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-   -   How to Fabricate Engine Brackets (http://www.vettemod.com/forum/showthread.php?t=8713)

68/70Vette 09-08-2012 07:39 PM

How to Fabricate Engine Brackets
 
Problem: You want to make a bracket that bolts into an existing hole in the cylinder head (forward facing surface) and an existing hole in the engine block (forward facing surface). For the raw undrilled bracket, you've got to drill two holes (in this simple example) where the centerlines of the holes are exactly aligned to the existing cylinder/block holes. How to?

Short tutorial: Buy an October 2012 copy of Hot Rod magazine. Go to page 132 and read the "how to" article. What are the size of the head/block holes - diameter and pitch you're working with? Go to Amazon.com and buy the Heimann Transfer Screw set for this diameter/pitch.

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Longer tutorial: Insert (screw in) the transfer screw into the cylinder head hole and screw another into the block hole. "Transfer screw" is, to me, not very descriptive. The so called transfer screw is really a plug. On it's outward facing surface, it has a small conical shaped protrusion. When you screw in the plug, the small conical shaped protrusion extends above the surface of the cylinder head/block. The tip of the conical protrusion is sharp and hardened. Now lay your undrilled bracket blank on top of the two protruding tips. Bang the bracket with a mallet. The surface of your blank bracket will now have two very small dimples where the hole center lines are. (To make the dimples easier to see you can paint the metal surface with Dykem.) Next take a punch and bang the dimples to give them more definition. You're now ready to drill out your holes.....but if you're concerned about accuracy and don't want you drill bit to wander off the dimple, get a "center drill." It has an initial very small bit to drill into the dimple, and then after the initial part of the bit has drilled into the dimple, a larger diameter part of the center drill, cuts out the profile diameter of the drill bit you're going to be using for the full size hole.

If you're really interested in reading the article and can't get the Hot rod magazine, I can scan the article and email it to you.
.........................

Why am I interested in making brackets? It's because of my 1970 project car. I wanted to add a serpentine belt kit on the engine nose. The March kit, beautiful and pricey, requires cutting a hole in the crossmember under the crank pulley. No way. They crank pulley is way oversized and they refused to make a custom smaller diameter pulley for me. (This was a few years ago...maybe they have amended their ways). An economical way to go is to buy the GM Performance Parts (GMPP) catalog Big Block serpentine kit. I did. But.....gross....the brackets were cast iron. No way am I going to mount cast iron brackets on an all aluminum BB. I returned the kit to Summit. At that time, someone on eBay was selling adapter plates that allowed mounting the GMPP Small Block serpentine kit onto a BB. The SB serpentine kit is all aluminum. I've done that to my BB and it fits and looks nice. My only concern is that the air con compressor (an R4) may interfere with the BB hood. ......The adapter kit seller apparently no longer sells. I've often wondered how I could, if I wanted, make the adapter plates to essentially duplicate the ones I bought, but lowered the left had adapter plate to provide more clearance for the AC compressor. . Now I think I could repro the plates if I really wanted. They are of approximately triangular shape and have three holes in them. (Interesting, the plates I bought were cut out of sheet stock with a water jet.)

JeffP1167 09-08-2012 07:58 PM

If you can by adapter to mate SB serpetine to BB why not use a corvette serpentine drive. I have one on my 82 and it clears everything perfectly.


68/70Vette 09-08-2012 08:15 PM

The GMPP SB Serpentine kit comes with all new stuff. It's very economical; i.e. cheap for what you get. The GMPP SB kit will fit all the traditional Chevy small blocks. The GMPP kit is really the 1990, 1991 Camaro and FireBird serpentine assembly. My 68 has a ZZ4 and I have the GMPP kit on it. I don't have an AC compressor on the 68 installation, but from what I've read, the R4 compressor, if added to the GMPP SB serpentine, will clear a SB Corvette hood. A BB engine is longer than the SB. Being longer, the compressor is positioned closer to the front of the car, where it appears to interfere with the hood, even thought the BB hood does have a little extra space....Not really sure I have an interference problem.

The adapter plates I bought were specifically designed for the GMPP SB serpentine kit. I don't know if a Corvette serpentine kit of other years would fit the adapter plates I bought. ??

JeffP1167 09-08-2012 10:56 PM

the 4.3 a/c brackets look the same as the 5.0 & 5.7 brackets but move the a/c compressor closer towards the intake manifold.

