More Miata questions.

Me again. I have the newly acquired 1997 miata. 

A couple of things are bothering me. The previous owner said it has a COP conversion from a hayabusa. I’ve checked the internet, and while a COP conversion is common for forced induction, I can’t find any record of a hayabusa being the donor. I just want to know what the part numbers are for repairs. 

Second question- this Miata has water in the radiator, no coolant. But it also has rust in the water. It’s brown, rust looking sediment. Also has a brand new radiator in it. At first I thought It was oil in the water, but it’s not. It’s rust. Any thoughts on WTF? 

The car came with an Apex’i turbo timer and bosch fuel pump kit from AEM. 

Im kinda suspect at this point. I’m thinking they planned a turbo for this car, then it maybe overheated and they swapped the radiator. Potentially a water pump failed? I don’t know. What I do know is the PO was quick to get rid of it. 

In reply to _ :

Miatas are typically surprisingly robust. I’d flush the cooling system until no more gunk came out, then fill with the typical 50/50 mix. 

Maybe it had a turbo, but it was blown & removed?

Sorry, no help on the COP conversion. Are there any markings on yours at all? There should be something to help identify them. 

The common COP conversion is using Toyota coils, from the 2005ish gen corolla I believe?  But yeah, finding a part number is the only way to be sure.

Any iron blocked car will rust if you only put water in it.  That 50% glycol and other things are rust inhibitors as well as lubricants for the waterpump seals.  Don't be too surprised if your water pump starts leaking if it's been run like this a long time.  That's why racers who aren't allowed to have glycol in their cars run water wetter, because in addition to being a surfactant (reduces surface tension of water for better thermal conductivity), it also acts as a rust inhibitor and lubricant for the seals.

I agree with Pete, sounds like it had a turbo and it was removed.  Check the oil pan below the exhaust manifold and see if it has a bung tapped into it.  I'd also do a leak-down & compression test on the engine before you spend any money on the car.

I'll bet there's Water Wetter in that rad. You often get a scum on the surface with it.

 Interesting, I will have to look on the COP to determine if there are any part numbers and report back. There is no tapping on the oil pan for a drain. 

I am not too afraid of a blown engine or overheated blown head gasket. I found a source for a low mileage Japanese engine for only $900, which is probably less than I would spend to rebuild a 200,000 mile engine, right?

Possibly, although there's no paper trail to authenticate that 'low mileage'.

 I’ve bought engines from Foreign Engines before. their company is actually pretty good and I’ve never had a problem with an engine I bought. And the engines are actually from Japan. a couple of my Honda engines I had definitely had Japan only intake manifolds and ECUs. 

Mr. Tanner, do you think a 1.8 engine could be rebuilt for less than $500 back to factory specs by an amateur? This is of course, assuming that it had a blown head gasket.

Oh, I don't doubt they're covered in magic JDM sprinkles. I just have trust issues about a 20 year old engine with no paper trail being "low mileage". I like US engines where I can run the VIN and see the actual history, especially when there's nothing actually special about a JDM mill.

So the budget just dropped from $900 to $500?  It depends on what you consider a rebuild. New bearings and rings and gaskets - I guess it depends on the source of the parts. I've gotta think you'd be pretty close to that budget with Rockauto parts. If you need machining, the machinist will want to feed his family.

Do you have evidence it needs a new engine?  Have you done a compression or leakdown test yet?

Rust in the radiator is normal with low levels of rust inhibitors, when flushed and replaced with a proper mix (I usually go 80/20 water/coolant) it'll be fine.  

The Toyota COPs look like this:

Eh. 500-900 is about the range I’m willing to go.  I figure, $900 to rebuild doesn’t make as much sense since I’m getting no performance out of that. Just stock. $500 for a stock engine rebuild would be worth the time and labor on my part. 

Edit- I just now got what you were saying. Whoops! That was a typo on my part, it was supposed to say 900 and not 500! Still, I’ll stand by what I said above.

In reply to codrus :

That is definitely not what my COPs looks like. When I get home from work I might post a picture, I will also try to scan the COP’s for a part number. That is definitely not what my CO PD looks like. When I get home from work I might post a picture, I will also try to scan the COP’s for a part number

_ said:

Eh. 500-900 is about the range I’m willing to go.  I figure, $900 to rebuild doesn’t make as much sense since I’m getting no performance out of that. Just stock. $500 for a stock engine rebuild would be worth the time and labor on my part. 

 

Edit- I just now got what you were saying. Whoops! That was a typo on my part, it was supposed to say 900 and not 500! Still, I’ll stand by what I said above.

I'd take a $900 rebuild over a $900 JDM engine. Heck, I'm doing just that with a Subaru engine. For that budget, you should be able to do a pretty nice DIY rebuild. It won't get you better performance than stock, but it should get you better performance than 200k miles.

The only problem would be the amount of down time for a rebuild. I would almost think I could swap another engine in to drive, and in my spare time do a performance rebuild on this engine. 

Know a good website that talks about upgrading and  modding the 1.8?

The COP you're probably looking for is the Fab9  COP conversion. They used coil pencils from a GSX-R, IIRC.

_ said:

The only problem would be the amount of down time for a rebuild. I would almost think I could swap another engine in to drive, and in my spare time do a performance rebuild on this engine. 

Know a good website that talks about upgrading and  modding the 1.8?

Common thought process. I don't know how many people actually go through with it. At that point, you're spending the rebuild money AND the new engine money. If you're planning a big power build, it makes sense. If you're looking at no more than 250% of the original power level, there's no reason for a performance rebuild and you can just stick with a healthy stock engine.

I know a book that talks about upgrading and modding the 1.8. I'm sure there are a bazillion YouTube videos and forum posts about it of varying levels of quality and accuracy. No matter what your source, step 1 should be defining your goal. Then you can figure out how to get there.

 I saw your book on flying Miata, sounds like I might buy it. I definitely do not plan any major upgrades for this engine, since I kind of enjoy the power band and power level that it has right now. My last car was the crazy vehicle that I took to whole new levels and did a ton of modifications to. I’m over that now.

Just be aware that it's not a cookbook that says "to make 200 hp naturally aspirated, you must do this and buy these parts".

Keith Tanner said:

Just be aware that it's not a cookbook that says "to make 200 hp naturally aspirated, you must do this and buy these parts".

Yeah, such "cookbook" recipes have been posted on various forums in the past, and everyone I know who's tried to follow them has wound up with about half the gains that were promised.  There seems to be a lot more to it than just bolting some parts together.

Ok, the coils are 129700-5150. They are cbr fireblade 1100rr coils. The “module” or control box, or whatever is an Audi part number from an A8. I can’t find anything on this, so I’m guessing it’s some kinda home job. Regardless, it’s not a huge issue for me, since I don’t “plan” anything wild, especially forced induction  

After some further research, I find that someone on Miata Turbo has posted the dwell graph for this set up. Apparently it is no stronger than the factory ignition system. Oh well, good thing I never planned on going forced induction!

That's the case with a lot of COP setups. Shhh, don't tell!