Preparing For Honda K24a3/AST5 6spd Conversion

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

  1. lookforjoe

    lookforjoe True Classic

    Some interesting ideas. I guess I may have to wait until I have the motor mocked up in the bay to determine clearances, etc. Not sure if I want to go that route (waiting to make an intake until after it's going in), have to see how I feel about that.

    Motor/Trans came today. Started stripping the basic stuff off.

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    The engine harness even includes the B+ cabling into the relay box, not that I need it.
    .
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    Exhaust manifold off
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    Engine harness, ECU with car side connectors, etc.,
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    RBB intake is ridiculously complex. Heater & PCV elements throughout. I'm wondering what drives this level of complexity. One would think heating the intake & TB to this extent would not be productive, but clearly they had their reasons.

    These are the short runners. Rad hose neck on right I can likely chop off & re weld facing straight forward & down to make it easier routing a rad hose, unless that puts it smack in the path of the TB extension layout

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    PCV looks to use a design not that different than mid 2000's Volvos - crankcase breather draw through the intake / gasket - doesn't have the reed valves integrated in the gasket though. EDIT - this is an air induction for cold start idle offset.

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    Thermovalve mounted in the air passage built into the runner section, unlike the PRB intake on Rodger's K20

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    This upper runner section maybe a great take off to build my own plenum. I'd want to chop off that whole coolant channel/housing (on right in pic) & separate that out - except the head doesn't have the mount points (right side end of intake) for separate coolant neck, so I'll likely have to weld at least an upper standoff in place to make that work.

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    I've also ordered a basic PRB K20 RSX Type S intake like Rodgers - so worst case I have a more usable (simple) intake to work with.



    Curious as to whether there is room to make a new cap for the t/stat housing that diverts downward to connect with the under car pipe, rather than replace the whole thing with more complex routing. Does it stick out too far rearward?

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    Wondering what the function of this valve/mechanism that appears to attach to the coolant system on the exhaust side of the head.

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    Last edited: Mar 25, 2019
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  2. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    That's the VTEC solenoid. Looks like you have jumped in with both feet! It's interesting to see the similarities to the K20A2 as well as the differences.
     
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  3. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    That looks pretty similar to the K20A2 thermostat housing. The angle of the spout puts it too far past the crossmember of the frame to be able to make the connection to the underbody pipes. That's why most of the K swaps I've seen pictures of come right off of the water pump and eliminate that plastic housing. I used the K-Tuned swivel neck, slightly modified, to get the spout pointing down and closer to the block.
     
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  4. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    I should let you know: I have a silly plan for this. The problem as I understand it is that the stock tstat inlet points right to the frame rail. It needs to point downward. Also, the return line from the radiator is the inner-most tube under the car (opposite of what you want here). My plan is to fabricate an extension and push the entire assembly inboard about 1.5 - 2.0 inches.
    Screen Shot 2018-09-04 at 10.25.04 PM.png

    I've seen your work Hussein - this is easy: a plate, some tube another plate. On the right-most plate, rotate it forward (outlet down) so it clears the frame rail. Then you get the benefit of keeping the stock housing with the stock recirculation line to open the tstat when at temp. I might relocate the heater return line to the housing as mentioned earlier by Pete Whitstone if I remember correctly.
     
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  5. hotx19

    hotx19 Daily Driver

    Have a look on the ktuned website all the hard work is done for you
    A thermostat housing that fits inside the chassis rail and outlet points down
    Inlet at the rear of the head and a inlet for heater piping when you fit the rbc manifold
     

    Attached Files:

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  6. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    hotx19 - I've seen a K-Tuned t-stat housing (Rodger got one - his thread starts here) but not large block you show here:
    Screen Shot 2018-09-04 at 11.34.14 PM.png

    maybe this is an older unit?
     
  7. hotx19

    hotx19 Daily Driver

    Nope
    What you may have seen is the swivel neck that bolts to the original housing
    This is new it gives you the correct outlet position as well as the heater and recirculation pipes
    So much easier than the Midwest setup
     
  8. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
  9. lookforjoe

    lookforjoe True Classic

    Thanks for the feedback.

    Must be this one: KST-WPM-350
    Can’t paste a link.

    Not sure I want to spend $230 on a t/stat housing :D I’ll have to look at making my own first, it’s possible it’s not worth the time, given the two pipes that come in on top. Rotating the entire housing will mess with that. I dunno. Have to look at it more closely.
     
    Last edited: Sep 5, 2018
  10. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    That housing (V2) from K-tuned is new from when I was doing mine. That is a much better solution than mine as it eliminates the need for that bulky (and expensive) external thermostat. I like it. I’ll have to look at it closer and see if I want to revise my plumbing.
     
