bluedragon

[B]Hey guys,
I've heard several people talk about carbon locking in the engine and I was just wondering if someone could explain what carbon lock is and how it happens? Thanks a lot!

-=Rowdy=-

I think it's a really light padlock made for high performance?

DEMdriver

lmao :D ....

I ran a google search and couldn't come up with anything substantial.

RX8SaxMan

From what I understand, it's when carbon deposits build up in the combustion chamber making the rotors freeze up. I don't know what causes it though...

RX8PDX

From what I have heard, driving like a sissy too much, causes it. And rich conditions ?

You need to get the temps up there to make sure the carbon goes out with the exhaust.

I dont drive fast all the time, but when I do go from light to light, I still let the RPM's climb to 5-6K.

I so mostly city driving. I am noticing that the more I keep it above 2K, the less gas I use also. If I gear too low, even though it doesnt feel like I am boggin, it seems to suck the gas. Is this a fuel map problem?

I dont know what ECU version I have either.

RenKat

All the seals (Apex, Side, Corner and Oil Control Rings) are spring loaded.
If you run the engine below 4K rpm all the time carbon will build up under the seals and lock the springs from moving. Once this Happens the seals can get stuck down causing low compression (Hard starts and poor performance).
Sometimes you can get it back by running ATF+High RPM maybe.

English

I thought it was when there's a buildup of gunk on the back side of a piston, so it cannot completely cycle through it's motions....this buildup can grow and further buildup causes a loss of power because it's missing in timing and unused fuel is exhausted....I'm not sure how it would apply to the rotary engine....anyone REALLY know?

dcfc3s

There's 2 things that can be construed as carbon lock.

First, general carbon buildup on the rotors that builds up around the seals and keeps them from moving. This is common on motors that aren't driven hard at ALL - the rotors are THICK with carbon deposits.

Second, it can build up so much that a piece of carbon sticks between the rotor housing and apex of the rotor, keeping the rotor from spinning. The starter motor can't get enough torque to break past the bit of carbon, so the motor is essentially locked. This can be tricky to remedy, as sometimes pushing past the carbon deposits can snap apex seals.

It takes a VERY long time to build up serious carbon deposits, though - you guys have another 8-10 years before it's a concern . It is a good idea to run your car to redline every now and again to blow the crap out of the motor - don't just drive it easy around town.

BTW, on the various FC motors I've been through it's more common to see a heavily carbonized motor on an automatic. I guess more automatic drivers just gimp it along nice and easy .

Dale

army_rx8

hehe oo so it's good i dirve it liek i stole it

No More Oldsmobiles

The AT tends to shift before redline unless you're WOT or thereabouts. Another reason to use the manumatic and redline it once in a while.

WhiteDealershipRice

There was a nice article about it on GRM a couple months ago. I'll see if I can find it.

staticlag

Sounds like a plus for synthetic oil.

juikster

Yes, drive it like ya stole it, he!he!

RotaryJeff

Whats "ATF"?

No More Oldsmobiles

I don't think we're supposed to use synthetic oil in the 8. The engine needs to burn a bit of the oil, I've read.

Anyone have the cite on this?

-=Rowdy=-

Ah-you opened a can of worms with the synthetic discussion :D

Razz1

ATF = Auto Transmission Fluid

Another form of carbon lock up is when a pc of carbon braks off and lodges in between the
spark plug gap.

JM1FE

https://www.rx8club.com/showpost.php...&postcount=328

https://www.rx8club.com/series-i-tech-garage-22/cumulative-synthetic-oil-discussion-52856/

Enough said.