My compression test results?

[D2BBA]

Hi Folks,

A trip to Mazda this morning revealed the following compression test results on my \'93 Rex (52K miles on the clock and standard lump).

The guys were most helpfull but couldn\'t tell me a thing about what the readings show!!??

Any ideas?



Help much appreciated!!

Ta
Chris
(D2BBA)

[James S]

im no expert on this but i think these  are quite strong results!

If ive worked it out properly this is what it is in BAR:

9.3 - 6.90

8.3 â€" 6.90

sorry couldnt be more help

:wave

[bnaellis]

I think Mazda tech didn\'t know what he was doing.
It\'s impossible to get 9.3 compression also.

rgds

[Oedipus Rex]

just out o interest, what did mazda charge you for the test?

they quoted me £70!!!!!!!!!!!!

[MikeLMR]

looks like they didn\'t have a proper tester ! you should have 3 readings from each rotor ... what it looks like they have done is taken a reading for each plug :rollin and no doubt using a p1ssedon engine tester too.

[James S]

there is a price of £49.35 on the sheet :p

i would be taking it back and telling them to do it again if that is the case :reallymad

[scooby_si]

& unless im mistaken it\'s upsidedown! lol
Si

[D2BBA]

Hi guys,

Sorry its taken sooooo long to get back, me server has been down!

Cant believe i\'ve just thrown £50 at something thats no use, would have thought Mazda would know their onions, but who can tell:( :rolleyes: :reallymad

Just thinking being as i\'ve spend the cash, is there ANYTHING that these results can tell me about the condition of the engine.  I dont really want to start on even basic tuning without some knowledge ( in case cash is needed quick:eek: !!!).

Being stranded in Newcastle, i\'m a bit out of the area for well known tuning companies.  I know Pip is the man, but the fuel bills to head south for a compression test are rather high!  Anyone closer, or in Scotland?

Thanks guys, sos for the long post!
Chris D
(D2BBA)

[D2BBA]

BTT,

Any thoughts gents?

[Oedipus Rex]

My thoughts are that you should take it back to them and ask for someone who knows what they aredoing to run the test again.

[Glenn Butcher]

From what I understand of the Invoice, one rotor has 120psi, the other has 135psi (looks like average readings, across the individual rotors, not the individual rotor faces).


But what you are really interested in is the differences between the chambers themselves.

Here is a graph from another guy on the Forum, who has a proper (30 year old) Mazda compression tester.

Each line is a pulse from a rotor chamber, and although the numbers aren\'t there (you have to interpret the graph, which I think is around 128-130psi) - they are high and consistent, indicating good compression for both rotors.

They should be able to produce some sort of graph for you, but they may not have a proper compression tester (although they should with the RX-8 being here now!).

Go back to them and ask for more detail.

[MillSpeed]

Wow, look at that. The peaks are almost identical. I\'ve always been intersted to learn how a rotary compression tester differs from a conventional one?

[D2BBA]

Thanks lads!!:)

At least I have something to show Mazda now when I try to explain what I need!  Fingers crossed.........

Cheers again
D2BBA