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help settle compression numbers. getting two different opinions from mechanics
Bottom rotor Top rotor
Im looking to a purchase a '09 rx8 gt with original motor at 112k miles for $5500. I've asked two people to review these compression numbers and they're in disagreement. One says it failed the compression test because they should be producing at least 110 at 300 rpm, the other mechanic says it's fine because you're within 15% of each other and the car is a steal at $5500.
the barely pass/fail limit on normalized numbers is 7.0. Which 4 faces fail, the other two aren’t far from it.
So the engine is in need of replacement now, unless you know RX8s inside out and have another 5 or 6 grand to replace it now you would be well advised to exit, stage right.
the engine is in need of replacement now, unless you know RX8s inside out and have another 5 or 6 grand to replace it now you would be well advised to exit, stage right.
Well I went ahead and purchased it for $4500. Im putting back money for an engine replacement but it's currently starting up immediately, both hot and cold. I feel like I can ar least get a couple years out of it, ignition system seems very healthy as well and I'm still issuing my old Buick as a daily to keep miles off the 8.
you already have issues, but the best lessons are hard earned, wish you well.
Yes but the body, interior, and other most everything else is immaculate. Would you disagree that I could get a few years out of the car? I imagine continuing to use my other car would only extend the life further and as previously mentioned, I'm okay with replacing the engine eventually.
Guess I'm just slightly bothered because between this forum, others posts I've made, other websites with information, and just general research it seems like 4500 was a good price for current compression. I even spoke with several rotary mechanics and they seemed to agree that there's still life left in the engine and that the numbers are bare minimum and could potentially last years.
I dont regret my purchase, but I guess your post just scares me a little bit like I've made a horrible decision.
well there are likely other things that aren’t immaculately apparent to your eyes that are either worn or soon to fail with that mileage, but maybe you’ll luck out and I’ll be eating scrambled egg off my face for breakfast over the next several years. I suppose we’ll find out. But maybe it’s because I still remember that Triumph TR6 I rushed into buying without having any clue way back when, lol. The funny thing is, I loved that thing regardless. Like I said; the best lessons are the hardest earned. The same is true for memories. It will all work out in the end.
well there are likely other things that aren’t immaculately apparent to your eyes that are either worn or soon to fail with that mileage, but maybe you’ll luck out and I’ll be eating scrambled egg off my face for breakfast over the next several years. I suppose we’ll find out.
Any sagely advice for me moving forward that I might not find on the forum? Things to have checked out that might fail or cause problems that might not be evident? It's a 2009 gt, 112k miles.
Verify the ignition. "seems" is not a measurement. It's the number one killer of engines and catalytic converters. Also, verify the catalytic converter is in good shape inside.
rx8help.com was written by a member here, read through it.
The fact that it doesn't have symptoms is good, but there is no forecasting how long that will continue. Could be 50 miles or 50,000. But probably not 50,000.
Verify the ignition. "seems" is not a measurement. It's the number one killer of engines and catalytic converters. Also, verify the catalytic converter is in good shape inside.
rx8help.com was written by a member here, read through it.
The fact that it doesn't have symptoms is good, but there is no forecasting how long that will continue. Could be 50 miles or 50,000. But probably not 50,000.
I've actually already ordered BHR coils + wires, and OEM plugs, I wanted to start fresh and upgrade the coils and try to increase longevity until my eventually engine rebuild.
I'll look around and try to figure out how to check cat health, it isn't glowing and the vehicle was purchased in Texas so I assume that gives some insight into cat health sense they require emission testing.
I already gave you the best “dad” advice I had, but it was too late.
Start setting aside more than you had planned. If it goes in your favor having extra is never a bad deal. If not, you’re covered.
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Well I wish you had been so blunt sooner, he was originally asking 6k, and I had many people tell me that $4500 would be fair with those compression numbers as long as the rest of the car was in "great" condition. I still would have purchased it, but I would have brought physical cash and talked him down to $3500 at least.
I see you in a lot of threads offering advice from my research, I imagine I'll see you more. I wanted an rx8 in 2004 and now I'm 31 years old and I finally feel confident enough to own one. It's my dream car in the same way that other adults dream of owning a Lamborghini. I look forward to your kindness and advice as I travel this journey.
Your compression numbers really aren’t that bad. I’ve found anything above 6 bar is fine. Car will hot start without issue with a good ignition system. You will have reduced power, up to 15-20% from stock. Expect to replace engine, so long as you take really good care of it, in roughly 15-20k miles. I have to say, it’s in immaculate condition. Definitely a good candidate for an engine swap. Good buy and welcome to the club.
Last edited by CaymanRotary; 04-17-2020 at 12:56 PM.
I was in the same boat but paid 3000$ for my 04. Almost 5 years and $15k later I'm happy lol. I noticed your passenger side dash is cracked. Is mine the only 8 with a good interior. (my wife takes care of my car lol)
I was in the same boat but paid 3000$ for my 04. Almost 5 years and $15k later I'm happy lol. I noticed your passenger side dash is cracked. Is mine the only 8 with a good interior. (my wife takes care of my car lol)
What did you spend $15k on to be happy? And ya, interior is immaculate other than dash. My defrost button isn't even cracked!
What did you spend $15k on to be happy? And ya, interior is immaculate other than dash. My defrost button isn't even cracked!
Alot of little things. But few top ones are a:rebuild engine that got both housings replaced and the center and rear iron replaced ( reman parts I believe).
A Bennet built and a bhr coil kit (don't ask)
clutch kit ( bought new pins and bolts too)
omp (not even using it but need a working one plugged in)
optima red too batt
starters (two new one used)
Fuses (more expensive then you'd think)
a few sets of spark plugs
Wiring
I could go on. I'm sure I'm missing alot as it's been spread out over the years.
Izvzlm you have a lot of areas to address with that car. If you ignore any, they could cascade into even more serious issues:
This is also the long term recommended maintenance list from us here on RX8Club.com.
Car mileage over 30,000:
- Replace Ignition coils
- Replace Plug wires
- Replace Spark plugs
- Clean MAF (mass air flow sensor)
- Clean ESS (e-shaft sensor)
- Reset ESS profile
- Clean power steering connections
- Clean battery terminals and clamps
- Replace transmission fluid
- Replace coolant (Mazda FL-22 is highly recommended, read this thread for why: Issue Many Are Ignoring: Most Coolants Contain 2-EHA (which 'eats' silicone))
- Replace air filter
- Replace brake fluid (fluid in the brake lines AND the clutch line) ~$300 USD in parts if you shop smartly.
Car mileage over 60,000:
...all above, plus...
- Clean all chassis electrical grounding points
- Replace accessory belts
- Clean OMP lines
- Replace rear differential fluid
- Replace thermostat
- Clean / Straighten AC condenser fins
- Clean / Straighten oil cooler fins
- Inspect catalytic converter
- Clean / Inspect intake valving
- Consider / inspect all points in 90,000+ as well, many items fail early ~$130 USD in parts if you shop smartly.
Car mileage over 90,000:
...all above plus...
- Replace coolant bottle
- Replace radiator hoses
- Replace radiator
- Replace front O2 sensor
- Replace motor mounts
- Inspect clutch pedal assembly for flex / weld breaks ~$900 USD in parts if you shop smartly.
At 100,000 miles, anything still original in your entire cooling system and an original catalytic converter are the greatest risks to your engine. Replace immediately.
Last edited by gwilliams6; 04-18-2020 at 02:52 PM.
04-06-2020, 02:55 PM
