Performing Honda K24a3/AST5 6spd Conversion

Discussion in 'Workshop Forum' started by lookforjoe, Aug 11, 2019.

  1. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    Hmmm, Expansion tube... By moving the expansion of the AC gas to the front trunk you may have to also move the pressure switches or install a binary switch for the fans/high pressure switch to operate. The metal body of the expansion tube may not get hot enough for the switch to operate due to it being made from metal and conducting heat away from the switch by the expanding gas. A possible solution is to move the switch closer to the condenser. In Bob Martin's AC install I just have the fans come on any time the AC is running with an interposing relay.

    As I look at all of the detailed pictures of this swap first off I would like to say, I love your hand made sketches, always impressive. On another note, I was always under the impression that the K20 and variant swaps were let's say rather simple and the Abarth Swap was more complicated. Looking at your build I come to the conclusion that all swaps are labour intensive, have several issues that need to be resolved by custom fabrication and at times have trade off's that must be accepted.

    Thanks for all of the pictures that explain the process of bringing this all together.

    TonyK.

    Grimsby Ontario Canada.
     
    kmead likes this.
  2. lookforjoe

    lookforjoe True Classic

    Hello Tony.

    Thanks for the comments & input. I'm happy with the progress overall, even if it is taking longer than I'd like :D As you said, compromises abound as one moves along with this type of thing. I'm trying to avoid too much scope-creep - so I'm going to leave the fusebox for now, besides adding the new feeder wire. If I get into reworking that, I'll loose a week I'm sure. There are other areas that need attention that I am also ignoring for now - the DS floor pan, the frunk inner strut walls, the dash layout, etc., etc., If I digress into those areas the swap won't be complete for another year. I really want to drive it before it's just too cold/wet to do so.

    I think the orifice tube will be OK - the two switches were previously clamped to the hard pipe going into the receiver/drier - the only question is whether the aluminum will heat sufficiently (compared to the steel pipe) to trigger the high pressure cutout & fan if/when the time comes. They will be mounted on the high side of the tube, I will have to see how it goes in practice & adjust if needed.

    I'm going to use the Honda EMS control circuit for the (AC) fan onset - the Volvo Fan Relay (laying in frunk) should work for that as it grounds through the ECU to set high/low speed.
     
  3. lookforjoe

    lookforjoe True Classic

    Tidied up the fuse/relay panel. Took awhile. Just have to attach the battery feed. Moved on the AC lines - remade the forward line that I had had made years ago when I did the condenser upgrade. They didn't crimp the beadlocks very well, and it leaked all the freon within a short time. Another reason I bought my own crimp tool.

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    pressure switches - have to wrap lines with butyl after I draw down the system to make sure there are no leaks

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    Then I hooked up the shifter cables, after installing the heat sheath, added some shrink wrap over the grommet. I see I haven't properly installed the square grommet ....

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    made sure they are not hanging below subframe

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    need a support here to lift them off the crossmember

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    OK clearance here

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    new teflon & steel washers for the ends

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    Using hairpins instead of the cotter pins, was able to access this with the intake piping and coolnt tank attached, which is good.

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    Last edited: Nov 27, 2019
    kmead, NEG and dllubin like this.
  4. lookforjoe

    lookforjoe True Classic

    Figured out a suitable placement for the charcoal canister, clear of the fuel lines, shifter cables, engine harness, etc.

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    bolted the right side from the trunk , since that section needs to be removable. really wanted the cannister tucked fully behind the left panel, but it is what it is.

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    Cut a section off the heater hose, it's always been pushed out against the AC tray and hoses. Has clearance now. Harness cleaned up for now.

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    Put coolant in it, and found a drip from the T/stat housing-to-adaptor seal :(

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    This is what the seal looks like (spare housing) - I'm assuming the flange is not true, otherwise it wouldn't be leaking. I'll have to pull it all apart & rework the flange. There isn't room to remove the t/stat without dropping the adaptor as well.

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    Last edited: Nov 28, 2019
  5. lookforjoe

    lookforjoe True Classic

    Had about an hour to look at the T/stat housing seal. Even though I can't get all the bolts out due to lack of starter motor clearance, could get two out & pull it away from the extension housing enough to add a gasket. I figured since the leak was so small, if I could resolve it with adding a gasket, that would save me several hours required to remove all the plumbing required to get the whole housing out. Fiat used a gasket and square cut seal for the X1/9 thermostat cover, so I don't feel bad about doing it this way.

    Used a spare housing to form a card gasket. Had to cut a slot in the upper rear (leftside) ear, to allow the gasket to slide inbetween the two housings and around the one bolt I couldn't remove.

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    Just had time to tighten it all down, so tomorrow I'll refill the coolant & see if it's resolved.

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  6. lookforjoe

    lookforjoe True Classic

    Removed the whole housing today -was able to remove it without removing the main pipe

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    The seal seems to have even clearance

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    I planed it again anyway - with 200 & then 400 grit

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    Shortend the one bolt that couldn't be removed with the starter in place, and the lower rear one that was just awkward to remove

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    Now I can remove just the T/stat for service

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    Put it all back together, and it still seeps. I think at this point I have stripped the threads in the aluminum adaptor housing. I'll have to remove it again & put helicoils in it. After that, I'm just going to apply HondaBond to the seal seat.
     
