Longitudinal
True Classic
Keep going. You'll find it.
Performing Honda K24a3/AST5 6spd Conversion
- Thread starter lookforjoe
- Start date
lookforjoe
True Classic
Nothing I can do about the no start until the sensors arrive. So, I worked on adding wiring to resolve the ECU fan switched power. I thought about moving the source, however I decided to add a (+15) junction to allow for other changes as needed.
I have also found that I never made an overall harness diagram for the EMS
splice from a main (+15) supply to the trunk
Volvo (+15) power supply junction will go here, next to (30) and (31) rails
junction housing riveted in place
(+15) supply feed to rail
blue-orange feed to ECU fan relay 86 moved from JPT 6pole pin 5 (30) to revised (+15) supply. 5 other spots in case I need to add circuits
I have also found that I never made an overall harness diagram for the EMS
splice from a main (+15) supply to the trunk
Volvo (+15) power supply junction will go here, next to (30) and (31) rails
junction housing riveted in place
(+15) supply feed to rail
blue-orange feed to ECU fan relay 86 moved from JPT 6pole pin 5 (30) to revised (+15) supply. 5 other spots in case I need to add circuits
Last edited:
lookforjoe
True Classic
I'll just put this here
Cam sensor pickups are fine
Cam sensor pickups are fine
lookforjoe
True Classic
When one of the Honda guys asked if I had checked the pulse wheel on the cams, I didn't make sense to me, since I didn't see any way it could possibly come loose, and there was no damage to the sensor. However, since it was clearly not the sensor at fault and it was still having a code for lack of signal, I figured I might as well pull the valve cover and just check for the heck of it. Just looking around I saw that the chain had too much slack in it and that was that.
So with my Honda experience, I've had a rusty cylinder bore to be addressed, I've had bad head gasket, I've had what is probably bad rings, and now a broken timing chain. Not feeling so happy with the whole Honda drivetrain thing right now. Even though it's probably my fault, since I didn't buy a Honda OEM timing chain, even then one would think that an aftermarket one would be good for more than 5,000 f****** miles
jimmyx
True Classic
I seem to remember that the Achilles heel on the K series is the poorly designed tensioners that can lead to chain failure. May not be the result of a defective chain? I think one of the aftermarket vendors has an upgraded unit to eliminate the issue, but I don't remember where I ran into the info originally. Info has got to be somewhere on one of the Honda forums.
jimmyx
True Classic
Found these so far...
skunk2.com
www.hybrid-racing.com
340-05-0002 - Skunk2 Racing
<div id="magicdomid18"><span class="author-6hOG0xVBAmdz">The Skunk2 Racing K-series Timing Chain Tensioner is the ultimate safeguard for all Honda K-series engines. The Pro Series Tensioner body is machined from high-quality steel which allows for greater
skunk2.com
Hybrid Racing K-Series Timing Chain Tensioner
Dual ratchet design. Tighter tolerances than OEM Honda chain tensioner. More durable than OEM unit. A must have if your using aftermarket cams and valve springs. Description Vehicle Fitment Technical Data Included Install Guide Despite being a fairly robust motor, k series engines have been...
www.hybrid-racing.com
lookforjoe
True Classic
Thanks for the suggestions!
I think in this case it's just low quality - besides the complete break there are several individual teeth broken, like the 2nd pic. I should have just splurged for the OEM chain. I know upgraded tensioners are required for high output/high rpm setups, however mine only runs to around 8K max, not the 9K+ of the K20 screamers.
Pic of setup from original install for reference - I hope that with those guides the chain couldn't have hacked up too much inside the case when it broke. It didn't make any mechanical crunchy noises when it died, just a 'pop'
Longitudinal
True Classic
I'm glad that you found it, but not so glad about what you found. With that being said, anything is better than a mystery that you can't solve.
Looking back, do you recall that the sound of the engine cranking wasn't right? IME, when an engine loses its timing belt/chain, cranking sounds irregular.
Looking back, do you recall that the sound of the engine cranking wasn't right? IME, when an engine loses its timing belt/chain, cranking sounds irregular.
lookforjoe
True Classic
I was so focused on the lack of rpm pulse, I really didn't pay attention to the engine note - I should have registered the cranking sound was off
kmead
Old enough to know better
Man that is such a bummer. A huge amount of work to resolve. When I first saw your pics I focused on the broken link sticking up and didn’t register the chain had a beginning and an end…
Tell me again how much better timing chains are than belts?
I recall companies lauding their change from timing belts to timing chains, the primary reason was for reliability and reduced maintenance costs. For some companies it was about better packaging of the engine as timing chains could be engineered into less space (which is true) allowing a wider engine or narrower bay depending on what was needed.
On forums today, particularly on BAT whenever a Fiat comes up for sale, people obsess over when was the last timing belt change. I always find this humorous given the relative ease of changing one, even on a difficult car, which vintage Fiats are about as simple as a change can be.
VW is the worst failure on this front going from cars which would rarely have failures to a guaranteed failure in an owners time with their cars.
Honda in general did a good job with their change with the K engines for normal use, like all things when run outside the intended performance envelope they aren’t as reliable.
Sorry to see this bite you, I have found that for certain things on Hondas one needs to spring for their OEM parts if one wants actual reliability (based on my experiences with the three Elements I do maintenance of).
Does this require an engine pull to resolve and find all the broken parts?
