Preparing For Honda K24a3/AST5 6spd Conversion

Discussion in 'Workshop Forum' started by lookforjoe, Aug 31, 2018.

  1. lookforjoe

    lookforjoe True Classic

    There is another bolt hole on the back of the block I can utilize

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    So I'll make a brace that connects that to the lower bell housing hole with a captive nut for the MWB upper mount point

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    kmead and dllubin like this.
  2. kmead

    kmead Old enough to know better

    Location:
    Michigan
    I would think about a flat plate to go from the existing threaded hole in the block with captive nut to receive the bolt from the MWB side and then weld on a reinforcement plate at 90* to then grab the large threaded hole to the left in the transmission. I am busy today so I won’t be able to make an illustration until this evening.
     
  3. lookforjoe

    lookforjoe True Classic

    That's the plan, so the bracket is triangulated.
     
    kmead likes this.
  4. lookforjoe

    lookforjoe True Classic

    Worked on the bracket today

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    Junk S40 left today, so I had room to get the X1/9 out & make some room to work in the garage .

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    Mike Schofield, kmead and dllubin like this.
  5. kmead

    kmead Old enough to know better

    Location:
    Michigan
    Oh my. (George Takei) about the car outside the garage

    I envisioned the bracket a bit differently. It looks a bit light on gauge but should work as is. I would keep an eye on it.

    Creative approach.
     
    Last edited: Mar 29, 2019
  6. lookforjoe

    lookforjoe True Classic

    It's 1/4" stock, should be more than sufficient. Probably didn't even need the vertical leg. I'm thinking of adding a web on the backside of the vertical & horizontals, but any load would typically be fore/aft when the motor torques, I would expect. What is not obvious here is that there are two 'arms' to the MWB bracket, so the load is not carried by this alone.
     
    kmead likes this.
  7. Michael Albers

    Michael Albers Daily Driver

    Location:
    Barboursville WV
    Bracket solution looks good. Remember the engine torque loads this mount upwards and back, should not be a problem.
     
    kmead likes this.
  8. kmead

    kmead Old enough to know better

    Location:
    Michigan
    I’ve been wrong before.

    Car looks great.

    75E0CA54-1773-4762-B686-A41A8C564914.jpeg
     
    Last edited: Mar 29, 2019
  9. lookforjoe

    lookforjoe True Classic

    That way would have made sense, the rigid edge is in keeping with the torque direction :D - my way required the web to ensure no flex.

    Finished it up today

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  10. lookforjoe

    lookforjoe True Classic

    Started stripping all the stuff back off the motor & removed the transaxle, in prep for dismantling the front casing & pan/oil pump swap. Steel pan won't work, period - with MWB subframe.

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  11. kmead

    kmead Old enough to know better

    Location:
    Michigan
    I wouldn’t have thought of your approach, it is clever and uses things at hand.

    I presume a K20 alloy pan will work or do you have to fabricate your own to do this or modify the K20 further to work with the differences of a K24.

    Stupid question, does the K20 by its nature rev higher and therefor require a different oil pump as a result or does Honda include sufficient capacity in all their units?
     
  12. lookforjoe

    lookforjoe True Classic

    Yes, the K20 has a higher rev limit. The K20 aluminum pan will fit without modification. The K20 oil pump is different & required for the pan to work. The base of the pump has to be modified. Unfortunately the pump chain is also different & is mounted behind the cam drive chain, so all that has to be removed. The K24 setup is bulky - it has balance shafts. Apparently the K20 is somewhat rough running by comparison, with the smaller pump/ no balance-shaft setup.
     
    Last edited: Apr 1, 2019
  13. kmead

    kmead Old enough to know better

    Location:
    Michigan
    So without the balance shafts will the K24 end up rougher still due to the great reciprocating mass?
     
  14. lookforjoe

    lookforjoe True Classic

    Well, I don't know exactly, however I have read posts that suggest the oil pump swap will create a less smooth (than a stock K24) running motor. I don't know if that means rougher than a K20 is by comparison, or equal to.
     
  15. Michael Albers

    Michael Albers Daily Driver

    Location:
    Barboursville WV
    Some people have reported that the oil pump swap results in a significant increase in vibration at idle. From what I have read on the K20 sites it seems the motor mounts used have a lot to do with the perceived roughness, and rubber mounts like in the mwb kit should help. It is also much worse if you use a lightened flywheel.
    You do get a net hp increase because the balance shaft pump really has a lot of drag from the rotating mass of the shafts.
    I did the same swap on my K20Z3, and I went ahead and changed the timing chain, guides, and tensioner. It wasn't terribly expensive and it seems that the timing chain is the weak part of the K20 design anyway so I figured it was cheap insurance.
    Of course, I wont have the thing in the car for quite a while, so I will have to wait and see.
     
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  16. Michael Albers

    Michael Albers Daily Driver

    Location:
    Barboursville WV
    I got an aftermarket kit off Amazon that had good reviews and was surprisingly inexpensive. It had both K20 and K24 oil pump chains and all the guides, and the tensioner for the oil pump and timing chains.
     
  17. lookforjoe

    lookforjoe True Classic

    Any chance you can look up the kit listing? Not finding one with everything.
     
  18. lookforjoe

    lookforjoe True Classic

    Flywheel & PP have hot spotting, so even though the disc has plenty of meat, I ordered a complete kit. The whole kit goes for the 3rd of the price of a Volvo flywheel :D. Also ordered the Honda Urea grease (08798-9002)
    for the splines & slave rod greasing.

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    Back of motor & bellhousing have a decent amount of oil/grease residue, but no typical spray pattern on back of flywheel that I would expect from a leaky rear main, and no oil on the clutch. I'll just do the rear main & input shaft seal to cover myself.

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    Also got the engine up on the stand & removed the oil pan today.

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    removed the pump

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    cleaned up the block. Next I have to remove the front cover to dismantle to access the oil pump chain.

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    Last edited: Apr 1, 2019
    Michael Albers likes this.
  19. Michael Albers

    Michael Albers Daily Driver

    Location:
    Barboursville WV
    I was mistaken, it was an ebay store.

    https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/360526000465

    I hope the above link works. If not, the seller is mizumo auto, and the item number is 360526000465.

    I dont know if you can get everything in one kit for your application because you have to use a K20A2 spec oil pump chain when you swap the pump, it is a slightly different length than the chain for the balance shaft pumps.
    The K24 block is a little taller than the K20 so the timing chain is a little longer. I believe that the guides and tensioner are the same though. Anyway my kit was a K20 spec kit and included two different length oil pump chains so the same kit could service any of the K20 variants. I dont think the K24 has ever been factory equipped with the non balance shaft pump, so you will probably have to piece that part together separately.
     
    lookforjoe likes this.
  20. Michael Albers

    Michael Albers Daily Driver

    Location:
    Barboursville WV
    I was a little apprehensive about the kit because it was only $60 and I was afraid it would be typical cheap Chinese junk, but it appears to be good quality and when I laid out the new parts on my bench and compared with the original parts I found them to be practically identical.
     
    lookforjoe likes this.

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