them down well!

Stay safe and best of luck!

Cheers - Jim

I welded up a pair of the Ruggles arms/brackets several years ago. They were a bit more work to use than I cared for at the time. I'm older now, so maybe I'll have a bit more patience to use them.

Do you have one of those "Sports Renault" cars? A bunch of years ago I had the opportunity to drive one of them on a short course. The main thing I remember about that experience was how tail happy that car seemed to be. Post some pictures sometime of your work on it, and what tweaks you're doing to tame it.