Engine Knocking. Spun Rod? Probably... Help?

[Luken10]

Been a while since I have been back on the forums, as the car has been fine for quite a while!

Sadly i developed a knock after taking a freeway connector very aggressive without the proper amount of oil in the car. I'm fairly certain it is a spun rod due the the circumstances. Where does one go from here?

I kind of just figured I am going to have to source a new motor. However, there are a few instances on the forums where people just replace the rod bearing and go on their way. How do I know if I can get away with just replacing a bearing? What else can get damaged?

The car has been driven maybe 10 miles since the knocking first happened. As of right now you don't hear it at idle, only once you get past 2000 RPM. Depending on the load and RPM while driving, you can't hear it at all.


If anyone has any reputable shops in the Socal/Orange County area please let me know! I have made an effort to do all of the work on this car myself, but sometimes it's better to have a professional take a look.

 

[MrGiggles]

When a bearing fails, debris is distributed through the engine oil, damaging the rest of them.

Replacing the rod bearings with the engine in the car is not done easily. The engine/trans have to be unbolted and separated to remove the upper oil pan. Even then, the crankshaft usually needs machine work for the new bearing to survive. Because of that, it is best to just remove the engine.

Since you caught the failure somewhat early, you can probably get by with pulling the engine, tearing it down, sending the crankshaft to a machine shop, flushing the oil passages as good as you can, and put it all back together with new bearings, gaskets, and oil pump. You'll want to check the cam bearings for scoring and look for trash on the oil pickup screen. Those will give you an idea of how much trash went through the system.

Additionally, with machine work and parts, a used engine may be the more cost effective option.

 

[Luken10]

Thank you for the reply! I can definitely see how just removing the engine would be the best option. I personally don't see myself reassembling an engine. That is something I would have a shop do. Would you happen to have any idea how much it would cost to do the work you described?

I can totally just see a mechanic tearing it apart and saying, "I'm going to have to replace more than we thought, this is now going to cost you." Just because of all the things that can be damaged in this scenario. That's why I am more keen on putting a used engine in and calling it a day. Unless the used engine has problems as well.... Choices I suppose!

I noticed you have a FS-ZE engine swap. I have been doing a ton of research on that motor recently. How did your swap go, and how does it run now? Are you using the NA or JDM ECU?

 

[Jackie chan]

If you aren't doing it yourself, a used motor would be cheaper. Ze is a good route. And the jdm ecu is for NA too, but it's obd1. The swap has been discussed at length in lots of threads on various forums.

 

[MrGiggles]

Thank you for the reply! I can definitely see how just removing the engine would be the best option. I personally don't see myself reassembling an engine. That is something I would have a shop do. Would you happen to have any idea how much it would cost to do the work you described?

I can totally just see a mechanic tearing it apart and saying, "I'm going to have to replace more than we thought, this is now going to cost you." Just because of all the things that can be damaged in this scenario. That's why I am more keen on putting a used engine in and calling it a day. Unless the used engine has problems as well.... Choices I suppose!

I noticed you have a FS-ZE engine swap. I have been doing a ton of research on that motor recently. How did your swap go, and how does it run now? Are you using the NA or JDM ECU?

Very few mechanics these days will tear down an engine for you. Engine building is pretty much done strictly by machine shops, a tech will only take it out and put it back in.

I was in the same boat as you, but with a severe oil burner, not a rod knock. The cost of parts to do a full rebuild will just about buy an FSZE, so I went that route. It runs great, I have nearly 30,000 miles on it now.

JDM engines can be a mixed bag. Many times the seller has no idea of the actual mileage or condition of the engine. The good ones will do a compression and leak down test before selling, and if at all possible, try to find a local importer so you can see the engine before money changes hands. Using a credit card is a good idea too, for further buyer protection. I believe there are at least a couple importers in California.

I am running the USDM intake, PCM, crank pulley, and sensors on the JDM short block. With this setup, you won't get the full potential out of the engine, but that wasn't my goal.

