First of all, this engine (d16z6) only has 100 miles on it since it was rebuilt. It got a completely fresh bottom end but the head was not touched.

I think the head is my problem but I'm not sure. I took some pictures of the plugs so hopefully someone can help me determine what the problem is.

The engine seems to run fine. But I keep failing emissions so I am starting to think I'm burning some oil. That's why I decided to do a compression test tonight to see if I could figure out the problem.

Here are my compression test results:

#1 - 180
#2 - 185
#3 - 135
#4 - 160

This engine should be between 180 and 190, so the 135 and 160 worry me a bit. Looking at the plugs from those cylinders leads me to believe that they may have a problem.

Here are the plugs.

Cylinder #1 (180 psi) --- Look at the top of the plug. It looks like half is white, and half is black. Any ideas on why it would look like this???



Cylinder #2 (185 psi) --- This one looks normal to me, but around the base of the threads there is some oil gunk buildup, and this is after only 100 miles. What would be the cause of this? It has brand new plug stem seals.





Cylinder #3 (135 psi) --- Definately a problem of some sort here. The whole end of the plug is black.





Cylinder #4 (160 psi) --- This one looks fine to me as well.



So what do you think?

I'm tempted to just pull the head off of there and put a rebuilt one on there. I don't know how many miles this head has on it and I don't know what kind of abuse it was put through before I got it. The bottom end of the engine was in pretty bad shape when I bought it, which is why I rebuilt it.

Should I order up a rebuilt head? What are your thoughts?

 

i dunno if u put new rings but they might not be seated yet. id say give it another 200 miles, and check it again. if its still bad then rebuild the head.

just my opinion

 

what are you failing emissions on hc? and co's? and from the picture the one with 135psi the black looks to be dry so the that would be fuel, if its wet it could be oil. but i cant tell from the picture so is it wet or dry?

chris

 

ya post of the e-test results, that would help determine the cause too.

Also, have you adjusted the valves lately? Maybe #3 is too loose letting alot of the compression out?

 

Thanks for the comments!

The plugs were all dry when I pulled them out. Also, I adjusted the valves when I put the head on the block just a few weeks ago.

I'm going to go ahead and just pull the head tonight to have it tested.

I'm almost 100% certain the valves in 3 and 4 aren't sealing correctly which is why I'm not getting a complete burn in those cylinders.

On 3, I think the valves are sealing so badly that the mixture isn't burning completely which would be why it looks like I'm running super rich in just that cylinder. I'm running a stock p28 and a brand new O2 sensor so the chances of me running too rich are pretty slim.

Also, this explains my idle. The engine would kind of shake when idleing at 750rpms. The uneven compression is definately the reason for that.

I just hope I wasn't washing out the cylinder walls in 3 and 4.

Anyways, I'm going to pull the head tonight and see if the valves are sealing correctly or not.

I should have known this was going to happen. I rebuilt the whole bottom end but didn't touch the head. I guess I was just hoping that it didn't have any problems. I also should have inspected the engine better before I bought it. When I first bought it I didn't really know what to look for and the guy said it was running fine...

I pulled the plugs when I got it home and they looked like complete ****. The ground strap on two of them was burnt off and the other two were bent, which means they were getting WAY too hot. I'm beginning to think this guy was spraying on the engine.

Anyways, I'm learning lessons slowly but surely.

 

the first plug is half black/half white, I was told when they do that its due to the fact the way they were facing - exhaust valves. A honda tech told me that.

 

u can get your plugs out a big to u i havent been able to get #2 out for years even with a 4 foot breaker bar with a 3 foot lead pipe so it's been in there still firing off for bout 2.5 years now i think my grandpa (who isisnt to smart with cars) put one in from a vanagin. and the threads have melted together on the end of it.

 

Rebuit ormall means ALL of the engine not just the few bits you thought to replace. Normally Honda engines need head work before rings/bearings. Yours needs New Guides and New seals possibly new valves as well. also don't forget to get the head measured and resurfaced if it measures warped.
Freshly rebuilt Civic engine normally tests below threshold levels of the Emissions test, that as in Zero measurable polutants :-)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DieMaster &raquo;</TD></TR><TR><TD CLASS="quote">u can get your plugs out a big to u i havent been able to get #2 out for years even with a 4 foot breaker bar with a 3 foot lead pipe so it's been in there still firing off for bout 2.5 years now i think my grandpa (who isisnt to smart with cars) put one in from a vanagin. and the threads have melted together on the end of it. </TD></TR></TABLE>

wtf, I've broken off sparkplugs in my head with a regular old ratchet... maybe you're on crack.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bare &raquo;</TD></TR><TR><TD CLASS="quote">Normally Honda engines need head work before rings/bearings. </TD></TR></TABLE>

I dunno about that...