Designing main girdles

Would anyone have any experience in desiging and building the main cap girdles they would be so kind to tell? I am not wondering about a particular engine, just in general design and best & strongest way to manufacture when somebody is on a low budget trying to strengthen the bottom end.

I know there isn't a girdle out there for each engine, thats why I ask for some basic insight.  

a few things up front...

do you have precision measuring devices.... like a vertical mill where you could bolt the block onto so you can get exact measurements between the studs...

this way you can create a drawing of it.. for water jet cutting or drilling on a vertical mill so the bolt holes are perfect..

you can .. if you have a lathe.. create a pile of  cut up bolts.. where you chuck it up in the lathe with the threads double nutted to allow easy centering in the 3 jaw chuck.. cut the hex off the head.. then cut the end to a sharp point..  

doing as many bolts like this so you can thread them into the block.. lock them with nuts to lock them at the same height..    you can now lay the steel plate over the transfer punches you have made to get each bolt hole center punched into the plate..  this is the hard work...   you may want to be sure to tighten the jam nuts to spread the load of the hammer impact to the mounting face .. not the threads them selves..

you could now.. create a duplicate pattern in cardboard or plastic to mount to check for crank clearance..  going through several generations ..

then you could transfer the window pattern to your punched steel plate.. for drilling and then either milling or sawing between the holes.. leaving extra metal to remove as you want to get the cut out area edges absolutely smooth. to remove any chance of stress points..    you do want round corners on the windows you cut out..

this sounds like a fun project..

you may want to bend a indicator stand out of some steel .. so you can run the ends down the oil pan rails.. to measure the height of the main cap nuts prior to installation of the plate..

how thick to make it...   if you can get large hex main stud nuts from ARP or other suppliers..      if you get a box of the nuts.. and you are only going to be working on one motor.. if the nuts have enough height.. you could grind them slightly to give you a totally flat mounting..  but the plate will flex slightly so that point might be moot.  a plywood board with numbered dowels to keep the nuts in order..

there is the choice of bending the sides of the girdle past the windows in a big press brake... as that would really increase rigidity...     this is what the front would look like... upside down....\________/    the angles would not have to be that much..


the other thing that might need to be discussed.... is if to search out and find enough tapered split cones that are used on truck axle flange ends..  as these might be better at transferring the side to side motion to the plate...  as they work really well for the drive axle end to the brake hub face for transferring the torque loads to move the trucks..  these would make tear down a SERIOUS pain..  and the plate would need to be thicker..   with a lathe.. you could create your own shallow angle cones to do a similar function and be easier to remove for tear down..   precision measurements would be needed to make these of proper use..  

Wayne thats some info bud:

Fahlin_Racing: I want a cut when you patent it.....LOL  

I made one back in the day in a shop class for the beginning of the engineering courses I was taking. I used a windage tray as a template and it worked out near perfect. You may want to see if that engine your thinking about has one available?

It wasn't a 1,2,3, deal either believe me. It was for a Ford Hi-Po 289. They have a beefier bottom end as compared to the stock 289 non Hi-Po. Give that a try. There weren't any water jets around back then. It was a work of art. While other guys were making lamps from bowling pins, I did that.  

Great information Wayne. Fabrication is in your blood! This would be the first engine part I will stick my hands into as far as designing. I have others in mind too but for other situations.

Thank you wayne, thats going in the notebook!

Pepsi, I would have to comb the aftermarket to see but, I was thinking in general. Nothing really specific.  Your template of the windage tray is a good idea to use for anyone wanting to experiment. Engineering huh, did you follow through with the degree or whatever it may have been you were pursing? I wish I could attend some engineering schooling.

Ford actually made 4 different models of the 289 I believe Hi-perf, standard, low output and one other rated mill that has slipped my mind. If I had my engines at hand I could tear the pans off each and just kind of walk the steps. I think if its even possible, is look into if the particular engine could utilize 4 bolt main caps to help stiffen it some more. But thats just my curiousity talking.

I just don't have access to the mill. I however work at a truck equipment company where I can get the steel bent and welded etc. I have a dial caliper large enough to measure the bolt on-center on the main journals etc I believe they are accurate to .001". I will have to check out the machine shop I bring my stuff too though.