  7. lookforjoe

    lookforjoe True Classic

    Took the entire housing back out again. Installed M7x1 timeserts. This time I put a schmear of HondaBond on the Volvo seal as well, not wanting to do this anymore. Have to let the Hondabond set, so tomorrow I'll add coolant.

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    Hooked up the vacuum pump & drew it down, after 1/2 hour. Had to shut it down, so I'll have to see if I can get it to 30" tomorrow.

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  8. lookforjoe

    lookforjoe True Classic

    Added coolant today, and it is still seeping, very slow but still there. I need to get a mirror back there and confirm that it's 100% that junction & not something else with the housing itself. I have the spare one, so I may just swap it out, in case there is a stress crack I'm not seeing. Alternatively, I can try shaving the seal side of the housing so that the seal has deeper 'squish'.

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    I could also fill in the seal ridge with epoxy & sand it flat, then use just hondabond or a regular gasket. Unfortunately, I'm not going to be able to move on to other things until I fix this once & for all.
     
    Last edited: Dec 2, 2019
  9. lookforjoe

    lookforjoe True Classic

    Frustrating. Pretty sure the problem all along was the feed neck, not the housing seal. Leaking down the backside of the housing, and along the flange.

    Hose ID

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    Neck OD

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    Because of that, I had added a compression ring

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    The problem, I'm pretty sure was that the clamp I used was too wide, and was not actually sealing the hose to the tube (compression ring is set down to top barb on installed housing).

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    I rectified the clamp situation, but.. with the addition of the HondaBond the flange is seeping around the three bolts. So, I need to remove it again :D I think I will fill the seal groove on this one, and then use just HondaBond to seal it, works fine for the other flange.

    Also, with the cooling system full, I found the Water Outlet Passage I modified is also leaking where I welded it, so I need to remove & re-weld that.

    on top, left side

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    and on the right side, outer edge

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    I've ordered some new gaskets, and another housing in case I can't resolve this one. I'll take it all apart once I have all the parts. Relatively minor issues, really, just frustrating.

    To feel like I am moving forward, I started on the exhaust. Made SS plates that bolt to the existing hanger location & will have the hangers welded to them. Messed here also though - I cut up the (specially ordered 13" wide) trunk floor pan to make one of these by mistake. Now I have to fix that as well :(

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    Cat I bought was supposed to be 2.5" - of course it's not - it's also not 2.75"

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    so I took 2.5" V band flanges & had a recess cut that fit this, that way I can connect it to the 2.5" piping

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    Same for the 3" V band here- this one had no locating recesses, so I had it cut also. Much easier to weld with it located thus

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    Have to figure out how I'm going to route the exhaust, it's really tight. I need to find the rear grille to make sure I allow clearance off that - another thing I can't figure out where I stashed it for safe keeping :D
     
  10. lookforjoe

    lookforjoe True Classic

    Exhaust is going to go similar to Rodger's layout

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    Cat will be underneath, in space beween elbow and "U"
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    Going to try & cut the "U" on the left down to absolute minumum swept depth - it's about 5" or so now. I'd like the muffler to sit further leftwards. Muffler is # 11236, 4x9" oval, 14" body, 20" total.
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    Last edited: Dec 5, 2019
  11. stingray250

    stingray250 True Classic

    Location:
    Oz
  12. lookforjoe

    lookforjoe True Classic

  13. lookforjoe

    lookforjoe True Classic

    More playing around with layout.

    Flex will go here

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    "Rigid" liner style

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    It was suggested that a resonator would be a good idea. Probably a different muffler, also.

    I have Magnaflow resonator from my old Volvo setup. 14", 3" I/O. Not gonna work, too large. I remembered I have the full exhaust off the S40 AWD, so I cut the resonator off that.

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    13", 2.375" 1/O

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    Cut a little more off the left muffler inlet, and the 180º, cut the ends off the cat to allow it to sit as far to the left as possible. With that, the 13" resonator should fit along these lines - I'll cut some off the muffler outlet & add a section of curved pipe for the transition.

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    Need to start tacking all the vBands & flanges, so I can better test fit the cat & muffler properly. Too many variables at the moment.

    EDIT: Planed the mating surface of the spare T/Stat - found that it was off by a few thou from the outside to the center. Maybe that's enough to make a difference. I'll try this one with the seal. If that still leaks I'll fill the seal seat with epoxy, plane that and then use HondaBond.

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    Last edited: Dec 8, 2019 at 12:58 PM
  14. kmead

    kmead Old enough to know better

    Location:
    Michigan
    Great progress on all the fussy, painful tasks of making it a fully functioning sports car.

    Being the design engineer, fabricator and assembler is a tough set of tasks. I continue to be impressed at your ability and drive, I find myself struggling with a broken suspension bolt on our (new to us) Honda Element though buying better drill bits made it go much easier.

