So I have a 2004 NB Miata that we were getting track and race prepped for my son. A home oil change went wrong and the engine seized while in use. Tried the penetrating lubricant trick with no success. So my options are to swap the engine or sell the thing and get something else. I can get a replacement 1.8L miata engine for about 3K, and the boy and I both have friends willing to help with labor to swap the engine. It would be a good learning experience for him, so I'm sort of leaning that way. However, is there anyway to figure out how much the vehicle is worth as is? I checked for comps online and they are all auctions or wrecked. This vehicle is in great condition aside from the engine being seized.

Any advice on finding a good market price or tips on an engine swap would be appreciated

What penetrating oil brand did you try? Kroll Original Penetrating Oil is usually the gold standard and always had great luck using Kroll over other brands

I pulled the spark plugs and shot PB blaster down the holes daily for 5 days. Put my breaker bar on the crankshaft and it wouldn't budge

Explain "oil change gone wrong" please.

My guess is forgot to put the drain plug back in.

And…obligatory LS swap.

maroon barchetta said:

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Explain "oil change gone wrong" please.

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Long story short: oil filter cross threaded and leaked. Not noticed initially and car driven without lubricant about 3 miles and seized going about 40 mph

MoreCushing4thePushing said:

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My guess is forgot to put the drain plug back in.

And…obligatory LS swap.

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Close!

And I wish, but if I had 15-20K to burn I would just buy a different car

Build a Fox Body Mustang with a Gen 3 5.0 Coyote for the win

Yikes. It didn't leak when y'all started it after the oil change and checked for leaks while it was still jacked up?

Although frustrating to happen, it sounds like this car wasn't a daily driver, so that's a bright spot if you're looking for one.

No. I blame myself for letting my teenager change his own oil

I changed oil at a place in CS in the early 2000s. Changed the oil on an 01 Silverado and saw he needed a state inspection so I pulled it off the lift and into a different bay. Saw oil puddle a few minutes later because the old filter seal has stayed on and I had threaded new one on, causing the leak. Got lucky that day because he need the inspection, otherwise, he would have driven off and lost all the oil pretty quick! I knew to always check for that, but missed it that day.

https://kpower.industries/collections/kmiata-swap-parts

My last oil change at the dealership, the new filter was cracked. They were filling from the top and it was draining right out through the filter.

Swap in a Ferrari F136 V8?

https://www.thedrive.com/news/ferrari-f136-v8s-are-shockingly-cheap-but-buying-one-is-the-easy-part

ramblin_ag02 said:

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No. I blame myself for letting my teenager change his own oil

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It happens. I bet he will never make that mistake again as some lessons are best learned the hard way! My favorite mistake was draining 7 qts of oil into my drain pan when the the drain pan top plug was not open. The top part only holds about 2 qts until it runs over...

If you decide to get rid of it, post here first

Ecoboost 2.0/2.3 has the same bellhousing pattern as the NC miata trans. Just sayin.

I'm looking into that, but price is a problem. This was completely out of the blue. I think I can get a 1.8L miata engine with 50k miles and swap it with no fuss for 2500 and the labor of myself, my son, and our friends. Every conversion kit for Miata to other engine I see is at least 3000-4000 even before you buy the engine, and cheapest engines I can find are 1500 unless it has 150k miles or damage. It's looking hard to beat 2500 to get the car back on the road and that's before I get anything for the seized engine

Not the cheapest option but if the budget is there buy an NC for the replacement. Reason being it's a better car and has very reasonably priced engine swaps thanks to Ford who owned a part of Mazda during the years the NC was in production.

IntensivePurposes said:

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Ecoboost 2.0/2.3 has the same bellhousing pattern as the NC miata trans. Just sayin.

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But, it doesn't drop into an NA/NB.

https://texags.com/forums/50/topics/3444576/1#last

After talking with my local Miata race and track team, shout out to Rapscallion Racing in Cresson, we're going to pull the engine and take it to a engine machine shop to assess. Worst case scenario we can always swap a new engine. Best case they can fix this one up and I can keep my part numbers matching.

Anyone have any recommendations for engine machine shops around Ft Worth that's comfortable with a Japanese turbo inline 4?

Bumping this thread so I can update and get some advice. We took the engine to Wayne Calvert in Denton. Dax did most the work there on the block, and he's been awesome and my point of contact. Steve did the head work. We got the engine back a few months ago. With some busy nights and weekends and a lot of help from friends, we were able to get the engine assembled, back into the car, and running smoothly. I will edit to add the video of this from my phone. We only had 2 problems. First, a small air leak at the throttle body due to me putting the gasket on backward. Second, it was leaking coolant like crazy.


We replaced all the coolant hoses and no improvement. Google and reddit searches showed the fuel pump being the issue. We stripped the engine down to the fuel pump and had to remove all the front hoses, disconnect all the eletrical, remove the radiator, remove the power steering module, remove the valve cover, remove part of the turbo tubing, remove the airbox, remove the spark plugs, remove the water pump pulley and crankshaft pulley, and remove the front shroud. From there we found the problem with Dax's help. The outflow connection from the water pump was loose due to some stripped threads and the gasket failed. We fixed this with a longer bolt and a new gasket, and the no leaks since. We put everything back together and fixed the backward gasket at the throttle body.



edited for link from before when it was running smooth. Current video in the next post if it works

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had to remove all the front hoses, disconnect all the eletrical, remove the radiator, remove the power steering module, remove the valve cover, remove part of the turbo tubing, remove the airbox, remove the spark plugs, remove the water pump pulley and crankshaft pulley, and remove the front shroud. From there we found the problem with Dax's help. The outflow connection from the water pump was loose due to some stripped threads and the gasket failed. We fixed this with a longer bolt and a new gasket, and the no leaks since. We put everything back together and fixed the backward gasket at the throttle body.

