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86Z24 hybrid engine build - Advice?

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  • 86Z24 hybrid engine build - Advice?

    I have been watching this site for some time, and I think that I have found some rather intelligent, and very knowlegeable people on here, so I am posting this in hopes that some of you can help me.

    I have an '86 Z24 Coupe, 2.8HO, with a 4-speed stick. Absolute BLAST to drive - with a non-functional cluth petal, I was still taking on 5.0 Mustangs, and first gear was really hard on tires. Unfortunately, after little more than a year with the car, my ignorance got the best of me, and I put #4 rod out the front of the block and starter. Rather than just drop another stock HO back into my girl, I opted to be a little more adventurous, and build a Hybrid 3400, instead. The car has been sitting in my garage for about 5 years, now, and I finally had the money to start my little project, this year. I am now the proud owner of a freshly built Hybrid Shortblock, sitting all nicely wrapped up on the floor of my garage, but I have run into some nasty stumbling blocks, and I am coming to you guys for help.

    Components:
    Block, oilpan, factory roller cam/lifters, and injectors from an '01 Grande Am GT (3400 SFI)
    Crank, rods, pistons, and high-volume oil-pump from DOHC 3.4L (age/application unknown)
    Heads, plenums, TB, intake and MAF are all ORIGIONAL to the car, to maintain the Stock appearance under the hood, with the exception of the actual intake vent for the air cleaner, which thanks to some minor body damage just above the grille, now has a vent directed through the header panel into the air cleaner, similar to the Grande Am GT's Ram-Air setup. I will be replacing the plastic intake ducts with either PVC or Stainless, and using a cylinder type K&N-style air filter in the factory housing, and finishing the "Hole" through the header panel with Fiberglass, similar to the old square-bodyTurbo Firefly/Sprints.

    Where I'm running into glitches now, is that the DOHC pistons, when installed in the engine, are extending rather noticably PAST the surface of the deck of the block, and I'm not sure now, if even the .062" DOHC head gasket will be thick enough, or if using an "aluminum head" head gasket with a cast iron head will give me problems with leakage due to different expansion/contraction rates.

    Any help/advice you could give me would be most welcome.

    Also looking for a reasonably priced set of headers that I can use on this setup, used is OK, as I am now on a limited budget to finish the engine, due to a change in employment (read:INCOME), but would still like to drive the car sometime this year, and the stock exhaust manifolds are way too restrictive for this much of a change in displacement and RPM range. Again, advice welcome in this dept.

    Thanks.

    PS: I know that this setup can be done, as most of my parts combinations have been coming from a running Fiero with a very similar setup
    Calgary Fiero Owners Group, The official home of the Calgary Fiero Owners Group located in southern Alberta, Canada

  • #2
    First step... get rid of those heads/top end... use the 3400 top end... you'll gain an easy 40-50 HP. Keeping it stock looking will cost you alot in performance...


    Not sure about the DOHC pistons, but the stock 3400 pistons pop out about .020" or so.
    Past Builds;
    1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
    1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
    Current Project;
    1972 Nova 12.73@105.7 MPH

    Comment


    • #3
      i built a cast ironhead motor for my 86 cavy. ill tell ya, ill never make the mistake of using ironheads again. it cost me a lot in performance. i have a motor with simular components to treez24 (he has a 3.1l hybrid) and he runs 14.22, i run 15.6. use the gen 3 top end, grab an 89-90 cavalier v6 engine wiring harness (it will plug into the dash harness and body harness) and you will be set.

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      • #4
        I've been hearing about the newer heads, but I intend to keep my intake, etc, and ESPECIALLY my distributor, so i guess the next question becomes: can you bolt the old top-end to the aluminum heads?
        I'm keeping the distributor over the DIS system because in spite of people saying that the timing is not adjustable with the distributors, I know from my own tinkering when the origional 2.8 was still running, what a drastic difference a little twist can make, and you just can't do that with DIS.

        BTW sharkey, nice 86... RS with Z grille, looks good.