The 85-87 vette a/c bracket is independent from all other brackets and holds the idler tensioner as well. It also mounts the compressor lower then a f-body.

this is probably the kit you have



here is the 85-87 vette bracket


68/70Vette 09-09-2012 01:30 AM

Quote:

Originally Posted by JeffP1167 (Post 101948)
the 4.3 a/c brackets look the same as the 5.0 & 5.7 brackets but move the a/c compressor closer towards the intake manifold.

The 85-87 vette a/c bracket is independent from all other brackets and holds the idler tensioner as well. It also mounts the compressor lower then a f-body.

this is probably the kit you have



here is the 85-87 vette bracket


Do I understand this correctly? I should try to get a 85-87 AC bracket because it'll lower the compressor? Not a problem. I'll just get in contact with J&D Corvette in Bellflower, Ca and buy one of these brackets. This is so much fun!!!!!! Thanks a lot for the suggestion. ....... By the way, If things don't work out buying this bracket , that's OK. Thanks for a possibly helpful tip.

BBShark 09-09-2012 02:24 AM

Quote:

Originally Posted by 68/70Vette (Post 101941)

Why am I interested in making brackets? It's because of my 1970 project car. I wanted to add a serpentine belt kit on the engine nose. The March kit, beautiful and pricey, requires cutting a hole in the crossmember under the crank pulley. No way. They crank pulley is way oversized and they refused to make a custom smaller diameter pulley for me. (This was a few years ago...maybe they have amended their ways). An economical way to go is to buy the GM Performance Parts (GMPP) catalog Big Block serpentine kit. I did. But.....gross....the brackets were cast iron. No way am I going to mount cast iron brackets on an all aluminum BB. I returned the kit to Summit. At that time, someone on eBay was selling adapter plates that allowed mounting the GMPP Small Block serpentine kit onto a BB. The SB serpentine kit is all aluminum. I've done that to my BB and it fits and looks nice. My only concern is that the air con compressor (an R4) may interfere with the BB hood. ......The adapter kit seller apparently no longer sells. I've often wondered how I could, if I wanted, make the adapter plates to essentially duplicate the ones I bought, but lowered the left had adapter plate to provide more clearance for the AC compressor. . Now I think I could repro the plates if I really wanted. They are of approximately triangular shape and have three holes in them. (Interesting, the plates I bought were cut out of sheet stock with a water jet.)

Thhose adapter plates (from the Ebay guy) don't mount low enough on the engine to clear a BB hood. I have drawings for the plates you need. Also there is a 12% underdrive pulley that you can buy so you don't have to notch the crossmember.

I'll see if I can come up with some info on this.




JeffP1167 09-09-2012 04:57 AM

Quote:

Originally Posted by 68/70Vette (Post 101955)
Quote:

Originally Posted by JeffP1167 (Post 101948)
the 4.3 a/c brackets look the same as the 5.0 & 5.7 brackets but move the a/c compressor closer towards the intake manifold.

The 85-87 vette a/c bracket is independent from all other brackets and holds the idler tensioner as well. It also mounts the compressor lower then a f-body.

this is probably the kit you have



here is the 85-87 vette bracket


Do I understand this correctly? I should try to get a 85-87 AC bracket because it'll lower the compressor? Not a problem. I'll just get in contact with J&D Corvette in Bellflower, Ca and buy one of these brackets. This is so much fun!!!!!! Thanks a lot for the suggestion. ....... By the way, If things don't work out buying this bracket , that's OK. Thanks for a possibly helpful tip.

I'm going to be selling this serpentine system in a few weeks. Putting my 90 L-98 in this 82 vette.

JeffP1167 09-09-2012 04:59 AM

have you looked at a chevy 454ss trucks setup?

phantomjock 09-09-2012 10:01 AM

First - Thanks for that TIP! An yes, Please, I could use a copy of the HR article - but do get the "drift."

Now Serpentine - Mine will be coming up for sale (as well) so there will be a few for buyers to pick from.

My Serpentine setup is similar and holds the large case Alternator (CS 144) but doesn't give me enough clearance from my high rise valve covers - So I too now build brackets...

GREAT TOOL - AND TIP! THANKS AGAIN! :thankyou:

cheers - Jim

BTW Wholesale Tools has the "screw-in" portion - no holder - on clearance in bags of 12!
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GT6Steve 09-09-2012 04:18 PM

Those transfer screws are really handy but get expensive when you start collecting the sizes. I have a set in 3/8-16.

A cuppoint setscrew threaded backward into clean threads will work just about as well for pennies. Just don't thread it in so far as to lose grip on it or you will be thorougly screwed, if you'll pardon the pun.:wink:


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