Cat info 3406b needed

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Catmando, Jun 15, 2021.

  1. Catmando

    Catmando Light Load Member

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    I thought I knew about 3406b's pretty well until I ran in to this motor.. long story short.. I this bought this project truck..81 Pete 359 with a 3406b...
    Washed it up and the only number I can find anywhere on the motor is on the side of the injection pump this injection pump is what I would call the (Industrial application) like I've seen is used on a dozer or irrigation motor...when I finally got it clean this is the only # I could find on the motor this is the # ....7W3906.. I need to get some parts and the Cat parts man told me that number wasn't enough to help him out...
    Moral of this long winded story .. is does anybody have any ideas where there might be another # on this motor ..or exactly what this motor is ??
    The pervious owner is not of any help and I'am not very Confident in much of anything he has told me and the Cat parts man doesn't want to put much effort in to any research
    Any help or input would be much appreciated...Thanks
     
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  3. Judge

    Judge Road Train Member

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    I’m thinking that 7w3906 is just the fuel injection pump

    this guy knows a lot about these engines
     
  4. Catmando

    Catmando Light Load Member

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    Well thats what I think too and I have spent along time searching this motor for some sort of number with no luck
    Your right that guy is really good with cat motors !! I have watch alot of his videos
     
  5. Judge

    Judge Road Train Member

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    The serial number should be stamped on the right side of the block towards the rear. A lot of motors have a right side water filter, it would be behind it. If the motor has several coats of paint, it could be covered. The serial number for a B model Cat that you are looking for is on the block, not the head or anywhere else. The numbers are very small and hard to see, they are not big like casting numbers.


    Hope this helps, I know it sucks sometimes trying to find info, I’m just trying to remember, last truck I drove with a B model was a 80 or 81.. that was over 20 years ago
     
  6. Judge

    Judge Road Train Member

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    3406B REMAN ENGINE 7XC
    3406B TRUCK ENGINE 2EK
    3406B TRUCK ENGINE 3ZJ
    3406B TRUCK ENGINE 4CK
    3406B TRUCK ENGINE 4MG
    3406B TRUCK ENGINE 5KJ
    3406B TRUCK ENGINE 5YG
    3406B TRUCK ENGINE 7FB
    3406B TRUCK ENGINE 8TC
    These are all the prefixs of 3406B serial #s. I would suggest taking brake clean to the engine block to remove dirt and grease.The serial # plate should be on the drivers side, on a flat spot about 2"x4". If you see the flat spot and no plate It might have been removed. Also you might try cross referencing the trucks serial #.

    Now your trying to make me remember years ago...
     
    BoxCarKidd and Bean Jr. Thank this.
  7. circle h

    circle h Bobtail Member

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    Western states caterpillar in Spokane has a tech line. I have always spoken with a retired mechanic named Kenny. Their main number is (800) 852-2287 . Have you called the dealer? I had an 88 379. My dealer had my motors serial number in the build sheet. Best of luck.
     
  8. Catmando

    Catmando Light Load Member

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    Thank you both for the info....Judge.. I pressure wash this motor then degreassed it too still couldn't find a plate.. if you seen this mess nothing would surprise you.. I'am guessing this motor was a transplant this truck is the poster child for what not to do when you own a truck and why some tards should not be allowed to own a truck.. the only thing straight on this truck is the cab & frame & sleeper and drive line components everything else is a abortion
     
    Last edited: Jun 15, 2021
    Bean Jr., baha and Judge Thank this.
  9. wore out

    wore out Numbered Classic

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    The 7W 3906 was the 2nd design of the B model pump. Could be on a 7FB or a 4MG. Could be a spring return advance or a hydraulic return. The serial number is between 5 and 6 cylinder under head on a flat spot. You really gotta clean to get down to it.
     
    beastr123, Roger McG, Catmando and 2 others Thank this.
  10. wore out

    wore out Numbered Classic

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    CHASIN THE DEVIL'S HERD
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    The motor is definitely a transplant if it’s a B. The B made its debut in 84. They were made in 285hp, 310hp, 350hp, and 400. Then in 86 ATAAC was added to go to 425. In 1990 the 460peec was introduced.

    they all have different pistons, timing, nozzles sometimes pump cams and of course turbos. Air to air doesn’t guarantee it to be a 425. There were way more 310 and 350’s than anything. With an engine of that age anything could have been done so even having the serial number is no guarantee. I can’t tell you how many big flashy Pete’s I have seen bought with a 310 engine cause the 425 went up in smoke. Course they use enough 425 stuff it’s mask it till you load it. Naturally anything can be fixed with money lmao. I personally liked the JWAC 400 better than the 425
     
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  11. Catmando

    Catmando Light Load Member

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    Its a transplant no doubt about it .. the super trucker wind bag I rescued this truck from had more BS coming out of his piehole than I have in my trailer right now and I haven't washed out in 4 days
    I have cleaned that area real good woreout cause thats where I know they normally are I can't find it.. its starting to really piss me off.. in fact I got back to the shop late last night and spent 2 hrs going over every inch of the right side of the motor looking for it when I should of been taking a nap
     
    Last edited: Jun 17, 2021
    wore out Thanks this.
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