s-rx8

Hey Everybody,

I've been a long time admirer of the RX-8 and finally pulled the trigger on a 2004 with some issues. I'm been a piston guy for a number of years and wanted to learn about the rotary engine, so here I am.

All the symptoms I've read lead up to the low compression issues so today I went ahead and tested with my standard compression tester, and recorded it at a high rate. I disconnected the esscentric shaft sensor and I assume that is what gives the RPM reading? I was planning on using Torque to record the RPM during the test but after seeing no signal, I pressed on thinking I'd review the video and count pulses per second.

Upon review of the results, my averages at 16' ASL, 78deg F, 1 plug out at a time, WOT:
Front, Leading: 64 68 62 psi
Rear, Leading: 76 89 86 psi
During a 7 second period, 65 pulses were observed.

My RPM question:
- That equates to 557 RPM, am I supposed to divide this by 3 to get an accurate count? Or is my starter on supercrack?

I'm quite surprised that a cold start is decent and running, good enough to play around town with. I put 550 miles on the car during the drive home, runs great at speed. Can't shut her down and expect a restart. Oddly enough, a pop start kicks it back over without issue. The starter seemed to be replaced with a 2 amp CarQuest starter. Previous owner owned for a short time and didn't know history on it.

My starter / coil question:
- If this is indeed 557 rpm and not the 186 (if dividing by 3), could this starter be drawing so much current for some reason that it would draw power from the coils to a level that is enough to kill em during hot starts?

Link to video:
Thanks in advance!

200.mph

iTrader: (9)

your starter is not spinning at 500+rpms. the s2 starter is about 300 iirc and the s1 upgraded one is about 260ish

RX8Soldier

iTrader: (24)

You really need to invest in a rotary specific compression test in order to get the proper results.

Also, we need a bit more information to assist you. How many miles? Any mods? When was your last maintenance performed?

I doubt your starter is drawing so much juice from the coils. That just doesn't sound logical to me.

s-rx8

I've been looking into the rotary specific testers, but a short test as I did I figured it would allow me to see if I had sharp differences between the apex seals and/or rotors.

88k miles, drop in K&N, I see this newer'ish starter and looks like the cat was either removed and gutted or replaced b/c there are weld marks on both sides.

Maintenance, the previous owner didn't give me the impression that he did anything but a battery, but the battery had a bad cell upon purchase, so I put one in that night before the drive home. Plugs / wires / coils are in the mail right now, I plan on having them in before new year.

I'm working up the video now to put on youtube and share with everyone. Hopefully in a couple hours I will have a link for you.

Thanks!

200.mph

iTrader: (9)

rotary comp testers are either expensive or hard to find. if ya need parts check my part out thread

s-rx8

Link to video added in original message.

04Green

iTrader: (1)

I have to agree with the need for the specific compression tester. I often wondered if you could test compression that way. Then I borrowed one from a friend.

IMHO, the speed on the video sounds about right'ish. But, all the compression numbers are low. 90 is passing for "about right'ish" on the speed. Each pulse is one revolution of the crank. The rotor spins at 1/3 of crank speed.

I do not know of a tester in your area. I do know of one in Lakeland. I think the dealer chargers a couple of hundred bucks for the test. A rotary shop would likely charge less.

If you need a motor, um, my car was recently totaled by a young lady who did not understand the concept of slowing down for traffic at a toll booth. The engine is less than 6 months old. The car I bought does not need it. PM me for data, but get a reliable compression test before you make any decisions.