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  1. #1

    1300r pressure test... What is acceptable?

    I pressure tested my fresh bottom-up rebuild and thought I was happy with the results, but I want to get some input before running it and blowing it apart again...

    Bone stock engine using Lowell's PT kit.

    Here's what I'm getting.

    Inflating to anything past 9psi I get an obvious leak around the crank at the rear seal. I can hear it and bubbles when sprayed.

    Inflating to 8.5psi I lose 1 psi in the first 2 minutes and it slows after that. Can not find a leak anywhere @ 8.5psi.

    After 10 minutes I lose an average of .33psi/min total. I've run the test 10 times and this avg holds true every time.

    When inflating to 8.5psi I can not find a leak anywhere and have soapy water absolutely everywhere.

    Wondering what everyone here deems as acceptable for these motors.

    If the crank seals need replaced, have any of you ever split the cases on these upside down? By that I mean leave the top end bolted together, flip the motor upside down and split em. It's common practice with other motors I've worked on, just wondering if there's any hang-ups that would stop you from doing it with these.
    Last edited by blackedout96; 06-14-2014 at 04:05 PM.

  2. #2

    1300r pressure test... What is acceptable?

    Last test...

    Starting @ 8.5psi

    1m - 8psi
    2m - 7.8
    3m - 7.2
    4m - 6.8
    5m - 6.5
    6m - 6
    7m - 5.75
    8m - 5.5
    15m - 3.8

  3. #3
    Here's my thread from the other day, same problem leaking around the crank at the pto end. I found a couple other small leaks on my pulse plugs and reqorqued bolts and only pressurized to 7psi. Then the leak down was 1 psi in 10min. More along what you want. 3psi in 10 is too much. You've got another leak somewhere too. Make sure the mag cover is off and spray the thing down with soapy water or wd-40. Bolt hole leaks are a common culprit as well.

  4. #4
    Yes you can pull the bottom off, just be sure no accessories are connected to both halves, like the mag cover. Put the #2 piston at tdc to minimize pulling the pistons out. Lift the crank a couple inches, change seals and clean everything up real well. That's the pain as red loctite doesn't like to come off if you used it on the bearing surfaces.

  5. #5
    Yeah I didn't use any loctite on the bearings. I honestly don't know what I'm even going to change though... 9psi and below I can't find a single bubble anywhere. Guess I'll recheck torques

  6. #6
    Yeah I just popped mine in the hull. It's a lowell 1390 build but the seals are new and oem and I used grease. I think mine will run in after a little heat and pulsing. Groupk recommends checking under pressure AND vacuum as the crankcase pulses. I just don't know other than to try mine and keep an eye on it as it breaks in.

  7. #7
    Wondering if I've missed plugging anything... below 9 psi I can't find a leak and have sprayed every square inch of the engine along with the head of every single bolt.

    This is a 1300r efi motor
    Using Lowell's kit with the exhaust plate and 3 TB boot plugs. Oil lines are all T'd together and not leaking.

    Have I missed plugging anything?

  8. #8
    Totally lost now. Filled to 10psi. No more leak at the rear seal, sprayed everywhere, every nook and cranny... Nothing. No leak anywhere but still bleeding off pressure. I'm almost wondering if the gauge it's self is no good. The air is coming out, but from nowhere.

  9. #9
    JKR1300's Avatar
    Join Date
    Jan 2006
    St Louis & 6mm LotO
    I've had cylinders leak internally to the water jacket

  10. #10

    1300r pressure test... What is acceptable?

    Great, these were just plated. I guess it could be the exhaust... Or the head gasket. Is it safe to coat these head gaskets with anything to help seal?

    I'll loop the water pipes and see if it holds.
    Last edited by blackedout96; 06-14-2014 at 11:08 PM.

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