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Melling Sbc8 Cam

Discussion in 'Early CJ5 and CJ6 Tech' started by 53A1, Jul 1, 2019.

  1. Jul 23, 2019
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
    Messages:
    447
    Yesterday the temp climbed up to 220 and I had to shut it down. My coworker said the timing may be retarded with the new cam profile and adding to my overheating problem. Timed it by vacuum today and advanced it from 5 to 15 btdc. Gets on it now and runs cooler. Added a shroud and it stays around 190 now in 110 desert heat.
     
  2. Jul 23, 2019
    Chilly

    Chilly Active Member

    Joined:
    Mar 12, 2007
    Messages:
    1,486
    You need not worry about your cam being hard on valve train. Hardly any catalog cams would be made that way. My experience is with a Harley. Cam makers for Harleys sometimes do strange things, borderline silly things. But many Harleys need only last for a few dozen thousand miles (toys) so crazy cams arent a big deal. Mine is a rider and I chose a little too aggressive with cam in the cylinder pressure dept. Problem was solved with a cam having more duration, which shifted the torque curve up a bit. But that makes more sense for a lot of very pragmatic reasons.
     
  3. Jan 24, 2020
    John Gedde

    John Gedde Been around the block once or twice...

    Middle Island, NY
    Joined:
    Oct 23, 2019
    Messages:
    125
    I know this thread is a bit old, but I'll add to it another option - which is the one I went with. The TA Performance RV10 grind for the Buick 225. The cam is made by Crower.

    Power Range: 1000 to 4300 RPM

    Lift (Intake/Exhaust)
    .450/.475 with 1.6 rockers

    Duration @ 0.050 (Intake/Exhaust)
    205/214

    Advertised Duration (Intake/Exhaust)
    255/262

    Overlap: 0

    106 degree ICL. I forget what ECL is...

    Here's what TA Performance says about this grind:
    "Excellent stock type replacement cam which gives an average power gain of 10 HP over stock. Strong low rpm torque, ideal for heavy cars, tow vehicles, V6 Jeeps. No other special parts required. Smooth idle. 8.0:1 to 9.5:1 CR"

    I haven't started the engine yet so I have no idea how it runs or drives. It'll be awhile before I know about how she drives since the Jeep is apart for full resto.

    Since the exhaust through the head on the 225 V6 is so feeble, I liked the idea of using a split profile with increased exhaust duration....

    One issue I had was that the cam was 10 degrees off across the board. An adjustable timin set would only give me 8 degrees so I elected to machine a new keyway in my crank timing sprocket 170 degrees away from the original one (for machining convenience.) After I did that, the cam tracked the cam card within 1/2 degrees across the board. Lesson learned: always degree your camshaft!

    The other issue I had is this cam with the Delphi lifters I used required adjustable pushrods to get the proper lifter preload. The stock ones were too short.

    John
     
    Tom_Hartz likes this.
  4. Jan 27, 2020
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
    Joined:
    Nov 12, 2009
    Messages:
    1,381
    When I had my engine rebuilt I change the push rods over to the type that had a hole in them to push oil into the head. New rocker assembly, lifters and push rods, everything bolted in. Got it from some business in California , I think.
     
  5. Jan 27, 2020
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
    Messages:
    447

    Based on the article I linked your cam is ideal for off road. I can't comment on real world applications other than the Melling but in theory your cam will work very well.
     
  6. Jan 27, 2020
    John Gedde

    John Gedde Been around the block once or twice...

    Middle Island, NY
    Joined:
    Oct 23, 2019
    Messages:
    125
    Interesting article! I got excited when I saw the table for the OEM cam specs. Then I saw the duration and overlap numbers were from 0.004" lift. That makes them basically useless figures for comparative purposes. Just for the sake of why let's say a 252 degree cam (example) could have a duration at 0.050" that ranges from around 190 to around 220 degrees and still drive a tappet without flatting out on the lobe.

    Cheers,
    John
     
  7. Jan 29, 2020
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
    Messages:
    447
    Real world, my Melling seems to work very well around 1500-200 rpm. I have an TH350 auto trans so this works out very nice and I have a surprisingly low crawl ratio at that RPM. I think it has to to with the torque converter. I imagine yours it going to work well at even lower rpms which will be great with a manual trans. Update this thread when you have a chance to run it.
     
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