    Watching this, one easily understands why so many engine transplants end up unfinished. It is not easy nor clear how to solve the myriad of problems attendant in bringing all the mechanical systems together.

    In regards to the AC hoses and their proximity to the hinge, I would be tempted to create a steel shield going over the hoses and attached to the engine to ensure during the course of accelerating, decelerating and cornering the engine rocking won’t cause them to contact the hinge. I do see clearance but as the hose is fixed at both ends, as the engine moves the hose will tend to flex upwards towards the hinge. One could wait until seeing evidence of contact after getting the car into service to see if there is actually a need.

    73710C87-BA4B-4EFD-BB99-011D33A6A29A.jpeg C9E5E673-460C-4060-A4DD-4FF77AC135F9.jpeg

    The resonator arrangement looks a bit funky.
     
    lookforjoe likes this.
  15. lookforjoe

    lookforjoe True Classic

    Thanks Karl.

    I will need to keep an eye on the AC hoses - everything is close clearance. I also will likely make a belt guard to prevent a broken serpentine from eating the hoses - my Volvo has such an item.

    Yes, the resonator setup is funky. Won't be quite as ungainly when I get it properly aligned. I'm not sure it's worth buying a new one, as 12" seems the shortest, and that's only an inch less that what I have.

    I got the flanges tacked to the cat (at least 2" cut off each end of cat), the collector (mostly) welded to the headers, the vband and taper pipe & elbow tacked, and the flex tacked to the elbow.

    I've ordered a different chambered muffler (Stainless Works) after conversing with Rodger & Doug. Similar dimensions to the Magnaflow, slightly narrower - 4"x8"x14" oval, vs. 4"x9"x14" oval

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    inside the Volvo resonator, does not appear to be directional - I'm not sure which way it was oriented on the Volvo exhaust at this point.

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    I also installed the revised t/stat housing with a new Volvo gasket (# 8642620) - that alone is at least .030" thicker than the one I removed. Between that, and truing the (t/stat housing) flange, I'm hoping that is done now. Still waiting for the cylinder head water passage outlet gaskets, so I'll wait to add coolant again.
     
    Last edited: Dec 6, 2019
    kmead likes this.
  16. lookforjoe

    lookforjoe True Classic

    More work on the exhaust layout, with the Magnaflow. Using vbands wherever I can, to make it easier to swap out sections.

    getting it all aligned - set just below floor height. 180º is to be welded directly to muffler. No room for vBand there.

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    best clearnce I can manage off the left frame

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    This section won't change. I'll weld a new 180º section to the SW muffler when it comes., so I can swap out just the muffler. The resonator/tailpipe will be another removeable section, as long as I can make the VBand work with the tight offset.

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    Close clearances, but still clearance
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    cut off the right side mufler outlet section after this - otherwise the elbow sits too far right

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    resonator/tailpipe

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    Last edited: Dec 7, 2019 at 1:04 PM
    Mike Schofield likes this.
  17. Mike Schofield

    Mike Schofield True Classic

    Awesome set-up! I’ve been watching your thread for a while now and look forward to each update.
    I have a quick question about the v band clamps. I’m going to be installing a Vicks header and muffler soon and want to have the flex section to be removable from the header. Maybe a silly question but do the flanges need to be welded or are they “clamped” by the v band??
     
  18. lookforjoe

    lookforjoe True Classic

    Hello Mike. Thank you. The Vband flanges are welded to the components on either side - the clamp centers and joins the two flanges.
     
    Mike Schofield likes this.
  19. lookforjoe

    lookforjoe True Classic

    More work on the exhaust. Got the tailpipe/resonator laid out & tacked after some back & forth

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    After that, I started on the exhaust hanger setup - left side

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    welded heavy wahers to the muffler pins to prevent the hanger walking sideways

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    Right side

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    Clearances all seem ok - has enough wiggle to not hit the chassis

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    May need another hanger on the left front of the muffler or the rear side of the tailpipe, to keep the exhaust from rocking. The flex coupler allows a subtantial amount of tilt and twist.

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    Not much clearance off the planned floor pan - may have to raise it

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    RedTail (2.5"x3.5"x4") L exhaust tip - will be going on the SW chambered muffler/open tailpipe setup. I'm not expecting to leave the Magnaflow on.

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    Have to figure out the header support - going to cut the ear off the old manifold, make an brace from that to the block or the rear MWB mount bracket to the header collector, whichever works.

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    O2 sensor will go about here. Glad I didn't drill on the otherside where I was going to put it- that has insufficient clearance from the muffler now

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    WBO2 sensor will go around here, probably at 12 o'clock, if it will clear the floor OK, don't want it inline with the other O2

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    After that I started on the replacement water passage - cut the flanges off more cleanly than the previous. Heater pipe welded - that went better than last time also.

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    Rad hose outlet will be something like this - have to remove the old one first to confirm placement

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  20. lookforjoe

    lookforjoe True Classic

    Had about an hour today, so I removed the TB (to adjust the throttle plate return spring tension) and the water passage outlet. Test fitting the replacement housing to determine junction needed

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    Last edited: Dec 9, 2019 at 11:07 AM

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