Preparing For Honda K24a3/AST5 6spd Conversion

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

  1. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    Looks pretty clever. I am a bit concerned that the supply connection to the radiator could be partially blocked by the angle of the thermostat housing. Wouldn't it be better to get the engine in the engine bay and then worry about the thermostat design? You will most likely be putting the engine in and out a few times to make sure you have all of the clearances good.
     
  2. darwoodious

    darwoodious Darin Nelson

    Location:
    Seattle, WA
    Looks like you'll be OK Hussein. I think Rodgers right tho - your ECT forward port gonna be blocked by the hot line to the radiator (which is the passenger-outer side feed tube below).
    COOLING-SYSTEM-PLUMBING-1_zps65860279.jpg
    In one of the MWB photos online they show an inverted "J' shaped hardline going around all the return/thermostat business - so it gets tight there. You might be able to re-route the hot radiator supply line but it gets pretty cramped in that area.

    And like Rodger said - you'll be putting the engine in/out 3-5 times. Just happens.

    I certainly like your solution tho. Yet another option for K swappers!
     
  3. lookforjoe

    lookforjoe True Classic

    Yeah, I guess so :D

    That pic does make it more apparent. I was assuming the feed could be worked around the return. I'll play with it a little more to set it close to the block instead of pushed out, since I have the time right now.
     
  4. Pete Whitstone

    Pete Whitstone True Classic

    Location:
    McKinney, TX
    There's not a great deal of room to work in there, that's for sure. Here's what mine ended up looking like. One thing you can do to save room is to switch from the silicone hose to a run of aluminum tubing in the tight areas, that cuts a quarter inch or more out of the overall diameter.

    IMG_0154.JPG

    IMG_0153.JPG

    I think the above 2 shots were an earlier configuration I tried. Pretty sure the shot below shows my current configuration, but it's been a year or two since I've been in there. Both configurations use Lancia thermostats, but there are 2 different styles as you can see.


    IMG_0134.JPG

    I do agree with Rodger and Darin, you're not really going to know what fits until the engine is in place. As I said, it is super-tight in there. To the point where you are trying to figure out how to get a screwdriver or small socket in there to tighten the hose clamps.

    Pete
     
  5. lookforjoe

    lookforjoe True Classic

    Thank you for adding reference pics, Pete.

    I really want to avoid the over-abundance of hose clamps and junctions. If I need to run a hard pipe up for the rad feed I can easily do that.

    I reworked the adaptor today after work. Needs cleanup of course. Straight out, so T/stat sits (almost) right up against the block and the starter. I realized it didn't matter, since the whole thing can drop out, or the t/stat cover can be removed from the underside. I'll leave it as is (once detailed) & see what happens when I put it in the car.

    [​IMG]

    Underside
    [​IMG]

    About 1 1/2" from extension to edge of ancillary housing. I'm assuming I can get a (feed) hose between these, even if that flange is real close to the frame.
    [​IMG]

    3" spacing should be enough for other hose. I want to attach the heater return to the underside of the extension close to the flange, unless there is a reason that won't work?

    [​IMG]

    Have a 20" line to use for the clutch feed, but need a 12x1.25 female to 10x1 male adaptor to make it work

    [​IMG]

    Only ones I have are 10x1 by 10x1 conversion flare.

    What is this type of flare on the clutch line? It's not a bubble flare (or is it?) or inverted...

    [​IMG]
     
    Rodger likes this.
  6. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    Looks really good. It looks like there should be enough room for the hot water supply to the radiator to go nicely by the smooth part of the extension. Adding the heater return to the underside of the pipe extension would be the perfect place to put it. Nice work.
     
  7. lookforjoe

    lookforjoe True Classic

    OK. I'm assuming that the heater connection I add should point straight down, not angled towards the frame? Looks like at least 5" drop to where the lines come out under the chassis, using Darwooodious's pics (thank you!) for reference

    [​IMG]
     
  8. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    I would go straight down. I also found that I had to cut off some of the heater pipe under the car as the stock pipe came too close to the subframe to make a comfortable connection.
     
  9. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    Now that I think about it, I would go straight down with the connection but angle it about 20-25 degrees toward passenger side. That way you can use a 90 degree hose to connect to the under car pipe and it will clear the hot line connection to the under car coolant pipe.

    Again, you may want to wait until you have the engine on the subframe and in the car to make the best choice in direction.
     
    lookforjoe and fiatmonkey like this.
  10. fiatmonkey

    fiatmonkey Tim Hoover

    Location:
    Redwood City, CA
    Love how many k series swap experts we have now!
     
    lookforjoe likes this.
  11. lookforjoe

    lookforjoe True Classic

    Thanks Rodger. There also needs to be a feed from the expansion tank to here, correct?
     
  12. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    Not sure I would qualify as an expert. Maybe if I can actually finish it and it runs. :)
     
  13. Rodger

    Rodger True Classic

    Location:
    Olympia, WA
    Yep. I would bring it in from the top.
     
