compression test - Page 2

haseeb · Oct 28, 2009, 02:24 PM

Hmm ,is it ok to drive the car as its still runing like a champ ?and the smopke is barable also ,but io really dun wana hurt the car and make is worst

Murf · Oct 28, 2009, 02:34 PM

you are taking a chance of having a bad failure and having to do an expensive rebuild. What I told you was just my problem does not mean that it is your problem. Myself and most others here would find problem and not take the chance. You very well could have bad rings in that piston..do a wet test on that cyl.. warm up car, remove plugs, disconnect cam angle sensor, press gas to floor crank 3 to 4 rotations. see if you get same compression as before. if so pour a little motor oil in cyl. (don't go crazy just a little I used 1/2 of a oil bottle cap full some use 1 cap. do test again. if compression jumps way up its your rings.
I also had that problem.

haseeb · Oct 28, 2009, 02:37 PM

Well that's gr8 ,ill do it tomarow ..
Thanx

Murf · Oct 28, 2009, 02:45 PM

Oh the car will smoke like a M'fer until the oil you poured in the cyl is gone..just a heads up.
question for you on you compression tester...are you using one that screws into head then hose then gage? you are not using an extention are you?..personal exp.. the extentions will give false readings..low false readings.

xRoguex · Oct 28, 2009, 05:48 PM

search on how to do a compression test -- do a wet test also - its easier then pulling the head and will tell you if its top or bottom end problems.

RSMike · Oct 28, 2009, 11:45 PM

dont forget that dynamic compression and static compression are different. just cause you have 8.6 static compression ratio, doesn't mean you'll get OEM pressures for your compression test. you might have large cams?
i'd say talk to your engine builder, he could point you in the right direction.

haseeb · Oct 29, 2009, 12:04 AM

yes ur rite ,ive got bf 272 cams ..
and jam stage 3 short block ,
talked to them and they said there is nothing to wory about and they wanted me to do the compression test when the car is cold instead of warm ..

moses_4g63 · Oct 29, 2009, 12:25 AM

yes it very well could be you have a bad ring on that cylinder ! id take it to a nearest shop and have them put a boreiscope in that cylinder and see if it apperars to be wet due to oil makin its way into the cumbustion chamber! could very well be a valvetrain issue also!

haseeb · Oct 29, 2009, 01:15 AM

ohk ,but wat will be the best way to find out the problem as i really dint understood to check it with boreiscope ,or there is any other way to check ?now if there is the ring problem in cilender num 1 shud change the rings n all the cilenders or just for the cilender 1 ?
i had a built short block by jam and i dun really want mess it here in my country by opning it all ..

haseeb · Oct 29, 2009, 03:57 AM

Wat if we don't disconect the cranck angle sensor ,cause I dint disconected it during the compression test ..

batty200 · Oct 29, 2009, 07:31 AM

You should definately do the compression test when the engine is warm especially on a forged piston motor as they expand and contract when hot/cold. Also do each cylinder twice and a tester can stick or act funny so I always do everything twice. Also pressing the accelerator is recommended for #'s but if you are not and they are consistent the # is somewhat irrelevant. Also if you can buy a leak down tester that will tell you if you have a bottom end problem or a top end problem.

linuxman51 · Oct 29, 2009, 07:33 AM

you get fuel in the cylinders if the ecu is seeing rpm. this can alter your numbers somewhat. either unhook power to the injectors as well as the coils, and hold the throttle body open whilst cranking, or disconnect the crank and cam sensors so the ecu doesn't see engine rotation.

zedevo · Oct 29, 2009, 12:29 PM

Sorry Hasseb : I have an Impo Question to ask .
I have the same set up 2.3L with 9.5 comp ratio Pistons ... with BF Cams and it gives me 195Psi On each Cylinder ... Im pretty sure its weird ... Cant go High Boost On Pump gas ... But is it ok ? Or at least how much should me The compression on a Normal 2.3L ?

xRoguex · Oct 29, 2009, 05:43 PM

Quote:

Originally Posted by haseeb

yes ur rite ,ive got bf 272 cams ..
and jam stage 3 short block ,
talked to them and they said there is nothing to wory about and they wanted me to do the compression test when the car is cold instead of warm ..

http://my.prostreetonline.com/t405.htm

haseeb · Nov 7, 2009, 08:23 AM

i just poured a tea spoon of oil in that cilender but there is no increase in the compression ,
its the same

now tell wat is cud be ?
its smoking as it was ..