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I don't know how much of the NVH can be attributed to the style of engine mount vs the overall nature of a K24 with no balance shafts, but years ago there was something of an "a-ha!" moment on the board with respect to these through bolt, poly suspension bushing type of motor mounts. Going from Blackbird """Street""" mounts to Innovative Mounts with a tapered bushing took my car from "no way I can handle poly bushings" to "This is pretty nice!"
My other thought is that the Miata engine mounts are positioned pretty close to the crank centerline. I've long thought an additional third mount to the cylinder head, much like your standard torque arm setup seen in a lot of FWD cars, could go a long way towards taming engine movement without ridiculously stiff bushings. Soft bushings don't transmit NVH, and a longer lever arm further from the crank would let a soft bushing vibrate a few mm for NVH isolation, but resist larger movement from engine torque or hitting curbs.
That said, I'm pretty sure those LS rubber mounts that KPower sells still don't make people happy with the NVH, so maybe it just is what it is.
The rest of the engine looks nice and clean. There are a few scuffs in the block casting at the bottom of cylinder 4, around the oil squirter, but not show stoppers.
My original plan was to pull the crank and replace the timing plate.
Another option is to spend $600 with KPower for their "hybrid" timing cover, which would allow me to run the earlier nose-mounted crank trigger wheel. I'd also have to ask them to sell me just the windage tray, rather than an entire oiling system.
Pulling the crank seems daunting to me right now, even if I leave the head in place. I have to remove the oil pump and timing chain, remove the rods from the crank without smashing them into the head/valves... there's a whole plate holding the crank in, not individual main caps. But all it (should) cost me is a few Honda bolts and the trigger wheel, call it $200 or so.
Is it even going to be possible to pull this crank without removing the head?
You posted so fast I missed the second post about the windage tray. I was thinking that didn't look OEM and had to search this thread to check. I've seen a few homemade and aftermarket baffles/windage trays fail. Honestly, it makes me second guess putting any in mine, but I'm doing it anyways.
I figured there was no way Honda built a part with that many stress risers. KPI having sold this for an engine known to shake the car to bits and that they usually advise you to remove the balance shafts on seems to fall in line with other things I've read about them lately. I'd probably go back to stock if any aftermarket option you're considering looks similar to this. I can't stand it when designers put slots into parts for ease of bending in a press brake.
Sorry to see this, hopefully the rest of the damage is limited.
I don't know how much of the NVH can be attributed to the style of engine mount vs the overall nature of a K24 with no balance shafts, but years ago there was something of an "a-ha!" moment on the board with respect to these through bolt, poly suspension bushing type of motor mounts. Going from Blackbird """Street""" mounts to Innovative Mounts with a tapered bushing took my car from "no way I can handle poly bushings" to "This is pretty nice!"
My other thought is that the Miata engine mounts are positioned pretty close to the crank centerline. I've long thought an additional third mount to the cylinder head, much like your standard torque arm setup seen in a lot of FWD cars, could go a long way towards taming engine movement without ridiculously stiff bushings. Soft bushings don't transmit NVH, and a longer lever arm further from the crank would let a soft bushing vibrate a few mm for NVH isolation, but resist larger movement from engine torque or hitting curbs.
That said, I'm pretty sure those LS rubber mounts that KPower sells still don't make people happy with the NVH, so maybe it just is what it is.
That is a brilliant insight about the bushing face being part of the problem in the type of bushing we're discussing. If I could award you more than one cat, I would. I've applied this to the mental design I have for the new engine mounts.
You posted so fast I missed the second post about the windage tray. I was thinking that didn't look OEM and had to search this thread to check. I've seen a few homemade and aftermarket baffles/windage trays fail. Honestly, it makes me second guess putting any in mine, but I'm doing it anyways.
I figured there was no way Honda built a part with that many stress risers. KPI having sold this for an engine known to shake the car to bits and that they usually advise you to remove the balance shafts on seems to fall in line with other things I've read about them lately. I'd probably go back to stock if any aftermarket option you're considering looks similar to this. I can't stand it when designers put slots into parts for ease of bending in a press brake.
Sorry to see this, hopefully the rest of the damage is limited.
Other vendors modify the K20 windage tray by adding an extra "foot" that reaches over to a part of the oil pump support system. Not the clearest example, but see https://prlmotorsports.com/products/...p-diy-swap-kit
I could get a stock K20 windage tray and see how it would fit, but from other pics I've seen, it seems questionable to me.
Do I really need a windage tray at all? That would be the easy button.
That is a brilliant insight about the bushing face being part of the problem in the type of bushing we're discussing. If I could award you more than one cat, I would. I've applied this to the mental design I have for the new engine mounts.