  14. lookforjoe

    lookforjoe True Classic

    Just got back from the New Jersey meet. Was cloudy, then decided to rain around 6:30, so my wife was done :D

    This morning, I located the required adaptor to use my 20" hydraulic line.

    Right to left: 1/4" inverted flair tube nut (to replace stock 12x1.25 tube nut) into 1/4" (American, inverted)- 3/16" (American, inverted) then 3/16" inverted female to 3/16" 10x1 flare :D

    [​IMG]

    OK. Gonna add a NPT underside fitting to use for the heater return. Stock Recirc hose should work cut down a little.

    [​IMG]

    Repurposing the stock heater (hard) line for the expansion tank feed. So, I'll make a tube fitting to match the depth & shoulder in the stock housing, and weld it onto my extension so that the factory line oring seal does the job (barrel will be shoved up against the flange). This way, I can keep the soft line off the expansion tank reasonably short up top.

    [​IMG]

    Fitting will be bored to 1" ID with a step seat.
    [​IMG]

    I'll chop off the rad feed fitting & weld this Volvo one on facing straight back. I'll also chop off that Heater feed pipe & reattach it facing the front of the car underneath the extension housing. Housing Gasket # 18714-RAA-A01

    [​IMG]
     
    Last edited: Sep 10, 2018
  15. kmead

    kmead Old enough to know better

    Location:
    Michigan
    Leg bone is connected to the ankle bone...
    6EB47E1A-6DAF-4978-8EB1-C92BB6D1B013.jpeg

    Funny how so much of the job is just the plumbing and in this case there is a lot of plumbing.
     
    lookforjoe likes this.
  16. lookforjoe

    lookforjoe True Classic

    Had an hour or so this morning to work on the recirc & T/stat extension.

    With the K-Tuned housing, the stock recirc hose # ( 19504-RAA-A00 ) will work with the Volvo T/stat housing, shortend about an 1" each end

    [​IMG]

    Got the (heater) return pipe (which will be my expansion tank feed) junction sorted out in terms of offset & placement on the extension. New Oring # 91315-PNA-003

    [​IMG]

    Tomorrow I'll get it machined to 1" ID with a stepped seat and chamfered entry to match stock housing port, then I'll weld it, hog out the I/O ports & clean it all up.

    [​IMG]
     
    Last edited: Sep 10, 2018
    Rodger likes this.
  17. lookforjoe

    lookforjoe True Classic

    Looking at the upper rad feed port some more, I think I better angle the neck downhill on a fair angle to make sure I can use a 90º elbow hose off it & not run into whatever I do for the TB - plenum extension

    Pete's

    [​IMG]

    Rodger's

    [​IMG]

    I was thinking of welding it facing straight forward, but that would have been a mistake for sure. In many ways I think the housings on the K24 seem easier to repurpose than the K20 variants. My Rad neck is already lower and angled somewhat forward off the bat. The heater feed is also, in that vs. the head port like Rodger's, easier to cut, drop, & flip 180º, & run underneath the rad hose.

    [​IMG]
     
    Last edited: Jan 12, 2019
  18. lookforjoe

    lookforjoe True Classic

    Tim, do you have any measurements of the distance from the intake flange to the point where the intake goes into the firewall on these?

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    [​IMG]
     
  19. fiatmonkey

    fiatmonkey Tim Hoover

    Location:
    Redwood City, CA
    Hussein - I don't have measurements and that car is about 130 miles away. I do have the intake mani at my local shop in the other car (reversed direction) but could get some rough pics of how it doesn't fit going toward left :) I will see the car tomorrow.
     
  20. lookforjoe

    lookforjoe True Classic

    If you can measure the depth of that manifold for comparison, that would be great :)

    I'm trying to gauge how much space/depth I have to build my own plenum off the RBB runners, VS using a PRB intake (which I have coming). I want to keep the crankcase breather functional. The one built into the RBB intake is a good design, simiar in concept to the one Volvo has used on the RNC motors. Those don't have crankcase blowby issues even running twice stock boost, so it works. I don't like to VTA the crankcase, the smell bothers me. I don't know what the K20 does for crankcase breathing, since the intake doesn't have this setup on it:

    [​IMG]

    As it so happens, I went to the machine shop this morning to get the piece of aluminum stock turned for my TStat extension, and this was sitting on one of his carts :D

    RBC Intake
    [​IMG]

    So, now I know :D

    depth off flange: approx 10" - 8" runners
    [​IMG]

    over length of plenum: 13" to TB flange
    [​IMG]

    Plenum depth: approx 5"
    [​IMG]

    EDIT - which means approx 12x5x2", or 120 cu in., which is about 1970cc, so close to the K20 displacement. I need to shoot for 8" runners & 2.4l plenum.
     
    Last edited: Sep 13, 2018

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