I had planned to post a different kind of update this morning, but I got distracted by all that clutch stuff.

I finally cleared off my workbench so I could pull the crank out of the K motor. I don't know that the Pig Mat is necessary, but it certainly looks nice and keeps the oil from puddling everywhere.



The workbench was clear for less than 24 hours before I loaded it down with parts. With the exception of the crank trigger wheel and a bit of the block at the bottom of cylinder 4, everything looks very, very clean. I measured the connecting rod end play before I removed everything, 1 and 4 were 0.2mm, 2 and 3 were a touch larger at 0.25mm. Yes, I used metric here because I actually have a set of metric feeler gages, whereas I don't have metric dial test indicators. The book calls out a Standard (New) measurement from 0.15-0.35mm play, so these are excellent.



I won't subject you to individual pictures of the crank journals, but suffice to say they are shiny and show no signs of any junk going through them.

The main bearings look fantastic. What's really interesting to me is that these have some tooth to them. Not in a scratched way, but in a way that makes me think they're designed to hold oil. Where the journals and rod bearings feel slick, these have just a tiny touch of traction to them.


Here is the extent of the damage to the block. Thank goodness this was just a piece of sheet metal flying around, it had a lot less energy than the bolt that destroyed the last engine. There are a couple of ridges that got kicked up right at the bottom of the cylinder bore, but I'm inclined to leave them there. The piston skirt does come down past this edge, but I think there's plenty of clearance there and any filing or deburing I would do here would create debris that I just don't want in my engine.


Question for the hive-mind, since I am but a humble cog who knows nothing:

My rod end caps look like this underneath the bearing. The bearings clearly have not spun, but there seem to be wear marks underneath them. It's not discoloration, these marks can be felt with a fingertip or nail.

The bearing itself looks and feels fine.

The back of the bearing though, looks funky.


Can anyone teach me what is going on here?

 

most random engine failure ever

 

This is the second engine failure that's taken out the crank position trigger wheel. The first time it was a stubby M8 bolt that got thrown around by the crank, took out the trigger wheel, and exited the block. The second time it was just a little piece of sheet metal that got thrown around and hit things. The hard steel bolt wasn't a survivable FOD failure, but if the trigger wheel wasn't on the crank, this failure would have just resulted in a bunch of debris in my oil pan and a very loose windage tray.

On the one hand, I'm glad the engine stopped because it made me find the windage tray destruction before that went too far, but on the other... actually, this was probably the best outcome. If I had driven this until the windage tray fell off completely or bounced into the crank, I think I would have lost an engine. I only had to pull the engine tear it down so I could pull the crank. That's not so bad. And I found clutch issues which lead me to update to a newer release cylinder design. And I'm going to replace the windage tray to address some shortcomings there.

There's a bunch of upside to this failure, but it's easy to forget about that when I think about the money and time I'm spending on it.

 

You are one patient dude.

Wish I could weigh in on the rod bearing cap question but I can't. Curious to see what you find about it, though. Maybe @emilio700 has seen something like it before?

 

Fretting?
https://www.mahle-aftermarket.com/me...s-brochure.pdf

 

Beyond me, sorry

 

I forwarded the images to my team of powertrain nerds at work. Admittedly some are out of office and haven't had a chance to respond, but...

Majority (including myself) are a little stumped given your "the bearings clearly have not spun" comment, but the general consensus I've got is "I've not seen that unless the bearing had relative movement to the rod (aka spun or loose)", which aligns to the Mahle report and fretting comments. The darkened discoloration on the bearing surface shows that it was getting hot.

 

Possibly of import: were both bearing halves seated squarely inside the rod/cap when you removed it? Or to put it better, the bearing wasn't rotated at all? Obviously if they were, I'd think it'd have been mentioned, but still gotta ask.

 

God I love this place, thank you all for your input.
Wow, I'd never expect this sort of service, thank you! As I know nothing, let's go back and re-examine that statement. When I pulled the rod caps off, in two cases the bearing stayed attached to the crank and in two cases they came off with the rod cap. In all cases, the bearing halves were still perfectly aligned with the cap-to-rod split, so I thought that there had been no rotation of the bearing within the bore of the big-end of the rod. I'll post up pics of the rod journals on the crank, but they look beautiful to my untrained eye - no marks, just smooth metal. This lead me to believe that the crank was spinning freely from the bearing. There is no glitter in the oil - I didn't send it out for analysis and I'm not sure if the dregs that have collected in the oil pan after I drained it would give reliable oil analysis results, but we can discuss that.

