NavsENG

Hi, new here.. I have a question, I have a 93' Civic with a 1.6 in it. I am having issue with compression, first of all I ran a compression test on the cylinders and it would not build compression. Even with oil I could only get up to around 60 or 70.

Weird thing is I checked the timing mark, I rotated the motor (same direction it runs in) and lined up the notch on the timing cover with the white mark on the balancer. The cam gear then had the 'UP' mark up and the two flats looked to line up with the head surface.. Ok this looked good to me. When I crank the motor it sounds like there is no compression at all, cranks way too fast.. Checked fuel and spark that is all there.. I don't know hondas that much but i know what a motor sounds like when its cranking, with ignition or not.. I ended up pulling the head thinking maybe the belt stretched or something and maybe it bent the valves, but those look good too..

I'm lost what could be the problem? Maybe it was the timing belt that got stretched? I dont know how much tension the belt should have but it was pretty loose, I could slip it off the cam gear without much effort. Seemed a bit loose to me..

ThoughtS? thanks

jbpnoman

If it isn't building pressure with oil in the cylinders, either you cracked a cylinder wall, or your oil control rings (piston rings) are shot.

BoostedLsdHatch

Or their very well may be a whole in the piston if you dropped a valve from the loose timing it s possible id take the spark plug out and rotate the crank and look into the hole.

mech187

my 88 was cranking like a champ and I had spark and fuel right up to the throttle body, after racking my brain for an hour I changed the injectors and the damn thing fired right up.......sometimes it's just the simple things.

NavsENG

I pulled the head, everything looks ok.. It is weird, because it doesn't sound like it is cranking normal, it sounds and feels like it has very low compression. I just cant see the rings being smoked because the last time I tried to start it after sitting for a while it stumbled a bit, then I tried to start it real quick and it just spun quickly, like the timing belt was busted... It was running fine before this. Maybe I need a new motor!

jbpnoman

Or maybe you need to disassemble the bottom end. There's no way to know the condition of the rings without removing the pistons.

NavsENG

I guess I will have to.. Why did you suggest the oil control rings are the problem? Those don't hold compression

jbpnoman

They're the last line of defense for holding compression. If you did a wet compression test, and still lost compression, either your rings are shot, or your sleeves are cracked. If your oil control rings weren't shot, you would have held compression during a wet test. Since you've already pulled the head and said everything looked OK, you probably didn't crack your sleeves. Just start hoping you don't have fucked up ring lands.

It's all good though, almost every D16 engine running right now could use a fresh rebuild, and it's a good way to learn everything there is to know about a motor.

aavtec

Maybe you have some burnt or bent valves. Pull the head of and inspect everything.

stevenr2894

Are you loosing oil? White smoke coming from your exhaust? Sounds like you need to take the block to a machine shop. Get new pistons and rings.

stevenr2894

Usually low compression is associate it with bad piston rings or piston slap. Oil blow by is for sure going to happen

hwyix

iTrader: (1)

What is the history of the car? How long have you owned it? What has been done to it?

Did the car run perfect yesterday and the next day drop compression on all cylinders down 60 psi. Maybe timing belt skipped a tooth. You must be forgetting tell us something important. Like you just bought used junk yard engine/changed timing belt/replace head gasket/adjusted valves/etc....