Putting a Serpentine System on My '78 Z

Discussion in 'High Tech Retrofits' started by PFZ28, May 1, 2011.

  1. PFZ28

    PFZ28 Veteran Member

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    After fighting with pulley alignment issues on the new engine in my '78 Z28, I decided to put a serpentine belt system. Since this has been a real learning experience for me, there are several things I would do differently next time. One might just be, "Not use double-hump heads." But oh, well - this engine was given to me, already having been sorted and built with some great parts. Beggars can't be choosers.

    Before I go into the installation process, let me show you the pitfalls I ran into when selecting my system. When I was complaining about my original pulley alignment issues, a friend of mine let me know he was going to crush a '94 GMC Safari van, and I was welcome to have the serp setup. The van had the Chevy 4.3L V6, which is 3/4 of a SBC 350. Here was an opportunity to fix my problem for "FREE". Sounded good at the time. This turned out to be my first serp system, and would not work with my double-hump heads.

    One of the attractive features of the van's setup was that the alternator was on the passenger side, and the air-conditioning was on the driver's side. This is the same as our 2nd-gen Camaros, so I was excited because I thought the re-wiring and re-piping for the AC would be minimal.

    However, there's one bolt hole needed that's just not available on my old heads, and there's no way to drill it. See the picture below. The van's mounting bracket on the driver's side has two mounting bolts on the head and one down by the crankshaft. This is all goodness, indicated by the green arrows. :cool:

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    GMCVanSerpSetup.JPG by pfz28, on Flickr

    The passenger side gave problems. With my old camel-hump heads, there were two bolt holes missing. The yellow arrow shows one that could be added, but the red arrow shows the one that just can't. There's no metal there to drill. The van setup might still work with Vortec heads (except for hood clearance problems, which I never got far enough to experience).

    There was another problem with the van setup specific to my engine - I have tall aluminum valve covers and the van's AC compressor would not have cleared them since it's not the pancake-style.

    I later got a system from a '94 S-10 Blazer. See the image below. Note how the aluminum bracket comes all the way down the block and bolts in by the fuel pump. This only required the one accessory hole to be drilled.

    [​IMG]
    IMG_1805.JPG by pfz28, on Flickr
     
    Last edited: May 1, 2011
  2. PFZ28

    PFZ28 Veteran Member

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    When doing this conversion, you must get the water pump and fan for a serpentine-enabled engine. The serp belt drives the pump "backwards" compared to the v-groove setup. My friend had recently replaced the water pump on his van, so I'm willing to use that one. Normally, I'd have bought a new one. No sense in doing this job twice. :confused:

    If you tried to use your original fan, it would blow air from in to out and you'd have cooling problems. There's no danger of this really, because the bolt pattern is slightly different for the fan mount. I found that I couldn't attach the old fan to the pulley even if I wanted to.

    For comparison, I placed my original fan next to the new one. You can see that the blade pitch is opposite.

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    IMG_1834.JPG by pfz28, on Flickr

    Even when I turn the blades around on my original fan, they still point the wrong way. The old fan can go to Craigslist with the old pulleys, water pump and alternator.

    [​IMG]
    IMG_1835.JPG by pfz28, on Flickr

    The new fan only has 5 blades, but the diameter is a skosh bigger. This will require lots of patience when fitting the fan shroud.
     
    Last edited: May 1, 2011
  3. PFZ28

    PFZ28 Veteran Member

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    So, time to put another hole in my head. ;) In order to put a serp system on an engine with antique heads, an accessory bolt hole needs to be drilled on the passenger side head, close to the intake.

    A close-up shows the boss on the head where it 'wants' a hole. You can see the location of the dimple where I used the centering punch to mark it through the aluminum serpentine bracket held in place with the other two bolt holes.

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    IMG_1801.JPG by pfz28, on Flickr

    First I mounted the bracket to get the hole located.

    [​IMG]
    IMG_1806.JPG by pfz28, on Flickr

    Then I used a centering punch to put a mark on the head. The centering punch was a little too narrow, so I built it up with painter's tape. I tapped it with my hammer to make the little dimple (first pic above).

    [​IMG]
    IMG_1804.JPG by pfz28, on Flickr

    To figure out how deep to make the hole, I put the drill into the existing accessory hole and marked the depth with a bit of painter's masking tape, like a flag. I used two drill bits. A small one to get the hole started, then a big one to finish the hole. I copied the depth flag from the small bit to the large one.

    [​IMG]
    IMG_1802.JPG by pfz28, on Flickr

    After I made the dimple I pulled off the bracket and remade the dimple with a punch, to make sure the drill didn't wander.

    [​IMG]
    IMG_1807.JPG by pfz28, on Flickr
     
    Last edited: May 1, 2011
  4. PFZ28

    PFZ28 Veteran Member

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    Okay, here goes. I put a bolt into the existing hole to give myself a visual reference for drilling "square". I would have had the bracket on there instead - that might have been a better reference - but the pocket was too deep to get my drill in there.