        Comment


        • #5
          old intakes won't bolt to gen 3 heads

          not to be a dick

          but its proven don't be a retard and waste your time

          gen I & 2 junk <Gen III
          sigpic

          1993 Cavalier Z24, 3.1/3400 hybrid, crane 272 cam, LS6 springs,port and polish,2.5 exhaust to 80 series flowmaster,solid mounts

          Comment


          • #6
            No, the iron head intake will not work with the aluminum heads.
            -Brad-
            89 Mustang : Future 60V6 Power
            sigpic
            Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

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            • #7
              PS: BTW dave.
              I can't use the 3400 heads w/DOHC pistons, unless I can figure out a way to run 18:1 C.R. on pump gas.
              There would be approximately 30 cc difference in the combustion chambers between the two.

              Comment


              • #8
                Originally posted by 86Z24hybrid
                PS: BTW dave.
                I can't use the 3400 heads w/DOHC pistons, unless I can figure out a way to run 18:1 C.R. on pump gas.
                There would be approximately 30 cc difference in the combustion chambers between the two.
                I'd just use the stock 3400 ones, they'll handle more HP than a N/A 3400 will put out...

                Guys are pushing 3400 powered Jbodies into the high 13's, with your old top end you seriously would have a hard time breaking into the 14's even with headers and a huge cam...

                check out this thread and some of our engine builds...

                Past Builds;
                1991 Z24, 3500/5 Spd. 275WHP/259WTQ 13.07@108 MPH
                1989 Camaro RS, ITB-3500/700R4. 263WHP/263WTQ 13.52@99.2 MPH
                Current Project;
                1972 Nova 12.73@105.7 MPH

                Comment


                • #9
                  Originally posted by Superdave
                  I'd just use the stock 3400 ones, they'll handle more HP than a N/A 3400 will put out...

                  3400 pistons? or heads?

                  Oh, and interesting thread, chuckled @ JJ's 3.1's...
                  Presume he's pretty good with heads?
                  Also noticed that lots of guys running headers, any suggestions for finding a set (New or used)?

                  And I wasn't going to leave the ironheads stock... They will be getting a good port/polish/valve job, and (Much?) bigger valves, as well as stiffer springs.
                  (BTW - anyone know how big valves you can put in ironheads before you start shrouding the valves?)

                  I've also been looking into overbored TB's, as the 3400 TB is only 4mm bigger than mine, but that will come as finances allow.
                  Last edited by 86Z24hybrid; 08-10-2006, 12:07 AM.

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                  • #10
                    the pistons
                    sigpic

                    1993 Cavalier Z24, 3.1/3400 hybrid, crane 272 cam, LS6 springs,port and polish,2.5 exhaust to 80 series flowmaster,solid mounts

                    Comment


                    • #11
                      Originally posted by Syn
                      the pistons

                      I can't use the 3400 pistons, never got them with the engine, and the shortblock is already built and sitting in my garage with the DOHC pistons in it.

                      Comment


                      • #12
                        so what heads can u use to avoid that crazy compresion ratio?
                        sigpic

                        1993 Cavalier Z24, 3.1/3400 hybrid, crane 272 cam, LS6 springs,port and polish,2.5 exhaust to 80 series flowmaster,solid mounts

                        Comment


                        • #13
                          my two options are the DOHC heads (not really an option), or the origional cast iron heads.

                          My heads have been CC'ed at 52cc, vs. the aluminum heads at 25 to 26cc.

                          That's a major part of the reason I opted for the DOHC piston/Ironhead combination. Estimates from other sources put the C.R. at about 9.6:1, while the C.R. generator here puts it at about 10.35:1, which is JUST within the limits of pump gas (although expect it would run MUCH better on racing fuel, if and when I decide to take it to the track).

                          I have another query to add to my list...

                          I just brought one of my heads in from the garage, and pulled one pair of valves out, and noticed a large fin(?) in the intake runner.
                          I was wondering if it served a purpose, or if I should hog them off when I do the porting?
                          Last edited by 86Z24hybrid; 08-10-2006, 03:12 AM.

                          Comment


                          • #14
                            With the proper tuning, there have been a few people here running around the 12.5:1 range on mid-grade fuel.
                            -Brad-
                            89 Mustang : Future 60V6 Power
                            sigpic
                            Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

                            Comment


                            • #15
                              I am building a 3400 shortblock with 3500 top end using 3.4 DOHC pistons. Its roughtly 12:1 range. I dunno where you got 18:1 with 3400 heads but that is just crazy. The DOHC pistons should not extend as far out of the deck as the 3400 pistons either.
                              Ben
                              60DegreeV6.com
                              WOT-Tech.com

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