Hope you guys had a good thanksgiving! I did, the turkey knocked me out for about an hour lol  

Pepsi, what did you use to make your piece, did you use a press or something of that sort?  

Wayne, being able to read your post over once again, reading the last paragraph, you mention..

:
is if to search out and find enough tapered split cones that are used on truck axle flange ends..



I work at a truck equipment company and these are on the shelf in varying dimensions. So I guess I could grab them when I need them. They come split or non-split.  

Fahlin_Racing I apologize for taking so long to get back too you. I was having problems with my lap-top

This was back in the day. We all had the same pieces towork with. They were 327 small journal engines that was it. Nothing fancy. They were scheduled for Dyno room. I used a 3/8" and 1/2" boiler plate steel, aluminum moved and twisted. We have better and little metals today. You can probably make it out of aluminum or carbon fiber today. It was hard to keep the boiler plate from twisting so I went to 3/8" 1/2" was much better. I'll tell you it was a file fit and hand stroking the boiler plate.

Everyone in the class that was making a main girdle was using straight bolts. I opted for a long stud. We didn't line bore any of the blocks.

There were 6 of us that were doing the same project. The other 5 guys that used straight bolts all had bearing problems,(MONKEY SEE MONKYDO) I remember two had engines lock up after an hour on (the water brake)the dyno. They beat my engine to near distruction and then we started draining oil out to force fail it they (When I say they) the head engineer said to me will break it. I said NO SH_T. I can do that! We didn't spin them to hard back then 5,500RPM to 6,000RPM was it.

Finally the head engineer said to the dyno operater, run it on 2 quarts in the pan and 1 in the filter. They made a couple pulls to 4,500RPM. Same go around pull another quart out of it. I was thinking we are going to see carnege now.3K 3.5K the lifters weren/t pumping anymore. Intake vacuum was 7" at 4K 4.5 it was really starting to rattle, now the death rattle 5.5K BOOMB. It all stayed inside.If you want more of the story I have to go into my photo memory bank further. It was cool the way it turned out.

My dad if he were alive would tell you I did things opposite the normal. I never followed. fahlin_racing I told Wayne I was cursed with a photo-graphic memory, it's starting to fade a little...LOL...It really is a curse    

No problem, life rolls the way it rolls.

Good story, pretty dependable setup you had there! I was thinking of using 1/4" or 3/8" steel hopefully, I will have to check what the machines at work can bend up safely.  

Yeah bend it cold if you can,I really think the heat weakens it for sure. Good Luck  

What are your, or, anyone's views on hardening something like this?  

Why not harden it. If you can check the Rockwell on it once in a while. You don't want to make it too brittle.

For example. Production ring and pinions, are maybe a rockwell of 70. You take a racing ring and pinion and the rockwell is maybe 30. Thats because the racing set needs to flex, and take shock load. Hope that helps and makes sense..MERRY CHRISTMAS..

If you have a way to cold roll and not heat the metal even better.    

Plus I believe the heat cycles through use will cause it to continue to situate or settle.  

At engine temperatures yes. If you are heating the metal to bend it, it could get brittle. But I would go for it. If I could ask what engine are you you trying to make a girdle for. Ford or Mopar? I have been cleaning out my cabinets and I found a Moroso Catalog circa 1977 and it had girdles and stud kits for small block Fords. I hope your having fun, it was something I took on when I was young,and  as an experiment for my engineering course. Mine was the better of the six they tested. The suckers worked great.  
Good Luck
Thanks
Bob  

They had the girdles for the V-6 Buick when they ran them in the Busch Series for NASCAR.
Bob  

Well for the most part it will be bent by machine, cold. I haven't quite come up with how I want to situate the 'final' position. But that will change between each engine. I, right now have no particular engine right now to build for. Maybe just go through a process or perhaps setup the process I plan to use to make the first piece. I am only 26, if I were back in Minnesota, I would have GM, Mopar or Ford to experiment with. For now, its a waiting game until I get some money and buy an engine from the salvage yard   (hoping after my tax return)

I have a How to Hot Rod your Buick V6 I got for nothing when my cousin bought his current house. I try to keep an eye out for old motorsports books. I scored Grumpy Jenkin's first SBC book published in 1970 from a friend of mine, couldn't be any better for its age. It would be kool to see that 1977 Moroso book