radkins

I started noticing a vibration in the clutch pedal while driving the car, and on my way home it seemed to get much worse. I shut the car off to get gas and it didn't want to start up. I had to jump it and it seemed to run fine, but when you pushed in the clutch it felt like someone was tapping on the pedal with a small hammer. I thought it might have been the throwout, but Zavier from the RX7 Store told me to check the oil for shavings. Sure enough, there are traces of copper in the oil. Not a lot, but half a dozen pencil lead or smaller sized chips along this some copper dust. I don't recall hearing any noises like squeaking or knocking though, but my belts started squeaking during the last mile or so. What cha think?

HAI-TEK7

iTrader: (31)

Rebuild time.

PhatManBUD

is that from scrapping the rotor housing?

PhatManBUD

spun a rotor bearing...is that possible?

villision

I personally think you spun the bearing. Who built your motor and when was it built? If it did spin, you may need new Iron's and e-shaft. Sorry about your luck, my friends just expeirenced the same thing.

Ty

poss

iTrader: (5)

Don't want to hijack your thread, but what causes a spun bearing?

I am getting ready to rebuild mine and last time I had it apart, the bearings were usable, but I would feel better about replacing them this time around. I just want to make sure this doesn't happen to me.

radkins

Here are some pics I took. The motor only has a few thousand on it, but we decided to reuse the bearings. THe last time I took the car out before this I was tuning up to 8500rpm, so I was doing 150 in 4rth. I'm sure that put the nail in the coffin, but I would think they would take that to some extent.

Rotary4tw

iTrader: (3)

It is likely that it is a bearing. Read Damian's thread of his recent troubles with his bearing as well.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/have-you-ever-herd-these-idle-knock-engine-rattle-462619/

I got a chance to look in his oil pan, and the copper shavings in there were very simmilar to the first image you posted.

Good luck bud and I'm sorry it happened. (If it did happen)

-Rotary4tw

(Here are some images that I snapped of coper that we found. The bearing that went was the one inside the front housing. The first image shows the catch filter clogged with shavings and silicone)

Stanello

iTrader: (1)

Yes, you spun at least one bearing.

What weight oil were you using, and what were the outside temps?

radkins

Temps were cool, oil was 20-50

GoodfellaFD3S

iTrader: (213)

I've blown many motors from detonating (usually with shitty hurley apex seals) but have never spun a bearing. That def should not have happened. A good friend just spun a bearing in his modded FD, but his bearings had over 100,000 miles on them.

sucks, hang in there man!

villision 1revin7

I just went through the same thing. I tried tuning my car when it was hot out spun a bearing and had to replace the e-shaft. I was using 25-50 castrol. sounded like I had a loose pulley, and you could feel it in the clutch. I am kind of anxious to know who built your motor,becouse I have been hearing about a lot of spun bearings from the same engine builder.

Mr rx-7 tt

iTrader: (5)

This is a big problem that I keep seeing lately with spun bearings. All it takes is a small amount of dirt or a lack of oil on the bearings to ruin one. Pay attention when you put your oil pan back on and don't use 4 lbs of silicone.

BTW: When you spin a bearing and get your engine rebuilt make sure you have flushed ALL your oil lines and your oil coolers!

GoodfellaFD3S

iTrader: (213)

These motors fail enough as it is from detonation......we need to keep the spun bearings to a minimum. In my opinion, when it comes to detonating, "**** happens" when you are pushing the horsepower envelope on pump gas, but there really is no excuse for a spun bearing wrt to engine building.

Jason

iTrader: (5)

spun bearings usually have nothing to do with the build of the motor. Most problems come from dirty oil or some sort of oil starvation issue. Also over revving can cause problems.

Snook

iTrader: (12)

I'd consider 8500 over revving. That is what I was thinking the whole time. It's pretty obvious that's too high of a rpm

I think radkins builds his own engines. He's done it all on 3d gens! I really thought you had this problem once before didn't you?

Mr rx-7 tt

iTrader: (5)

8500 rpm isn't over reving, you just aren't making power with the twins. I have run engines to 10,000 plus RPM DAILY for years and got 120,000 miles out of the engines.

