i posted this up on CTRO forum a few months ago - explains all the different blocks that can be used:
Credit to Hybrid Racing and K-series.com, I have made a few minor updates in red to make things relevant to the UK market
K24a1
Honda CRV comes in with 9.6:1 compression and 2.4 liters of displacement. The motor is rated at 160hp at 6000rpm and 162lbs-ft at 3600 rpm. This motor does not use the conventional VTEC mechanism from the earlier B series motors but does have VTC. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lobe. This motor has no VTEC mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening. It also has smaller ports than the Type S and Type R. The motor also comes with a 5 speed transmission instead of the 6 speed and has no LSD.
K24a2
The Acura TSX (
EUDM Accord Type S) comes in with 10.5:1 compression and 2.4 liters of displacement. The motor is rated at 200hp at 6800rpm and 166lbs-ft at 4500rpm. This motor uses the conventional VTEC mechanism as the older B series motors but with the addition of VTC. This motor uses a drive by wire throttle and has EGR castings on the manifold. This motor comes with a 6 speed transmission and no LSD. If using k24a2 block and head, please note that you will need to block off the EGR port when you swap the intake manifold with the K20.
K24a4
The Honda Element and Accord come in with 9.7:1 compression and 2.4 liters of displacement. The motor is rated at 160hp at 5500rpm and 161lbs-ft at 4500rpm. This motor does not use the conventional VTEC mechanism from the earlier B series motors but does have VTC. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lobe. This motor has no vtec mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening. It also has smaller ports than the Type S and Type R. The motor also comes with a 5 speed transmission instead of the 6 speed and has no LSD. If using a K24a4 block the pistons will need to be swapped with aftermarket or a1, a2 pistons to avoid valve to piston contact.
EDIT Not listed in the original article is the the 2009+ K24z3 (found in the newer Acura TSX and Honda Accord Type S). This is the pick of the crop IMO due to 11:1CR Pistons (just like the K20) and stronger rods. This engine makes 201hp and 172lbs in stock trim. :thumbup:
How to build a 'frank'
First, make sure you have all the necessary parts to perform this motor build. There are many parts that are interchangeable from the K20 motor to the K24 motor. Some of these parts include crank pulley, water pump, oil pan and pickup. I will keep you informed of which ones I used and why as we get to those parts of the install. Some things you need that are not interchangeable are the timing chain, timing chain cover, and dipstick from the K24. You will also need a service manual for one of the K24 motors or K20A2 for all the torque specs.
Start off by draining all fluids out of the motor and bolt it to an engine stand. You can then start to disassemble the motor. I would start by taking off the valve cover and timing chain cover. Next, remove the k24 oil pan and oil pump if you want to use the aluminum oil pan and pump from the K20. (Note: If using the K20 oil pan, you will need the longer oil pan 10mm bolts.) The K24 uses a pair of balance shafts in the oil pump and an abbreviated windage tray that just adds extra weight to the setup so we will be using the K20 parts for this.
Note the RRC oil pump kit is a direct fit!
If using the k20 oil pump you will also need to use the k20 oil pump chain. If you look in the picture below you can see the differences in the two. The chain on top is for the k24 and is a little shorter. The k24 chain also has 3 darker links to line up the balance shafts with the crank.
Once you have the block disassembled you will need to get a machine shop to drill a hole out for the k20 oil cooler setup. To run this setup you will also need a k20 water pump housing as it is different than the k24. The K20 water pump housing incorporates a coolant port for the oil cooler that the K24 housing does not. (Note: When removing parts with Hondabond on them, you will need to clean the Hondabond off both surfaces to create a clean and flat surface to reapply Hondabond.)
Once you have your bottom end prepped, you can begin to put the cylinder head on. Remember that you will need a K24 head gasket due to the 87mm bore size. We opted to use a Cometic K24 head gasket for our project. Instead of using the stock cylinder head bolts we bought a Golden Eagle head stud kit for our motor. You may use the stock head bolts but before doing so you will need to measure them and make sure they are not out of spec. Measure the bolt in 4 different places along the threads and if any diameter is less than 10.6mm (0.42 in) replace the cylinder head bolt. If using aftermarket head studs please read and follow their instructions carefully as they will most likely be different than the OEM instructions. After you torque the head down you can install the rocker arm assembly, cams, and caps. Be sure to use some type of assembly lube when installing the cams so there is some lubrication on the cams when first turning the motor over instead of the bare metals rubbing against one another. You can either install the cam gears to the camshafts before or after installation.
After the head is attached to the block you will need to move the cams and crank to top dead center. After this is done you can install the K24 Timing chain which should have 3 darker links than the others. The two dark links that are closest together line up with the marks on the top of the cam gears and the other dark link lines up with the dot on the bottom gear attached to the crank. Once you have these lined up you can install the chain guides and tensioner. When this is completed, you will need to put the crank position sensor plate on and can then start to put the K24 timing chain cover back on with Hondabond in the necessary places. The crank pulley can now be put on and torque to the proper specifications.
The last thing you will need to do before installing the motor is to attatch your K20a2 engine harness to your setup. Every plug should fit to a connector on the motor except for the crank position sensor. For this you will need the clip the crank position sensor plug off your K24 harness and solder it to your K20a2 harness in place of the stock plug.
Always remember to check the motor for all fluids before attempting to crank or turn the motor over, for ex. Oil, coolant, trans. fluid etc.
Final note: a CRV side mount is needed in an EP chassis and your header might need adjusting to clear the front ARB, as the cylinder head will sit 17mm taller on the new block.
