bigshoe

iTrader: (2)

Ok, I just finished a compression test, and I had some funny readings imo, I could have possibly did it wrong, but my search didnt come up with too much on how to compress air, what I did is just turn the motor over just a little bit more than it takes to start the car, so thats probably 5-10 or so revolutions? Motor was cold, and I did NOT disconnect the fuel injectors. here are the results of my compression test:
(where i have two numbers and a comma, i retested)

cyl#.......bank1........cyl#.......bank2
...1........145,150.........2...........149
...2..........155............4...........152
...3........153,150........6...........166
...4...........152...........8...........148
Now, i'm trying to understand if I have all low numbers besides #6? A few years ago, when i first got the car, i missed a few shifts, and overrevved the motor (3-4miss near redline), it was good my tires sucked and that I actually had wheel hop, so the motor didnt make it all the way up to whatever rpm, but I did pull the pushrods after that, they all seemed straight, but there was the slight "tap" against glass as I rolled them down it, so i replaced them, and now i granny shift. Anyways, I probably had some valves tap my pistons? since it happened 3 times, i'm wondering if all but cylinder 6 have a small seal issue since then? The variance is over 10% between cylinders since i have that one really high reading, i think this is whats considered unacceptable, so how worried should I be?

Now, i plan on doing a tr224 cam REALLY soon (have everythign but valvespings), I need to determine if i may have some head problems before i put money into the valvesprings...opinions appreciated please.

now, for my spark plugs, to me everythign seemed normal, but on bank 2, I had some different looking plugs, these are tr55's that are 2-3 years old, maybe 40-50kmiles. The plug on the left is the #2 plug, and it is doesnt have what I think is carbon buildup like the other 3 plugs. I dont have pics of bank 1, everythign is installed again ---- again, opinions appreciated.





thanks in advance

soundengineer

iTrader: (16)

those plugs are worn out...especially if they are TR55's.... should change out copper plugs like every 10K(sometimes less depending on driving style and conditions) miles I.M.O....you can get longer out of them...but they drop off in performance pretty quickly

couldnt tell you for sure about the compression... I had to do a check once..and I just turned the key to use the starter to do the turning for me...Did you do it that way..or by hand???
I know that compression PSI will vary per vehicle depending on the cam and the amount of valve overlap you have...

PHTCBRA

As far as I know, You should be doing this, while at full throttle. Make sure that the throttle plate is fully open. Ovbously keep any fuel from entering the fuel rails. HTH

wrencher

iTrader: (2)

To do an accurate compression test you must do all the steps. Motor warm/hot all plugs out fuel /spark diabled & throttle wide open. Then when cranking the engine doe the same amount of compression cycles per-cylinder. You can hear the motor when itcranks over with all the plugs out & the comp. tester in one cylinder. You will hear each puff, do 4 'puffs' cranking for each cylinder. That way it is consistant. The first puff should also be roughly 50% of your total #.
If you analizing plugs they need to be removed after a wsarm up as well. Not after an extended idling period either.
Does the motor miss or run rough? Your prolly fine no damage that is, it would have did push rods in if valve & piston contact had occured. The real test to tell cylinder sealing ability is a leak down test. You need a leak down test gauge to perform them though.

bigshoe

iTrader: (2)

thanks for your responses, guys,

well, I did it wrong for sure, but it gave me an idea, and i guess for now thats all I really need. The purpose of my compression test was to decide whether or not i should do heads(which i really cant financially) or not if i do find something wrong before i do my cam install.

btw, the motor was cold, and no it doesnt run rough, and I do not think it misses more than normal either.

again, thanks for the help

Viper

iTrader: (6)

bigshoe

I held my throttle open with a rag and disconnected the fuel.

What's the decision on the heads?

See ya at the Lizard