Short story, shorter.....

Have overhauled an engine, with the workshop claiming to replace all parts... housing, rotors, apex seals, sidewalls, and reused the corner springs (as they said this needs no replacing) with mild porting...

So far, engine does not suffer any loss of power. Pickup is fantastic!

However after running in, i decided to do a compression test...


1st workshop = failed
( just for info... front rotor at 182rpm ------> 0.55 / 0.55 / 0.51 rear rotors cant read)
--> Front rotor @ 250rpm 0.65 / 0.65 / 0.61
--> Rear rotor @ 250rpm 999 (means, no reading)


2nd workshop = passed (but remarkably? let me know)

*first he said that 04' (pre-fl rx-8) has a weak starter... The FL rx-8 (think here it is called s2 units) has a better starter.... (anyone knows where to get them?)
Thus he say he needs to use this conversion to get the results... It wont differ much, he said...

http://virusakos.freevar.com/web/RX_...alculator.html

Choose measurement unit: PSI
Choose results unit: PSI

Front Rotor:
RPM = 187
First Chamber = 100
Second Chamber = 98
Third Chamber = 100

Rear Rotor:
RPM = 187
First Chamber = 116
Second Chamber = 115
Third Chamber = 114



After conversion........................................ ....................

Front Rotor:
First Chamber [ 98.6, 120 ] : 122.11
Second Chamber [ 98.6, 120 ] : 120.11
Third Chamber [ 98.6, 120 ] : 122.11
Chambers Difference [ <21.8 ] : 2

Rear Rotor:
First Chamber [ 98.6, 120 ] : 138.11
Second Chamber [ 98.6, 120 ] : 137.11
Third Chamber [ 98.6, 120 ] : 136.11
Chambers Difference [ <21.8 ] : 2

Rotors difference [ ,14.5 ] : 16


- So is my engine reading like it is brand new or just fairing well?

- Is it true that the 04-08 models starter are weak? I have read abt these and it seems to be true... Is this starter one of the possible cause why i have a slight delay when cranking up the rx-8? (i use to think that my delay in cranking was because of my relocation to the rear boot) the delay is like 1 or 1.5 sec delay compared to other friend's stock rx-8...

- why the difference is the two workshops? any truth?

- anyone knows how to convert the readings in the 2nd workshop to readings of MPa instead of PSI?

Any help or shedding more light on this matter is greatly appreciated..


Thank you.

 

1) Yes.
2) Perhaps.

Rather than be concerned about "conversions" and such, please simply provide the actual pressure readings you are getting. We will do the rest for you.

 

??


The above are the actual readings that i got.... the first workshop gave me the above readings stated above...


the second workshop, did the readings... then he used the website as stated above and did the conversion....

 

I don't have time to decipher all the different data, which was why I asked for whatever numbers you want those willing to help you to use. Better than that, if you REALLY want an accurate diagnosis, here is what we need to know;

1) Cranking RPM.
2) Compression values.
3) Altitude.
4) Intake manifold vacuum readings.

 

i guess this are the only numbers i have...

Readings from 1st worshop....
Measurement units MPa
--> Front rotor @ 250rpm 0.65 / 0.65 / 0.61
--> Rear rotor @ 250rpm 999 (means, no reading)




Readings from 2nd workshop.......
Measurement units: PSI

Front Rotor:
RPM = 187
First Chamber = 100
Second Chamber = 98
Third Chamber = 100

Rear Rotor:
RPM = 187
First Chamber = 116
Second Chamber = 115
Third Chamber = 114

 

Converting Mpa to PSI:
Front rotor @ 250rpm 94.274505 / 94.274505 / 88.472997

Using this that I ripped off from here somewhere


As far as I am aware, at 250rpm, the fail/minimum PSI is 97.

As for the starter, the SI had an updated starter about late 2004 so any SI car MY2005 or later should have the latest starter. This new starter cranked MUCH faster but required a MUCH stronger (CCA) battery.

So considering below 97 is fail, your Workshop 1 are way low. And considering at 190rpm "standard" compression is 101, your workshop 2 figures seem high on the rear and out of balance with the front.

Dont know if that helps.

 

that helps alot and makes the picture much clearer... how did u convert the MPa to PSI?

and the picture... cannotz be seen...

PS: thanks auzoom!!! u helped alot! thanks for shedding some of ur knowledge on this... think i have to change the starter first and see what the results would be like...

 

Can you see the img attached to this post?

To convert anything, just use google, "convert MPa PSI".

 

190 -ish rpm ? sounds like old starter to me.

You can grab one of those starters at places like Autozone or Advance Auto Parts. Both have promotions/coupons that you can use to get the price ridiculously low.

but it looks like your engine is running alright, but not great if the first number is right.

what parts did you re-use ? your post was really confusing.

1. Im really confused by your numbers.
2. Yep, see solution above this msg
3. Some guy fucked up.
4. MPa or PSI doesn't matter, its just a value. You just need to convert it thats all.

 

that is why... i am as confused as you... when to 2nd workshop to get confirmation if engine was really not doing well after overhauling... will try to get the new starter soon and do the test again...

so to confirm, healthy ranges in terms of PSI is 97 - to ?

thanks nycgps for posting...

 

thanks a lot for the pic !!!


now i can save it and show it upfront that, thatz what a standard or high rated compression should be...