Big Cam Injector timing - Diesel Truck Forum -
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post #1 of 4 (permalink) Old 03-19-2017, 07:40 PM Thread Starter
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Big Cam Injector timing

Was told injector timing for this engine is .070.I checked timing on my Big Cam 400 I'm getting .050 on the injector at .2030 BTDC If I take all of the gaskets out the best I can get is .065 and I know I have to have one gasket that is .017 any suggestions on how to correct this or what I should check next?
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post #2 of 4 (permalink) Old 03-20-2017, 12:45 AM
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I do not know about all that but would double check your info. It could have the wrong cam key. Some were straight and others were offset. It could be somewhat sheared or the wrong cam. If you are looking for the most jig time each box. Don't check the front and same shim the rest.
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post #3 of 4 (permalink) Old 03-21-2017, 05:48 PM
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There were a few different timing settings for Cummins big cam 400 engines.
I rebuilt a lot of them over the years my favorite CPL number was 0449 which
was timed at .070". Different CPL numbers "control parts list" used different compression ratios
that required different cam timing.
Your engine may not have been rebuilt to the CPL number on the data plate.
Where did you get the .070" spec from.
How did the engine run? Was there blue exhaust smoke when the engine was warm?

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post #4 of 4 (permalink) Old 03-22-2017, 03:59 AM Thread Starter
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This is what I have found. the cam number is on back end of this cam the number on it is 3020914 (anybody know what this cam is for or is it a aftermarket replacement ) the cam that suppose to be in it is 3049024 or 3026975 . the cummins injection timing chart says the key should be a 3021596 which is a offset key. It appears to be a straight key that was in it. the chart shows injection timing to be .065. according to my calculations changing key should put timing where it is suppose to be. I also talked to a couple of different people Describe what it was doing Rattles under load when in throttle and higher than normal pyro (injection timing advanced) and that is what I have. The Question I have now will this cam work with timing corrected?
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