Tested my compression today. I believe it is still technically "good" but it is very close to not being. Any opinions?

R1: 7.2, 6.9, 7.1
R2: 6.9, 7.0, 6.9

Both are normalized to 250rpm's.

Engine is a Mazda reman with around 20k. I always premix my fuel and change oil on time with 5w30 oil.

 

Yeah, right on the edge. "6.9 minimum". Some dealers would count 6.9 as failing, others as 6.8 as failing.

 

Any warranty left?

 

No, way out of warranty. What kind of life do you think is left? It runs and drives great still,
No starting issues. Also I just checked my battery it's resting voltage is 12.0V, does a dying battery yield lower compression results?

 

A dying battery will reduce the starter speed, but that can be corrected with the normalization.

Any idea how much carbon is in the engine? It's likely that the engine is just a crappily built reman considering how even all the scores are, but any carbon caking would at least be somewhat solveable. Not enough mileage for the seals to have worn a dependancy on carbon caking.

 

Well I drive the car to redline every couple days but that doesn't mean it isn't caked with carbon, I don't think it's ever been sea foamed

 

It might be worth a doing a good steam clean. (seafoam works just as well as distilled water, while costing 80 times the price)

 

Where does one steam clean their engine lol

 

Read this thread: https://www.rx8club.com/series-i-tec...r-pics-241867/

I tested various decarb methods, borescoping the rotors to see the effectiveness for each, and there are a couple examples in the thread of how to set up water ingestion for a steam clean.

It's also popular on RX7Club, and there are more examples there.

 

Well I know the owner before me and I know he wouldn't allow carbon build up and I know I didn't, so mazda remans can have carbon build up when they are put in initially?

 

No, they wouldn't. However as long as you are using gasoline, there will be carbon buildup at some level. No one has documented how much carbon builds in how short or long of a time, I'm the only one that I know of that has borescoped their Renesis, and i did all of that about 2-3 weeks before I sold my 8.

Again, I'm not saying that carbon is your problem, but since you are so borderline, decarbing is a shot at restoring some compression. If the reman is just crappy quality, then no, decarbing won't help you much, if at all. Decarbing is basically the only thing you can do to see if you can improve the results, short of replacing the engine, and yes, it may not actually improve the results.