knightrider56 Posted October 24, 2008 Report Share Posted October 24, 2008 (edited) I did a compression check today.....Starting with the back part of the valve cover (BREATHER PORT). And ending in the front (PCV valve) I got>>> 120= 60=120=120 Could it be i need to adjust the valves?...or can it be my rings? i got a new marnel head installed, i got from dad= 8V non jet head with studs assembled with 1.00 OS stainless valves, New valve seals, Schneider HD6610 springs, new Retainers, spring seats and keepers. set up to accept up to .500 valve lift ...i used my old cam and rockers Hope someone can help with this one..thanks... Edited October 24, 2008 by knightrider56 Link to comment Share on other sites More sharing options...
scott87star Posted October 24, 2008 Report Share Posted October 24, 2008 You've got a problem, can you do a leak down test in #3 (your second measurment)? You don't even have to have a fancy setup, just get that cylinder to TDC on the compression stroke and pressurize it with 100 psi compressed air. Then listen to where the air is going, it should be obvious with a leak that bad. Scott Link to comment Share on other sites More sharing options...
knightrider56 Posted October 24, 2008 Author Report Share Posted October 24, 2008 You've got a problem, can you do a leak down test in #3 (your second measurment)? You don't even have to have a fancy setup, just get that cylinder to TDC on the compression stroke and pressurize it with 100 psi compressed air. Then listen to where the air is going, it should be obvious with a leak that bad. Scott How do i put the cylinder to TDC...I have a small pancake compressor, can i use this to check....and if i hear air escaping, what does that mean? Link to comment Share on other sites More sharing options...
scott87star Posted October 24, 2008 Report Share Posted October 24, 2008 Take the valve cover off and the spark plug out. You need to be able to turn the crank clockwise so get a socket and 1/2" drive, I can't recall the size of the crank nut but its close to 23 mm. You should be able to get very close to TDC watching the cam and rockers and using a flashlight to see the piston through the spark plug hole. I have used a pencil in the past to watch the piston rise when I'm turning the crank but for god's sake don't drop it in there and be careful not to get it wedged so it snaps in half, you don't want to leave anything behind. Once you get the piston close to TDC on the compression stroke lock the motor into place so the crank can't rotate and use your air compressor and the hose from the compression tester to put some pressure into the cylinder through the plug hole. It should be at least 50 psi so you can hear WHERE its leaking, out the intake is a bad intake valve, out the exhaust is a bad exhaust valve, out through the crankcase is bad rings. Do that and let us know. Scott Link to comment Share on other sites More sharing options...
chiplee Posted October 24, 2008 Report Share Posted October 24, 2008 I did a compression check today.....Starting with the back part of the valve cover (BREATHER PORT). And ending in the front (PCV valve) I got>>> 120= 60=120=120 Could it be i need to adjust the valves?...or can it be my rings? i got a new marnel head installed, i got from dad= 8V non jet head with studs assembled with 1.00 OS stainless valves, New valve seals, Schneider HD6610 springs, new Retainers, spring seats and keepers. set up to accept up to .500 valve lift ...i used my old cam and rockers Hope someone can help with this one..thanks... are they hyd or mech lifters? if they were adjusted properly there's no way the lifter is going to cause that compression problem, but if not, maybe. Link to comment Share on other sites More sharing options...
knightrider56 Posted October 24, 2008 Author Report Share Posted October 24, 2008 are they hyd or mech lifters? if they were adjusted properly there's no way the lifter is going to cause that compression problem, but if not, maybe. How can i tell if there hydrolic or mech. Link to comment Share on other sites More sharing options...
knightrider56 Posted October 24, 2008 Author Report Share Posted October 24, 2008 Take the valve cover off and the spark plug out. You need to be able to turn the crank clockwise so get a socket and 1/2" drive, I can't recall the size of the crank nut but its close to 23 mm. You should be able to get very close to TDC watching the cam and rockers and using a flashlight to see the piston through the spark plug hole. I have used a pencil in the past to watch the piston rise when I'm turning the crank but for god's sake don't drop it in there and be careful not to get it wedged so it snaps in half, you don't want to leave anything behind. Once you get the piston close to TDC on the compression stroke lock the motor into place so the crank can't rotate and use your air compressor and the hose from the compression tester to put some pressure into the cylinder through the plug hole. It should be at least 50 psi so you can hear WHERE its leaking, out the intake is a bad intake valve, out the exhaust is a bad exhaust valve, out through the crankcase is bad rings. Do that and let us know. Scott ill get on it first thing tomorrow morning i rent out a garage and does not have any light, and it just got dark out, ill let you know the results as soon as im done, if it were coming out the crankcase the sound would be coming from the bottom then, right? Link to comment Share on other sites More sharing options...
