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Technical Early 331 Hemi Oil Pump Options

Discussion in 'Traditional Hot Rods' started by ace high, Jan 9, 2018.

  1. Luke,
    I have been reading your diagram and believe that the distributor is the main problem.
    Although you do have limited engagement with the distributor tang into the intermediate shaft,,,,there is still clearance at the top of the intermediate,,,and the shaft can push back up into the distributor shaft.
    When this happens,,,,the bottom of the intermediate disengages from the oil pump.
    All of the tolerance stack up is catching up with you.
    Limited engagement with the oil pump.
    Limited engagement with the intermediate.
    Too much clearance between the distributor and the intermediate.
    I think these are all combining to cause your problems.
    However,,,my feelings is to fix all three issues,,,,any of them will cause a failure if left alone long enough

    Tommy
     
    LukesMotorShop likes this.
  2. LukesMotorShop
    Joined: Jul 31, 2019
    Posts: 10

    LukesMotorShop
    Member


    Thank you Tommy, I'm in the same boat!

    I slept on it and this weekend I'm going to go ahead with the plan of basically "push everything up"
    Step #1) press the intermediate shaft up ~0.150" to get approx .250 engagement with the distributor (then redrill the set pin)
    Step #2) press the oil pump shaft up ~0.400 (which is 0.150" from Step #1 + 0.250" for the engagement of the pump)

    I will be measuring everything twice again so they still have clearance and are not binding up etc.

    BUT STILL THOUGH .... why do i have to do this??!!?? ....

    Trying to keep those "should have just done an LS swap" out of my head!!! HAHAHAHA

    THANKS AGAIN GUYS!!!

    I'm recording everything I'm doing and I'll post the video on here ...
    (I've got other videos up of what I been doing if anyone wants to check them out! link is in my signature)
     
  3. Hey Luke,

    Are you sure the intermediate has not been moved up and re pinned already.
    From your pic,,the shaft protrudes from the top already,,,,About .100,,,,right?
    I just checked two shafts that I have and both are recessed down in the gear about.300,,or so.
    That being said,,,the distributor shaft is supposed to sit in the cavity at the top of the gear.
    It helps to control it at RPM,,and keep it from wondering around.

    Now,,,I have been checking and a 318 distributor is about .400 shorter than a 331 Chrysler,,,at least from the info I have .
    I just measured a 5.2 distributor I have and it is about.300 shorter than my Desoto distributor,,,and a 331 is supposed to be .100 longer than the Desoto,,,,approximately.
    I took a few pics,,just for reference .
    Oh yeah,,,forget about the LS,,,the Hemi will be much nicer,,,,I promise!

    Tommy
     

    Attached Files:

    LukesMotorShop likes this.
  4. If you look at the distributor pic where the tang is,,,look at the discolored part near the bottom.
    That was sitting inside the gear top opening,,,very close to .300 or thereabouts.

    Tommy
     
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  5. Beanscoot
    Joined: May 14, 2008
    Posts: 3,041

    Beanscoot
    Member

    The end of the shaft in this picture is blurry, but it looks like the piece it drives has come close to popping out and made a round dent in the metal:

    [​IMG]
     
    LukesMotorShop likes this.
  6. Been running the stock 331 pump in my hemi (bored 1/8" over to 354) for 30 years with zero problems.
     
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  7. Okay guys. Without reading every post here were I in your spot I think we all agree you need pretty much full engagement of both tangs on all 3 parts. Yes the Dist shaft should be down in the top of the Drive gear to keep it centered. At this point were it me I'd use a small amount of modeling clay on both ends of the center shaft and bolt things back together. Then remove all 3 parts and with the clay left behind you will know exactly where the parts sit to each other. I believe the 392 Dist is one to itself due to the shaft length being longer than the 354 - 331 motors. Not sure of interchange of Dodge and Desoto Dist but on a bench to the eye they all look the same. A miss labeled Dist could be the root of your issue letting the center shaft not stay where it belongs. Maybe you've already covered all this and I just didn't catch it. If so, sorry to waste your time. I'm more curious about the cure than the issue being I have a fresh machined block on the stand right now and don't want to have the same issues.
     
    LukesMotorShop likes this.
  8. What kind of engine are you building Wizard?