Reading section 10 "Insufficient Crush" of the Mahle document (the only place I found "fretting" described in there), this makes sense to me as the possible cause of these marks. Maybe I just caught it early as a result of the other failures, but it seems like something is going on here. There are no ridges or pock marks on the rods or back of the bearings, just discoloration that you see there. The idea of the bearing not being tight enough and having some elasticity that rubs it against the big end journal and leaves these marks seems logical.

The two that came out with the rod caps, absolutely. The two that stayed with the crank, I'd say yes in that the edges were aligned with the rod/cap split and when I was measuring the rod play, there were no tight spots like it had shifted sideways off the cap.

So now what? Honda has left me all sorts of clues to what they thought the measurements of the crank and rod diameters were when they manufactured this engine. Do I use their shop manual to select new bearings for these rods using their tables and formulas? Do I pull the head, remove the rod/piston, and have a shop select and install the right bearings? Do I pull the head and replace the rod/piston with aftermarket? Do put it all back together really carefully and just hope for the best?

Your insights are highly valued.

 

I have only rebuilt a couple of engines for Lemons racing... so verify anything I recommend. If you want it perfect, take it to a reputable machine shop.

Do you have good c-type micrometer to measure if the crank journal diameter is in spec and uniform? I think you need three measurements in two orientations if I remember right. If in spec you could just order standard sized bearings and check clearances with plastigauge. You could also measure the rod ends as well. If not in spec, you need a machine shop to grind the journals to the next bearing size.

Is it possible the rod caps were installed in the incorrect orientation or on the incorrect rod? Those rod ends look like they were scored and then cracked apart as part of the manufacturing process, so they are not interchangeable.

Apologies if you know this already.

 

I spent the weekend hunched over a keyboard doing the work that puts food on my table and car parts in my garage.

I did measure the rod journals and they are freaking spot-on.

I have not measured the rod bores.

I will be ordering some King bearings, because frankly their website helped me a lot, whereas ACL's website, which helped me some, was not confidence-inspiring.

Planning to buy from Kseriesparts.com if anyone has had good experience with them. They show the bearings as in stock, with an actual stock count. Or at least a stock count that's believable.

I plan to buy CR4542XPCSTDX unless someone here suggests otherwise. These are the STDX size, which increases the bearing ID by 0.0005" for extra oil film thickness. See https://www.llracing.eu/difference-b...-stdx-bearings

I am shooting from the hip a bit here, but it's a counter-swing to my desire to "get to the root of the problem", which would probably just run me in circles. I do not know the rod bore dimension. I honestly don't know how it would help, other than to show me that it's not way off factory spec. There's no damage evident that would suggest that it's been "wallered out" beyond Honda's tight specs. I mean jeeze, the tolerances on this engine are specified in 0.0001"s. The stock bearings come in steps of (IIRC) 0.0004".

For the $65 or so bucks it'll take to get the King bearings to my door, I'm going to buy them soon and just hope when I assemble it all it's fine.

In other news, the order I placed with KPower last Monday has not shipped yet and I've received no updates from them. Polite inquiry sent. Eyes rolled. Everything else I ordered last weekend/Monday has arrived already.

I napped for a couple hours this morning, but otherwise I'm running on caffeine, adrenaline, and oh look, shiny! Back to my usual level of insanity soon.

 

Those King main/rod bearings are the same ones I run. I believe I also sourced from Kseriesparts, as well as most of my engine internals. No issues with them over a half dozen orders.
I personally like the King bearings better than the ACL, if for no other reason then the packaging. King shrink wraps all their bearings together and tosses them into a cardboard box. I've sent back bearings that had obvious wear marks from the bearings rubbing against each other during shipping. King sends theirs with the bearings protected in individual plastic trays that doesn't allow any chance of damage.

Don't forget your thrust bearings while your in there, OE's are like $15... pretty sure Kseries parts carries them as well.

FWIW, first time I rebuilt my(stock) motor I threw standard bearings in all locations, just plastiguaging to ensure nothing was miles off. Honda's bearing sizing with the numbers and colors gave me a headache trying to interpret so I skipped it. That motor never had a bearing issue.

 

Wonderful feedback, thank you and have a cat!

I was planning on keeping my thrust bearings, my crank play measurements showed that I was on the new side of the tolerance. I'd almost rather keep the stock bearings in place rather than possibly cause trouble by replacing them with new, even if it's only $15 for the parts. Is there a good reason to change them now? I'm also planning to keep the stock main bearings.

