While driving up a normal hill using mild acceleration my engine decided to lock up on me! Oil level was at the full line, this is the second engine, the original engine threw a apex seal when I let the oil level go 2 quarts low. When that happened the engine still ran on one rotor, no lockup. So I paid attention to the oil level on the replacement from Atkin's, Checked it once a week and topped it off. Changed it every 90 days! Not gonna get caught with my pants down again!

Oil pressure I assume was good since no buzzer went off before it seized. After getting it towed home I tried to turn the crank pully bolt both ways with my breaker bar, no movement at all, just loosened the bolt. I heard of carbon lock, but it should of moved a little, shouldn't it? I had 3mm apex seals, if one of those came out would that lock it up that tight?

Now the big one, what happens when a main bearing goes? The paperwork from Atkins plainly states that the failure of the bearings is NOT covered by the warranty! What does he know, if they look good and measure in tolerance he does not replace them? Is that a wise thing to do?

Has anyone dealt with failed bearings, if so, what gets damaged when they fail? Can I replace the damaged parts instead of buying another rebuilt keg? I have plenty of time but not money, so fixing the existing engine would be preferable.

Let me know what you think, by the way, I purchased this new off the showroom floor back in Feb 1989. 1988 GXL
Gary

 

Speculation can only get you so far. The only real way to diagnose the issue is to do a teardown & failure analysis. Assuming you had the engine rebuilt by Atkins based on what you are saying, they will let you know if its covered under warranty. I've never dealt with them much, so I'm not familiar with their policies. Generally, warranty only covers defects on workmanship/labor. Do you have paperwork for the build? It should show what all was replaced, but that won't really help much aside from letting us know what went back into the engine.

It looks like time may not be the resource you need based on what you are describing, though. Hopefully you get it sorted out.

 

Drain the oil. If you gets large specs of metal in it, you've spun a bearing, which usually means almost the entirety of the metal is now garbage.

 

How long since you purchased the engine? If you're still in the warranty period I would contact Atkins and see how they want you to proceed. If it's possible this could be a warranty claim they may not honor it if you disassemble anything. From digging around on their site it sounds like they may want it shipped to them complete with the oil still in it.

 

^I agree this is likely the best approach if the engine is still under warranty, but I think he may have a hard time finding a shipper that will accept an engine for shipment with oil still in it. Typically engines ship in crates, or strapped onto a pallet and dry.

 

Thanks everyone for the advice, I put about 70k miles on this engine so it has no warrenty on it. This forum got me in the mood after reading here how to remove the flywheel bolt. That seems to be the hardest thing to do on a rebuild! There was a link to Mazdatrix so I purchased the wrench and stopper for $92.55. Now the get an engine holder and stand.

One problem at a time.
Gary
p.s. someone uses a signature with their posts: "The natural habitat of a 7.......... on jackstands!" Thats a great line!

 

I've changed clutches on RX-7's a few times, it's not so bad to get off with a nice impact gun, it's the torquing it back on to spec that you need to be really careful about.

My personal greatest fear of building an engine would be clearancing the side seals. If the biggest fear you have is the flywheel nut, you should be home free.

 

Just a note that the oil level had nothing to do with the previous apex seal failure. Engine holds 5 quarts anyway. Quite likely it was just worn out because of the silly 3 piece apex seals Mazda used on the FC.

"Carbon lock" is almost a myth. It doesn't happen to a running engine and frankly, virtually never happens at all.

3MM seals are basically the same as 2MM seals except generally used to make worn rotors salvageable. From Atkins they will be 2 piece, so don't suffer the ware problems that factory 3 piece seals see.

If the engine doesn't rotate, it will not be an apex seal issue.

Honestly, when a main bearing fails, it generally trashes most of rotating assembly. Mail bearings, rotor bearings, eccentric shaft are all suspect after a main bearing failure. Depending on how bad, the bearings can spin in the stationary gears trashing them as well. If the failure is over the long term, metallic particles could have circulated through the engine also abrading down the rotor thrust surfaces and irons. Plus little things like trashing the oil pump, regulator, clogging up the cooler, etc.

Now that said, main bearing failure is very rare.

The only cause aside from over-revving is oil starvation.

The buzzer SHOULD have sounded, however that assumes the oil level sender is indeed working. Note the buzzer sounds only for oil level, not pressure. Is it possible an oil cooler line let go? If so, you'd know because the engine bay would be covered in oil.

Another potential failure is the o-ring between the front cover and front iron. If it lets go, most oil pressure bleeds off under the front cover.

Check the oil level. Any shiny on the dipstick?

Until the engine is broken down, it's hard to say.

Here's an example of a worst case scenario I helped with many years ago:
Engine Damage! (aaroncake.net)