Technology Posted October 25, 2008 Report Share Posted October 25, 2008 Did you have the throttle plate floored (wide open) when you did the test? If not, do that, then get back to us. Link to comment Share on other sites More sharing options...
Dad Posted October 25, 2008 Report Share Posted October 25, 2008 I did a compression check today.....Starting with the back part of the valve cover (BREATHER PORT). And ending in the front (PCV valve) I got>>> 120= 60=120=120 Could it be i need to adjust the valves?...or can it be my rings? i got a new marnel head installed, i got from dad= 8V non jet head with studs assembled with 1.00 OS stainless valves, New valve seals, Schneider HD6610 springs, new Retainers, spring seats and keepers. set up to accept up to .500 valve lift ...i used my old cam and rockers Hope someone can help with this one..thanks... Is this just installed? You don't know if it's hydraulic or mechanical? you trying a comp test before starting it? More details please? No start conditon? Dad Link to comment Share on other sites More sharing options...
knightrider56 Posted October 25, 2008 Author Report Share Posted October 25, 2008 Did you have the throttle plate floored (wide open) when you did the test? If not, do that, then get back to us. when you mean floored , you mean like hold down the acceleration pedal? Link to comment Share on other sites More sharing options...
knightrider56 Posted October 25, 2008 Author Report Share Posted October 25, 2008 Is this just installed? You don't know if it's hydraulic or mechanical? you trying a comp test before starting it? More details please? No start conditon? Dad Is this just installed?= The head was just installed You don't know if it's hydraulic or mechanical?= No you trying a comp test before starting it?= No, i had the head done about a month back, i drove her maybe about 10 miles on new head More details please?= i been trying to fix an oil burning problem i been having, car would be sluggish in normal driving conditions, but when i build up boost she would take off, and when i build up boost and let go of the pedal thats when i get smoke coming out of exhaust, it would go away after about 30 sec No start conditon?= She starts up and is drivable, but i just need her to be perfect..... Link to comment Share on other sites More sharing options...
knightrider56 Posted October 25, 2008 Author Report Share Posted October 25, 2008 i just couldnt help it , i went back to my garage to go check on her again, and there was a friend of mine there who is quite a good mechanic, he told me to check the #3 cylinder again with the tester and said when you get a reading, check to see if the needle on the tester moves down a bit, but it didnt, i waited about 3 to 5 min. but the needle stood still on 60, he told me my ring was bad, but i still want to know if there is any other way to be positive on why i have low compression coming out that cylinder, I just dont want to do a ring job if i dont have to.....But if i have to i will.... Link to comment Share on other sites More sharing options...
Indiana Posted October 25, 2008 Report Share Posted October 25, 2008 its not rings that is a lame assumption from someone not to listen to he has asked too few questions if the lifters are there they are hydraulic and one needs bled if the rocker arms are mechanical then they need adjusted either way you have to remove the valve cover if they are mechanical it will be obvious, the end of every rocker arm over the valve with have a jamb nut on a bolt stub, if you have hydraulic lifters the ends will be smooth you can bleed the air from the lifters with a .5mm hard wire through the hole in the tip of the rocker arm, make sure the valve is closed and you may have to take the pressure off the lifter by loosening up all the cam tower caps just a little bit, if they are mechanical there are clearance specs you need to follow for the intake and exhaust rocker arms Link to comment Share on other sites More sharing options...
psu_Crash Posted October 25, 2008 Report Share Posted October 25, 2008 now I am curious to see what this ends up being. Holding at 60 psi seems awful odd to me ??? Link to comment Share on other sites More sharing options...
knightrider56 Posted October 25, 2008 Author Report Share Posted October 25, 2008 its not rings that is a lame assumption from someone not to listen to he has asked too few questions if the lifters are there they are hydraulic and one needs bled if the rocker arms are mechanical then they need adjusted either way you have to remove the valve cover if they are mechanical it will be obvious, the end of every rocker arm over the valve with have a jamb nut on a bolt stub, if you have hydraulic lifters the ends will be smooth you can bleed the air from the lifters with a .5mm hard wire through the hole in the tip of the rocker arm, make sure the valve is closed and you may have to take the pressure off the lifter by loosening up all the cam tower caps just a little bit, if they are mechanical there are clearance specs you need to follow for the intake and exhaust rocker arms thanks indiana, will do today, and give you all feedback when im done Link to comment Share on other sites More sharing options...
