big cam 400 cummins tricks

Discussion in 'Trucks [ Eighteen Wheelers ]' started by fullthrotle, May 10, 2007.

  1. V8Lenny

    V8Lenny Road Train Member

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    Yes, but why do they say that upping fuel pressure wears out your cam? Someone said it's just bad oil and long drain intervals, which is easier to understand.

    I am not the only one to disagree with Bruce about the timing. PP and GL are good advertisers, others build the best engines and stay quiet.
     
  2. ironeagle2006

    ironeagle2006 Road Train Member

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    More fuel EQuals More SOOT unburned Fuel and back BEFORE all the Sulphur was REMOVED more ACID in the oil. Sulphric Acid will eat Steel even Heat Treated Steel. Also with solid Roller Lifters there is no way more Fuel Pressure the Cam should wear out with Higher Rail Pressures. Were I have seen the wear since all the pressure is in this area is at the TIPS and only IN THE TIPS. Why do you think you hear of Tips blowing off. I have seen this happen and that is why you see holes burned in a piston. Think a Water Jet made of Diesel Fuel then light it off. Most Camshafts have a Steel that has a Yeild Pressure of over 8K PSI we normally run 600 Max rail pressure. Also we make improvements to the oiling system aka improve the feed to the cam to give it more oil on the Journals. When you raise the Oil Pressure you get way longer life from the mains and Camshaft. Now the one I drove we put a High Volume pump on it and also put in a Higher Pressure Spring set in it. Instead of the low Pressure IIRC this was 13 years ago going down the road I was sitting at 50-60 PSI instead of 20-25 PSI.
     
  3. CLC379

    CLC379 Light Load Member

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    but your response seems typical of the rest, lot of talk but no direct answer

    so far everyone i have seen claim bruce was stupid about something went on to prove themselves even stupider in a few posts?
     
  4. V8Lenny

    V8Lenny Road Train Member

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  5. ironeagle2006

    ironeagle2006 Road Train Member

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    Lack of OIL will wear out a cam faster than ANYTHING. That is why if you Bother to READ Bruces entire SERIES he put out the first thing he recommends if your going to jack a Cummions to the moon is IMPROVE the OIL SYSTEM and PRESSURE. Be amazed what happens when your giving your bearings the oil they need. My Oil TEMPS WERE LOWER due to flow alone. Second no typical big cam tap in the top end with the rockers getting the oil they needed. Lastly less chance of a MELTDOWN in the pistons since they were getting sprayed with enough oil to keep the crowns and skirts cool.
     
  6. V8Lenny

    V8Lenny Road Train Member

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    What a surprise...
     
  7. ironeagle2006

    ironeagle2006 Road Train Member

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    Cummions UNTIL the N-14 went with a LOW PRESSURE Oil System and with some of the Big Cams was running a Low Flow Cooling System. When you only have 25 PSI at WOT your Bearings and Camshaft and Rockers are going to take a freaking beating regardless of WHAT HP and FUEL PRESSURE YOUR SET AT. Now if you run a High flow and set the Pressure up to say 50 PSI all those ISSUES go away. Do not get me wrong Cummions made a decent motor at that time however the Engineers needed to be HUNG BY THEIR BALLS for thinking low flow cooling and low Oil Pressure was the way to go.
     
  8. V8Lenny

    V8Lenny Road Train Member

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    Drivers just don't understand low flow cooling system, it is meant to be run HOT. Oil volume flow is important, pressure not so much, it just makes heat and air bubbles, stock pressure is enough.
     
  9. ironeagle2006

    ironeagle2006 Road Train Member

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    Lets see here on my 44XT Before OH INTO A 720 HP BEAST WITH A STOCK LOW COOLING SYSTEM AND POS STOCK OILING SYSTEM IN IT. OIL TEMPS WERE ALWAYS IN THE 240-250 RANGE WATER TEMP AT 200 WITH 180 STATS AND A 4 CORE RADIATIOR. AFTER HAVING THE HORSEPOWER ALMOST DOUBLED AND CHANGING THE COOLING SYSTEM TO A HIGH FLOW ALONG WITH UPPING THE PRESSURE AND VOLUME IN THE OILING SYSTEM. WATER TEMP WAS 180 TO 190 EVEN AT FULL FUEL ANDF BOOST. OIL TEMPS NEVER HIT ABOVE 210 AGAIN AND THE OIL ANLYSIS SHOWED A DROP IN WEAR METALS AFTER THE OVERHAUL EVEN DURING THE BREAK IN PEROID. I rebuilt farm motors before going OTR and we always raised the OIL pressure and flow rates to reduce wear on the motors espically in the cam and main and rod bearings.
     
  10. V8Lenny

    V8Lenny Road Train Member

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    Water temp of 200F is just perfect temp without load. Anything under that is too cold. Were the oil temp that(250F) high even without load? How did you up the volume in the oiling system?

    You can have 650hp only from pump adjustment, how much did you pay for 720hp?
     
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