Snook

iTrader: (12)

Wow that's almost unbelievable. I used to worry when I'd have my rev limiter to 8100 and then I'd see 8,400 or so on the peak. What do you have to alter to rev the engine that high? I was told that past 8k or past 20psi the engine had to be built very carefully to hold together. At what rpm with the twins can you not maintain lets say 10 psi or can you?

Mr rx-7 tt

iTrader: (5)

Surge,
If the motor is built well it won't come apart. There really isn't a reason to rev it that high as you aren't making power. Shifting at 8000-8500 is all you need.

Mr rx-7 tt

iTrader: (5)

I was just looking at the area where the oil pan bolts to the motor. Notice the excess silicone all around the block?

potatochobit

iTrader: (1)

when i had my engine installed by the shop they used extra silicone on the outer edges. not sure why, i think its because how prone the gasket is to leaking.

LUPE

I've done this and seen a few like this. It was always the front stationary gear bearing. Cause was always, the front cover o-ring. So, oil starvation.

damian

iTrader: (2)

I have spun a few bearings in my race car over the years.

2 Front
- 1st was due to me being an idiot and running way to low oil in the pan at an event at RoadAmerica.
- 2nd, caused by engine building using way to much sealant and the sealant clogged the oil pickup inside the oil pan.

Rear
- cause was not determined, however we say from logged data that oil pressure looked very high and stable, and it was rear bearing (low oil pressure will cause front to go first) so most likey was unlucky debris getting into the oil.

Most the posts here are correct:

Front bearing (staionary gear)
If it is the front bearing (most common), then it typically is due to loss of oil pressure but can be unlucky debris getting to the bearing as well.

Rear Bearing (staionary gear)
This is typically due to debris in the oil, as loss in oil pressure would cause the front to go first since the path is rear to front. Over revving can cause this if the oil pressure is not maintained or the engine is not balanced well for very high revs and low oil pressure.

Rotor bearings
Typically these do not happen on their own, but will go as a result from the rear bearing going and sending bearing chunks into the rotor bearing oil, causing them to get destroyed.

Some things to note:

The rest of the bearings will typically be unusable and the e-shaft journal where the bearing spun may be damaged and the e-shaft may be unusable as well, however, ... typicaly the rest of the engine is undamaged and reusable, including the seals.

Out of the 3 engines that I have spun bearing in, all of them had reusable (undamaged) housings, irons, rotors, rotor seals, and basically everything else other than the bearings. The engine with front bearings that spun even had undamaged rotor and rear bearings, also reused.

The good news is that, most likely, you can replace the bearing(s) and put the engine back together with little cost since most the parts should be usable.

HOWEVER, like some mentioned above, IT IS VERY IMPORTANT to properly flush the ENTIRE oil systmne and oil pathways in order to remove any bearing particles. ESPECIALLY the oil coolers, oil pan, and oil pump. If not flushed properly, you run the risk of having the destroyed bearing paticles contaminate the oil and destroy the bearings all over again.

holla at me if you need any help with this

here is a pic showing part of my rear bearing all messed up:


pic of eshaft damage:

damian

iTrader: (2)

>>I am getting ready to rebuild mine and last time I had it apart, the bearings were usable, but I would feel better about replacing them this time around.

a note on this, out of many engine parts, bearings are one thing that you WANT to re-use if possible, if they are not damaged. The reason is that they are already broken in and have a proper clearance to the e-shaft. If you replace the bearings, the breakin proccess is much longer. For the most part, using the old bearings is a good thing, as long as they are in perfect condition with no damage, as they are already 'mated' to the e-shaft.

GoodfellaFD3S

iTrader: (213)

Damian, good info, thanks for posting

I will say that I have torn down quite a few engines with spun bearings and most of them did have damage to an engine rotor and the iron housings, as the rotor had come in contact with the housings at the corner seal tip. If you come away with less damage consider yourself lucky (relatively speaking)

Also, re: bearings. While it is a valid point about reusing perfect bearings, unless they have less than ~20k miles on them we always replace them at the shop.

Reason being, I have seen multiple instances of owners spinning a bearing at 100k+ miles. They had a previous rebuild at around 50-60k and the shop in question decided to reuse the bearings because they 'looked ok.'

Pressing bearings correctly (esp rotor) can be a pain, and it's my opinion that this is why it's not a very popular procedure.

But as they say, do it once and do it right. It does make for a longer breakin, but for a street car that is expected to have longevity out of the engine I think it's absolutely necessary