Performing Honda K24a3/AST5 6spd Conversion


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Started removing all the electrics - so happy I made all this easy to unplug & remove

hopefully tomorrow I'll get the suspension off & drop the drivetrain


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Took the suspension and then the drivetrain out today. Didn't need the hoist - just using a floor jack and engine brace worked, which makes it easier


progressively added additional 4x4 blocks, raising the jacks as I when, that gave me enough clearance to get the engine out the right side



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Had a nice walk around a sculpture garden up above New Paltz this morning with the Mrs and a couple good friends - so nice to be outside, even if masks are required. When we got home I still had an hour of so of daylight, so I got the replacement subframe forward section welded (take II)

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No, no cracks in the primaries or at the collector.
I refer to the circled areas. The internet can play tricks, but those look like cracks to me. The one on #4 even has what appears to be a water line from expelled moisture during warmup. I could be wrong, but it's worth having a closer look before reassembly.
InkedHussein Primaries_LI.jpg


Paul Davock
I refer to the circled areas. The internet can play tricks, but those look like cracks to me. The one on #4 even has what appears to be a water line from expelled moisture during warmup. I could be wrong, but it's worth having a closer look before reassembly.
View attachment 38198
A die penetrant and developer kit will give a definite answer.


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I refer to the circled areas. The internet can play tricks, but those look like cracks to me. The one on #4 even has what appears to be a water line from expelled moisture during warmup. I could be wrong, but it's worth having a closer look before reassembly.
View attachment 38198
Gotcha -no, those are all heavy welds I ground back so it wouldn't be quite so fugly - I had to re-cut and add pie sections to reshape the header, once I had the motor in place - I had initially made the header about a year prior. When I got to this stage, I realized the header angle wasn't going to work, even with the allowable range of collector placement

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Did you notice the cracks in the header primaries? Do you purge your stainless welds? Without purging, that black chromium oxide that forms on the inside of the tube will lead to premature failure.
Thanks again for your observation - I looked at the header again - it does look like the #4 has a crack where I ground the weld down. I'll have to address that.

worked on the tunnel cover some more - drilled and added rivnuts to retain the cover, applied body caulk to the inner seams & top coated



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Rained all day today, so I worked in the garage - welded the header, welded the broken ear on the AC compressor, added a fixed nut to the forward compressor mount bracket and took the cylinder head off.

Since I measured leakage into the coolant system - I would say the issue is the liners - I had the block decked - but there is a ridge you can feel with your fingertip between 4&3 and 3&2. -you can see from the head that that is where the small coolant passage passes above & below the junction

liner / casting from my old Volvo for comparison....

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So turns out it's not as dire as I imagined - spoke with the machine shop, and he lent me one of the certified flat bar stock they use for final decking. I went over the block with 180 emery liberally lubricated with wd40 (after blocking off all the oil & water ports) and was able to get the ridges gone without any drama, just about 1/2 hour - 45 mins work. Should be able to assemble the motor after work tomorrow, I hope



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Today I started putting the engine back together - first I had to fit the KTuned elbow on the head, which required drilling & tapping an M6 hole, and tapping the EGR port off #4 to block that from the water housing (using 1/4" NPT sleeve & 1/8" NPT plug)

OEM head gasket this time, no more DNJ

head positioned on the dowels at each end

head torqued to spec in 3 stages, 29ft/lb, 90º, 90º. I reused the head bolts - no stretching on any of them checked as per the shop manual

Assembled the valve train & cams, (sealant applied to back edge of carrier that falls outside back of head)

Cam timing verified prior to installing the tensioner

marked chain links used to locate reference dots on cams & crank gear

Timing cover & mating surfaces all prepped, so tomorrow I can get the rest of it back together, then I'll pull the transaxle & install the 4.00:1 ring & pinion
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Got the front cover caulked & installed, & crank pulley torqued to 180ft/lb



Valves adjusted - .008" intake, .010" exhaust. All were too tight with the TSX cams I am using vs. the K20Z3 cams that came with the head


spark plugs - every listing I found says .044" gap - both Honda-packaged and NGK came with .032" gap


Transaxle removed to install the 4.00:1 ring and pinion


Gearsets transferred to the new countershaft - that was a PITA - had to press the gears off consecutively, starting from the small end.


Screen Shot 2020-11-15 at 9.50.15 AM.png

Also problem - new shaft is 35mm OD - found a thread on these here


original shaft is 40mm. Now I have to wait a week or so for a different bearing (91003-PPP-004) for the 35mm shaft. Annoying, as I specifically asked mFactory if my bearing would work with the new shaft two months ago :(


Still have to transfer the ring gear over- after I find the torque spec for the bolts (found it, 89ft/lb)


Also need the torque spec for the bearing captive bolt on the countershaft. EDIT (thanks Casey) - should be around 80ft/lb another post


EDIT again - found it in the RSX manual -

Screen Shot 2020-11-15 at 9.56.27 AM.png
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Back when I I had to mod the AST5 casing to take the RSX shift assembly -

The problem with that is the RSX assembly flange sits directly on top of the old bolt hole at the right in the pic. It's been seeping fluid for the past 600 miles, so I figured I should try to rectify that whilst the case is apart.

I cleaned & filled the old passages with JB Weld - I'll sand & plane them to make a seamless seat for the shaft assy

I also installed the 4.00:1 ring gear on the mFactory LSD today - bolts torqued to 89ft/lb

Also have to replace the PS inner CV boot - it's only two years old & about 600 miles in use

Ordered an EMPI 86-2124D boot - I've had good luck with them in terms of quality

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Not much today - just cleaned up (block sanded) the flange surface -I'm reasonably confident it should provide a decent mating surface now


Besides that, I did some clean & paint on a few brackets, and installed a new Volvo thermostat (31319608) in the housing



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Busy day today. Got the water pipes fitted & the tunnel cover in place


Put foam under the pipe where it presses against the floor


2 1.25" SS clamps per side - screwed into the remains of the stock standoff


Set into the existing trough clamps



Closed cell foam at each end -


Thinner closed cell foam in the cover to press against the pipes


Cover in place, AC one clamps installed. Just have to make the lower end caps to close them off


After that, I finished welding the subframe and also the crack in the rear crossmember reinforcement. With that out of the way, I got the drivetrain back in the bay - got this far before running out of light


Put 12x1.25 time-serts in the rear cross member



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Today I only had time to install the subframe, then re-assemble the suspension, brakes and axles on the car, and start getting the coolant hoses oriented


Outer CV's torqued to 31ft/lb, control arms set to normal ride height prior to final tightening.


I had the heater pipe terminate earlier than stock



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Excellent work! Where do those stainless coolant pipes come from? I made one set from mandrel bent pieces all welded together. That was a time consuming job!