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Old 09-08-2012, 07:39 PM
68/70Vette 68/70Vette is offline
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Default 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.)

Last edited by 68/70Vette; 09-09-2012 at 01:46 AM..
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Old 09-08-2012, 07:58 PM
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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.

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Old 09-08-2012, 08:15 PM
68/70Vette 68/70Vette is offline
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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. ??

Last edited by 68/70Vette; 09-08-2012 at 08:19 PM..
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Old 09-08-2012, 10:56 PM
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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

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Old 09-09-2012, 01:30 AM
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Quote:
Originally Posted by JeffP1167 View Post
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.
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Old 09-09-2012, 02:24 AM
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Quote:
Originally Posted by 68/70Vette View Post

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.



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Old 09-09-2012, 04:57 AM
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Quote:
Originally Posted by 68/70Vette View Post
Quote:
Originally Posted by JeffP1167 View Post
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.
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Old 09-09-2012, 04:59 AM
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have you looked at a chevy 454ss trucks setup?
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Old 09-09-2012, 10:01 AM
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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!

cheers - Jim

BTW Wholesale Tools has the "screw-in" portion - no holder - on clearance in bags of 12!
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Last edited by phantomjock; 09-09-2012 at 02:08 PM..
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Old 09-09-2012, 04:18 PM
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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.
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Old 09-09-2012, 05:54 PM
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Quote:
Originally Posted by BBShark View Post


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.
Thanks. I have an underdrive crank pulley that clears the crossmember. It's a March aluminum pulley sold on one of their other applications. Certainly hope you can find the drawing.

I have a March under drive pulley on the SB Serpentine kit on my 68 ZZ4. When the electric fan comes on, I need about 1500 rpm on the engine to make enough electrical power for the fan and fuel pump.

Last edited by BBShark; 09-13-2012 at 12:23 PM.. Reason: fixed quotes
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Old 09-09-2012, 06:00 PM
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In the aviation world there is a little thing called "strap duplicators" Various sizes and lengths. One side has a pin that centers in the hole you want to drill, the other side is a sharp pin punch. Slip it over the bracket, tap with a hammer and a perfect center point. Used more for sheet metal applications, but with a little mod they work just fine on thicker materials. Thinking about it, since NONE of us EVER modify anything maybe not..



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Old 09-09-2012, 06:02 PM
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have you looked at a chevy 454ss trucks setup?
Yes, this is the BB Serpentine kit with the cast iron brackets. Bought one and returned it. Didn't want cast iron on the engine. Not a really 100% rational view. The extra weight wouldn't have been that much. But then again, my entire project of rebuilding a technology upgrade for a 70 Corvette is not, by itself, very rational in some people's opinion! Thanks for replying with a suggestion however.
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Old 09-09-2012, 06:14 PM
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Quote:
Originally Posted by JeffP1167 View Post
have you looked at a chevy 454ss trucks setup?
Yes, this is the BB Serpentine kit with the cast iron brackets. Bought one and returned it. Didn't want cast iron on the engine. Not a really 100% rational view. The extra weight wouldn't have been that much. But then again, my entire project of rebuilding a technology upgrade for a 70 Corvette is not, by itself, very rational in some people's opinion! Thanks for replying with a suggestion however.
what about mercury BB serpentine brackets and stuff.
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Old 09-13-2012, 01:18 PM
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Originally Posted by BBShark View Post


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.
Thanks. I have an underdrive crank pulley that clears the crossmember. It's a March aluminum pulley sold on one of their other applications. Certainly hope you can find the drawing.

I have a March under drive pulley on the SB Serpentine kit on my 68 ZZ4. When the electric fan comes on, I need about 1500 rpm on the engine to make enough electrical power for the fan and fuel pump.

It's been a while since I did this so I'm a little fuzzy on the details. I have asked another member who did this more recently to comment.