STUPENDOUS!
Interesting! My SM mount definitely has poly touching the outer part of the mount like that, I'm only running one of them in their "hybrid" mount setup and NVH isn't too bad but this is an interesting discussion none the less.
It's not something I'd remove, especially if you want to follow through on the thread title.
It's not strictly "needed" but it helps separate the oil from the crankshaft and reduces windage losses. The oil will slosh around during hard driving and contact the crank, whipping it up and sapping horsepower and heating your oil, and possibly increasing oil consumption too. Think of it this way - Honda put that even in the versions of the K24 they put in a vehicle as high performance as a minivan, right? Best off keeping it even in a commuter car. For the amount of work involved to get back here it's well worth $200.
This is definitely a stupid question, but with so many vibration-induced failures why not add back the balance shaft? Or would that not reduce vibrations significantly?
It's not something I'd remove, especially if you want to follow through on the thread title.
It's not strictly "needed" but it helps separate the oil from the crankshaft and reduces windage losses. The oil will slosh around during hard driving and contact the crank, whipping it up and sapping horsepower and heating your oil, and possibly increasing oil consumption too. Think of it this way - Honda put that even in the versions of the K24 they put in a vehicle as high performance as a minivan, right? Best off keeping it even in a commuter car. For the amount of work involved to get back here it's well worth $200.
I think my approach will be to simply buy the stock K20 part and modify it myself as-needed for this particular use-case. It'll involve some trimming and welding, but I feel better about this approach than buying another stress-full KPower part.
PRL posted better pictures of their modified K20 windage tray in a news/blog post, separate from their product page.
This is definitely a stupid question, but with so many vibration-induced failures why not add back the balance shaft? Or would that not reduce vibrations significantly?
It would make the engine too tall to fit in the Miata, even with a non-stock subframe. The K24Z balance shafts (and I believe the K24A is the same) sit below the crank, which makes for a very, very tall engine.
ETA: After looking at a pic of the balance shaft/oil pump assembly, the problem is that the balance shafts would occupy the same space as the steering rack. It's not a subframe issue, it's steering rack issue. I think.
Balance shafts can't be added back in without guaranteed steering rack interference (and likely subframe interference).
I looked back on my engine build photos, and I found that I used the OEM Honda windage tray with my KPI pump. I didn't even realized a different one was offered by anyone, but it seems silly to move away from the nicely radiused OEM tray made via what appears to be a forming/stamping process.
I looked back on my engine build photos, and I found that I used the OEM Honda windage tray with my KPI pump. I didn't even realized a different one was offered by anyone, but it seems silly to move away from the nicely radiused OEM tray made via what appears to be a forming/stamping process.
Yeah, the problem is that that the K24Z motors have different mounting holes than the other K24 motors for the windage tray. I'm definitely going to buy an OE part and modify it.
Not much progress over the last week, I had a "zero" day on Saturday where I just collapsed on the couch and slept or zoned out to TV all day. I then spent most of my wrenching time Sunday re-mounting the motor to the engine stand, since two of the mounts I was using are going through the plate that holds the crank in place. These, of course, required bolts that were longer than anything I had on hand, and required me to remove one of the engine mounts. Thankfully I had some 1/2-13 threaded rod on hand, so I cut that in two and made what I needed. Now the only thing holding me back from removing the crank is clearing off my workbench so I can have a clean, flat area to put everything.
I went ahead and measured the crank end play, which was easily within spec.
I measured in several different places within the crank rotation and they were completely consistent. I didn't leverage the crank back and forth as indicated in the service manual, I just pulled with my fingers as far as it would go. I measured 0.008" of movement, consistently. Yes, the parallax error and such make this picture look more like 0.0085, but trust me, it's really 0.008.
Spec from the Service Manual - Standard (New): 0.0039-0.0138 in. Service Limit: 0.0177 in
So I'm right in the sweet spot of the Standard measurement. Nice.
Not much of an update. I guess I should also mention that I finally got a set of dollies to put the car on, so I was able to roll it out of the way and create some more room near the workbench. Small garages suck! I went with the Summit brand ones and I'm happy with them. Nice thick steel, casters seem robust. We'll see how they hold up to use.
Yeah, the problem is that that the K24Z motors have different mounting holes than the other K24 motors for the windage tray. I'm definitely going to buy an OE part and modify it.
I keep doing double takes with some of your pics, and then remember that it's a K24Z. I often wonder if going with the K24A helped me dodge some of these bullets....
F'in KPI. You know, after some traffic on the K-swap FB group and some self-reflection, I was starting to feel that maybe I had been a little harsh on KPower. This morning though (and I literally just found this, so I am a bit fired up), I decided I'm back on the pissed-off bandwagon.