vbrad511 Posted October 25, 2008 Report Share Posted October 25, 2008 Like the others said, pull the VC and figure out which rockers you've got and if they need bled or adjusted. Your compression gauge will have a check valve in it that won't let pressure back off. You can unscrew it from the cylinder and it will still hold the reading. When you run this test you need your throttle to the floor, ALL the plugs out, and a fully charged battery. After checking first, add a little motor oil to each cylinder and try again. If your numbers come up, it's your rings. Of course that weak cylinder has an issue, whether it's rings, or a hung valve or rocker. Link to comment Share on other sites More sharing options...
knightrider56 Posted October 26, 2008 Author Report Share Posted October 26, 2008 (edited) ok did another compression test this time with throttle open==== 1=140 2=140 3=70 4=140 then i added about a capful of oil to the #3 cylinder and i got 75 Edited October 26, 2008 by knightrider56 Link to comment Share on other sites More sharing options...
patra_is_here Posted October 27, 2008 Report Share Posted October 27, 2008 you should be doing the compression test with the car warmed up BTW. but it sounds like you've got a valve issue if adding oil didnt really bump up the compression. although a 'capfull' might not be enough. we still need to know if you have mechanical or hydro lifters. do ALL your intake and exhaust rocker arms have an adjusting screw similar to the one pictured here (these are mechanical rockers) http://www.hdjxcn.com/bigimg/695.jpg http://www.hdjxcn.com/bigimg/695.jpg Link to comment Share on other sites More sharing options...
Dad Posted October 27, 2008 Report Share Posted October 27, 2008 Valve issue , hung lifter if hydraulic, or to tight of a setting if mechanical or blown gasket, scuffed cylinder bad piston. Leak down test will help also. How did it run up untill having to do the test? Dad Link to comment Share on other sites More sharing options...
Shelby Posted October 27, 2008 Report Share Posted October 27, 2008 i'd sugest you stop right where you are and eather get some one that knows a little about an engine or do some reading and rescearch on your own , as it's going your worst then a blind man in a crowd'd room this may help you a great deal if you'l spend some time there http://starquest.i-x.net/viewtopic.php?t=997 Link to comment Share on other sites More sharing options...
Technology Posted October 27, 2008 Report Share Posted October 27, 2008 Yeah, could possibly have a bad seal between the valve and its seat. Does the car drive ok? If so, just get a bigger turbo. Link to comment Share on other sites More sharing options...
89PalermoSHP Posted October 28, 2008 Report Share Posted October 28, 2008 hmmm, sounds aweful familiar. Link to comment Share on other sites More sharing options...
knightrider56 Posted October 28, 2008 Author Report Share Posted October 28, 2008 you should be doing the compression test with the car warmed up BTW. but it sounds like you've got a valve issue if adding oil didnt really bump up the compression. although a 'capfull' might not be enough. we still need to know if you have mechanical or hydro lifters. do ALL your intake and exhaust rocker arms have an adjusting screw similar to the one pictured here (these are mechanical rockers) http://www.hdjxcn.com/bigimg/695.jpg http://www.hdjxcn.com/bigimg/695.jpg YES thats it......thats how it looks Link to comment Share on other sites More sharing options...
knightrider56 Posted October 28, 2008 Author Report Share Posted October 28, 2008 Valve issue , hung lifter if hydraulic, or to tight of a setting if mechanical or blown gasket, scuffed cylinder bad piston. Leak down test will help also. How did it run up untill having to do the test? Dadit runs pretty decent, but i can tell some loss of power....as far as the head goes i bought it from your place like last month along with the ajusa head gasket with the stainless steel valves, you had some package there on a head for about 7 and change....thats the one i bought.the guy who installed it for me said the cylinder looked very good and didnt notice any scuffs Link to comment Share on other sites More sharing options...
vbrad511 Posted October 28, 2008 Report Share Posted October 28, 2008 If you've got mechanical rockers, like the one pictured above, try adjusting it. it'll take all of 15 minutes start to finish to see if one's out. Hit Autozone and get a set of feeler guages if you don't already have some. Bet you've got one too tight. And if that's the case, and you keep driving it, you're gonna burn valves, if you haven't already. Link to comment Share on other sites More sharing options...
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