The difficulty is the alternator bracket. You have to get the top of the alternator low enough to clear the BB hood but high enough for the PS pulley to clear the crossmember. The challenge with the AC bracket is hood clearance and clearance with the inside of the upper A-arm pivot.

Here are a couple of pdf's that have the head adapter plates. the pdf without dimensions should print 1:1 and the one with dimensions will allow you to check the scale.

The pictures show the AC side plates (upper and lower). Unfortunately I don'y have any good pix of the alternator side.
Attached Images
File Type: pdf Head Plates 102509.pdf (50.2 KB, 26 views)
File Type: pdf Head Plates wDIMS 102509.pdf (49.8 KB, 30 views)
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Old 09-13-2012, 01:20 PM
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Forgot Pix:







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Old 09-14-2012, 12:34 PM
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Shark's way is the way to go. I used a 91 S-10 V6 pick up set of brackets and accessories, because the brackets from a pickup don't have the air pump mount. I used 3/4" aluminum plate for the brackets from Sharks drawings. To get everything to line up, I milled 3/8" off the back of the A/C bracket and added 1/2" of shims to the crank and water pump pulleys. The water pump has to be a reverse flow BTW, I used a Flow Kooler pump with 30% more flos than stock. I couldn't find an aluminum pump, so this one's a really heavy piece of iron! I don't have good pics of the lower brackets, but they're also from 3/4" plate and locate on the two threaded holes in the block on either side of the timing cover. If you make the head brackets first, the lowers will be obvious. I used the crank pulley that was with the brackets and it ends up really close to the cross memeber (there's just enough room to change the belt), but I have a 2004r trans and modified the stock the crossmemeber, so that may have something to do with it.

Here's how it looks:









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Old 09-16-2012, 03:24 AM
68/70Vette 68/70Vette is offline
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Just a quick reply for now. Thanks for all the really great info. I think I have a local machine shop that I can use for custom parts. ($$$???)
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Old 09-16-2012, 12:21 PM
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If you want to do this, the brackets you need are:

AC 10118751
Alt 10233233
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Old 09-18-2012, 03:53 AM
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Quote:
Originally Posted by BBShark View Post
If you want to do this, the brackets you need are:

AC 10118751
Alt 10233233
Thanks!

Do you know what model of car/truck they were originally made for? The first thing Ill try to do is dig up a parts list for the GM SB Serpentine Kit system to see if perhaps they are similar. I'll have to seek out a local machine shop to make the adapter plates.
...............
About making

Last edited by 68/70Vette; 09-18-2012 at 04:45 AM..
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Old 09-18-2012, 02:29 PM
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Quote:
Originally Posted by 68/70Vette View Post
Quote:
Originally Posted by BBShark View Post
If you want to do this, the brackets you need are:

AC 10118751
Alt 10233233
Thanks!

Do you know what model of car/truck they were originally made for? The first thing Ill try to do is dig up a parts list for the GM SB Serpentine Kit system to see if perhaps they are similar. I'll have to seek out a local machine shop to make the adapter plates.
...............
About making
The brackets are from a Chevy V8 or V6 truck. About 88-94.
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Old 09-19-2012, 12:52 PM
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I got mine from a 91 S-10 V6 pick up. If you get the truck brackets, they won't have the big open space for the A.I.R pump, as trucks didn't need them. I got the brackets, pulleys, bolts, alternator, ps pump and AC comp for $200 from bone yard. I did use the stock alternator, but had it reworked to a 140amp unit. The AC comp and ps pump were also replaced. I'm sure the alt and ps pump were okay (I still have them) but figured while I'm at it..... Oh, the aluminum plate was like $25 with shipping.

I was able to fab the brackets using a band saw with a metal blade and a drill press, then polished them on a buffing wheel I have. When I went looking for a shop to do it, they wanted to retire on the job (without polishing). I did have to take the AC bracket to a shop to mill the 3/8" off the back, I think he charged me $30.

Last edited by damoroso; 09-19-2012 at 12:56 PM..
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