GentleBen

First post.
Let me begin by thanking eZone, the regular posters and all who have posted info on this forum. You have been a tremendous help! The problem with the 2001 Civic LX Coupe started with the dreaded P300 CEL code, Cylinder Misfire. This Civic has been an excellent and dependable vehicle for its nearly 296,000 mostly highway miles. I have really enjoyed this car but now what? Is it done, caput, finished, time for the scrap heap? Time for some research. Actually, a lot of research since I have practically zero knowledge or experience in this. First, what is causing this code? So following the knowledge and experience of others (no need to reinvent the wheel, right?) I did a compression test. The results:
Cylinder 1 to 4 : 170, 174, 185, 115. Whoa! 115? Even a novice can see something is wrong here. What can be wrong with cylinder 4? Rings, valves,or what?
So I called my trusted local Honda mechanic and described the problem and compression test results. He says that Hondas, in his experience, do not have ring problems and that it is probably the beginning of a burnt valve. How much is this repair? $1000 to $1200 depending on what the machine shop has to do he says. No way can I afford that. Why not do it yourself? Brilliant idea right? I do not believe that any novice enters into a decision like that with knowing the extent and scope of what he is about to experience. Head removal, torque values and sequence, lapping valves, TDC, timing marks? No clue. Thankfully, I had a lot of time (months) to research, complete a step, research some more, complete another step, and so on. Baby steps, but I had other transportation so no rush to finish by the end of the weekend or even next week. Got the head off and sure enough there was one burnt exhaust valve in cylinder four. All of the other valves looked good (to me). It was the only valve that was gapped at .007". Guessing that is why it burned. The others were .009" or .010".

Long story short: I ordered an exhaust valve and head gasket kit from Majestic Honda, lapped the new valve and all of the other valves, checked the head and block for any warping (.015" feeler gauge wouldn't pass under the straight edge), water and air tested the valves for leaks. I now know that water is not the best fluid to use in testing valves due to its surface tension (thanks to eZone), cleaned the block with carb cleaner and razor blades, replaced all gaskets with OEM Honda gaskets (removing those valve stem seals was like pulling teeth!), and then put it all back together. My fear at each step was that I had done something incorrectly or left something out and it would end in disaster.

Now for the moment of truth. Turn on the ignition and that little beauty comes to life just purring as pretty as you please! And no CEL light! What a tremendously gratifying feeling after so much work and apprehension. After driving it several times there is still no CEL light, is running very smoothly and has more power. That may not last as I know that lapping valves is not the same as having them done at a quality machine shop but am very happy with the results thanks in large measure to you guys and gals on this forum.

GentleBen

I did another compression test after finishing and got the following:
Cylinder 1 to 4 was; 196, 193, 192, 194
Not the best but I'm guessing not that bad for an engine with nearly 300,000 miles.
Has anyone lapped their valves instead of having a machine shop do them? Was it successful and how many additional miles did you get on that engine? Any educated guesses how many miles I can expect on this engine assuming their are no other major problems?

NDNV

Rock on brutha!

ezone

Good deal!

Yes
Yes and no, no clue
No clue




I know it's not the best practice, but only lapping is pretty common when someone doesn't want to spend money.

I've seen only lapping be successful many times, but then I've also seen other techs have comebacks after only lapping. IDK what went wrong, wasn't my work.

With 300k, I'd expect some valve guide wear that might cause issues.

GentleBen

Thanks ezone.
What issues are caused by worn valve guides?

ezone

Depends on how much wear, of course.

Probably.....occasional misses, either random or rhythmic, because the valve has room to rock in the guide it doesn't always close quite squarely and seal perfectly.

The guide wears in kind of an x or hourglass, wider at the ends. (wear patterns depends on forces imparted by the rockertrain)

Google search for more info?

dsm482

I lapped by hand all valves when i did my civic.. I bent few from cam bolt coming loose.
I used a drill to make it easier and saved my elbows. you can test the fit, and pour gasoline in the chamber and let it sit, and see if any fuel droplets get by..
I use to test every machine shop back in the day ..

only reason you might have to use a machine shop if the edge or angle is to far gone or damaged.

I also used a granite block to sand all my cylinder heads and sometimes they come better than a machine shop. .

GentleBen

That all certainly makes sense.
Possibly also increased oil consumption as it gets past the valve stem seals?

GentleBen

Ezone,
That all certainly makes sense.
Possibly also increased oil consumption as gets past the valve stem seals?

GentleBen

I also used a drill with a piece of vacuum hose connecting the drill and the valve stem and ground slowly, listening for the change in pitch.
Granite block sanding? Wow. Learn something everyday.

ezone

Meh, probably at 300k the original seals were worn or even hardened. Did it smoke after sitting and idling for long periods?

Wouldn't fresh seals be more pliable than original, thus seal better?

GentleBen

Yes, for sure. I'm glad that I replaced those valve seals. Didn't have excessive smoking before the valve job.

dsm482

I replaced the seals on mine when i did it.

GentleBen

How many miles do you have on this engine since the valve job?

dsm482

yes valve grind compound for the lapping.


yes you can look it up on u tube..

i have a pprecision cut granite piece i bought of used..
Old scholl way of saving dollars.. you will need elbow grease and sand paper.

works very well.
in the eastern block, or africa, if they don't have machine shop , thats how it was fixed. in one of my safari's they were fixing a toyota land cruiser ).

GentleBen

Yes, I did have to check it out on Youtube. Many times.
Otherwise I would have been as lost as a newly hatched chick in tall weeds.

