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Posts posted by madkaw

  1. On 9/15/2019 at 10:18 PM, Zed Head said:

    What cylinder pressure do you get?  CR is the calculation but cylinder pressure is the detonation cause.  As I understand things high CR needs to be matched with "big" cams.  I think that some people think of the whole package in terms of "dynamic" CR.

    210 average by the gauge 

  2. Just love breaking this engine in! The torque is very strong. I’ve limited myself to 5500 at this point, but still pulling very strong. Have to be careful not to hit it too hard in lower gears or I just break the tires loose. 

    Able to run 35 degrees timing so far, but probably close to the limit. Need to break this bad boy in and and get to the dyno to dial it in. Running very similar tune I did with my 2.4, just more fuel. Seems to be doing rather well on the MPG- beauty of EFI. On the dyno I will probably advance the cam a bit too if I can get away with it. I’ll see where the power curve comes in. 

    Took a peek at the cam and everything looks peachy.

    Just finishing up the install of my old motor in to the customers car. After it’s gone I can devote more time to tuning. Right now just driving around and letting Megasquirt do it’s thing.


    • Like 4

  3. My 2 cents . I agree with the diagram above. Your chain wears which changes the relative position of the cam to the crank. Flipping around the sprocket to a different index hole and ALIGNING the cam to that hole advances the cam. I’ve done a lot of cam degree-ing with a fresh chain and sprocket . You have to move the cam in order to get the sprocket to index in. Nothing gets moved on the chain. 

    Not sure if that helped or not. 

    • Like 1

  4. 37 minutes ago, Captain Obvious said:

    Awesome! What kind of gas are you going to use with that CR?

    And BTW, when I run the CR on your combo, I get a slightly higher number than you do. I get 11.42:1, but I've not reached the point where I'm completely confident in my numbers, What number are you using for head gasket thickness after it's been crushed into place?

    I get 11.42:1 with a .120 thick head gasket on an F54 and a 39cc chamber.

    Rut roh - maybe more than I thought ? 

    And I shaved .005 off the block -eek

    Should be .049 or 1.25mm thick. 

  5. 10 hours ago, grannyknot said:

    While there are so many good minds talking about this subject I would like to ask a question about a timing fact/myth I've heard many times. 

    Starting with a new chain, by deliberately advancing the cam gear to #2 or #3 you can gain more low down torque. True or false?

    Bruce, this is one of those great lines that should be permanently fixed to bottom of each post regardless of whether you are right or wrong:beer:

    I would say true. Closing the intake valve earlier will get some low end grunt . 

  6. 9 hours ago, Captain Obvious said:

    @madkaw, another question... What is "a bunch"?

    Did you advance it to bring it back to stock timing, or did you go beyond that and advance the timing past the original stock settings?

    I was running 8 degrees in advance and wouldn’t have minded some more . Running the ISKY 290 duration put the power band up pretty high. About 4K+ is where she started to really “ come on the cam “! 


  7. On 8/31/2019 at 9:24 AM, duffymahoney said:

    Well I looked into the Jeep. I found a nos Jeep unit and vapor blasted my pedestal. 


    I will take it to my machine shop on Tuesday. I will have it matched to the stock spline and I will use the stock shaft bushing. 




    I see you found the thread . I just cut and notched my shaft carefully with a cut off wheel. Curious what year sensor you bought and what you got for the connector. Believe it or not I never finished what I started . One main reason is I was having difficulty finding the correct wiring harness connector . I ordered one and it wasn’t quite shaped the same way. Got sidetracked and never finished the install. Car ran well with batch fire for now. 

    Definitely takes up less room!

  8. You need to look and mark your timing marks on the pulley carefully. I almost bet you are sitting at 20 BTDC at idle and not 25. More than likely you have 17 degrees of mechanical advance with that dizzy and that would total you out at 37 WOT.

    20 degrees idle advance would start and idle easier without choke because all that advance makes for a strong idle. Does your vacuum advance work? That’s where you might run into issues . You might be adding too much advance at cruise and be causing detonation that you can’t hear . Might suggest getting an Advance type timing light to check full mechanical advance and vacuum advance. 


    Check your vacuum advance is working properly and not sticking 

    I’ve run all my motors with close to 20 degrees at idle ,  with no vacuum advance. I also had cams that ran better that way. Figure out what dizzy you have with the chart below. 

    Just 45 miles south of you I noticed!


  9. If you are trying to find a coolant leak in the timing cover you need to pressurize the system. Go to Oriellys or Autozone and rent a coolant pressure tester . Put 15lbs on there or so and take the valve cover and listen. It will hiss if it’s pissing coolant . You might even be able to see it will a flashlight looking down the chain .

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