Tell me again how much better timing chains are than belts?
I recall companies lauding their change from timing belts to timing chains, the primary reason was for reliability and reduced maintenance costs. For some companies it was about better packaging of the engine as timing chains could be engineered into less space (which is true) allowing a wider engine or narrower bay depending on what was needed.
On forums today, particularly on BAT whenever a Fiat comes up for sale, people obsess over when was the last timing belt change. I always find this humorous given the relative ease of changing one, even on a difficult car, which vintage Fiats are about as simple as a change can be.
VW is the worst failure on this front going from cars which would rarely have failures to a guaranteed failure in an owners time with their cars.
Honda in general did a good job with their change with the K engines for normal use, like all things when run outside the intended performance envelope they aren’t as reliable.
Sorry to see this bite you, I have found that for certain things on Hondas one needs to spring for their OEM parts if one wants actual reliability (based on my experiences with the three Elements I do maintenance of).
Does this require an engine pull to resolve and find all the broken parts?
lookforjoe
True Classic
Yeah, hindsight is always 20/20.
I figured that since I wasn't going crazy with output or rev limit, a chain is a chain- after all - why would a company sell a kit that will fail within a few thousand miles, right?
I've ordered an OEM Honda chain & tensioner. I already have most of the other replacement items, since the block needs to be swapped out anyway. I just hope I don't have all kinds of carnage behind the cover & in the head. I cranked it over many times checking the test procedures.
Entire drivetrain has to come out, which means suspension removal, all trunk access & exhaust removal & everything else. Takes a solid day if I'm lucky to remove it all & find places to stow it. The engine cover & trunk need space to prevent any damage, I'm running out of that...
kmead
Old enough to know better
Sorry wasn’t dinging you on your choices, one would think a part intended for a 300000 mile capable engine would be good for at least half that.Yeah, hindsight is always 20/20.
I figured that since I wasn't going crazy with output or rev limit, a chain is a chain- after all - why would a company sell a kit that will fail within a few thousand miles, right?
I've ordered an OEM Honda chain & tensioner. I already have most of the other replacement items, since the block needs to be swapped out anyway. I just hope I don't have all kinds of carnage behind the cover & in the head. I cranked it over many times checking the test procedures.
Entire drivetrain has to come out, which means suspension removal, all trunk access & exhaust removal & everything else. Takes a solid day if I'm lucky to remove it all & find places to stow it. The engine cover & trunk need space to prevent any damage, I'm running out of that...
One has to wonder what caused it to fail with so few miles.
Longitudinal
True Classic
It's more work, but done less frequently. I used to be in the "belts, not chains" crowd, but I reformed. Typical engines run for 200k miles on their original chain. This includes K engines, even high-revving K20A2 engines. Guides might not last as long, but they're usually not a terrible job.
Part of me does miss a simple VW 8V non-interference engine with a belt that lasted 100k miles, but that's not how we do engines these days. I'm sure that somebody out there is still building a belt-timed engine, but I don't know who they are.
Longitudinal
True Classic
Found these so far...
340-05-0002 - Skunk2 Racing
<div id="magicdomid18"><span class="author-6hOG0xVBAmdz">The Skunk2 Racing K-series Timing Chain Tensioner is the ultimate safeguard for all Honda K-series engines. The Pro Series Tensioner body is machined from high-quality steel which allows for greater
Hybrid Racing K-Series Timing Chain Tensioner
Dual ratchet design. Tighter tolerances than OEM Honda chain tensioner. More durable than OEM unit. A must have if your using aftermarket cams and valve springs. Description Vehicle Fitment Technical Data Included Install Guide Despite being a fairly robust motor, k series engines have been...
Dear me... $315 for the HR unit. Cheap-ish insurance and all that, but man that's not a small amount of money. I don't know at what point people actually run into trouble with the factory tensioner, but I have seen OE K20 timing components beaten on pretty hard without consequences.
jimmyx
True Classic
Really hard to say, but the various Honda forums have lots of failures noted. One never knows because many of these forum posters are far from professionally trained mechanics, so you have to take a lot of it with a grain of salt. I'm certain more than a few failures have been self-induced. On the other hand the tensioner is a little complicated. It utilizes a ratchet, spring pressure, and oil pressure - all of which have their specific failure issues. The common thread through many of the posts were swapped cams, swapped oil pumps, cam sensor cel shortly before failure, low oil pressure reading at idle, and on and on. A chain can certainly be defective, but it's on the low tech scale of things so failing at 5,000 miles would be unusual even for an aftermarket part. It very well could have been the root cause, but to go through all the agro involved tearing this down and getting it back together, I wouldn't feel too comfortable until the actual cause of the failure is identified.
lookforjoe
True Classic
Not sure if I will be able to discern cause - the tensioner will have extended fully. I really feel it's the chain, there are multiple single links that are broken, I can't see what could possibly cause that besides the chain material. Would a weak tensioner cause 'chatter' that stresses the chain? I dunno - none of the Honda people I know have seen this specific failure before
Longitudinal
True Classic
Given the way the guides are set up, supporting a long length of the chain, I doubt there is any way to blame the tensioner short of the tensioner somehow overtensioning the chain--and that is a stretch, so to speak. I certainly don't see the tensioner allowing any harmonics to build up in the chain. You probably just got super unlucky with the chain you got. Are you planning on one of those upgraded tensioners when it all goes back together?