    Tommy
     
    Last edited: Sep 20, 2019
    LukesMotorShop likes this.
  9. 392 Chrysler. Street motor, vehicle for it still undecided. Kind of leaning toward this. Only thing stopping me is Common Sense, but I am building the motor and machine work on Block, Crank and Heads is done. No nuts or bolts in place yet.
    Things to come 001.jpg
     
  10. Oh man,,,that will be Sweet!!!
    I wish I could find a nice 392 core,,,for decent money.
    They seem to have plenty of hot rod parts available.

    Not that I am complaining,,,I have two Hemis.
    1 is a 1955 291 Desoto,,,gonna make a really nice engine someday.
    The other is a darned old 1970 426,,,,,oh well,,,, I will struggle through somehow!

    Tommy
     
  11. LukesMotorShop
    Joined: Jul 31, 2019
    Posts: 10

    LukesMotorShop
    Member

    Hey Tommy, The shaft I have is the " Longer Intermediate Shaft" by HotHeads it is suppose to stick up outa the gear by about 0.100" to use the 318 distributor. but it still seems to short

    Yes exactly, end is all torn up. that pic is also AFTER i took it to the bench grinder to take the burrs ... it was worse

    Hey! thanks for the reply: long story short its a 318 dist .... longer shaft by HotHeads ... and the new style 340 oil pump.
    - my oil pressure dropped to 0 psi suddenly during initial tune
    - after measuring the the "Stack" of parts:
    -- The distributor is only engaging the top of the intermediate by approx 0.050"-0.100"
    -- The oil oil pump is only engaging by about 0.100"

    The bottom of the intermediate shaft got torn up. so now I'm adjusting the shafts positions to engage the distributor and oil pump properly.

    This weekend I only had a couple hours to dig into the mod ... I remeasured everything and modified the intermediate shaft.

    I'll mod the oil pump shaft next weekend and hopefully have it back up and running!!

    Thanks again everyone!
     
    Pist-n-Broke likes this.
  12. Luke,

    I just wanted to take a moment to reach out to you in regard to your problem, I just happened to stumble across your thread. I literally had this very same issue just this last December...... It’s hard to say if the intermediate shaft lifted and thats what caused my problem for sure but i did find some flaws in the Hot Heads oil pump adapter and the interference it has with the intermediate shaft. This can easily be remedied if you have access to a mill.

    Quick back story on my part. I had just finished up assembling my hemi and of all days on my way to a family Christmas dinner with less than 100 miles plus break in time, my oil pressure dropped to zero while i was zinging at 75 on the interstate and what do you know my engine rotating assembly gets smoked! No oil on the piston skirts at 3k and building boost totally destroyed my bottom end and wallet.

    I called Eric at HotHeads and he swore they have never had these issues in the past, but after talking with a few people i know who build and race early hemis this is not the first time this has happened. I sent him an email and i got no response for 5 weeks..... I’ve been hesitant to post anything because Hot Heads does sell some quality parts and I have used some on my engines and been very happy with them except for this particular time.

    I have built numerous engines and never had anything like this happen before. I can tell you what i did to fix my problem and what i found.

    Almost forgot but i am now running a stock 331/354 Ronco vertex magneto, stock intermediate shaft, modified HH oil pump adapter, my oil pump shaft.




    Sent from my iPad using The H.A.M.B. mobile app
     
    Last edited: Sep 24, 2019
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  13. this is the Hot heads intermediate shaft...
    20181229_210255.jpg
    and I later found the oil pump shaft was bent, I'm assuming it bent when the intermediate shaft ears sheared...
    20181229_211700.jpg
    2018-12-31 13.36.44.jpg
     
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  14. when I called Eric back initially all I wanted to do was inform him that I had a component failure and that he should look into it as possible batch of shafts that were not hardneed correctly. He did say he would press in a new oil pump shaft for me at no cost. when I got the oil pump shaft back he left me a note on the reciept. I ended up just turning out a new shaft of the same dimensions as the replacement and pressing it into place.
    20190128_061844.jpg
     
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  15. So what I found was that the oil pump shaft and intermediate shaft only had roughly 0.118 interface (the original hot heads shaft). To me that's just not enough when my oil pressure is at 75psi. I ended up taking a stock 354 intermediate shaft, pressing off the old gear and pressing on a new coated gear for the roller cam.