 

[Luken10]

Glad to have someone active on the forums who has done the swap. I am a little iffy on buying a used motor, just because as you said, it's hard to verify the condition. A big issue it seems is that all of the places with a warranty explicitly say it is only valid if a certified mechanic installs the motor. I am definitely planning on installing it myself in order to learn and save money. Which company did you get yours through?

I have been reading quite a bit on the forums about people who do the swap with the USDM PCM, and can't find a confirmed answer whether the engine runs reliably. Some people say it runs too rich, or too lean becasue the PCM can never compensate for the higher compression. Glad to see yours has worked well this long. Is there a reason you didn't use the JDM intake manifold? I have an MP3 ecu, so i am definitely intrigued by getting some extra power with a FS-ZE motor.

However, I have a feeling this idea may be short lived due to smog checks in California. Do you know if all of your OBD2 functions work correctly?

 

[NaturalFlavored]

It runs fine if you use the MP3 ECU which you need manual transmission for and if you swap over ALL of the sensors from the stock fsde engine.

 

[Luken10]

Swapping the sensors isn't a big deal is it? Is all of the wiring plug and play with the MP3 ECU? No splicing?

 

[MrGiggles]

Glad to have someone active on the forums who has done the swap. I am a little iffy on buying a used motor, just because as you said, it's hard to verify the condition. A big issue it seems is that all of the places with a warranty explicitly say it is only valid if a certified mechanic installs the motor. I am definitely planning on installing it myself in order to learn and save money. Which company did you get yours through?

I have been reading quite a bit on the forums about people who do the swap with the USDM PCM, and can't find a confirmed answer whether the engine runs reliably. Some people say it runs too rich, or too lean becasue the PCM can never compensate for the higher compression. Glad to see yours has worked well this long. Is there a reason you didn't use the JDM intake manifold? I have an MP3 ecu, so i am definitely intrigued by getting some extra power with a FS-ZE motor.

However, I have a feeling this idea may be short lived due to smog checks in California. Do you know if all of your OBD2 functions work correctly?

I got it from JDMEnginescorp.com.

I have had no trouble with the PCM. No codes have set except a very occasional P0140, which I'm sure is from the aftermarket header. I get a pretty steady 26-30mpg average. I also run 91 octane gas, but I haven't noticed any preignition with 87. All of the OBD2 monitors show completed.

I used the USDM intake just because it was more convenient, and I didn't want to deal with the process of deleting all of the butterflies and swapping the sensors. I was crunched for time, and did everything in the span of 6 or 7 hours.

The EGR still functions properly, and I don't see why it wouldn't pass emissions, but I have never needed to have it tested. The JDM engine had an EGR valve just like the USDM, so it is designed to have emissions equipment.

 

[Luken10]

6 or 7 hours? That's quite impressive. I always run 91 gas with my MP3 ecu, so that's a non issue. Glad to hear you haven't had any issues pinging, which I have read about on here. California doesn't do the sniffer test any more, so if the OBD2 monitors are good to go, so am I!

I found another thread where someone with a FS-ZE swap passed emissions just fine in California. Very reassuring.

Now I just need to figure out, for certain, how to identify a true FS-ZE motor. A couple of other threads say the intake manifold black box doesn't necessarily mean it is a ZE. If I end up doing this I would prefer to have the best motor I can get.

 

[MrGiggles]

6 or 7 hours? That's quite impressive. I always run 91 gas with my MP3 ecu, so that's a non issue. Glad to hear you haven't had any issues pinging, which I have read about on here. California doesn't do the sniffer test any more, so if the OBD2 monitors are good to go, so am I!

I found another thread where someone with a FS-ZE swap passed emissions just fine in California. Very reassuring.

Now I just need to figure out, for certain, how to identify a true FS-ZE motor. A couple of other threads say the intake manifold black box doesn't necessarily mean it is a ZE. If I end up doing this I would prefer to have the best motor I can get.

The intake cam, intake, and pistons are the only differences between the DE and ZE.

ZE will have FSH9 cast on the intake cam.

 

[Luken10]

From my understanding, it is those three things that will net me a small amount of extra power. If that is the only true way to know for sure, I might be a little screwed. I doubt the engine seller would pull the valve cover off.

