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Thread: Choise Cam for rallycross pinto

  1. #41
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    Re: Choise Cam for rallycross pinto

    Quote Originally Posted by Bakerk View Post
    Thank you for your advice/opinion. I had built this engine with more power in mind than the camshaft was able to deliver it seems. Im an amateur/home garage builder enthusiast not a master mechanic. I do think a faster cam will solve this problem. Thanks for your input .
    maybe, but if you cant get the timing reference correct you are guessing, what else did you guess? you cant build powerful reliable engines by guess work

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    Re: Choise Cam for rallycross pinto

    To summarize based on the very valuable advice from the experts and professional tuners;
    Although you call it a “ fast road “ camshaft, it seems that you have a cam with a good full lift figure (based on the limited cam info you have given). Pinto likes high lift & rather low duration. So going to a faster cam is another perspective which is nothing to do with your current problem ( heat )
    I think the first step ( as described very well above ) must be to set your ignition correct and correctly below 30.
    Then it may be wise to see if your cam timed correct and see what different cam timing doing on the dyno with the correct ecu mapping. Then analyze the graphs and see if it is serving to your competition purpose. ( gearing, track etc )
    Then if you are not still happy with the outcome, there may always be other profiles ( but not so many ) providing that you have an excellent cylinder head to get more horsepower in the upper rpm range but I also strongly doubt you have to go that direction. As a matter of fact, ( as also adviced) reducing the CR 0,5 point may certainly produce a better result, if the heat issue is still there with the ignition correction.

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    Re: Choise Cam for rallycross pinto

    Whoa ok guys ill try explain my reasoning. I seem to have caused some confusion. I had noticed the extra heat generated during summer here in Newzealand sitting in bumper to bumper traffic so took note and decided to rectify it next time i worked on the engine. I had already decided to change the camshaft and upon stumbling on this thread i noticed comments about heat and high compression. As we found when the engine was on the dyno we had to pull considerable timing in the low rev range it suggested compression was possible too high . As i had planned on upgrading Camshafts i thought it was a possibility i could kill two birds with one stone . I find the comments here invaluable and do not dismiss advice given . I was going to look at other areas while i had the head off for possible heating restrictions as well as smoothing some machining in the combustion chamber (lowering compression slightly) and also inspect the port filler i had used while i was there . I also was going to change out the valve springs for new ones and check the valve seating. As far as the timing issue goes , with an ecu you dont need to 100% know your zero point so long as its fixed and constant. if zero is in fact 5 degrees atdc you can simply adjust timing reading in ecu to reflect that value . In fact my setup has a camshaft trigger as well and initially it wad 360 degrees out . Instead of adjusting anything mechanical you simply add 360 degrees to the timing figure to bring it back to zero. Another nice thing about efi is if i want to change the cam back after upgrading the cam retuning and not liking it i can simply swap the camshaft back and reload the old tuning program stored on my tuners hard drive ( oh and possibly a thicker head gasket if need be ) . Once again thanks for advice and i mean no disrespect.

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    Re: Choise Cam for rallycross pinto

    i agree if things are optimized it doesnt really matter what the tdc reference actually is, BUT form a development perspective, you do need to know, if 33 degrees is really 38 or 25 then you want to know, because that will give you a better idea on whether compression really is to high or low or maybe you have poor cylinder filling or maybe a really good head

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    Re: Choise Cam for rallycross pinto

    Hi Graham do you mean for camshaft timing not ignition timing because i set that mechanically while the engine was out?

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    Re: Choise Cam for rallycross pinto

    im talking about ignition timing, as far as the cam timing goes you would assume that you used a dti gauge and degree wheel to accurately dial in the cam timing, if you didnt do that or swing the cam the timing using a vernier on the dyno you really are guessing/pissing in the wind

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    Re: Choise Cam for rallycross pinto

    Quote Originally Posted by Bakerk View Post
    Whoa ok guys ill try explain my reasoning. I seem to have caused some confusion. I had noticed the extra heat generated during summer here in Newzealand sitting in bumper to bumper traffic so took note and decided to rectify it next time i worked on the engine. I had already decided to change the camshaft and upon stumbling on this thread i noticed comments about heat and high compression. As we found when the engine was on the dyno we had to pull considerable timing in the low rev range it suggested compression was possible too high . As i had planned on upgrading Camshafts i thought it was a possibility i could kill two birds with one stone . I find the comments here invaluable and do not dismiss advice given . I was going to look at other areas while i had the head off for possible heating restrictions as well as smoothing some machining in the combustion chamber (lowering compression slightly) and also inspect the port filler i had used while i was there . I also was going to change out the valve springs for new ones and check the valve seating. As far as the timing issue goes , with an ecu you dont need to 100% know your zero point so long as its fixed and constant. if zero is in fact 5 degrees atdc you can simply adjust timing reading in ecu to reflect that value . In fact my setup has a camshaft trigger as well and initially it wad 360 degrees out . Instead of adjusting anything mechanical you simply add 360 degrees to the timing figure to bring it back to zero. Another nice thing about efi is if i want to change the cam back after upgrading the cam retuning and not liking it i can simply swap the camshaft back and reload the old tuning program stored on my tuners hard drive ( oh and possibly a thicker head gasket if need be ) . Once again thanks for advice and i mean no disrespect.
    This is totally madness, you don't have to set the reference at TDC because you can compensate in the setting!!!???!! It also means, you don't HAVE reference.

    Boy, trying to help you is going to be tricky. I believe everybody here is willing to help but this has no sense, please don't get me wrong but this is pub talk. Some people here are independents, just like me, taking dear time to help people out of troubles free of charge, costing them money.

    Next, if you are overheading at slow traffic, it has NOTHING to do with cam's ,CR or whatever, the engine is not even making power. You probably need an electric fan.

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    Re: Choise Cam for rallycross pinto

    Quote Originally Posted by onyd View Post
    Next, if you are overheading at slow traffic, it has NOTHING to do with cam's ,CR or whatever, the engine is not even making power. You probably need an electric fan.
    That was just to obvious to suggest!

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    Re: Choise Cam for rallycross pinto

    Quote Originally Posted by onyd View Post

    Next, if you are overheading at slow traffic, it has NOTHING to do with cam's ,CR or whatever, the engine is not even making power. You probably need an electric fan.
    that or a better radiator, we have fitted quite a few uprated radiators and electric fans to v8 rover P5B's, they go from running hot to being difficult to get the coolant hot enough to actually see if the fan works!

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    Re: Choise Cam for rallycross pinto

    And I thought it was a kind of competition car and the heat problem was occurring during the race.

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    Re: Choise Cam for rallycross pinto

    Quote Originally Posted by hawk1903 View Post
    And I thought it was a kind of competition car and the heat problem was occurring during the race.
    Without correct info, you are indeed nothing. There was not much reliable info anyway

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