Comp Test at Dragon Today

[Gatesy]

Had a compression test done at Dragon today (Big thanks to the guys there) and had the following results:

Front:
6.5
6.3
6.3

Rear
7
6.8
6.8

Do those results sounds like ones from a healthy engine to you guys?

Just a bit concerned about the difference between the fronts and the rears.

Was fantastic to see Dragons new track monster down there as well......WOW!

[ENVYD]

any thing below 6.5\'s should be a rebuild, so i have seen many times!

[G@NDY]

Didnt they give you any feedback on the results??
Ive read that anything under 6 and it will get harder and harder to start. They arent the best figures to be honest. But it could last a while yet.!!!

[Gatesy]

The guy down at dragon (tall with with huge arms) told me that compression tests arent the B-all and end-all on rotary\'s and that if an engines going to let go whether you have good results or not.
Car pulls like a train and never misses a beat.

[G@NDY]

^ Thats true, I had high 7\'s on mine wine it went !!!

[interloper393]

what rpm was that cranking over at bud? mine has similar results but was cranking slow due to a crap battery, was told it`ll be in the 7`s with a good bat fitted..

[Fish]

Depends on how ported the engine is.

Fish

[20B_boy]

The guy down at dragon (tall with with huge arms) told me that compression tests arent the B-all and end-all on rotary\'s and that if an engines going to let go whether you have good results or not.
Car pulls like a train and never misses a beat.

I\'d go along with that, higher would be nice but if it starts ok (from hot esp) and pulls ok then, well, enjoy it now and worry about it when it happens

[logicalChimp]

fwiw mine was having starting problems (front hot only) at around 5.7 - so you may be ok for a little while...

[welshrx-7]

will you have trouble starting it if the orings have gone?

[Gatesy]

Car starts first time hot or cold every time, no blue smoke, doesnt use any water and about the usual with oil.

Had a long chat with the missus last night and we decided to keep the RX and we will sell her FTO instead as the rx is just a weekend car but I have been warned that I\'m not allowed to spend to much modding her.

Going to drive it until my insurance runs out in september and then SORN her until I can afford a rebuild with new housings, water seals and tips :cool

[Fendamonky]

The consistency between faces is good. Though I would start saving for a rebuild, looks to me like she\'s just around the corner.

Taken from rx7club.com\'s FAQ Thread:

28) What should the compression be?
       
      Compression test results are reported as six numbers: 3 per rotor. (This is not the same as the compression ratio). Higher, more equal numbers are best. The original Mazda specs dictate 8.5+ kg/cm² as new (121+ psi), with 6.0 kg/cm² (85 psi, 690kpa) being minimum acceptable. Maximum difference should be 1.5 kg/cm² (21 psi, 150kPa) from the highest to lowest value. It is important this test is carried out using proper equipment and under the correct conditions for rpm and engine temperature. Mazda dealers are generally reliable for performing this test, so long as they follow the procedures precisely.

However, rumor has it that the \'93 shop manual differs from later year manuals.  \'93 states 7.0 kgf/cm2 minimum,  which is roughly 100 psi. Though 6.0 kgf/cm2 (roughly 85 psi) is the \'94+ shop manual stated minimum.