Does anyone know the bolt spacing on the diff and trans on the C-beam. I know the trans has 12mm bolts and the diff has 14mm bolts but I was wondering if anyone has the spacing between the two 12's and the spacing between the two 14's. I'm looking to make my own c-beam plates.

Thanks for the help!
Colton

 

If I were going to construct my own plates I'd want no one's information other than my own. Get your prevailing torque nuts and the balance of your materials together and I'd think any sort of a competent fabricator could have them done, in hand and installed the same afternoon with a break for a sandwich and a chilly.

The nuts "float" but the bore in the plate bottom and the pilot on the top need to be precise.

I just can't imagine trusting "someone else's" information. I believe I'd prefer to take the dimensions from a differential and a transmission extension rather than rely on c-beam dimensions. They elongate quite easily.

Where are you located?

 

Nuts float on the plates you buy, I got mine form Zip with a discount code. Already on the car so no help on any measurements.

 

I'm a machinist so I understand what goes into this. I was hoping for a factory spec sheet that might have it listed, I could go under my car and take the measurements but I just thought I could see if anyone had the spec sheets before I did. These plates aren't as precise as it seems. Their job is to disperse the load off of the bolt head throughout the plate to give a larger pressure surface. The plates don't hold the bolts in place, the holes through the trans and diff do that, the plates are simply there to hold the nuts from spinning and to spread out load. I plan to cut slots (larger than diameter of the flats on the bolts, but smaller than the diameter of the edges, essentially allowing the nut to float but still hold it when its tightened down. (and close enough not to let it round off) The slot will be cut along the plate so there is room for the nut to position itself front to back (front to rear) while being held in left to right (driver to passenger).) The plates only need clearance holes for the bolts (usually 1/32 over size in standard.). So as long as the information someone had was with a 1/16 (1/32 for each side) of an inch it would work rather well. I can even slot out the holes in the plates if I find them to not fit since it's only a clearance hole. I hope I explained this well haha i did my best. Anyway, if anyone does have the pattern Id be pumped!

 

If you're a machinist then I'd think you could work with the "center to center" of the bolt heads on your car as a more preferred measuring dimension to be used. The closer the bore in the plate is to the required spec the more efficient they'll be. The bore in those on the market aren't elongated and I don't believe they should be.

Less than 10 minutes on a lift gets you what you need for a confirmed dimension that could likely be very efficient.

Sent a PM

 

 

Yes i understand that and I will work with them on center. Once again, I was only hoping for someone having a spec sheet because I would trust a spec sheet. I didn't mean to come off as an a-hole if I did.

 

And I understand that the plates arent elongated, there is no reason for them to be elongated. I was trying to make the point that those holes are simply for clearance and nothing else and to reinforce that point I stated that the holes could be elongated and it would have no impact.

 

The plates are to simply increase clamping area to allow the c-beam to do it's job under increased stress. As long as the contact area of your plates is more than the old washers you have an improvement.

edit: The main reason I bought mine and didn't make some is because the ones you buy are SS and I hate rust. I am not set up for SS welding and do not have a tig.

 

well I made my own beam plates. Rather than use flat bar, I used angle iron which wrapped down over the C-bam (upper plate) and upwards over the c-beam (lower plate). Angle iron plates are much stiffer that flat bar plates of the same thickness.

to capture the nuts on the upper beam I sawed apart four appropriately sized six sided sockets and welded them atop the front and rear C-beam plates.

If the c beam mounting holes are elongated, worn oversized, or egged shaped, repair or replace the beam.

do not attempt to use the c-beam as a measuring aid to locate the center to center distances for drilling the mounting holes in the beam plate, instead use the mounting holes in the transmission tail shaft housing and differential snout...these are the dimensions that determine everything.

Experiment, I don't have the diameter, but I found that one size up in regular SAE bolts over the stock metric bolts fit and removed a potential source of future slop.

In the mounting webs on the tailshaft housing and differential snout I cut short section of pipe, inserted them between the webbing and filled the webbing voids with "Devcon Steel" epoxy designed for machinery mounts. It doesn't matter whether you use beam plates or not, the final end point are these mounting webs, and once they start to crush it doesn't matter how tight you tighten the mounting bolts, in fact, it will only make a bad situation worse.

when you drill the holes in the c-beam plated, only drill them as small as possible for the bolts to fit through...which will probably be smaller than the factory holes in the aluminum c-beam; the reason is that when things start shifting around, you want the bolt to contact and wear against the hard steel on the c-beam plate and not the soft aluminum of the C-beam.

I even drilled and mounted the top beam plates with 3/8 bolts to limit any tendency for the plate to shift atop the C-beam.

don't forget the factory used adhesive when the C-beam was mounted; I used "Liquid Nails, contractor grade"

good luck

 

Because the two bolts are parallel, measure he center of head distance between the two tranny bolts and the two differential bolts from the bottom. The distance will be the same on the top.

 

I just use flat bar,top and bottom. not really a whole lot going on there. the torque is only 40 ft lbs on the bolts. I have had them on and off a few times and never seen any signs of deformation.