KB oil pressure bleeding away.

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by BBFA_Pilot, Sep 11, 2010.

  1. moparchris440

    moparchris440 Member

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    Agreed! Had same problem here on the race pak 140 lbs of pressure leaving the line and at the stripe 50 lbs with 14 quarts on a BAE hemi, added 4 quarts problem went away. also switched from 20w-50 Brad Penn to straight 50. I'm running .080 restriction jet in the bottom of the stands.
     
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    Last edited: Sep 12, 2010
  2. fastavenger 588

    fastavenger 588 New Member

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    oil pressure

    u need more oil :eek:
     
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    Last edited: Sep 12, 2010
  3. rb0804

    rb0804 Member

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    Is the valley of the new block different then the new one? For example is the old one much more open to aide in oil drain back then the new one? You may want to consider an oil drain back tube from the heads back down to the oil pan.
     
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  4. Brent

    Brent Member

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    We shimmed up my k.B. billet to get more oil pressure this year and ended up hurting the motor by sucking the pan dry too quick. On Robert's advice I phoned Steve at System 1 and he recommended 15 quarts in the motor and a 3 quart accumulator as he said their doing that to a lot of the Pro mods now.After a couple of passes the bearings still look like new and we like that we can pre lube the motor with the accumulator.
     
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  5. jim phillips

    jim phillips ta/fc

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    some one may have said this already but check the screen in your filter you can go from 120lbs to 60lbs and think WTF and all it is that screen needs to be cleaned i have had it happen twice and thought i had had some thing go wrong in the motor and all it was i hadnt cleaned the filter in a while

    ps run brad penn 70wt you will be glad you did in the long run
     
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    Last edited: Sep 13, 2010
  6. Flyboy68

    Flyboy68 Member

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    We had similar problems...kb stage 10, titan oil pump, straight 50w, on startup had about 120-130, then would go down to about 40-60 after a minute at idle. Regulator was all the way in. We were running 11-12 quarts, but w/ a 3 quart accumulator (so roughly 8-9 in the pan). Added a couple quarts, ran 14 quarts w/ accumulator full (so 16-17 total), pressure is good now, will start up to 120ish, then after burnout we're at 80psi before launch. Data logger shows it'll go up to 120-130 during run. I highly recommend an oil accumulator.

    Josh
     
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  7. QPM

    QPM New Member

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    More oil

    If it is a shallow funny car pan minimum 14 quarts up to 16. Deep, dragster style, pan minimum 19 quarts. The return holes in the block, from the heads, are not big enough in a hemi and they carry a lot of oil in the heads. You need to compensate for it with the amount of oil you put in the motor.
    We had a similar problem, but not as extreme, started with 14 quarts and the pressure would drop 20-30 lbs after burnout, added 2 quarts plus a quart of Lucas and the pressure drops maybe 10lbs. And, like Scouder said, you definately need it for the shutdown area.
    Hemi's arent like BBCs the pan is all below the crank so fillit up to the top. Our car is filled just above the pan rail. on a moroso funny car pan, with a 1.5 quart kickout added.
     
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  8. d jackson

    d jackson New Member

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    kb oil pressure

    my friend had the same problem as you are having
    it was a bbc still same problem
    his problem was he had put a stand rod bearing on a .010 crank by mistake of the suppler
    and not confirming what size the bearing was sent to him
    so he put the correct size bearing in and corrected the problem
    ck and see?
    all things are possiable
    d jackson
     
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  9. BBFA_Pilot

    BBFA_Pilot Member

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    Hi guys, we think we have made a possible breakthrough.

    After making some observations and checking all the main caps and lines, we went to check the crankshaft itself. After looking at the crank (which is a Keith Black 4.250" crank) we found that numbers 2 and 4 journals have 4 oil drillings instead of the normal 2 (90 degrees to each other, meeting in the middle as a 'X')

    We are finding that those two extra drilled holes are causing a large exhausting of oil away from the bearing which is most probably causing the huge fluctuation in oil pressure, pressurising and then exhausting away twice as fast as normal.

    So with this said, my next question is, does anyone else here run a KB crank? And if so, does their no. 2 and 4 journals have the extra holes drilled? Am I assuming with this, that racers are running the higher flow / higher pressure billet oil pumps to compensate for the extra drillings? We are running a normal cast KB racing pump.

    We have run this crank before, but with a billet pump back when we raced in TAD, so perhaps this was the issue after all.

    In regards to everyone mentioning levels of oil, be it on this thread or via PM's etc, I appreciate your input definitely. I was informed we ran 8 quarts, but that is only what we put into the sump. We put a extra two quarts worth to prime the filter and the lines, so we actually run about 10 quarts all in all. We might well put a extra one or two in to be on the safe side as so many people said to run a bit more. We are all definitely to try something new to keep our engines going. :)

    But I digress, if anyone does run a KB crank and has the two extra drillings (Or know of this design), then let me know as we look to cure this problem once and for all.
     
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  10. REEHL EQUIPMENT

    REEHL EQUIPMENT Active Member

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    There may not be too many KB cranks left, because they haven't made them for 10 years, I think. Velasco tried this I believe. You may CALL him, and ask. He'll tell you why.
     