    [​IMG]
    IMG_1810.JPG by pfz28, on Flickr

    I drilled down to the depth of my flag and stopped. Then repeated the process with the bigger drill. I believe the big drill was 3/8", but I'll find out and edit the post.

    [​IMG]
    IMG_1811.JPG by pfz28, on Flickr

    And, Voila! A new hole, and I didn't even strike oil! (Or water!)

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    IMG_1816.JPG by pfz28, on Flickr

    Next step was to put in threads. There are two taps to use. One has some shallow threads at the end to get things started, and the other one has them full depth. I started with the shallow one. I believe the taps are3/8", 16 threads per inch, but I'll check. They were loaned to me by my engine builder.

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    IMG_1818.JPG by pfz28, on Flickr

    I twisted them both in carefully and slowly. The cast iron is soft enough to cut the threads without any cutting oil.

    [​IMG]
    IMG_1821.JPG by pfz28, on Flickr

    After I was done, I threaded in the stud. Turned out I had my drill tilted a couple of degrees down. As a result, when I put the bracket on, the bottom bolt hole was off by one RCH (about a 32nd of an inch) :crazy:

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    IMG_1822.JPG by pfz28, on Flickr

    I just bopped the stud once with a rubber mallet and brought it into line. Then the bracket went gracefully into place!

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    IMG_1825.JPG by pfz28, on Flickr

    I didn't get any pictures of the driver's side install, cos frankly, it just fell into place. I was able to use my Camaro's original power steering pump because the new bracket's PS mount holes lined right up with the old pump. Thanks, Chevrolet! :bowtie:

    The only difficulty there was pulling and putting the PS pump pulley. This is possible with the aid of a PS pump pulley puller (try to say that 5 times fast after a few brews :lush: ) that you can borrow from Advance/AutoZone/NAPA) And, a fair amount of grunting. Man, those pulleys go on there pretty tight!
     
  5. PFZ28

    PFZ28 Veteran Member

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    Well, I wasn't out of the woods yet. Putting on the serpentine system did solve my pulley alignment woes, but now I had to figure out how to convert to the new-style alternator and re-route my upper radiator hose.

    The '94 GMC Safari van's alternator is (I believe) a CS-type, where the Z's original is an SI. I couldn't find a real definitive post about doing the conversion, but several posts mentioned it was easy as long as you have an ALT light on the dash. This acts as a resistor in the circuit and helps excite the alternator. I'm definitely not an expert in this area, maybe someone can help out here.

    I bought a conversion harness from NAPA, model ECH-EC82. This converts from an SI to a CS alternator. I was very excited, but when I brought it home, I found that the plug would not fit my alternator. Then I was bummed. Here's a pic of the two plugs together. The one on the top is the EC82. It has a keyed section on the left that's thicker.

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    IMG_1838.JPG by pfz28, on Flickr

    I'm sure there's a way to solve this, but the Coy's Bandimere swap meet was the next day, and there I found a rebuilt CS alternator with the correct plug for twenty bucks. I snapped that up!

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    IMG_1836.JPG by pfz28, on Flickr

    Now with the different alternator on and connected, I'm ready to fight the radiator hose. I tried multiple hoses, each one almost worked. Problem was that the original water neck points right at the alternator. The one that worked out came from a mid '90s chevy truck, with the neck pointing up at 80 degrees or so, and clocked to about 5 o'clock. The original was clocked to 3:30 or 4. This water neck is a bit narrower than the original, so I'll be watching the temp gauge with interest.

    The truck's upper hose worked pretty well, but it was a little too long. I cut it down by small sections until it quit sagging into the fan. That might not have been an issue except I had cut back the fan shroud a bit to accomodate the new bigger fan.
     
    Last edited: May 1, 2011
  6. Philip

    Philip Veteran Member Lifetime Gold Member

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    Nice work and write up.
     
  7. PFZ28

    PFZ28 Veteran Member

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    Thanks, Philip! I failed to mention before - Philip helped me get started and sent me some pics of his own head-drilling project. Thanks again! And thanks to all you NastyZ28'ers out there. I could not do this stuff without you!
     
  8. Philip

    Philip Veteran Member Lifetime Gold Member

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    BTW I live with a red head if you need that dimension verified :)
     
  9. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    nice write up. I didn't even bother with the missing hole. But I used 3rd gen setup and I think it might have more bolts. I know I was not concerned. I ended up using the stock 77 upper hose after trying a number of other ones.
     
  10. PFZ28

    PFZ28 Veteran Member

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    LOL, Philip - go ahead and check that out for me, will you? :happy: And BH, same here, I could probably use my old '78 rad hose if I had the right swivel neck thermostat housing.
     

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