68-72 Front (under radiator support) crossmember weight?

[69427]

I saw somewhere a while back where a guy was making an aluminum version/copy of the front (bolt-on) crossmember that the radiator support and front bumper vertical supports bolt to. I lost track of where that was. Anybody have a stock steel one laying around that they could weigh and give me a number? Just kicking around the pros and cons of an aluminum one.

TIA

 

[BBShark]

Need to update the Weight Saving Options in the tech section
68-72 Front (under radiator support) crossmember weight=14 lbs.

 

[69427]

Thanks, Larry!

It's a down the road sort of project, but given that this crossmember is in front of the axle centerline, it might be interesting to do this.

 

[69427]

While on hold for some computer repair, I was reading "The complete book of Corvette" by Richard M. Langworth. On page 208 regarding weight reductions in the 1980 model, it says "Curb weight was pared by about 250 pounds by using aluminum instead of steel for the front frame cross member and differential housing."

Is the (aluminum) crossmember statement true? If so, any pictures?

Thanks,
Mike

 

[Twin_Turbo]

The diff in the 80 is a Dana 44 with a batwing, like your C4 unit, the 70-82 frame doesn't have a diff crossmember.

The front frame has no aluminum parts the impact bar is partly from fiberglass with the square block impact absorbent stuff on it over a steel crossmember (and it's heavy). The rear impact bar is aluminum however.

82 Dana 44:

 

[69427]

I had never seen any aluminum up front that resembled the description in that paragraph. I assumed it was an error, but I had to check for sure.

Thanks again,
Mike

 

[68/70Vette]

The front crossmember (removeable) is heavy. I've installed two of them and always thought that if I had the time, I'd have one fabricated in aluminum. Seems like it's be relatively easy. There might be some differences in hole dimensioning for the various years. 69 through 72 I would guess are the same. 68 I think is slightly different (at least the frame extentions are), 73 might be different than 74, etc.

 

[69427]

What's involved with removing this crossmember (outside of just a bunch of bolts)? IIRC, the front end and the radiator bracket will still all remain in place, correct? I'd need to take the present one out to use as a pattern to make the new one. Anything to be concerned about during the process?

 

[BBShark]

You just need to remove the outer bolts and the bolts that hold the horse shoe bracket to the nose. If you cut the steel hat section off the plate you could probably remove half the weight of the crossmember and wouldn't have to make a replacement.

I think the bottom part of the crossmember is only there to serve as an underbody over rider for curbs and such. I doubt if you are going to be mashing your car into parking lot curbing :amused:

 

[68/70Vette]

What's involved with removing this crossmember (outside of just a bunch of bolts)? IIRC, the front end and the radiator bracket will still all remain in place, correct? I'd need to take the present one out to use as a pattern to make the new one. Anything to be concerned about during the process?

Best I can remember, it can just be unbolted. You'll have, of course, to loosen or remove some of the bumper bracket hardware for clearance. I think the radiator brackets can just be unbolted also. I've removed this piece from a 68 and a 70. I think the 70 is identical to the 69. (The 68 radiator attaches a little differently than the 69/70.)

 

[69427]

Took the crossmember off this evening. Took all of ten minutes, including the time it took to douche all the threads with WD-40. There were four bolts in the middle that were probably the only parts on that car that had not been touched since it left St. Louis.
My scale reading matches Larry's (14 pounds), so now we'll see what the replacement crossmember ends up weighing.
I recently had knee surgery, so I can't operate the clutch for a while, so I might as well use the downtime to tear the car apart and do a couple new projects.

 

[69427]

Version 2.0

I started on a replacement crossmember a couple weeks ago, using some tubing bent to mimic the basic shape of the original part. Spent a crap load of time trying to make the idea work, but it just wouldn't package very well. The major obstacle was the number of tabs I was going to have to weld on to make all the bracket attachments. (The long bolts were used for tab alignment.)



Decided that a shape similar to the original would make life easier. Picked up a bunch of aluminum yesterday and have been generating a bunch of aluminum filings trying to get everything to fit properly for welding and to look reasonably symmetrical. An early mockup during the fitting process:



I'm hoping to finish the fitment stuff tomorrow, and start on the welding. The initial weight looks to be in the 8 lb area. I've got to add some weld bead weight, but I also have to drill a few more attachment and access holes in it.

 

[phantomjock]

Planning on hitting something?
Thats a pretty big piece for a plastic car!
-- Oh now I see -- Is that Channel not solid!
-- Ok -- Got it! That'll be a good option!

Cheers - Jim