7/17, emailed KPI, asked about some replacement parts I couldn't find on their website, namely a clutch friction disk and the bearing/piston for their concentric slave cylinder.
7/23, emailed KPI again, asking if they had seen my previous email.
7/23, receive an email from KPI with a link to their product page for the friction disk and asking for more details about my particular slave cylinder.
7/23, respond with details.
7/23, receive affirmation of response, part and price info from KPI. They ask for shipping address and phone number in order to create a custom invoice.
7/23, respond with requested information.
7/25, send follow-up, indicating I'm ready to pay as soon as I receive the invoice.
And then today...
I decide I may as well just order the friction disk since it's available for order on the website and my piston is probably fine. After adding the friction disk to my cart, I start browsing their site to make sure there's nothing else that I could possibly need from them. At which point I see that they have a V2 of their clutch hydraulic kit. At the bottom of the description, I find "If you purchased an original KPower release bearing that's still working well but you would like to upgrade, please contact us for a special discount. And if you have an original unit that has failed prematurely, we'd also like to help"
Why in the holy flying hell wouldn't the person responding to my emails at least say "Hey, did you know we have a V2 of this product?", and "Instead of replacing this piston, why don't you take advantage of our discount on this upgraded part?"
I mean, the odd bouncing between taking days to reply to me (or not replying at all) and exchanging multiple messages in one day is frustrating, but this really takes the cake.
I have some questions about the effectiveness of their "secondary bleeder line and port", as well as the (damn I'm angry, I can't come up with the right word) wise-ness of having so many hydraulic fittings in a row, hanging off of one port. But damn, it would be nice to have gotten a heads-up.
It's amazing how much goodwill they've burned through. I'd say it's wild that they have managed to keep going, but I've seen far worse and less polished operations manage to soldier on and still somehow sucker more enthusiasts in.
I shouldn't problem-solve when angry, but given that I've had some really weird clutch wear with my current setup, I think it makes sense to try something different.
I'll have to order a 6-speed input shaft cover since I think I must have recycled mine when I did the initial swap. And I'll have to order a stock clutch master cylinder.
I reached out to Cameron at ETM this morning on Facebook, got a response back faster than I thought possible, and he had my order boxed up and ready to ship within minutes. I'm looking forward to seeing how this turns out.
That looks really similar to a GM/corvette internal slave. They supposedly "self bleed" after the initial near impossible to reach bleeder is used, the rest of the air travels up the fluid line into the reservoir between pumps. They almost never work, at least in my experience, and there's a million aftermarket solutions similar to KPI's product to aid in bleeding. The dual fitting positioned in the high point, so air should travel up the 2nd line to the bleed valve.
If you imagine KPI's two lines going into a channel machined into the cast slave cylinder body, it would basically look like a C5 slave. That channel is just made of fittings in KPI's product. What it's survival rate is with the K24's vibration issues is another story.
Not really trying to stand behind KPI, but I think their shop was at RA gridlife this weekend, or at least maybe their customer service/tech line. Would be helpful if they posted on their website or social media when they'll be out of the shop. That's what we do at least.
That looks really similar to a GM/corvette internal slave. They supposedly "self bleed" after the initial near impossible to reach bleeder is used, the rest of the air travels up the fluid line into the reservoir between pumps. They almost never work, at least in my experience, and there's a million aftermarket solutions similar to KPI's product to aid in bleeding. The dual fitting positioned in the high point, so air should travel up the 2nd line to the bleed valve.
If you imagine KPI's two lines going into a channel machined into the cast slave cylinder body, it would basically look like a C5 slave. That channel is just made of fittings in KPI's product. What it's survival rate is with the K24's vibration issues is another story.
Not really trying to stand behind KPI, but I think their shop was at RA gridlife this weekend, or at least maybe their customer service/tech line. Would be helpful if they posted on their website or social media when they'll be out of the shop. That's what we do at least.
I can answer some of these questions. So far I think I have more k-swap users than I do ecotec users with the slave kit. Haven’t had one vibrate itself apart yet and to my knowledge no failures in the field. My personal prototype is still going strong and has hundreds of endurance racing hours on it.
regarding the bleed procedure, as long as you can follow the instructions you won’t have an issue. Feel free to send me an email at info@ecotecmiata.ca or FBM
Yeah just to clarify, it's a lot harder to hand bleed the vette slaves (if you forget to before installing the trans), since you have to drop the subframe, trans, torque tube, and THEN the bellhousing/slave. That's all my shop has experience on, and only a handful of those. Follow the bleed video Cameron has on the ecotec site and it's pretty easy.
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