The Lonely Driver

iTrader: (1)

Glad you have your running how you would like! Did you ever redo the compression test to see how it looks? Even though I think mine was good, while trying to troubleshoot my own separate problem, I think I have a blown coolant seal (which can happen even with good compression as I understand it) and am looking at a rebuild. But Ill do what I must to make my baby run nice again, just might be a while lol

S4 Vert

Thanks!

No I have not performed another compression test since, but I really need to just to be sure my compression is within good standings. But now I have a new problem as of this morning, I can't get my car to go into gear when the engine I running. If it isn't one thing it's another ha ha : /.

Is your engine using a lot of coolant, or smoking? I hope that your water seals are good and that your engine does not need a rebuild.

Grinch

iTrader: (2)

I tried min today and need some input from you guys. 1. car was not warm up 2. my tb is off due to a lot of changing stuff but i figure would be the same as holding the gas down.
rear

front

S4 Vert

It hard to tell where your readings are in the pictures, however they do look very low from the sweeping motions.

It is best to perform your compression tests when your engine is warmed up, and be sure to remove the valve stem from the compression plug. Also be sure to look back on the previous post in this thread to make sure you are following the proper steps as described.

Is there any way you can video record your tests? That would help, or if you can tell us your three pulse psi results, ie 70psi, or 80psi.

Grinch

iTrader: (2)

my bad I thought it would take you to the video. Only reason not sarted it becuase I just put big injectors aem coils and a single setup and have no map yet and was to the point wanted to make sure it was good before kept going. Mistake of taking the guys word for it claiming comp was 120. note this is my first rotary car.
rear
F52B00CB-F155-44A4-B262-09586A1F1A7F-1045-0000013250329C1F_zpsf19261fd.mp4 Video by lanet420 | Photobucket
front
F6C8A5F9-31C7-45C0-A00F-A1BBF03EE7D6-1045-00000131E2C97878_zps0098eb26.mp4 Video by lanet420 | Photobucket

S4 Vert

First RE car? Welcome to the world of Rotary!

Your rear rotor reading look very low, the front rotor looks a little better though. As I was advised in this thread, be sure your battery is fully charged. Maybe the throttle body might need to be installed to get a better reading.

Lets see what some of the more experienced members have to say, they can give you better advise than me.

Grinch

iTrader: (2)

battery was fully charged to do this. this was done with the valve removed. I didn't eve put it back in to see how high comp was cuz it looks like the rear has blown apexi seal from the reading I've done. If its blown I'll probably part it all out and do a ls swap Thanks for the help and info guys!

S4 Vert

You are welcome.

LS swap sounds like a plan, a turbo LS swap would even be better .

Fritz Flynn

iTrader: (263)

Rear rotor looks like one apex seal is gone (1 high followed by 2 low) but the front is fine.

In general I think the piston testers will test low.

S4 Vert

Well I just purchased three more fc's that were running but have been sitting for years. I have tried starting the s5 vert, but it did not turn over, so I performed compression tests on the front and rear rotors.

Here are the video:



What do you think?

misterstyx69

iTrader: (142)

Your rear is crappy..
I mean, it is rebuild time..
your engine..not your ***..lol!

Just to let you see for yourself,watch the video of the front..3 nice even bounces.
The rear does not have the 3 bounces..it is like one good one,and a pooooff..

S4 Vert

Ha! Ha! Crappy rear, that is funny! Thank you for clarifying what you meant .

Ok, I guess it's time to role up my sleeves and get busy.

S4 Vert

Ok, so I performed compression tests on my GXL. This time around I got much better results, but I am still not sure if the reading are satisfactory. The engine would not turn over, so I am thinking maybe fuel is not reaching the fuel injectors.

Front rotor compression test:


Rear rotor compression test:

lduley

iTrader: (1)

front rotor on the GXL is toast, that needs a rebuild also, rear rotor is good, which is surprising since usually the rear rotor goes bad before the front

but, anything can happen

RotaryEvolution

iTrader: (30)

the last test on the GXL seemed to give strange results since it wasn't always 2 low peaks but alternated from 1 to 2 low peaks. it could be an issue with the gauge but the starter follows the sound, so i'm guessing they're both toast.

IMO a digital system isn't much more to put together than buying a new mechanical gauge. i just put together a dual transducer unit to test both rotors at the same time for under $100. you can also use the data to calculate cranking speed during the test as well for more definitive results. after building it i regret not doing it sooner.

credit given here:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/$150-pc-based-compression-tester-1021454/

credit to me: the unit listed is out of date though and the DI-145 is capable for only $35 shipped. the resolution on the DI-145 has much to be desired though at only 240 samples per second if only one channel is enabled where the DI-149 has 500 times that resolution for $59, both would work fine but if i want to test both rotors in the same sample or a piston engine's cylinders all in the same test i would choose the DI-149.

even a chinese transducer will work but the scaling will suffer somewhat since it is a 5v 150psi sensor so the PSI readings will have a 3% margin of error(read as 3psi, the logger has a .02v interference factor) based off my tests at 100PSI, a 10v transducer will read more accurately but they also cost over $100 each. a generic 100psi sensor will have less error margin but the peak would be at 100 and no further info given for those with healthy engines.

http://www.ebay.com/itm/Pressure-transducer-or-sender-150-psi-stainless-steel-for-oil-fuel-air-water-/251362960044?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a866662ac&vxp=mtr
disregard the 5v input reference, it will work with 12v as well as a 5v input, you could even run the system off a 9v generic battery. so digital sampling can be done as cheaply as $70 with a single sensor system and your computer.

S4 Vert

man... I was hoping the GXL had a good engine. So now I have two rebuilds I need to do.

Would low compression cause an RE not to start?

Thank you for your input fellas.

RotaryEvolution

iTrader: (30)

in those cases yes, it will make an engine very difficult to start.

in most cases a single failed seal makes these engines more difficult to get started than if a rotor was completely blown, because the backfires in the intake(although discrete) disrupt both rotors.

S4 Vert

Ok. Thank you again for the confirmation.

Rebuild time it is.