MG Sports Cars

Lotsa bearings Gary, everywhere you could put one. ;-)

Jim

New brake rotors: These are Speedway .81 x 12.19" and weigh 6.1 lbs each. Apparently made by CNC machining a standard rotor with the scallop pattern. About fifty bucks each. The tape is a size reference.

Jim

Light enough for you Jim? Those are going to look awsome through those wheels you have on the car.

Wow, that's half the weight of the 12" Corvette rear rotors I'll be using and 1/3 the weight of the 13" fronts. How much does the hat weigh?

Jim, if I use the Willwood aluminum hats I've heard they are 1.6 lbs (but I've also heard 1 lb.) Steel isn't much heavier. Plus a few ounces for the bolts, so figure about 8 lbs. The calipers are 2 lbs each, and I don't have the pads yet, probably another pound or so there, so about 11 lbs total. Which I think is about as light as you can get without going to exotic materials. Well actually I think you can drop almost another pound by going with the 11" rotors, and for most cars that would be worthwhile. Cheaper too by about five bucks.

Here's a neat little piece, though the photo is crappy:



This is the saddle for the blower snout support and the stainless strap with the glass beads laying on it will go over the top. The saddle gets welded to a 3/4" square support stay that bolts to the front cover and also supports the belt idler assembly. There is one more piece missing because I haven't made it yet, a somewhat trick little tensioner rod that goes through the saddle and secures the ends of the strap then pulls it down using the two 10-32 SHCS in the photo. Not many of you will be able to visualize just how that is going to work, but bear with me, it should be finished and all polished up in a few days, along with the idler assembly. Then I'll post photos of the completed rig all installed.

Jim

Well, that last bit was poorly worded and didn't come out very good. Like anyone, I can be an idiot sometimes. I just meant it'd be hard to visualize how it will look, so I will describe it. Basically the cross pin will have round ends and a roughly elliptical mid section. The ends will be 5/16" diameter but the ellipse will be 1/4" tall by somewhere between 3/8 and 1/2" wide. It will have two vertical #10-32 threaded holes matching the holes in the saddle (which only go through as far as the bore of the cross hole) Then the strap will have a pair of 5/16" holes. To install it, the cross pin gets inserted and the screws threaded loosely into it from the bottom, then the strap is fitted over the blower drive shaft and sprung over the ends of the cross shaft which will project just a little on each side. The elliptical cut, which is on the bottom, will provide a seat, capturing the strap against the saddle as the cross pin is pulled downwards by tightening the capscrews, whose ends bear against the body of the saddle. In this way the clamping force of the capscrews will tighten the band around the nose of the blower driveshaft housing, holding it tightly to the saddle. Since there is no relative motion between that and the front housing, bolting the strut at the bottom will create a rigid assembly capable of supporting the idler group once torsion stresses are directed through a separate attachment point.

...maybe a picture would be better.

Jim

Jim, I'm sure it sounds a lot more complicated that it will be when completed. I think I've got the idea though but then I saw the blower snout where you'd machined it to accept the support so I have a bit of an advantage over the others. When you get finished the engineers in the crowd will drool and the racoons in the group will as well.!

And you do the herky jerky and you turn yourself around.

Uhm, I get it but unless you have an engineering degree, the picture will be needed.

Once again Jim "too cool for school" you continue to impress!

Cheers
Fred

Made a little more progress. That brace is finished except for drilling and tapping one hole and polishing it. I sort of stalled out on the belt idlers for awhile trying to design the tensioner device but I think I've got it now. It'll be another week before I can weld it up.

However, I did make a couple of key purchases with my tax money. A matching pair of full sized condensers, one for the A/C and one for the intercooler, and a set of 42 lb injectors. Those will all be here in another week or so. Plus I've asked Matt Cramer for some help sorting out the hardware of the new Megasquirt controller as it will be pretty complex. It includes transmission control and will eventually have 8 EGT inputs and individual COP ignition. So there is a lot to do there and I might as well get started building the boards.

