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I don't know that I'd go that far, but I'd say that I've made a shifter with an inconvenient reverse lock-out (that could also be used to lock out 1-2).
Originally Posted by curly
The rubber plate doesn't seal against the shifter well, especially once it wears out a little, allowing fumes and heat in. The rubber boot that is supposed to replace the stock lower boot is a round boot on a squarish/round shaft, so they don't seal well and I've had a few leak turret oil in the interior. Mid race or mid race weekend trans swaps are that much more annoying because of the one bolt that requires a wrench. Once removed, you need to brake clean and scotch brite both the trans and shifter and RTV it on to seal. The side bolts and detent spring are a constant balance of too tight or too loose, allowing play when loose or binding the shifter if too tight. For the BMW shifters, the aluminum lower bracket needs to be replaced with a steel unit, and reverse lockout cable pulls out, and the lockout button sticks when down. I've had one miata shaft snap while running P2 at laguna, and I've had two of the tiny set screws that holds the steel insert into the bottom of the aluminum shift shaft come loose, which not only causes shifting issues, it also enlarges the hole and you need to replace the entire shift shaft.
Wow, that's quite the list. Thanks for sharing Curly! I may attempt to proactively address some of these. Too bad I'd have to take the shifter off the trans and clean up the mating surfaces...
That list is far from final too, I’m sure I’m forgetting a few things. This is all based off experience of 4-5 Miata’s and 2-4 BMWs, maybe a few more. GL!
Pictures and details later, but I had a great weekend at Sonoma with NASA NorCal, running the NASCAR layout.
@richbobby visited my garage a couple weeks ago to check out the swap and talk details; he came out on Saturday and I gave him a ride in the second session. I had to cut the session short because my fuel gauge was showing empty, I had stupidly forgotten to top off beforehand. He was able to stick around for my third session, which was an absolute ****-show of traffic and idiots, but was pretty fun anyhow. Props to him for riding shotgun without showing the slightest bit of apprehension at my mediocre driving.
I utterly failed @codrus and @icantlearn when they came to tech for different reasons - sometimes timing just doesn’t work out. I love helping people, especially the good eggs, but when tech is slammed, we’re slammed. It’s either feast or famine - mornings are terrible as we handle all the “I didn’t know I had to tech my car” HPDE drivers or the “but (other org) didn’t have a problem with (clear safety issue)” racers needing a race car inspection. After that, it gets pretty quiet until a race group lines up for the scales and impound.
The car ran just like a stock-engined Miata this time. I hammered on the thing during my sessions and had no issues with heat in the engine, footwell, or anything. Drive it hard, park it, check tire pressures, go out for the next session.
In the second-to-last session I was coming out of “long 7” and applying throttle when the exhaust noise went up suddenly to “deafening”. I got out of the throttle and limped it to track exit. Turns out I broke a weld in the exhaust directly underneath the transmission. Complete failure of the weld all the way around the pipe. I need to clean it up, mark the proper alignment, and see about having it re-welded.
I’ve had a small leak around the rear of the engine that may have gotten worse. When I get under the car later, I’ll have to look into that and decide if I’m pulling the engine.
I’m still waiting on the results of the oil analysis I sent to Blackstone weeks ago. They’ve now had the sample for over two weeks and no results. I spoke to them last week, apparently if you send the sample to them overnight, they’ll get you results within a business day, otherwise it just goes in a queue. The more you know!
It's freaking awesome to have a 12V DC QuickJack on hand at the track. Sure, it's heavy to lug out of the trailer and requires some setup, but it really makes lifting the car effortless and simple. No dragging a noisy jack around, going up in multiple lifts, placing jack stands just-so.
Here's the exhaust after the failure. I'm lucky this was the end of the day Sunday and not Saturday morning.
It should go back together pretty easily - there are some scrapes on the cross-over part from finishing my lap and going to my paddock space, but it's not like there was a lot of weight pushing the pipe into the ground and causing wear.
I'm guessing the weld penetration wasn't as good as it should have been, but I don't know all that much about welding.
Remember how I said this car shakes things loose? I swear there was a bolt on this engine mount before the weekend began, and it was tight. Now it's missing. This likely allowed more movement of the exhaust, which probably lead to the failure.
At the top-center of this picture is one of the other two bolts holding the engine mount together. It's backed out quite a bit. I can't get a good picture, but it also looks like the nyloc nut on the long through-bolt of the engine mount has backed off a few threads. I'll have to address all of these when I take the exhaust off. I guess I'm not going to be able to leave the first part of the exhaust connected to the head.
