Compression test!!

[ReX 813]

Tbh, starting it from cold isnt a problem, it can be a bit of grief when its warm though,
those readings are from a mazda dealer in dartford, got it done yesterday coz i wasnt convinced when he told me he had carried out a test and it was all o.k, i would just like him to admit there is a problem with the car and stop fobbing me off with technical crap!

[royston1xx]

I should have thought that it was obvious that something is wrong with this engine John.
Surely even you can see that.:rolleyes:
Regards
Carl

Oh no, here we go again:Yawn

[John Yorke]

I should have thought that it was obvious that something is wrong with this engine John.
Surely even you can see that.:rolleyes:
Regards
Carl

Normal responce from you eh! my question was quite simple and Rex 813 was good enough to respond, some comp tests AS YOU KNOW if not done correctly or with the correct equipement are likely to give incorrect readings. sheesh you try and put some level of calm to a situation and you get this type of reponse...........do you have a problem with me Carl??//

[kev-yorks]

Forget about the actual reading John whatever they used for the test it should be giving more or less equal figures across all three lobes on each rotor. The readings on the rear one are far from even and without doubt there\'s a problem there.
Kevin

[Carl]

This car also has high knock readings from another thread on here.
Regards
Carl

[rx7veilside]

starting from cold shd be ok as the compression is better but with those readings starting from warm must be a nightmare as mine were higher than yours but car was a bastard to start when warm and this was on a very fresh rebuild..that engine will need stripping to find out where it is loosing compression as it is u may even end up flooding it when warm..as a guess it prob starts on one rotor and then gradually catches on the other as opposed to firing on both when it is cold..mine was fine when first starting but when warm it was very hit and miss...ask any unbiased engine builder about those readings and he will tell u the engine will need stripping i am afraid to say.try calling pip at wgt he is other end of the country and ask his opinion of those readings and i guarantee he will tell u the engine will need to e stripped and that will be a very unbiased view as he has nothing to gain as its unlikely u wld travel to him for the work

[elford_tim]

Tbh, starting it from cold isnt a problem, it can be a bit of grief when its warm though,
those readings are from a mazda dealer in dartford, got it done yesterday coz i wasnt convinced when he told me he had carried out a test and it was all o.k, i would just like him to admit there is a problem with the car and stop fobbing me off with technical crap!

IMHO, anything below five is definitely not OK. Even five isn\'t, TBH.

250 rpm is a tad low for a compression test in my opinion but that doesn\'t change much. Can you get the Mazda dealer to confirm that these readings aren\'t OK?

I think rx7veilside\'s suggestion of talking to Pip is probably a good one, although Carl pretty much suggested that the numbers aren\'t good. You could get try to get something in writing out of both (or either one) stating that the compression readings you mentioned are too low for a good engine. That should at least show your engine builder that you\'ve done your research...

[Carl]

250 rpm is the standard at which compression test\'s should be measured according to Mazda.
If the rpm is higher then the reading will be higher.
A proper comp tester for rotaries will adjust the reading to give the figure for what it is at 250 rpm.
Regards
Carl

[rx7veilside]

when carl tested mine my figures were higher than this and that was a bitch to start warm so god knows what his must be like trying to start warm
my suggestion is use pip to get a totally unbiased opinion as long as he doesnt mind being used as a sounding post and then go back to the engine builder whoever it is and insist on having the engine stripped and the fault put right as even a novice like me knows those figures are way to low especially on a rebuilt engine..mine is having 3mm tips and carl could prob give a very good idea of what sort of comp readings this engine should be giving .a 6 month old engine giving these readings has a big prob,,wehats it going to read in 10,000 miles high 2,s all round???

[RedRummy]

As an aside, isn\'t it a shame that even the main dealerships aren\'t able to care for cars in their own domain...

Its left to independent workmen.   :reallymad

Good job too, or we\'d all be screwed...  (Hug your local rotary expert, they\'re gold dust! :Hammer )

I don\'t know much about inner engine workings, but I DO know that uneven and low (sub 6.0-7.0) compression figures "are a bad thing" for the rotary engine.

I feel for ya bud  

:2Mad  :2Mad

[rx7veilside]

if the car was showing these symptoms/figures when u bought it then the guy selling has shafted u and the engine builder is now trying to do the same as even novices know these figures are stripdown time as u wont be able to fix low comprression with tearing it apart.its a joke that u are being fobbed off and told that those comp readings are fine.i would be interested to know who has built this engine and claiming that the comp figures are fine.as carl has said the comp test has been done at the right rpm and over all 3 faces so i doubt that getting a second test will achieve anything.as u are getting poor warm starting then that just confirms the low compression.my advice is to contact builder and insist on a rebuild and a new comp test after the rebuild
with mine i decided to bite the bullett and get carl to strip my engine and he is now rebuilding it properley as his engine building is second 2 none
if u only have low comp the cost may not be too bad as u may need just new side or apex seals
i understand fully how gutted u must feel at the moment after being led to blve the engine was new and expected many miles from it.i too felt gutted when my new engine showed low compression
take the car to the engine builder with a witness and ask for him to do the comp test and tell him it is totally unacceptable for a new engine to be showing these readings
as u either have wear on the rotors or housings or ur seals are out of tolerances either way he has warranted the engine and ur engine is without any doubt shagged
for future business choose ur tuner carefully

[clive]

I should have thought that it was obvious that something is wrong with this engine John.
Surely even you can see that.:rolleyes:
Regards
Carl

Oh no, here we go again:Yawn

Carl and John please keep this thread about what it should be about ( someone in trouble ) and neither of you use it to air your personal grievances against each other.

And yes John, Carl does have a problem with you, and likewise you have a problem with Carl


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[peterwolds]

Guys what do you make of this....

results for comp test...

front chamber   5.4     5.3    5.2

Rear chamber  5.5   4.5   4.8

.

Sure looks like you have had your leg lifted,sorry - definately need to go back to builder.
i joined MRC before i bought an RX7,read loads especialy about compression readings & bought a car off a member on here having read about his car postings from day  he got it,readings excellent 8.4 all fronts & 8.3 all rears test done by reworx.
good luck

[Ricco_04]

I had my egine compression tested at a Mazda dearler and at a rotary specialist.  The Mazda dearler quoted 4.7\'s and the specialist quoted 7.5\'s.  I pretty much guarantee that the Mazda probably didnt do the teat anyway.

I have to say that I had nothing but trouble from that dealership and the fact that they said they could import brand new engines so I could buy one of them! :eek  So thats why I ghot a second opinion.  NOT ALL MAZDA GARAGES ARE LIKE THIS!

The fact that your car is hard to start does suggest that the readings are correct.  I was told by a different Mazda garage that they usually rebuild when the engine goes down to 5.5bar compression.

I would take the car back to the dealership and ask for a refund.

[Ricco_04]

Rear chamber  5.5   4.5   4.8

2 of those readings are virtually 1 bar lower than the other - could this be damage to one of the Apex seals or the like?