Preparing For Honda K24a3/AST5 6spd Conversion

lookforjoe

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



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

 

kmead

Old enough to know better
There is another bolt hole on the back of the block I can utilize



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

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.
 

lookforjoe

True Classic
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.
That's the plan, so the bracket is triangulated.
 

kmead

Old enough to know better
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.
 
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lookforjoe

True Classic
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.
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

Old enough to know better
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.
I’ve been wrong before.

Car looks great.

75E0CA54-1773-4762-B686-A41A8C564914.jpeg
 
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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.





 

kmead

Old enough to know better
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?
 

lookforjoe

True Classic
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?
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.
 
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kmead

Old enough to know better
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. 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.
So without the balance shafts will the K24 end up rougher still due to the great reciprocating mass?
 

lookforjoe

True Classic
So without the balance shafts will the K24 end up rougher still due to the great reciprocating mass?
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.
 

Michael Albers

Daily Driver
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.
 

Michael Albers

Daily Driver
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.
 

lookforjoe

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

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.







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.



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






removed the pump



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



 
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Michael Albers

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

Michael Albers

Daily Driver
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.
 
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