"Nick Has an Exocet" (nickallain)
06/12/2020 at 00:55 • Filed to: None
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"Nick Has an Exocet" (nickallain)
06/12/2020 at 00:55 • Filed to: None | 0
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I did a compression test on the Miata last night. I’m not thrilled. #4 is a problem and the rest are pretty tired. #4 also has a problem with it’s head. The previous owner’s mechanic stripped the threads on the #4 spark plug and retapped it.
Warm numbers (1st crank / 5th crank):
90/155
90/170
95/165
65/125
Cold numbers (1st crank / 5th crank):
60/155
85/165
90/165
25/105
I’m pretty committed to this little Miata. I love it. I just replaced the top and am working on the interior now. It’s getting a full carpet kit, underfelt kit, restored dash, carpeted door cards, center console delete, leather door pulls, and some other little interior upgrades. I also have a fender to replace the dented one.
Now, as for engine options. I have...dreams. Dreams of a inline-6 BMW k1600 engine (160hp/129ftlb).
What I know:
The output is shaft drive, which should make mating to a Miata differential fairly easy.
Stock Miata engine + transmission + dressings (dry) is 360lbs.
K1600 engine + trans + dressings is 260lbs
The engine would sit towards the passenger side
Issues:
Engine mounts will be a PITA but not impossible
Clutch is hydraulic? Would need to adapt the Miata clutch.
Shifter............. yeah. I’m open to ideas. Current idea is to use a bistatic rotary actuator connected to paddle shifters or design a shift linkage that ends up in the cabin like a rally car. That wouldn’t really suit the design though.
Here’s how the gearing would work out with the BMW 6 speed and a 4.3 Miata
diff and with a 4.78 from an RX-7.
Wrong Wheel Drive (41%)
> Nick Has an Exocet
06/12/2020 at 01:49 |
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Yeah all of those compression numbers are pretty not good. I need an engine rebuild due to my numbers:
Dry I get 180 160 180 180
Wet I get 180 190 180 180
So I have a ring issue. I wish I had the money for an engine swap but a rebuild is much much cheaper. LFX swap would be my go to solution if I had money to burn. I have a misfire cylinder 2 code so I need to fix it to pass smog. Im pretty confident that wet compression issue is causing it because otherwise its a weird as hell coincidence.
Other swaps ive seen that i loved were k swaps and ecotech. Saw all three at Miatas at the gap one year. They all sound amazing and are way more interesting than LT/LS swaps that everyone does.
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Nick Has an Exocet
> Wrong Wheel Drive (41%)
06/12/2020 at 02:08 |
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Your numbers aren’t bad. 28psi is what Mazda says is the limit of difference between any two numbers. Rings would mostly be preventative maintenance .
I feel like I could do the bike swap very cheap. If I could get the bike for under $3500, I feel like the entire swap would easily stay under $5k.
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Wrong Wheel Drive (41%)
> Nick Has an Exocet
06/12/2020 at 02:15 |
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I just cant envision what else is causing my misfire. Having replaced plugs (twice), wires (two different sets of NGK), both coils, injector for cyl 2, cam sensor, and fuel pump. And then I found the mysterious wet compression issue on that exact cylinder.
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Nick Has an Exocet
> Wrong Wheel Drive (41%)
06/12/2020 at 02:30 |
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A couple things to check:
1) Lots of Miatas end up with arcing issues. Tough to diagnose.
2) A lot of NGK wires are fake
3) A lot of NGK spark plugs are fake
4) could be a bad seal on that injector or jusssssst upstream of the injector in the fuel system
my brain is mushy but I bet there are other things to check!
gettingoldercarguy
> Nick Has an Exocet
06/12/2020 at 02:47 |
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Is this for your exocet?