    You’ll have to basically measure what the dimension is from the top of the dizzy bushing down to the oil pump shaft at the top (plus where its been machined to interface with the intermediate shaft) when its installed (i got 5.343). take the difference of the intermediate shaft and the measurement from the bottom of the drive gear down to the oil pump shaft (i got 5.225) and mill the difference off the Hot Heads oil pump adapter (i cut 0.110 off) with a few thou for play. this gave me near 0.240 of engagement. I used a new dizzy bushing installed when I took all measements. This was my problem.... HH oil pump adapter. Your measurements will more than likely be a little different due to block machining tolerances and the overall thickness of the dizzy bushing flange.
    20190413_220703.jpg


    I have over 8 thousand hard driven miles and no problems since and I routinely spin it to 7k. next time I build a hemi I'll probably make my own shit and save myself the hasstle, time, and money.

    After all the measuring and investigating what could have caused all of this it turned out for me to be the oil pump adapter was to thick. Solution was to clamp it down already bolted up to the rear main cap and take a few passes off.
     

    Attached Files:

    Last edited: Sep 23, 2019
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  16. I jotted this down for measuring reference points. I saw what you had for measurements and they differ from what i have. I’m sure there will be some critics as to what i posted but this is what happened and what i found and what i did to resolve the issue.

    2019-09-24 00.59.20.jpg
     
    Last edited: Sep 24, 2019
  17. Marty Strode
    Joined: Apr 28, 2011
    Posts: 8,788

    Marty Strode
    Member

    Here is my story about the HH late oil pump conversion. 15 years ago, I built a customer a complete Track Roadster with a 241 Dodge. When were choosing engine parts I called Bob Walker and ordered a slew of parts, including the pump conversion. As Jeff Norwell stated, I had to hammer bumps in the pan to clear the pump. Meanwhile, I gave away the old pump and pickup tube to a friend. When the car was completed, and the engine run in, I was unhappy with the low oil pressure and intermittent lifter noise, but delivered the car to the customer. At short of 5000 miles (the speedometer was fast, so it was less miles than shown) the guy calls me, thinking the engine blew up, with no oil pressure. I hustled over and pulled the pan, this is what I found. I called Bob Walker, and he said I could buy another pump, and send him the bad one and he would do the forensics, so that's what I did. He determined the there was some Loctite in the pump, but he would credit me a certain amount. We installed the new pump, with another intermediate shaft and I thought the problem was solved. About a week later, with about 500 miles, it did the same thing again ! My friend gave me back the oil pickup and bought me Melling pump that was a replacement for the original from Mad Dog, Gary (73 RR) sold me a used intermediate shaft, and we put it back together. What an improvement, great oil pressure and zero lifter noise. The car is now pushing 30,000 miles and running great ! P1010242.JPG P1010231.JPG P1010232.JPG
     
  18. Amazing info guys and couldn't have come at a better time. Several thoughts have passed through my mind but then when buying one piece made for a specific job from a Co. that is currently the biggest name in the early Hemi world that you should have to check there Math to be sure there parts actually fit and everything related to them is actually correct? I don't know that I would have done that. I do know that I'm going to. I have a fresh 392 sitting in my Merc that Earl Floyd built for me. It's been a couple years since it was put together but I know that he bought the Pump and Adapter from Hot Heads. Lucky for me it has not been lit up yet. You can bet I'm going to find out exactly how much engagement I have at both points of the shaft before I even add Oil to the pan. I may have just dodged a big Bullet. I'm also going to contact a friend that just had his Desoto motor built and has not yet lit it up. He needs to be doing some Detective work just for some added Insurance.
     
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  19. LukesMotorShop
    Joined: Jul 31, 2019
    Posts: 10

    LukesMotorShop
    Member



    Thank you, thank you!!! It vindicates what I'm doing seeing someone else go through a mod like this.

    I played around with milling it down also. but i don' have mill or surface grinder I figured it was easier to play with the shafts than the milling option.

    Also; milling wouldn't have helped with the distributor engagement.



    Thanks for your drawing! I can see a bit of difference but same idea ... I'm triple measuring before and after each step to make sure!!


    Glad Its helping .... I'm still second guessing myself for doing this mod ... but I'm stoked to see it coming to an end


    Awesome! glad we can help!!!
     
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