ok heres the deal 90 civic si w/teg xsi b16 done the swap like 3 months ago no real problems with the swap, had to replace the dizzy (brearings started to go out) but all and all its been real good. ok so when i got it in and started i done a compression test it hit like 235 across and felt real good well like a week and half ago i swaped the M.C. and booster that came with the swap and i started to have some rough idle (a bit high and fluctuating) and i had just did the dizzy like 3 or 4 days befor so i thought it may have moved a bit. but i had changed the idle set screw befor so i tryed it and the idle seemed to smooth out, so ok its running fine and all seems well. so today i thought i would check it out a bit put the timeing light on it (dead on) and while i was at it i thought id check the compression,well here is where things go wrong hooked it up to #1 and hit the starter 120ish WTF so i do the rest of them and its hiting like 120ish across the board. ok so first thought head gasket well if the head gasket was blow it would more that likely be low on like 2 cylinder not all 4 but maybe. but heres the next prob. its not smokeing, its not useing any oil, its not loseing any water, and its still running like it was when i first got the swap done. it dont sputter it fires right up it does not dog around it fells really strong but the compression has droped like a 100psi all the way across. so i started checkin it out well maybe i could find something. first thought it has jumped time and bent the valves so i pull the valve cover and set it tdc, its dead on. well maybe the rings r going bad so i warm it back up and put a little oil in #1 and hit it up for the compression again no diff. i have no clue what it could be but im gonna do a leak down tomorrow but i really cant see any reason for the drop in the compression anyone have any ideas at all???





Modified by ]{iwi at 9:45 PM 10/18/2004

 

did you search for what compression numbers are normal?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drussell4801 &raquo;</TD></TR><TR><TD CLASS="quote">did you search for what compression numbers are normal?</TD></TR></TABLE>

from what i have found the compression was good when i tested it the frist time but i have not found what the sould be

the honda dealer told me today that no honda(or anycar that they had ever seen) hit over 175 on a compression check i was like i have seen many hondas with 180 -200+ compression when tested but i may just be stupid. l0l was not able to get a leak down test today no one i contacted could get me in so maybe tomorrow i can get it done btu everyone i have talked to thinks that 200+ compression is way to high for any motor but i have seen many hondas with that high compression when tested

anyone at all? any ideas? anything?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ]{iwi &raquo;</TD></TR><TR><TD CLASS="quote">anyone at all? any ideas? anything?</TD></TR></TABLE>

listen to the dealer.

Did you search to find out what the normal numbers are for your motor?

maybe the numbers you are currently getting are right.

 

...

 

...

 

Try plugging the vacuum line to the brake booster
and see if the idle smoothes out..

If the brake booster diaphram is bad and allowing a vacuum leak,
that could be the problem..

Are you checking the compression when
the engine is cold or at operating temperature?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">Try plugging the vacuum line to the brake booster
and see if the idle smoothes out..

If the brake booster diaphram is bad and allowing a vacuum leak,
that could be the problem..

Are you checking the compression when
the engine is cold or at operating temperature?</TD></TR></TABLE>

, and

also, put like half a teaspon of oil in each spark plug hole and do another test. (oil in the plug your testing only) then report back

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">

Are you checking the compression when
the engine is cold or at operating temperature?</TD></TR></TABLE>

 

Compression should be checked with the engine at operating temperature..
Otherwise the figures will be inflated because the clearances will expand when it gets hot..

Compression should be between 135-185 psi with no more than
28 psi of variance between cylinders..

[It will run with lower numbers than that,But usually not very well..]

Results of a cold compression test on a junkyard motor:225 psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">Are you checking the compression when
the engine is cold or at operating temperature?</TD></TR></TABLE>

yes i checked it at the proper temp with the fuse out and wot


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx_88_si &raquo;</TD></TR><TR><TD CLASS="quote">put like half a teaspon of oil in each spark plug hole and do another test. (oil in the plug your testing only) then report back</TD></TR></TABLE>

i tried that to it made no diff

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">Compression should be between 135-185 psi with no more than
28 psi of variance between cylinders..

[It will run with lower numbers than that,But usually not very well..]

Results of a cold compression test on a junkyard motor:225 psi

</TD></TR></TABLE>

thats for d series right this is a b16. my friend has a delsol vtec and his tests at like 220 on all with 160000 miles so mine sould be up in that range i believe

i have no idea what could have it so low on all 4 cylinders and it not be running bad i still have yet to get it in anywhere to get a leakdown test everywhere i have talked to said my compression sould not be over 170 and if they do a leakdown all they will be able to tell me is if it has a compression leak i donnt want to waste money to do a leakdown if all they r going to be able to tell me is it has a compression leak i thought with a leak down test u sould be able to pin point the problem a little more than "yeah there is a leak some where"

thanks for ur help so far any more ideas? anything? anyone?

 

Those fiqures are from the VTEC supplement for the B16
but are the same as the specs for the D16a6..

 

are you doing the comp check the same way. if you take out all of the spark plugs you will get a lower reading than if you only take out one at a time.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88DXCRX &raquo;</TD></TR><TR><TD CLASS="quote">Those fiqures are from the VTEC supplement for the B16
but are the same as the specs for the D16a6.. </TD></TR></TABLE>

hmmm well mine was higher than that my freinds is higher then that and another friend has a ls in his civic and it hit 190-200 on all 4 so i dont know

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by limpy &raquo;</TD></TR><TR><TD CLASS="quote">are you doing the comp check the same way. if you take out all of the spark plugs you will get a lower reading than if you only take out one at a time.</TD></TR></TABLE>

i tested it with 2 diff testers and did them 1 at a time both times

 

i guess eventually you'll listen.

 

You are supposed to remove all spark plugs
to balance the cylinders..
Hold the throttle wide open and make sure the battery is fully charged.
Limpy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drussell4801 &raquo;</TD></TR><TR><TD CLASS="quote">i guess eventually you'll listen.</TD></TR></TABLE> what the hell r u talking about u have asked if i had searched for what it suold be i have not been able to find what it sould be if it was new but i have said already i have seen other engines that test right about where my motor tested when i put it in and now i have droped like 100psi on all 4 but search is a good answer to all guestions on forums

 

ill try it again with all the plugs out but i really doubt it will make that huge of a diff the battery is only like 2months old so i would think it would still be good but i will check it to see if maybe it has droped some power thanks to all for the help so far

 

a b16 should be about 200psi compression across the cylinders. All of my d16s and even a d15 that i've owned all registered around 180psi across all cylinders.

his numbers are definately low. I can also verify that the honda dealership he talked to is ran by idiots.

 

anyone else have any insight on this

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ]{iwi &raquo;</TD></TR><TR><TD CLASS="quote">anyone else have any insight on this</TD></TR></TABLE>