 

You're in that deep, I'd replace everything. It's less then $150 for every bearing in the bottom end, why take a chance on reusing old bearings? Plastiguage as you go for peace of mind on clearances, but I would just about guarantee standard size bearings will drop into your motor without issue.

 

Well, that was an easy sell. I ordered all the bearings. KSP only had the ACL thrust bearings in stock, but they say they're the only thing they use in their builds, so good enough.

Looking forward to receiving the parts.

I did get a response from KPower yesterday. My order should be here this week. Woot.

I flopped the Honda K20 windage tray onto the ... main bearing support structure? not sure what you call the lower half of the block. Only two bolt holes line up. The one in the top-center isn't actually a bolt hole, it's some funky oil passage that needs to be blocked off by a special little KPower part. I have to overthink about how to attach this.

 

This stuff is scary. It’s Motorcraft ZC30A, silicone gasket remover.

In earlier pictures, you can see how much Permatex Ultra Black was left on here. It scraped off with very little effort.

I was very careful to wear a respirator for organic vapors and some good gloves. I’m glad I did. Scary good stuff.



In other news, the rod bearings I ordered yesterday arrived today. The rest of the bearings arrive in a day or two. Fast shipping.

 

We stock that stuff at my work, pretty incredible how effective it is.

On the engine I recently put together for my car, I hit the timing cover with some of that stuff and let it soak for a couple minutes. Couldn't find my scraper at the time so I took the closest item I could find, a shop rag, and removed the remaining silicone without any effort I'm surprised the stuff is legal for sale in CA to be honest.

Excited to see this thing start coming back together.

 

I have progress to share, but I have to actually do work today and earn my salary. Or something.

I was also surprised that this Motorcraft stuff is sold in CA. I actually went over the MSDS and from what I can see, one of its major components is some kind of citrus-based cleaner. Apparently the same stuff used for facial peels. Very surprising. I think a lot of the warnings must come from the fact that they're using propane as the propellant. There's also one other chemical that I wasn't really able to figure out its purpose, so maybe that's what's doing the job. Anyhow, I haven't blown myself up yet and my liver and kidneys haven't left my body, so I'm OK.

The bearings are in, I've measured the main bearing clearances using plastigage and measured the rod bores and rod journals (crank) using my neighbor the professional machinist. Let me just say that these are some very fine tolerances. I haven't plastigage'd the rod bearing clearances, which I'll do because in my bearing-clearance math I assumed that the bearings were exactly the thickness that King said they are.

My rod bearing clearances (calculated) are 0.0017-0.0019"
My main bearing clearances (plastigage) are all greater than 0.0015" and no more than 0.0020"

Going off of the Driven Oil recommendation list (https://www.drivenracingoil.com.au/p...ecommendations) I will start with a 5W-30 oil. Probably not a Driven oil, but something high-quality that I won't feel bad about replacing after very little use.

 

I made a bunch of progress today, I hope.

First up was to pull the welder out from behind a bunch of car parts and weld two new mounting tabs to the Honda K20 windage tray.

I made the tabs last night in a fit of Friday-night fabrication.



Not great welding, but hopefully good enough. Welded both sides of the tray, so I’m really hoping this holds.

So the windage tray is held on by two M6 bolts at the flywheel end and these two tabs at the crank end. It feels very solid.


I also took the time to Plastigauge the rod bearings, no surprises there, everything looked like 0.002” - there’s no discerning tenths with Plastigauge, so my calculations of 0.0019” seem validated.

I spent some time cleaning RTV out of the bolt holes for the oil pan and lower block half. That was tedious. I also ran a thread chaser through the oil pan bolt holes. Worthwhile, but tedious.

Also on the agenda was plugging the extra oil hole in the lower block half. KPower does this with a plug that’s held in place with a convenient M10 bolt. That won’t fit under the K20 windage tray, so I drilled the port just a smidge bigger and tapped it for a 1/8 NPT plug. I cleaned the hell out of this port to make sure no shavings remained, then applied blue Loctite and screwed in the plug. Job done.



Finally, I turned the engine over on the stand and sprayed everything inside with WD40. Lots of WD40. It was absolutely raining oil into my drip tray. Hopefully any crap that has fallen into the engine is flushed out.

Tomorrow the reassembly begins! I’m interested to see if I have to modify the windage tray any further - I’ve read that it might need some trimming.

 

Job done.

It’s 10:30 at night, but the bottom end is back together.



And the trigger wheel clears the modified windage tray. I need to hook up the timing chain so I can turn the motor over and check for rod bolt clearance.



God I hope this engine lives a long time!