And just for funsies - either I've got a LOT of iron shavings in my oil pan, or there's a lot of steel just on the other side of this pan. My Harbor Freight shop light actually sticks to the aluminum oil pan!
I finally got the oil analysis back from Blackstone. The engine was not rebuilt. I'm running an AEM air filter exposed to the elements, so maybe filtration is a bit of an issue. I'm not sure about the aluminum number, but I'll keep an eye on it. I ran this last weekend (4 hours) on the same oil that was analyzed, so I'm right around 12 hours on this oil change. I'm going to change the oil before the next event and do another analysis when I change it in 12 hours. I'm using just off-the-shelf high-quality synthetic 0w20, Valvoline at the moment, though I think the next jug up is something different.
...
After seeing some more posts about stuck throttles, I'm even more glad I went with DBW. I guess I have more faith in software than hardware. I haven't gotten an official dyno of my car yet so I don't know if I'll have to detune, but that's a nice option to have in my pocket.
It first happened on the dyno (I think), but then coming out of T11 the engine simply didn't respond to the throttle and subsequently died. After cycling the master kill switch and praying to Lucas, Prince of Darkness, it started again. Safety held me behind the wall at the drag strip complex and I idled the motor a bit to let it cool and to run my cool suit. It died once while idling, then again as I was returning to paddock after my session. I replaced the throttle body with my spare on Saturday night but in the first session on Sunday, it happened again and I had to be towed in. That was the end of my weekend.
I need to download all my data and look into it, but the Haltech had codes in it:
I found one post on a Facebook race car wiring group about the pins for the Bosch throttle being problematic. I've warmed up the engine and pulled/shaken all the likely wires, no result.
The Haltech page for these codes doesn't provide too much detail, I suppose an email to them will be necessary.
In other news, I have an appointment for TC Design to put a cage in the car at the beginning of September.
My kpower throttle started sticking open by the time it had about 20 minutes of run time and an autocross on it. It is already habit for me to crack the throttle like every 55yr old harley owner every time I start it the car or have to move it around paddock/grid.
Originally Posted by thebeerbaron
I have an appointment for TC Design to put a cage in the car at the beginning of September.
My kpower throttle started sticking open by the time it had about 20 minutes of run time and an autocross on it. It is already habit for me to crack the throttle like every 55yr old harley owner every time I start it the car or have to move it around paddock/grid.
Yaaaaas
ditto. They just told me they are aware of the issue and got new parts from the vendor. Installed one of their “new” ones on Saturday… same crap.
We've been through multiple Bosch throttle bodies on an endurance car. Word is that vibration kills them. We wound up mounting the TB on silicone couplers and haven't had the failure come back yet.
^Glad you posted that link up as I was just about to comment the same thing
the Bosch throttle bodies aren't a slam dunk solution until you have a way to isolate the vibration from them. The second order vibrations on K24's without balance shafts and rather firm engine mounts like "destroying" things... I've had a bezel on my headlight rattle loose from it. I've lost a cosmetic coil pack cover on track from a couple pieces of hardware backing out. I've had my intake manifold bolts loosen up. I've since mitigated all of the teething pains, but it sure makes anyone appreciate why balance shafts were put on these from the factory.
The provided Kpower throttle body sticking is one of the issues I haven't had though (knock on wood).
We've been through multiple Bosch throttle bodies on an endurance car. Word is that vibration kills them. We wound up mounting the TB on silicone couplers and haven't had the failure come back yet.
Now that looks like a solution! Unfortunately funds are short right now. I start a new job on Friday, which is good, but until I prove myself there, race car funding will be drastically reduced. And I've already got funds earmarked for the cage...
Originally Posted by Padlock
<snip>
the Bosch throttle bodies aren't a slam dunk solution until you have a way to isolate the vibration from them. The second order vibrations on K24's without balance shafts and rather firm engine mounts like "destroying" things... I've had a bezel on my headlight rattle loose from it. I've lost a cosmetic coil pack cover on track from a couple pieces of hardware backing out. I've had my intake manifold bolts loosen up. I've since mitigated all of the teething pains, but it sure makes anyone appreciate why balance shafts were put on these from the factory.
I've lost count of the number of bolts that have worked their way loose. I threw antiseize on pretty much every fastener when assembling this car - no way was galvanic corrosion going to set in on my watch! And now I'm replacing all that with Loctite. Of course, my friends already think I have a screw loose...
I finally consulted the Haltech logs and was surprised that there wasn't a new DTC for the throttle failure in my Sunday session. Instead, I feel like an idiot.
From top to bottom:
TPS
Fuel Pressure
RPM
Now to go dive into the Saturday sessions to see if I'm truly an idiot.
