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Discussion Starter #1
Hey everyone,
Been a long few weeks... I just put a k20A type r motor I bought from a reputable shop in my car. Its the second one of these engines Ive had in it.
It has been running great all week.. the motor is super quiet and sounds amazing.
Tonight on my way home from work I hit the rev limiter and the motor died. After I parked I turned it over and it keeps turning over but no fire. Checked codes and it threw P1362 and P0340.
Am I dealing with a broken timing chain? Is it possible its a wiring/sensor issue or for sure a timing issue? I am having terrible luck with this car / these motors!
Any ideas would be greatly appreciated!
 

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Discussion Starter #2
So I pulled the valve cover really quick tonight. I didn't have proper lighting so it was quite dark but it looks like 3 rocker bearings blew up on the intake side. The bearing races split in half and there are needles in the head.
Is it possibly the needles got in the combustion chambers? The plugs looks very clean.
The timing chain seems tight. But it must be out of time in some way to make those codes I am thinking?
I am assuming I will be dealing with bent valves?
 

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Discussion Starter #3
Looked at it a little closer today...
First I tried to turn cams with a wrench.. first thing I noticed is both cams turn very easily. Then I quickly noticed the accessory belt was NOT turning - looked down and sure enough crank was not turning.
I then tried to turn the crank with a socket and ratchet and noticed the crank bolt was about 3/4 of a turn from being 'snug'. As soon as I tightened the bolt enough to actually turn the crank it started turning the cams with it. Then when I turned the cams the crank turned as well.
So in the end I'm assuming this was all caused by the crank bolt backing off? The motor definitely has compression now when I turn it over with the ratchet.. but it doesn't feel like it has full compression. The chain is timed perfectly on both cams but I did not check it at the crank (TDC) which I know I should have. I didn't realize the crank pulley bolt backing out would cause the timing sprocket to spin free of the crank? Obviously I am going to be dealing with a few bent valves as well as the rocker bearings or is it possible the valves will be OK? Anything else I should look for? Obviously I am going to pull the head either way and to make sure I get all the needle bearings out.
Only TWO roller rocker bearings broke both VTEC lobes on cylinder 2 and 4.
 

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Discussion Starter #4
Any ideas here?
Going to pull the motor on the weekend more than likely. Talked to someone at the local machine shop the other day and I was told the engine should be salvageable and wont cost too much to repair as long as its not damaged more than I think/know of at this point.
 

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if the rockers broke, you likely bend the valves. This also in turn means the crank sprocket moved on the crank. This will have destroyed it. You are looking into a complete rebuild, at least head, and crank sprocket. Depending on severity of the impact and amount of hard metal bits released, your pistons are also likely shot as well as are the liners. If so, have a look at the main bearings and crank journals.
In any case, I‘d take that engine apart.

Crank bolt coming loose is not that uncommon and happens mostly due to install error.
If the shaft and pulley are not absolutely clean and most common bolt torque is not up to spec, it will come lose. Many engines have been lost this way.
Folks often omit the use of a torque wrench and totally underestimate how tight 245 Nm is.
They make the bolt up by feel and believe it is tight, but it will be far from it.
 

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Discussion Starter #6
if the rockers broke, you likely bend the valves. This also in turn means the crank sprocket moved on the crank. This will have destroyed it. You are looking into a complete rebuild, at least head, and crank sprocket. Depending on severity of the impact and amount of hard metal bits released, your pistons are also likely shot as well as are the liners. If so, have a look at the main bearings and crank journals.
In any case, I‘d take that engine apart.

Crank bolt coming loose is not that uncommon and happens mostly due to install error.
If the shaft and pulley are not absolutely clean and most common bolt torque is not up to spec, it will come lose. Many engines have been lost this way.
Folks often omit the use of a torque wrench and totally underestimate how tight 245 Nm is.
They make the bolt up by feel and believe it is tight, but it will be far from it.
Thanks for the reply!
SO far I have pulled the motor from the car but have yet to disassemble it. Looking into the exhaust ports all the valves seem to be in good shape but I know you cant tell for sure just by looks. I know for sure I will be dealing with at least a few bent valves. The plugs pulled clean so I really hope nothing got into the combustion chambers at all. I am hoping to not have to do anything to the block aside from a new crank sprocket.
My biggest worry at this point is both piston damage and crank damage from the sprocket spinning on it. Does this usually damage the whole crank or just the sprocket?
 

