shashumba

im looking to buy an rx8 and have found one that seems interesting. I have read around and learned a lot about rx8's but i am not anywhere close to knowing what to make of this. The rx8 in question is a 2004 gt with 100k km on it (about 60k miles) and it seems to be in good condition. the asking price is 500$ CAD. seems like a good buy but there were a few modifications done to it that worry me apart from the standard ones like suspension changes and regular maintenance. the original owner added a second oil reservoir to send oil straight to the apex seals so it does not steal any used oil from the engine... im not sure how it works but that was the explination of how it works that was given to me by the person selling it. secondly there is a midpipe instead of the regular catalizer and some sort of filter type thing to help keep the carbon from building in the engine. i think he called it a catchcan if im remembering correctly. any opinions on theses modifications before i go see it (and if i like it i will of course take it for a compression test).
thanks a lot in advance for any useful help

BigBadChris

iTrader: (4)

Welcome aboard.

I think you are describing a Sohn adapter. It is a block off plate that allows you to use a different type of oil for injection. Cleaner burning 2 stroke instead of dirty 4 stroke.

As for the catch can. That's not really a filter per se. It is more of trap to capture oil vapors. The plumbing was redone in cars sold in 2006 and later. The catch can traps oil vapor before it hits your air intake.

Check out the new member section, there are many helpful threads. A compression test will show you the health of the engine, and only the engine. Make sure whomever does it puts the car on a lift and examines the rest of the car. A $500 car can have a dark past.

Good luck!

shashumba

oops i forgot a 0 in the price haha its a 5000$ car. but thanks a lot for the input chris. Do these mods change the engines health as my biggest worry is the engine as i have no real no-how on rotaries. i learned most of it right here

BigBadChris

iTrader: (4)

I don't know the exchange rate, but here's my advice. Rotary engines are fragile creatures. If you love them, they will love you back. If you mistreat them, they will break your heart. A rebuilt engine can cost almost as much as your car is worth, and that can be a very hard pill to swallow.

shashumba

it is a sohn adapter and it is 6 years old at least, any possibilities that it might have messed up the engine without a compression test being able to see it?

BigBadChris

iTrader: (4)

What a question.

The compression test measures just that: the ability of the engine to compress air. If you have bad seals, you will have low compression. Generally, older engines have low compression. If compression is low enough, it won't idle or will die when you're coasting.

There are several ways an engine can die. Lost compression is one of them. The easiest one to test for is a blown water seal. Water gets into the rotor, rotor can't fire. You'll get a really hard start and sometimes a plume of white smoke/steam. A coolant pressure test is cheap and easy.

The only way a Sohn can malfunction is to stop doing its job, that is to say stop feeding oil. If you do not feed oil to the apex seals, they will wear out quickly. (Compression test will show this).

shashumba

so if say the compression is bad, the car just needs new seals and the engine should be good to go. am i correct? (not that i intend on ever changing the seals myself or anything hahaha just out of curiosity here)

BigBadChris

iTrader: (4)

Depends which seal goes and why.

A shattered or cracked apex seal can cause catastrophic damage. Chunks of metal, flying around your engine, dozens of times a second. The housing that holds the rotor will likely get damaged too.

A new housing is several hundred dollars. However, once the engine is apart, it's best to inspect all the parts. Seals checked for wear and clearance. Housings inspected for impact, corrosion, or pitting. You can replace just what broke, but it's best to replace it all once you're in there.

A rebuild is so expensive because the engine has to come out, and it takes between five and ten hours to remove, and another five to ten to reinstall. Mazda says it should drop out the bottom, but most guys pull it out the top because they don't have a lift.

Colon Terminus

The rotary specific compression test at a Mazda dealership reveals pretty much everything about the health of the engine. If it passes the test and you otherwise like the looks and condition of the car, buy it. The price is very good.