5.2 Magnum times ??

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  1. AustinGriggs

    AustinGriggs Active Member

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    A friend of mine had a 5.2 Magnum motor in a Duster 904/2800stall/3.21 gears. He now has a 5.9.... However, the 318 was stock bottom end with pistons down in the hole something like .120 (stock) heads had fresh new valve job and minor sanding role clean up. The cam was a Hyd. Roller don't remember the specs exactly but with the 1.6 rockers i know it had a lift of around .530. It used a 650 Holley, China air-gap intake and headers This is a daily driver that averaged 15-16mpg but was able to pull of consistent 8.40s at like 83mph. It ran strong and I hate that it never got some good pistons. Alittle more stall, pistons, and some 3.55s likely would have brought it down in the low 8s if not in the 7s. I'll likely try to pick up where he left off one of these days, but I'm glad i got to see what a true junkyard 318 is capable of which in this case equates to around a 13.20s 1/4 mile.
     
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    • 360duster

      360duster Well-Known Member

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      ok, time to update the 5.2 i´m preparing for my Buddy as previously described….on a Mission to get a 12 sec timeslip...

      Installed the new Oregon Cam, Grind #1341 (218/224° on 110 LSA / .482" Lift). 4° Advance Ground in, so installed at 106° ICL. Was dead on with the stock cam key, precisely ground.

      20191227_140648.jpg

      Next step: head porting. i put some real effort into improving the pushrod pinch....and found the weak point of the casting...sad. Good that i started with the intake ports at this head, not the bowls like the other head i did.....at least nobody can say i did not try it real hard ;-)

      20200114_173337.jpg

      My 12mm wrench served me well as a "checking device" for the first port i did…..but obviously not for the second one. Note to myself: use a 11mm wrench for the next head ;-)

      20200114_173726.jpg

      here´s another shot of the bowls (from the still intact head). I opened them up and removed all disturbing edges…..unfortunately no budget for a better Valve Job. I´ll do a back cut to the intake valves later. For working the intake guide i do not have the proper Carbide bits...but i think there´s not much to gain here if the pinch is the weakest point of the head. Maybe i give it a try while waiting for a spare head.

      20200110_175220.jpg

      more to come….first date at the track is middle of may. Think i have it done until then ;-)

      Michael
       
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      • 360duster

        360duster Well-Known Member

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        btw, this is the car the engine is for. I always tell him to adjust the front higher for better weight transfer....he likes the lower stance better. I keep trying ;-)

        IMG-20180620-WA0000.jpg
         
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        • stixx

          stixx Well-Known Member

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          Does the above head go to the scrap pile? Since you found water it probably can't be fixed?
           
        • 360duster

          360duster Well-Known Member

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          Hi Stixx,

          yes, this one is going to the scrap pile. the hole is in the runner, goes to the pushrod area (no water). You need it for further examination (aka door stop)? ;-)

          Michael
           
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          • Jadaharabi

            Jadaharabi FABO Gold Member FABO Gold Member

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            Can't you sleave the pushrod hole?
             
          • 360duster

            360duster Well-Known Member

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            there is no real hole in the stock Magnums, it´s an open area where you can´t locate / secure a sleeve. i thought about this but no Chance. the good Thing: my Buddy already has got another set that he got Pretty cheap….so no big loss. I´ll be more careful next time ;-)

            Michael
             
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            • stixx

              stixx Well-Known Member

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              I will only break my foot running against it... LOL.
               
            • BVoelzke

              BVoelzke Dart Racer

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              Mine goes low- mid 15s with a best of 15.04 in my 92 D150 s/b 2wd on drag radials ,with 4.10 gears, 518 with a shift kit, redone lockup converter, shorty headers, ram air system not real fast but goes rounds!

              View attachment 1715453100

              IMG_0424_2.jpg
               
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              • oldkimmer

                oldkimmer FABO Gold Member FABO Gold Member

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                U can epoxy that head no problem. Kim
                 
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                • 360duster

                  360duster Well-Known Member

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                  Hi Guys, just a little update here…..engine done and in the car….due to the fact that the spare heads were junk (massively sunk valves) i closed the hole in the port with epoxy, we´ll see if it lasts. Here´s a Video from first start with new cam / ported heads, sounds good. New cam is 218/224, 110 LSA around .480" Valve lift. I was concerned regarding Piston to Valve contact with the stock flat tops, that´s whyi kept the cam Pretty conservative.

                  Now i still have to do his rear axle, cone type sure grip not working.....first race middle of may. Will update this thread here!



                  Michael
                   
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