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brownmiata
09-22-2013, 08:44 PM
So 5 months or so ago I purchased a car from a guy with a good motor it just wouldn't start. It had tons of goodies (turbo, roll bar, panasports) so I bought it. I got it started a day later it had reversed fuel lines. The car overheated bad though. Head gasket was bad. So I replaced it and then it started knocking. I looked up the issue and was told it was because of bad head gasket swap.

I dumped the oil. Sure enough most of it was water. I then replaced the gasket the correct way, Drained everything out, Took the engine out,oil pan off (drilled and tapped it for oil drain) I started it up. Terrible knock. Bought a new motor off craigslist. Installed. Knocks just as bad. Bought a auto motor off craigslist and the short nose is all kinds of messed up. So now I'm sitting 3 engines in the garage with no clue what to do. What are my options as far as rods/ bearings Bla Bla Bla. I've read so much different stuff from throw em in, to you need a full $2000 rebuild. I'm so confused!

Thanks in advance.

BM

brownmiata
09-22-2013, 08:46 PM
Also, if any tolerances need to be checked I have a person very close that owns a machine shop that will do anything for me. (Family)

What I want to do is take the pistons from the auto motor, the crank and block from the best manual motor and get new bearings and call it good. But everyone gives me this "you are psycho" look and won't explain.

Thanks again!

Pfunk
09-24-2013, 06:16 AM
What are the exact engines you bought?

MX5RACER
09-24-2013, 08:23 AM
Are you sure this is rod knock? These cars have hydraulic lash adjusters and when they sit for long periods the oil drains out and then they tick loudly upon start up. Please upload a video of the engine running.

brownmiata
09-24-2013, 10:20 AM
I'm not sure what you mean by what engines.

It had a 1.6 manual
Then I put in a 1.6 manual
Then I bought a 1.6 Auto

Also am I sure it is rod knock? No. But it sounds just like the first engine and the bearing looked as if someone had taken the middle and pressed it till it stretched.

This car is making the same noise. I drove it around the block with little power. Couldn't hit boost and terrible knock.

Another thing. Ever since I've got this engine it has taken 2-3 minutes to start it. Never just fires always have to play with throttle and fuel lines sometimes.

Thanks again I will upload a video when I get home

psulja
09-24-2013, 10:56 AM
Sell all 1.6's buy 1.8.

No but really, if you are having that bad of luck with all these used engines, and if it is indeed rod knock, going for a rebuild so you know exactly what is going on with the motor and can start over fresh.

brownmiata
09-25-2013, 11:01 AM
Not sure what you can hear. My phone went into restore 10 seconds into the video so it was only 7 seconds long.

Let me know!

http://www.youtube.com/watch?v=xeVy7pIZllE&feature=youtu.be

BoBo
09-26-2013, 04:06 AM
Do you have a longer vid? It's hard to tell on the short vid. Like the other guy said, the early lifters are known to tick loud similar to a light rod knock, that might be your problem. If you can, swap a 1.8.

kung fu jesus
10-19-2013, 08:26 AM
I can't tell from the video.

If you need to check the rod bearings' clearances, then you can do it yourself. First is to find the min/max clearance. You may need to search the internet for this, a factory service manual or Miata perfomance book may have that info. I don't know them off the top of my head.

Second you will need to disassemble the motor. Now, doing that, assuming the motor is on a stand, remove the oil pan, tray and oil pickup to access the crankshaft and rods. You will want to disassemble ONE of the rod end at a time, using plastigauge to check the clearances. Plastigauge is a 'squishable' plastic you lay between the mating sufaces. So, remove the rod end, remove the bearings, clean them, lay some plastigauge in there, reassemble to factory torque specs, then remove is again to measure the 'squish' with the handy gauge on the plastigauge's packaging, record the number, measure the thickess of each bearing. Repeat for each bearing. The squished plastic is easily removable.

Third, compare the numbers you achieved to see if the they are to spec and fairly even. From there, you can choose to replace the bearings, discuss line-boring, polishing the crank, whatever. If you have family that is familiar with engine machining, that is a good place to start to ask questions...BUT you need to do your work first!

I know this sounds tedious, but this is the nature of building a decent motor, exacting detail and precision.

If I were to do what I described above, I would look into disassembling the block completely, have to cylinders rehoned (not punch the out), re-ring the pistons, new bearings as needed, gasket set, etc. Tank the parts so they are like new.

There is an indescribable feeling to building your own engine, even if it is just refreshing it, and have it run like a sewing machine. When you pay someone to do it, sure, you expect the same, but a lot of the disassembly/reassembly can be done by you, with a few rented/borrowed tools, and a bit of time. It feels sort of like this:

9649

Increase your shadetree rep, stop chucking money at unknown motors and crap off Craigslist.