I've also started on the structure for the new hinges for the forward tilt front end. If it will work out I think I'll use the BMW system with a front pivot rod that cantilevers the pivot to "lift and separate" before hinging forward.

Jim

I understand the rotors are lighter than conventional round, of same overall diameter. The loaded radius is also the same,(leverage). I wonder about the airflow, looks tortuous compared to round ? It would be nice to find ceramic rotors in aftermarket. Cheers, roverman.

Art, I think they just took their standard rotors and CNC machined them to get the scalloped shape. So basically more surface area for a given mass, but the same rotor before machining would have more thermal mass AND surface area so it would have more capacity, just be heavier. I don't think capacity is going to be a problem. If it is that just means I have the wrong pads.

Jim

Time to dig up this old thread I guess. No photos right now but I'll get some soon to show progress. I have added a pair of stiffeners to the front of the inner fenders which tie the top reinforcements to the bumper mount area, and have finished the serpentine drive except for the tensioner screw. That probably doesn't sound like much progress. Oh, I also mounted the condensers. Anyway it looks a little better and I can start on the bonnet hinges. Still a lot to do but not as much as there was.

Jim

Jim

I'm interested in your bonnet hinges as I'm going to start designing the ones for mine soon. I will also have a front tilting hood and will probably incorporate the grille in with the hood so the whole thing will tilt at the same time - my fenders will stay put though. Post lots of pictures



Edited 1 time(s). Last edit at 07/26/2012 12:51PM by Jim Stabe.

OK. The design I'm working on this time around has a lot in common with some older BMW's. A rod across the front ties to a pair of 18" long arms that pivot at a mounting point on the underside of the fender. The rod crosses above the slam panel and basically a 6" lift at the front gives a 2" forward motion at the rear, at which point a pair of locating fingers clear the rear lip and allow the whole works to pivot forwards and down. That basic motion is the same as the last hinge I used but is more robust as well as being balanced from side to side by the cross rod. As for the actuation, I've done away with the gas struts. I have a Mercruiser tilt/trim hydropack in the trunk and a couple rolls of 1/16" stainless tubing so all I need are some cylinders and I'll be able to open and close with the touch of a button. Provided it all works as planned. Hey, I'm all for labor saving devices and as often as this hood will be opened I should probably have a remote.

Needless to say this all adds a little weight. But the balance will be as good as it ever was, maybe better, and the ratio of sprung/unsprung weight will go up so the ride will only get better. The car was already faster than I am and I don't think that will change. So it's all good.

Might be a day or two before I get those photos though, got family visiting.

Jim

Photos finally!





The serpentine drive is completed, aside from one stainless setscrew to replace the black one and a nylon plug to go behind it. That locks the adjusting screw.

The difficult thing about this drive is the number of fabrication and machining steps required to make it. If a really sharp worker knew exactly what he needed to do he might be able to duplicate it working full time in a couple weeks if all went well. So at standard shop rates that'd be upwards of five grand. Sadly, very few people can afford those prices. So this is likely to be the only one like this that you'll ever see.

Jim

Jim, that's super trick looking and well engineered . don't guess too many orders are pending? Glad to see you ready for next step.

Jim:
Huge amount of measuring, head-scratching and time spent in front of a lathe and vertical mill. Awesome job and looking great!! Perhaps the next one could look like this? :~)

Aw... THAT is just completely SICK Phil :-)

Jim

Jim,

Looking real good there I must say! I want to see this running in the flesh.....Awesome fab work! The check list is getting smaller Jim.

It's still a pretty long list. I've started on the hinges and may be able to mostly finish those this week but it seems like I'm at the point where every piece has to be polished and buffed, which really slows things down. But all our racoon brothers would be proud. Anyway I'll be a lot happier when there are no more major pieces to make. Well, one at a time I guess.

Jim