 

[MrGiggles]

From my understanding, it is those three things that will net me a small amount of extra power. If that is the only true way to know for sure, I might be a little screwed. I doubt the engine seller would pull the valve cover off.

Any JDM engine is going to be an FSZE, even if not advertised as such, which was the case with my engine.

From what I gather, JDM FSDEs don't exist.

 

[Luken10]

That's what I thought at first, as well. However, I thought I remember reading about there being JDM FS-DEs. I could be wrong, time for more research! Thanks for all of your help by the way!

 

[Luken10]

So with a little more research, it seems there are more variations than I originally thought. According to the ProtegeFAQ there are three different variations of the FS-ZE with differing power levels. Two have 10.4:1 compression, while the third, Mazdaspeed version, has 10.7:1. The MS version also has a different cam(s) from what I remember. I don't see myself realistically coming across a MS engine, so my best case scenario would be finding an engine from before August 2002. The FS-ZE made after that have 5 HP less. Not sure why though, as all the specs in the FAQ are exactly the same. ECU tuning maybe? If this is the case then it wouldn't matter since I would be running a MP3 ECU, anyways.

I also found this post stating that there is a FS-DE engine from an MPV that came with the plastic intake manifold box, but doesn't have the power additions of the FS-ZE. I'll edit the post with a link once I can make sense of the million tabs I have open right now.

 

[Luken10]

Does anyone know if a plastic engine cover would indicate a Mazdaspeed Familia engine? https://www.ebay.com (commissions earned) to an eBay engine I found for sale with one. In the states I think MSP were the only cars to come with the engine covers. Would seem plausible. It would also be nice to have the cream of the crop NA motor. This listing even comes with the loom and ecu, if I ever wanted to unlock the full potential down the line.

My only concern would be if the engine isn't in the best condition because it was from an abused MS Familia. Plus, it doesn't help I'm on the opposite side of the country so I can't go look at it in person.

 

[MrGiggles]

I want to say that the stock photo of my engine showed the plastic cover, but it wasn't included. I think the valve cover had studs for it too, but I don't remember for sure.

Ebay has good buyer protection in the event that it's damaged. Maybe the seller will give send you some pics of the under-side of the oil cap.

 

[drexer13]

I bought my p5 with a pretty bad rod knock. The bearing had pretty much completely disintegrated. After the motor was disassembled I decided to just go ahead and rebuild it. The entire rebuild cost me just over 600.00 including the machine work. If your comfortable doing that kind of work yourself then that's the route I would take.
If you decided to go with a JDM engine first thing to do is a leak down test. If it tests good then replace the timing gear (belt, tensioner, idler pulley) the water pump and the oil pump while the engine is out of the car and the parts are easy to access. If the engine fails the leak down test contact the seller and ask him to use your warranty. You don't need to put the engine in your car to determine if it's good or bad.

 

[Luken10]

I haven't even heard of a leak down test before you mentioned it. The only test these online sellers claim to do are compression tests. I wonder if they would let me test the engine before purchasing it. I can easily see myself getting stiffed after the fact. I definitely plan on redoing a ton of stuff before the engine gets put in. Good advice, thank you!

To be honest I wouldn't be confident rebuilding an engine on my own. It is something I would love to try, but I don't have the time/resources/knowledge to do something that in depth. I am good with removing/installing things, but making sure all of the tolerances are perfect is something I have never dealt with before.

 

[MrGiggles]

I haven't even heard of a leak down test before you mentioned it. The only test these online sellers claim to do are compression tests. I wonder if they would let me test the engine before purchasing it. I can easily see myself getting stiffed after the fact. I definitely plan on redoing a ton of stuff before the engine gets put in. Good advice, thank you!

To be honest I wouldn't be confident rebuilding an engine on my own. It is something I would love to try, but I don't have the time/resources/knowledge to do something that in depth. I am good with removing/installing things, but making sure all of the tolerances are perfect is something I have never dealt with before.

If compression is good, there's no need to do a leak down. You usually do that if a cylinder is weak to see where the compression is going.