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~ The Barnacle ~ [CJ-7]

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    'Tall' Peter -- Former NJ Resident
    1962 CJ-5 ~ 1984 CJ-7 ~ 2008 JKUR ~ R/C Toys

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    • just throwing this out there!

      http://www.edelbrock.com/automotive/...ads/jeep.shtml
      Pete
      CJ 5.75

      Comment


      • Thought you were just getting it all dialed in.
        Why head pull?
        Dan M.
        Former President, Secretary, Treasurer
        48 days on trail in 2012!
        '85 CJ7 - 4.0L,T-18,4.10s,Locked F&R,35s,Caged,Winch
        '68 Kaiser Jeep M715 body transplant on '90 Dodge W350 in progress

        Comment


        • Originally posted by warthog_cj7 View Post
          Thought you were just getting it all dialed in.
          Why head pull?
          Ummm - as I recall, Pete has two less cylinders on one side, but another 4 on the other!

          I am guessing that he was tantalizing Tall Peter. This is way too confusing with Peter posting in Pete's thread, and then Pete responding to Peter about his rig! Or, maybe I'm just out of it....
          Larry Anderson - Just a quiet, little trail rig.

          NJJC Treasurer

          Comment


          • I was referring to the head pull on Barnacle, why pull?
            Dan M.
            Former President, Secretary, Treasurer
            48 days on trail in 2012!
            '85 CJ7 - 4.0L,T-18,4.10s,Locked F&R,35s,Caged,Winch
            '68 Kaiser Jeep M715 body transplant on '90 Dodge W350 in progress

            Comment


            • So whats with the head pull?
              Pete
              CJ 5.75

              Comment


              • well, it's bit of a story-

                The flattening of the manifold gasket surface (above) worked well, but the fiber gasket is just not up to turbo duty-- apparently no matter how flat and true things are. Multi Layer Steel (MLS) gaskets are a modern fix for such problems. Unfortunately no one is making a MLS gasket for the OBD1/7120 heads. Only the 0331 head has am MLS manifold gasket available-- I even looked into getting one custom made for the 7120 head, but no luck. The only option is to 'upgrade' to the 0331 head, thus allowing the use of the coveted MLS gasket set. (even the manifold builder Boostwerks went through all this himself)

                The 7120 head owed me nothing-- being a junkyard takeoff (with who knows how many miles on it) that I just dropped ontop of this engine approx 100k miles ago.


                So I bought a 'rebuilt' 0331 head off Ebay for $250 plus shipping. (This includes the core return shipping charge, as well). They were happy to take the 7120 head as a core for the 0331 head. For the time constraint (need to drive this to THe COve Crawl in 3 weeks), it was the best choice.




                The ports had a surprising amount of mold/casting flash that I just had to take care of-- have been grinding away and smoothing out all the corners for the past two nights.





                The biggest challenge with a new head is blocking off the 4.0 water passages, again. The 4.2 block is a little different design, and the corner closest to the head bolt hangs over the block y just the slightest. With the 7120 head. I used water dissolve-able packing peanuts and JB Weld to seal them. THis time I am looking to braze in some steel. Boring the holes round and then filling them in with 3/4" freeze plugs and copper-silver braze (it flows really well).



                'Tall' Peter -- Former NJ Resident
                1962 CJ-5 ~ 1984 CJ-7 ~ 2008 JKUR ~ R/C Toys

                Comment


                • I'm still confused. You have a new head, with smaller exhaust ports, and a hump in the intakes (what's that for?), but you are machining your old head? Also, what the heck happened in the second to last photo? It looks like one of my welding attempts?

                  Also, are you gonna polish your intake runners? Looks like a pretty major casting line in them!
                  Larry Anderson - Just a quiet, little trail rig.

                  NJJC Treasurer

                  Comment


                  • Originally posted by Fuzzy View Post
                    I'm still confused. You have a new head, with smaller exhaust ports, and a hump in the intakes (what's that for?), but you are machining your old head? Also, what the heck happened in the second to last photo? It looks like one of my welding attempts?

                    patience Larry-- I posted the pics with my phone an then logged in with the laptop to add the text. :)
                    'Tall' Peter -- Former NJ Resident
                    1962 CJ-5 ~ 1984 CJ-7 ~ 2008 JKUR ~ R/C Toys

                    Comment


                    • Originally posted by Jeep-Power View Post
                      patience Larry-- I posted the pics with my phone an then logged in with the laptop to add the text. :)
                      Enquiring minds want to know!
                      Larry Anderson - Just a quiet, little trail rig.

                      NJJC Treasurer

                      Comment


                      • Originally posted by Fuzzy View Post
                        Enquiring minds want to know!
                        I see that! :)

                        Before and after pics to come of the port smoothing
                        'Tall' Peter -- Former NJ Resident
                        1962 CJ-5 ~ 1984 CJ-7 ~ 2008 JKUR ~ R/C Toys

                        Comment


                        • ahhh - the text has magically appeared!

                          I'm still curious about the ports. The exhaust ports looks smaller, and the intakes have that hump, which looks like it is on the valve side. Is that "normal" or something for the turbo?

                          Finally, on your old head, it's very black around the exhaust ports. Is that because the gasket was failing, or at least leaking?
                          Larry Anderson - Just a quiet, little trail rig.

                          NJJC Treasurer

                          Comment


                          • The smaller and higher exhaust ports have something to do with effeciency- IIRC, they produce a higher velocity on the exhaust.

                            The 'humps' are clearance for the injectors. The later head had a different manifold. The manifolds do interchange, but i guess there are subtle differences in the injector location.

                            Yes, that black is where it was leaking- pretty much everywhere. Smaller leaks than before flattening, but more of them. :p
                            'Tall' Peter -- Former NJ Resident
                            1962 CJ-5 ~ 1984 CJ-7 ~ 2008 JKUR ~ R/C Toys

                            Comment


                            • Isn't the 0331 head prone to cracking?
                              But I think that only comes after an overheating issues.

                              That'll be a good fix, time consuming, but good fix.
                              Dan M.
                              Former President, Secretary, Treasurer
                              48 days on trail in 2012!
                              '85 CJ7 - 4.0L,T-18,4.10s,Locked F&R,35s,Caged,Winch
                              '68 Kaiser Jeep M715 body transplant on '90 Dodge W350 in progress

                              Comment


                              • The 0331 head was prone to cracking, but it didn't affect all 0331 heads. Typically if you made it beyond 60k miles you were in the clear. I have 110k miles on the XJ with the 0331 head and I overheated once or twice when working it hard and I have never seen any symptoms of a cracked head. I wouldn't stress over the possibility of it happening as it isn't that frequent.
                                Dave S. - Former NJJC Secretary
                                2011 Hard Luck Award Winner

                                Trail Rig: 2000 XJ Limited (4.5" RE SF, 35's, XJ D44 Rear, Locked F/R, Armored, Doorless, Caged)

                                Daily Driver/Hauler: 2011 Grand Cherokee Overland (5.7L, Quadra-Drive II, Quadra-Lift)

                                Sold: 2001 XJ Limited Pavement Pounder/Cream Puff (2" BB and 30's)

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