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Discussion Starter #8
I would expect the key has sheared off the sprocket. The crank is much tougher .
Exactly what I am hoping for. I can use the sprocket from my spare motor but not the crank. I should have time to take it apart before the weekend (I hope).
Do you think there is any chance of any other damage that I haven't mentioned? Key thing for me is the block being fine. I can rebuild the head no problem for fairly cheap but I dont have any spare parts for the block other than the crank pulley, and sprocket.
For the record - A couple of months ago my original motor was severely overreved (not 100% sure but assuming this is what happened) and it completeley blew up the block. There are only two valves left in the head which are severely bent and you cant even see pistons in the block. They were in tiny pieces in the intake and exhaust and belly pan and a rod went right through the block. I then dropped 2k on this used motor from kijiji, just to put it in my car and have it run amazing for a week.. then this happened.
 

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Exactly what I am hoping for. I can use the sprocket from my spare motor but not the crank. I should have time to take it apart before the weekend (I hope).
Do you think there is any chance of any other damage that I haven't mentioned? Key thing for me is the block being fine. I can rebuild the head no problem for fairly cheap but I dont have any spare parts for the block other than the crank pulley, and sprocket.
For the record - A couple of months ago my original motor was severely overreved (not 100% sure but assuming this is what happened) and it completeley blew up the block. There are only two valves left in the head which are severely bent and you cant even see pistons in the block. They were in tiny pieces in the intake and exhaust and belly pan and a rod went right through the block. I then dropped 2k on this used motor from kijiji, just to put it in my car and have it run amazing for a week.. then this happened.
If you are running kpro you might want to drop the rev limit down. Love hearing these engines rev, and it can distract you from shifting before hitting redline. This might prevent future engine damage.
 

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Rebuilding/boring a block is not expensive. But you need new pistons as bore size increases. You will only know once you took the engine apart.
If the crank pulley bolt is tightened with the specified torque, the bolt and washer lubricated as specified in the manual and things were clean during install, it won't undo itself no matter how long and often you hit the rev limiter. Miss any of the above steps, and you ask for trouble. You were just unfortunate that someone did not follow the correct procedure on the engine you bought. The only way to over these engines is misshifting. Hit 2nd instead of 4th at 8500 rpm and you ask for trouble.
 

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Discussion Starter #11
I have my rev limit set to 8600 which is the same as the car the motor came in stock (Integra DC5 type R). I assumed that as long as everything was setup the same as stock everything should be OK. I may consider dropping it down to 8200 however. The car has a professional tune and the first k20a in it ran great for 90 000km before the over rev blew it up.
When I looked into new pistons for the new motor I will be in way deeper than the 2000$ I spent on the stock motor so I might as well just get another stock one? OEM 11.5-1 pistons run $500+ alone. Another thing is I DO NOT want to have to get a new tune when this one is back up and running so everything staying stock is preferable.
How will I know if the pistons are damaged? I assume there is a chance the valves cracked them when they made contact? I guess if any sort of debris got in there what so ever it would have torn up the cylinder walls which in turn would have taken out the rings?
Cheers

I have had one timing chain break on me in my life years ago in a Pontiac and all I had to do was pull the head and replace 9 bent valves - put the head back on and I was up and running for many more years. I hope this is that easy
 

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Discussion Starter #12
So now I am wondering how the key works for the timing gear?
I pulled the intake, water pump etc off today along with the timing cover. I did not have a pin small enough to keep the tensioner compressed so I did not remove the timing chain yet. The timing gear does not even have a key or a slot for a key from the looks of it? Nothing looks damaged or even worn at all. The only thing I can see is there is a key only on the backside of the gear? How hard is it to remove the oil pump chain and does it have to be synced at all?
 

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look closely at this video at 5.05 onwards. you can see the tiny notch on the crank the chain gear aligns to. if it is allowed to slide forward even a small bit, it can freely rotate on the crank. This is at least my suspicion on what happened to your engine.

 

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Discussion Starter #14
When I pull the oil pump chain/tensioner does it matter how the chain goes back on. Does it need to be aligned/timed in any way? I.E. wont cause vibrations etc?
 

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no, there is no timing requirement for the oil pump or its chain. There IS a timing requirement for the timing chain driving the cams. But I think you are aware of this and its consequences of getting it wrong by now :cool:
Do you have a suitable Acura RSX shop manual? It describes every step of disassembling and assembling each nut and bolt of the engine. I would not even attempt assembling an engine the first few times without that documentation at hand.
 

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Discussion Starter #16
I have access to alldata. I am a technician at a local Honda dealer but don't have access to most Acura stuff unfortunately.
 

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try the following keywords in google:
Acura RSX shop manual pdf

a few links from the top, you'll find a result on reddit. In there is a link.
 

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Discussion Starter #18
Thank you very much!
Tonight I removed the cams and rocker assembly from the severely damaged motor... was planning on pulling both heads but forgot the head studs are 12 point and i left my 12 points in my box at work
 
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