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Minor little problem......

Once everything was put back together, the engine doesn't want to run again. Not a huge surprise, but it's driving me a little crazy. The engine cranks and sputters, but it won't run and it's not smooth. At one point it was throwing out an OBD code for the camshaft position sensor. I have since replaced that thinking it got damaged when we removed the valve cover. I also verified the crankshaft sensor is working, because other Miata people say that can throw the same code. Now I get no OBD codes. Spark plugs are firing, battery is good, fuel pump is working, gas tank 1/4 full with fresh high octane. Everything is hooked up the same way as I did 2 weeks ago. No luck so far with start fluid either. Dax suggested keeping the throttle fully open when using the starter spray, and I haven't tried that yet. Any other ideas? I'll add the videos of before and now if I can figure out how

It only took about 2 hours. I'm just listing everything in case it helps someone figure out what I screwed up

bump for videos. Any advice is appreciated

Howdy,

You've already stated what i think it may be, but it's still very likely associated with cam/crank correlation. We had an nb with the same cam sensor in the valve cover. any irregularity in depth on install would create the same symptom you have with crank/no start. We did also have a bad sensor right out of the box and had to get a 2nd cam sensor. finally getting it physically close enough to the cam sprocket fixed our issue. if you still have the old sensor, does throwing it back on make any noticable change?

Just spit-balling based on miata life: have you confirmed that it is still in time? Sounds like you got down to water pump, but can't tell if you had to touch idler/tensioner. I've had 1.6/1.8s jump a tooth when speeding through replacement.Mainly happened on the intake side. Now i use the crossed boxed wrench and a clamp method or 3d printed cam lock just to be sure I don't screw it up like I normally would.

Sorry I don't have more useful advice. If it's not firing with starting fluid down the pipe, based on your description of the issues and video, my first check would be physical timing.

Good Luck!

12thManChild said:

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Howdy,

You've already stated what i think it may be, but it's still very likely associated with cam/crank correlation. We had an nb with the same cam sensor in the valve cover. any irregularity in depth on install would create the same symptom you have with crank/no start. We did also have a bad sensor right out of the box and had to get a 2nd cam sensor. finally getting it physically close enough to the cam sprocket fixed our issue. if you still have the old sensor, does throwing it back on make any noticable change?

Just spit-balling based on miata life: have you confirmed that it is still in time? Sounds like you got down to water pump, but can't tell if you had to touch idler/tensioner. I've had 1.6/1.8s jump a tooth when speeding through replacement.Mainly happened on the intake side. Now i use the crossed boxed wrench and a clamp method or 3d printed cam lock just to be sure I don't screw it up like I normally would.

Sorry I don't have more useful advice. If it's not firing with starting fluid down the pipe, based on your description of the issues and video, my first check would be physical timing.

Good Luck!

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Thanks for the thoughts!

We replaced the cam sensor, but the codes remained. The new sensor was a little shorter and smaller than the original. So I replaced the replacement with one that looked exactly like the original, and the code went away. I know the crankshaft sensor is good, because the water pump starts up when I manually turn the tooth past the sensor.

We didn't touch the timing belt. I thought we were going to have to fix the gasket behind the water pump, but the problem ended up being with the outflow. So we didn't mess with the timing belt at all including tensioners and didn't remove the water pump.

It was doing similar stuff before, but it was an air flow problem. That doesn't seem to be the issue now. Also, we didn't touch the fuel system, so I don't think that's the problem. I appreciate the help and may try jacking with the cam sensor again. When it finally started running last time, it ironed out all those issues and ran smooth. I feel like it would do that again if I could get to to start up, but that's probably just wishful thinking.

Update:

So I think I figured it out, but I won't get a chance to try it out until tonight. I don't want to jinx it by saying it out loud. It's definitely a timing issue. We tested all the spark plugs and they are good. I can hear the fuel pump and the spark plugs smell like gas. Plenty of air as it is firing and doesn't improve when hoses are left to open air like it did before. So fuel, spark and air are good. Only leaves timing and I've got a likely culprit

pull the choke out juuust a hair past halffway.

timing was going to be my next suggestion.

also, where are you buying these sensors from? OEM parts?

Cheap $10 amazon for the cam sensor. It's $100 at autozone and $150 OEM, so I figured I'd at least try the cheaper ones.

Problem solved. It was definitely timing but not a sensor problem.



If you see them on the left, the crank pulley has 4 tiny timing teeth, and they are not evenly spaced. It's possible to misalign them by 90 degrees, and it will throw off all the engine timing. So I fixed that last night and the engine runs great again. Apparently it's not as idiot proof as they imagine, and I screwed it up putting it back on after fixing the coolant leak. All good now and just a few minor things to get it road and track ready