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1997 Civic DX Hatch
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983 Posts
Discussion Starter #1
so i to my civic to the drag strip for the 3rd time.

its my 11:1 cr d17y8. ive got it running on 91 octane.

well ive apparently got way too much crank case pressure cuz for the first time ever(ever is 5000 miles) my dip stick blew out of the tube and threw oil all over my bay.

i dont think i cracked ring lands or anything cuz i havent seen any loss of power or anything to make me think ive done so.

im running stock pcv system. valve cover to intake tube. and black box to pcv to intake mani.

im thinking of doing a vented catch can and assume that will be enough to ventilate the block enough.

id like to run both valve cover and remove black box put a bung there to the can.

so few questions.


does that sound like it would be enough ventilation?

also listen to my catch can idea and see if it would work(i assume it would but idk)

just one of those tin twater bottles.
drill a hole in top and 2 holes on the side.
filter the top and run from bung were black box was to the can.
run valve cover to can.
no drain back, no baffle,no inner filter or anything.

would that work?

i appreciate the help.

thanks.
 

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Brokedick Millionaire
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40,252 Posts
You have a blow by issue that needs addressed before worrying about a catch can.

10.7:1, 91 octane, stock PM6 ECU, no dipstick/PCV issues on a 225K+ motor.

Time for a warm leakdown test.
 

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Retired From Hondas
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2,796 Posts
All hondas have blowby which gets worse the higher you spin it. This is no secret.

This plays havoc with rings if its not vented.

I would ditch the OEM PCV set up. No need to lower the octane rating and introduce foreign compounds into the intake stream.
 

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()*#$(*$
93 Legend L Coupe.
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11,404 Posts
I've pulled apart engines with cracked ring lands that ran fine. I've seen many several endurance race teams run 130+MPH on engines with cracked ring lands. Assuming you have no cracked ring lands is . . . amusing.

Leakdown test for sure.
 

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1997 Civic DX Hatch
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983 Posts
Discussion Starter #11
okay finally got a compression test.

135-145 all the way across. so i guess now just better ventilation?

after more catch can research i decided leave black box and barb the pvc hole. run it to can then run valve cover to can. ventilate can. have no return or baffling in the can.
 

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158 Posts
What cam are you running? Those numbers seem very low for that high of compression. Its is very possible that your rings have not seated giving you a low but even compression number.

My d15b2 had 190-210 psi with 350k on it. That number is a little high but most like from carbon build up on the pistons. I would expect your engine to have numbers like this engine unless you are running a very aggressive cam.
 

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1997 Civic DX Hatch
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983 Posts
Discussion Starter #15 (Edited)
is there a difference in a leak down and compression test? i thought it was the same thing. lol.

and its a crower stage 2 cam.

alright. ill get a leak down test done and report back.

also. would i not be burning oil if my ring lands were cracked or nonseated rings? just curious?
 

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Premium Member
90 crx si/96 accord
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788 Posts
There is a HUGE difference ! The comp test will help u pin point a specific cylinder with an issue. The leak down will help u find out if the issue is rings valves valve stem seals head gasket etc.
Do more work!
 

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Brokedick Millionaire
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40,252 Posts
okay finally got a compression test.

135-145 all the way across. so i guess now just better ventilation?

after more catch can research i decided leave black box and barb the pvc hole. run it to can then run valve cover to can. ventilate can. have no return or baffling in the can.
Motor is fucked, tear is down. With your stated comp. ratio you should have 225-240 psi cranking compression when tested properly.

It knocked, rattled, and snapped a few ring lands or other issues.

So why did you not do the warm leak down test like I, as well as Acid Beav suggested?

Stock SOHC needs 120 cranking psi to run, lower than that and it will not fire. Stuck rings from cheap gas will do that as well as ring land damage from poor tuning or lugging the motor in 1500-2000 rpm.

My 10.5-11.0 225K D16A6 bottom end with Y8 head, HG thickness unknown REQUIRES 89 octane to be loaded below 2000 rpm. I have heard it rattle before on 87. It is the reason I haven't cranked the timing for better MPG.

If you want help, you have to pay attention closely. The cranking PSI test means the motor is toast, but the leakdown test could pinpoint which cylinder as well as wear the cylinder leakage is occurring.
 

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97 honda coupe
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7,611 Posts
is there a difference in a leak down and compression test? i thought it was the same thing. lol.

and its a crower stage 2 cam.

alright. ill get a leak down test done and report back.

also. would i not be burning oil if my ring lands were cracked or nonseated rings? just curious?
just did a bone stock d16Z6 compression test at 9:1 compression. it tested between 170 and 180 across all four cylinders, you definitely have major issues.

Im going to guess either

cam timing too retarded
ring lands/rings not seating/valves leaking
 

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1997 Civic DX Hatch
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983 Posts
Discussion Starter #20
Motor is fucked, tear is down. With your stated comp. ratio you should have 225-240 psi cranking compression when tested properly.

It knocked, rattled, and snapped a few ring lands or other issues.

So why did you not do the warm leak down test like I, as well as Acid Beav suggested?

Stock SOHC needs 120 cranking psi to run, lower than that and it will not fire. Stuck rings from cheap gas will do that as well as ring land damage from poor tuning or lugging the motor in 1500-2000 rpm.

My 10.5-11.0 225K D16A6 bottom end with Y8 head, HG thickness unknown REQUIRES 89 octane to be loaded below 2000 rpm. I have heard it rattle before on 87. It is the reason I haven't cranked the timing for better MPG.

If you want help, you have to pay attention closely. The cranking PSI test means the motor is toast, but the leakdown test could pinpoint which cylinder as well as wear the cylinder leakage is occurring.
i didnt know the difference and dont have a proper tester for either so i took it to the only mech i trust and said "i need a compression test" he said okay. lol

i will do a leak down test to find the specific origin of the problem.

just did a bone stock d16Z6 compression test at 9:1 compression. it tested between 170 and 180 across all four cylinders, you definitely have major issues.

Im going to guess either

cam timing too retarded
ring lands/rings not seating/valves leaking
we will see once i get this leak down test done.

my cam is rather far retard. so it is possible that its leaking through the valves i suppose.

but i fear the worst. since my compression is apparently way lower then it should be i assume rings are not seated.

thank you all for the help. will report back after leak down is done.
 
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