Here's where the car died on the dyno on Saturday afternoon. Not a fuel pressure problem.
OK, time to put on my thinking hat and get after this.
After I got towed in on Sunday, the car ran well enough to get onto the trailer, off the trailer, and then to run for a while as I shook wires and looked for a culprit. I can pump out the tank, but my fuel level sender indicates I have at least 5 gallons in there (and my mental math agrees).
It's been a while. I've been putting off an update because I've been hoping to gather more information, but after more than a month without progress, it's time to admit laziness and move on.
My engine had a bad day on the Saturday afternoon of the last event. I was putting my foot down coming out of turn 10 when I got a low oil pressure message on my dashboard. By the time I reacted, it was too late, though it may have been too late even before the alert.
You can hear me curse right before the flames show up - IIRC that was actually in response to a larger set of flames that came out the back of the hood, where the camera didn't pick it up. I don't have a fire system, so this became a get-out-fast situation. Hit the kill switch, grabbed my Element stick and abandoned ship. It really wasn't that bad - the cockpit got pretty smokey, but the fire was mostly out by the time I got out. I took a chance and carefully opened the hood a touch, saw minimal fire, and let the hood open itself. I had some fire at the rear passenger side of the engine bay, which I hit with the Element. From what I can tell, that was probably oil soaked into the fabric heat shielding I have/had to provide some insulation for the brake lines. To the safety crew's disappointment, it was all out by the time they arrived.
The cylinder 2 rod attempted to exit the block. I got towed in and that was the end of my season.
The car is still sitting in my trailer, undiagnosed. Because of this:
My new-to-me 1978 Porsche 928. Slick top, manual, no rub strips, with a totally-believable 58k on the (functioning) odometer. And the seller had a full set of factory service manuals!
I found this on Facebook Marketplace when I wasn't even looking for a project. Of course. A friend of mine from NASA knows all about these and basically told me while I was inspecting it that I'd be an idiot not to buy it. About the worst thing going for the car is a bad respray from white to ... whatever color this is. Bad as in much of the engine bay has overspray, the power mirror wiring was cut rather than unplugged, some door trim wasn't put back on, etc. Ugly and unfortunate, but not a death sentence. It's largely unmolested and most of the '78-only touches are still there. The interior isn't bad. I drove it an hour home from the seller's place and it performed flawlessly. I later discovered that one of the tires was a Bandag retread of a Pirelli P7 carcass. It hasn't moved much since then unfortunately and is currently inop and blocking the one garage space. Sigh.
This project is one I'm hoping might actually be profitable. I've learned that people love the '78s because they're the first model year and have some unique touches (read, Porsche was still figuring out how to build them). It's not going to be a concours winner, but I feel like the bad repaint gives me the freedom to paint it a better color one day - I'm thinking something that was available in '78 but that you don't see today. Signal Orange, Apple Green, etc. Not white, black, red, or silver.
The 928 is out of the garage and the race car is inside. I'm currently sorting out the clutch hydraulics on the 928, which is the bottom of a slippery slope I slid down when I replaced the front shifter bushing. It's good that I did all this work, but it's been a journey. Because German, the clutch master cylinder shares a fluid reservoir with the brakes and is located directly underneath the brake booster. There's some asphalt-like firewall insulation that has unglued itself and slid downwards to where it prevents the removal of the clutch master, unless the booster is also removed. Because German, there is one proportioning valve per rear brake, so lots of brake lines in this area. The booster can only be removed when the pedal has been fully depressed and the actuating rod is prevented from retracting. Otherwise there's not enough space in this corner of the engine bay to get the booster out. Needless to say, I am teaching the local children, crows, and squirrels new curse words as I untangle this mess.
I have made minor progress on the race car, since the NorCal season is under way. After getting the car into the garage, the first step was to address the issue of fishing the motor+trans in and out. The K motor is tall and I have a low garage door overhead. I sat and thought and schemed and finally drilled out the spot welds holding this bit of the not-a-radiator-support out, then cut it free with the Dremel. Far fewer cutting discs were used than I expected. I had hoped I could just drop bolts in to reinstall it, but given that the spot welds are so poorly located, that won't do. This is a problem for future me.
I've thought about cutting away the crash structure behind the front bumper, but I don't want to create more work for myself just yet. My goal is to get the old motor out, transfer parts to the new motor (on-hand) and get the car running. Minimal optimization or side-projects.
I have pulled the wiring harness, with the exception of the crank sensor that's hidden in the back. There are definitely some burnt-up wires that will require replacement, but the damage is not too bad.
There is a fine slick of oil on everything on the exhaust side of the engine bay. What a mess!
06-10-2023, 04:36 PM
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