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  11. jim phillips

    jim phillips ta/fc

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    is 10 quarts enough i dont run a dry sump but the guys that i do know run more than that good luck
     
    #31
  12. BBFA_Pilot

    BBFA_Pilot Member

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    i'm assuming by the lack of replies that no one really knows about the KB crankshafts and the extra drillings.

    I'll get in touch with Ken Black himself I think and see if I can put this thing to bed, racing next weekend and we need to get some decisions made pretty quickly.

    Thanks everyone.
     
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  13. badbird

    badbird New Member

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    you say 45 lbs thats at idle right,
    our presure starts at 150 and is down to 70 or sometimes lower as i stage if i was ott in the burnout but it comes sraight back when we drop the clutch, with no data logger you wont know that it dosnt ??? unless you watch the oil guage on a mid 6 second run and thats hard to do
     
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  14. BBFA_Pilot

    BBFA_Pilot Member

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    Graham:

    It's all fine and well when the pressure comes back when you rev the motor, but with ours in the current state it's in, it doesn't. It's not necessarily how low the pressure is going at idle, it's the fact it doesn't recover to normal amounts when you hit the pedal, thats my area of concern.

    As for reading a oil pressure gauge on the run, I never said I've done that. I made this discovery running the motor up on jack stands for a few minutes (To basically simulate time taken to start up, burnout, reverse, stage and the run) and monitoring the gauge. After this amount of time the motors pressure would drop and not recover, even when you bring the rpm up.
     
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  15. rb0804

    rb0804 Member

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    If you find out can you please post so we can all benefit? Did you make any 'improvements' to the oil system while the engine was apart? New pump, higher volume, shimming the relief? Some engines have too much oil pump and suck the engine dry before it has a chance to return.
     
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  16. john348

    john348 Top Alcohol

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    I have on KB crank left i think it has 9 passes on it now
    in our spare motor, oldy but goody
    you are refering to what i think was called pin drilling, smaller hole cross drilled
    this way the rod oiled every 90° instead of 180°, basicly continously
    Callies also did this when John Medlen was using them back in the day
    not sure that is your problem
    my money is you need alot more oil in the pan
     
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  17. moparchris440

    moparchris440 Member

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    OK I'll say what everybody is thinking! Why don't you fill it with oil like 90% of the people have tried with success and have suggested to you! Its a cheap fix and if anything else you can eliminate that from your quest to fix your oiling problem. Mine holds 18 quarts.... 12 wasn't enough! You don't have enough oil for a wet sump!
     
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  18. BBFA_Pilot

    BBFA_Pilot Member

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    rb:

    If i do find out then of course i'll post up, as i'm all for making a nice knowledge base for everyone to have. As for changes to the oil system we made a shim unit to put into the pump and it gave us much improved pressure from startup. That said, perhaps it could be sucking the pan dry. As we made it adjustable, we adjusted it and it made no difference to the fluctuation, but also didn't improve the pressure when the motor is hot.

    JohnHart: This is exactly the crank situation we have, but it's on the main journals and it gets oiled every 90 degrees. I need to find out if they are meant to be used with specific pumps and such like. We are unsure whether or not to thread two of the pin drillings; even then if it doesn't work we can always remove the blanks.

    Moparchris: It might well be this too, and i'll try it out the next time we get the car ready to fire up. We can then remove it from possibilities if it doesn't improve.

    Perhaps it is a combination of the pump sucking the pan dry and the extra drillings on the crank causing the pressure to leak away. Like I said earlier, my father ran this crank during our TAD days and ran a billet pump with no problems; i'll find out how much oil was run in the dragster in comparison to now. I will let you know what I find.
     
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    Last edited: Sep 17, 2010
  19. rb0804

    rb0804 Member

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    Did you happen to measure your side clearance on the rods when you installed the new crankshaft? Maybe you have an issue with excessive side clearance along with oiling every 90* and increased pump volume? On the other hand, it could be that you just flat out don't have enough oil in the pan and that is actually what caused you to hurt the parts in the old engine. Could it be possible that the same problem existed, just not as exaggerated? While we are on this topic what is a good (recommend) oil pressure to shoot for?
     
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  20. BBFA_Pilot

    BBFA_Pilot Member

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    Well we think we've cracked it.

    The two extra crank drillings which we found on main journals 2 and 4 we decided to blank off and also developed a threaded pressure pump shim adjuster (we kept the same amount of oil). Combined those two and the oil pressure during warm up was a very pleasant 110lbs of pressure which leapt to about 130 at about 6000rpm.

    Which meant we were able to run at the National Finals, run two mid 6's to get No.1 Qualifier and the bearings were coming out like new; it was incredible! This performance also gave us enough points to be the 2010 NFAA Champion, so a huge well done to my crew for winning me the title!

    Thank you to everyone who enquired, gave me ideas, solutions and helped me with this problem. Sadly the last run was rained off, so the car is ready to go for next season! Wonderful way to end the season!

    Thanks again everyone :D
     
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