  11. lookforjoe

    lookforjoe True Classic

    Ok, so basically just need a 2” block, with recirc and heater return, and possibly gauge temp sender port? I would make one that uses the stock T/stat and cover for simplicity sake

    Simplified sketch
    [​IMG]
     
  12. lookforjoe

    lookforjoe True Classic

    I ordered that upper coolant fitting, KTD-K24-IMA, not worth the time making that one. Thanks for the reference
     

    Attached Files:

  13. lookforjoe

    lookforjoe True Classic

    looking at Rodger's pic here:

    [​IMG]

    It looks like the return hose is at least 2-3" over from the housing flange, no?

    I looked at moving the stock housing outward & rotating it - I don't see that working as the recirc and heater return pipes will be facing the bulkhead.

    Can't just use the cover with t/stat in a extension sleeve, as the recirc block off will be pointing into the water pump channel.

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    So, I'm thinking I'll use the Volvo RNC T/stat & housing (serviceable)

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    Pointing downward like this:

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    an extension housing like this should work, I just need to know how deep it needs to be to get the correct alignment for the coolant pipe, and I will add a vertical tube for the heater return.

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  14. lookforjoe

    lookforjoe True Classic

    Also chopped off the flange from the plenum runners

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    This way I can build my own plenum and/or chop down the runners & repurpose the plenum. Gasket # 17115-RAA-A01

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    Also figured out that the cap on the runners is actually the PCV systemnot another heater system :D. I will probably keep this active.

    Gasket # 17146-RAA-A01

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    vent with valve that feeds the housing

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    and the upper coolant housing off the manifold flange

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    Last edited: Sep 10, 2018
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  15. kmead

    kmead Old enough to know better

    Location:
    Michigan
    Truer words have rarely been said
     
  16. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    That's about right.

    My plan was to also clock the thermostat 45º clockwise to point down. Yes, need to build a backing plate to fasten it but doable. Here it is without the backing plate just wedged with the stock bolts:
    IMG_2355.JPG


    I'm not sure what you think is blocking the recirc - this would end up pointing "up" more than back. That said, I think going to a Volvo or something else suitable is a fantastic idea and it looks to really fit the bill for what we need! (I don't have access to the myriad of Volvo parts you obviously seem to have)

    Perfect! Looks like you've got an even better plan than my feeble skills and imagination came up with.

    That said, I'm inclined at this point to suck it up and part ways with the $230 for the K-Tuned part. Does what I need, I don't spend another long weekend fabricating parts instead of doing other stuff.

    BTW, here's what I had planned...

    IMG_2353.JPG
     
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  17. hotx19

    hotx19 Daily Driver

  18. lookforjoe

    lookforjoe True Classic

    Sorry, the issue with the recirc would arise if one used only the tstat & cover - then the recirc wouldn’t work as it should.

    The problem I have now is I don’t know what angle the engine sits at in the bay, and as result what depth I have to work with relative to the water pump housing / ancillary bracket and the starter motor.

    I really don’t like the idea of having a fixed item that interferes with removal of the starter, as that’s just asking for trouble DTR.

    Futzing with the Volvo and Honda housings, the best I can come up with is about 4” “ rearward” offset from the housing . I just don’t know what offset I can work with relative to the frame rail and stick coolant pipe. If I end up with 4”, will a elbow hose suffice to mate with the coolant return pipe? Or will it interfere with the feed?
     
  19. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    Yeah, that is exactly the problem with the K-Tuned "V1". Stock with recirc the as block heats up it opens the thermostat (which also closes the recirc).

    [/QUOTE]

    attaching the best image I have.
    WP_20160531_22_54_19_Pro.jpg

    your safest angle is to follow the angle of the engine mount bracket ('the V one') IMO. You could even shoot further back. The coolant lines rise up between the body frame rail and the subframe rail.

    Here's a couple more where the subframe is in the chassis (but not engine). Might be helpful. Good luck!
    IMG_1740.JPG IMG_1741.JPG IMG_1743.JPG IMG_1744.JPG IMG_1745.JPG
     
  20. lookforjoe

    lookforjoe True Classic

    Many thanks for the pics!

    Using your frame pic & Rodgers bay pic I can get a pretty decent sense of it.

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    What I did after work was make the adaptor extension to fit the Volvo T/stat. Angled like this it puts the outlet such that with a 45º junction on the hose, it will sit pretty close to 5" on center. I wanted to make sure I could actually remove it in the bay if need be. Forward facing port is for the ECT. Not sure if I can utilize the Volvo one, or just leave it unused. The heater return will feed up from underneath into the sextension, so a standard piece of 3/8" heater hose will suffice. Have to hog out the inner flanges to mate at each end, I only drilled a 1" hole in the center of each to make sure the flanges didn't distort when welded.

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