BvdV - The Dutch Engineer
> Nick Has an Exocet
06/12/2020 at 04:24 |
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With the K1600 shaft coming out of the side of the block, are you planning to put it in sideways? Or do you have some idea to turn the shaft around
sony1492
> Nick Has an Exocet
06/12/2020 at 05:12 |
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Does this leave you with no reverse?
diplodicus forgot his password
> Wrong Wheel Drive (41%)
06/12/2020 at 06:24 |
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Could be a Headgasket. Had a mysterious misfire under load on an e30. No coolant in the oil but the coolant passage on the gasket had broken allowing coolant to spray right into cylinder 5
punkgoose17
> Nick Has an Exocet
06/12/2020 at 09:27 |
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Following other people. Just replacing the head and head gasket may fix your problem.
Highlander-Datsuns are Forever
> Nick Has an Exocet
06/12/2020 at 09:29 |
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13B swap.
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Wrong Wheel Drive (41%)
> Nick Has an Exocet
06/12/2020 at 10:01 |
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Yeah I feel like at this point it’s worth paying a shop to investigate that I guess. Considering I’ve been driving it over a year now and just trying to throw parts at it and eventually giving up because it doesn’t affect drivability once it warms up. Only obviously misses when still a cold engine. Somehow haven’t fried my cat yet.
I like the idea of the fuel injector seals but then again the electrical issues are super duper common on the ‘01 and other NBs. I also get a fair amount of soot on the rear bumper over time if I don’t wash the car after a couple weeks. Meaning I’m certainly not burning all of my fuel, which explains the lower gas mileage and the fuel not all getting spark/compression. But that doesnt really narrow down anything.
I did also once or twice get a pending random misfire code but I haven't been able to trace that. And I haven't seen that one since replacing the fuel pump which was definitely causing hesitation at Laguna Seca right after the straightaway.
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Wrong Wheel Drive (41%)
> diplodicus forgot his password
06/12/2020 at 10:03 |
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I should have cooling issues with a headgasket though, as well as coolant loss and I'd think it would get worse with heat, not better. But certainly a possibility!
shop-teacher
> Nick Has an Exocet
06/12/2020 at 10:10 |
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That seems like a crap ton of work, for not that much benefit.
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Nick Has an Exocet
> BvdV - The Dutch Engineer
06/12/2020 at 11:43 |
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The k1600 is transverse by design.
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Nick Has an Exocet
> sony1492
06/12/2020 at 11:44 |
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Sort of. The k1600 uses the starter to reverse the bike but I don't think that's strong enough. That's an issue.
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Nick Has an Exocet
> gettingoldercarguy
06/12/2020 at 11:45 |
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Nah, this is for my 91 Miata.
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Nick Has an Exocet
> shop-teacher
06/12/2020 at 11:46 |
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It’s really for the sound and novelty.
tromoly
> Nick Has an Exocet
06/12/2020 at 15:55 |
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Run a linkage to do sequential shifting and put a bike clutch lever on that, kill two birds with one stone.
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sony1492
> Nick Has an Exocet
06/12/2020 at 16:28 |
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You mentioned elsewhere that this isn’t for the exocet, its probably only gonna be worthwhile in a “racecar” application where you don’t care about reverse or mufflers. And being 150hp or so you’d want less weight.
For a novel swap that isnt crazy on the budget, consider swappping in a Toyota 1gz-fe with a 5 speed auto. Its 90s Toyota so getting it running on the stock harness won’t be difficult and all the modifications have to do with making it fit rather then engineering the drivetrain and shifter
https://en.m.wikipedia.org/wiki/Toyota_GZ_engine
The entire drivetrain can be had for less then 3k
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Nick Has an Exocet
> tromoly
06/12/2020 at 20:43 |
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I think that’s a great idea for a race car, but I’m not sure I would want to street that.
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Nick Has an Exocet
> sony1492
06/12/2020 at 20:45 |
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lmao. I love where you brain went on this. I propose a lightweight bike engine and you double me up to a V12. Hahahaahaha. <3
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tromoly
> Nick Has an Exocet
06/13/2020 at 11:34 |
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The above setup is in Matt Brown’s Honda S600 with a CBR1000RR in it, just an option.