xxi2icexx

so, i did a compression test because my motor was idling shitty for a while results were.
#1 60
#2 180
#3 150
#4 210
after that i performed a wet compression test (added 1 cap full of ATF)
#1 65~70
#2 210
#3 180
#4 210
sounds like rings right? except for #1 which should be valves.

mouab18c1

iTrader: (5)

Its time for a full rebuild

oldintegrao

Yeah that does not sound good at all, i ran some marvel X in my oil and it brought my compression up some, if you are still driving the car its worth a try. You can get it at walmart/autozone etc and its in a dark red bottle pretty cheap just seems really thin in comperision to motor oil but worked for me! good luck

xxi2icexx

sounds like a full rebuild !

sayanything

iTrader: (1)

im in the same boat. about to start the rebuil in a month. hopefully get it done in 2 weeks.

racebum

burned exhaust valve is my guess..these almost always go due to excessive oil burning. the valve gets coated and can't cool effectively on the seat, eventually they frag

MRQ06

Looking on cylinder 1 it seems like some sort of a valve leak, but if you look on how dramatically cylinders 2 and 3 inrcreased compressions sounds like rings on those cylinders.

TheAsian

I wouldn't say burnt valve it would be lower than that on cyl 1. Most likely with that number is carbon build up holding the valve open.

rickyracer

check the valve clearance also...might have to much pressure on the valve from the cam...

MRQ06

When i had a cracked exhaust valve, my compression readings on that cylider was zero. I took the head down couple days ago got done yesterday runs like a champ again!

xxi2icexx

hmmmm, i should check the valve clearance. im going to do that today. as far as number 2 and 3 cylinders that sounds like rings to me. + 30 psi gonna pull the motor sometime next week when schools out!

racebum

they don't always come apart large enough to equal zero, small chunks will do this but a leakdown test will show the cylinder not able to hold pressure. carbon build up happens everywhere BUT the seat, the repeated slamming prevents the actual seat from getting deposits. the entire valve may be coated however, often due to dat der oil burning but carbon on its own won't drop cylinder pressure like that unless it was so seriously excessive that oil just was pouring down the guide and the engine wasn't able to burn it off fast enough. as for the other cylinders you guys are guessing wildly if it's the rings, valves or a combination of the 2. at a bare minimum when you tear this engine down ALL exhaust valves need to be replaced and any guide that does not measure within spec. a new valve job on all 16 takes place and new rings and a hone go in. this of course only works if the cylinders aren't out of round. if they are you have to overbore. if you have visible bearing wear and or clearances above .0020 those have to be replaced too. this is bare bones minimums for parts, it should go without saying seals and belts are replaced. if you do an actual rebuild all moving parts are replaced or machined and you create a new engine.

MRQ06

what prompted you to do a compression test anyways? A bad or burnt exhaust valve would sound like this.....
http://www.youtube.com/watch?v=tKDMq...eature=related

TheAsian

I have seen carbon build up hold haves open before. Carbon over time will build up on the valve seats.

Op unless you have a optic scope you just need to pull your head. Its either gonna be a cracked valve, or carbon build up

xxi2icexx

yes, if i am going to pull the motor and do a rebuild i am definitely going to have the whole head checked out and the block, rings, cylinder walls, valves, valve guides, valve seals, either checked to see if they are in spec or replaced. wont know till i pull it out. hopefully its not too serious, and only a hone will be required and not have to bore it out oversized. the motor is a 97 motor (stamped 96) and i doubt its been rebuilt since.

xxi2icexx

i would doubt that my valves would have that much carbon build up on the valves to cause it not to seal. i always pump premium 91 76 gas. and ran some sea foam through the motor once a year or so i dont burn much oil at all the car consumes about 1 quart every 3k miles.

xxi2icexx

took the head off, intake valve was damaged.

racebum

wow, an intake? those things normally still look new after 200k, it's the exhaust valves that take a beating. what happened to the intake?

xxi2icexx

my bad it was a Exhaust valve.

xxi2icexx

heads back and looking nice, but the block head bolt threads are stripped . . . timeserts or new block...