GentleBen

ezone,
I cannot now find the post, but you indicated that after a valve job the oil and coolant should be changed due to dirt, debris, and cross contamination between oil and coolant. As I recall, you said that oil and coolant should be changed before starting the engine and again soon after and before the regular interval. How soon after?
Is this correct or should I start taking memory supplements?

ezone

Oil: Matter of cheap insurance.


Antifreeze almost always gets into the oil no matter how careful you think you are during the work. Fluids still remain in areas even though you drained them.
When you lift the head and when you tilt it to remove it, it happens.

Antifreeze in the oil can cause damage to bearings. Even miniscule amounts.

Oil floats on top of antifreeze. Antifreeze stays in the low areas.
(Antifreeze will eventually mix with oil given sufficient heat/time/agitation, but that requires running the engine)

The shape of the oil pan is such that you won't drain 100% of the oil without tilting, and depending on your lift equipment that's not always possible unless the pan is removed. (steel pan is more obvious, the location of the plug and the threaded nut inside determine how much cannot be drained easily)
Thus, any antifreeze that made its way into the oil areas and to the bottom of the oil pan tends to stay there and does not get 100% removed when the oil is drained.



So.. After assembly, I prefer to drain the oil and refill it.
Then start the engine and get it all warmed up and burp the cooling system and all that. Make sure the oil pan is hot.
Change the oil again and change filter.
Place oil change reminder sticker in the windshield for the next oil change, early. 100/500 miles depending on what I feel and how much I think may have been trapped.

If I had to remove the oil pan during the job for some reason, I don't go through all this. Simply clean out the pan, fill oil and replace filter and call it good.

===========

As far as coolant, I try to make sure I got all of the oil residue out of the block areas before I reinstall the cylinder head.
Oil in the cooling system can rot the rubber hoses and seals from the inside and make them squishy and unsafe.

Again, oil floats on top of the antifreeze. Any oil trapped in the cooling system should eventually find its way to the top/cap/reservoir areas.....and ruin the seals on the cap if it stays there

GentleBen

Thanks ezone.
That is even more detailed than your original post (as I recall).

I still probably ought to go ahead and order those memory supplements!

GentleBen

Ok. Got the oil and filter changed (again) after bringing the engine up to operating temperature and making sure the oil pan was hot. Hopefully all traces of coolant have been removed.

GentleBen

I guess no one caught it but I said in the original post that a .015" (15 thousands) feeler gauge was used to check for warping on the block and head. Just left out one little zero. Actually used a .0015" (one and a half thousands) feeler gauge.
May have been in trouble had a .015" feeler gauge passed under the straight edge!

ezone

You're right LOL

GentleBen

Wow ezone.
You must have an incredible constitution.

That same TP roll has lasted a VERY long time!

GentleBen

Lapping valves. Now that was an experience.

I placed all of the valves sticking in holes in a piece of cardboard and labelled them exactly as they were in the head.
The intakes didn't look bad at all but what did I know? This was my first experience with lapping and didn't have a clue except for the many youtube videos on valve lapping. Decided that all valves would be lapped...and lap I did...several times!

Lapped the valves the first time and then water tested them. Held water but got some air bubbles when air from an air compressor nozzle was directed at the valve stems. No go. Do it again.
At some point I got distracted and wasn't sure that the valves were still in order. It's important to keep them matched with their seats. So all over again.

Another time after water/air testing I put the head away with valves installed to do other tasks like testing and cleaning fuel injectors. Several days passed and the valves and seats were showing small areas of rust. Forgot to coat them with oil. So once again...lap time.

I believe that those valves and seats were lapped four or more times! Lost count.
It's been said that you learn more from your mistakes than from your successes. Well, let's just say that from this whole burnt valve repair job I've learned a LOT!

GentleBen

If you are new to this, like me, I would highly recommend keeping track of all parts, bolts, nuts, etc. instead of piling them in a magnetic tray or other container.

All bolts and nuts that could not be conveniently hand tightened back in its place on the engine I put in ziploc bags and labeled them with a sharpie. Made reassembly so much easier. Only lost one bolt. It was from the resonator which was inadvertently turned over after removal from the engine.

GentleBen

Engine is still running well with no CEL.
Don't know how long that will last.

Has anyone here lapped their valves instead of sending the head to a machine shop?
How did it turn out?

GentleBen

No one?

GentleBen

The LX is still running well with no CEL.

Having no experience with this repair, I had concerns all throughout the repair process and had to learn on the go.
One concern that I had (and still have) is bolt and nut torquing. I over torqued the two rocker arm adjuster nuts on cylinder #1 before realizing that the torque wrench was not properly calibrated.
They should have been torqued to 13 ft/lb. After calibration they were found to be torqued to 26 ft/lb !

I'm thinking the aluminum rocker arm threads were probably damaged to some extent but am inclined to leave well enough alone as long as the engine is running well.
Any thoughts?

ezone

It it had done real dmage to the threads you would have felt it get real loose instead of tighter. Threads would have deformed bad enough the bolt would slip or bolt would have broken.

If you backed it off and retorqued to spec and it holds, I would not worry about it.

RobertD

i have lapped valves on beaters with good results. a machine shop will ALWAYS seal better because when they do it, you get one crisp edge that seals (red arrow) because the different angles things are cut at, when people lap them at home, they end up with a thick band that looks shiny, but doesn't seal nearly as well. if you lap the valves, just stop as soon as you get a shiny ring around the valve. the thinner the better. spray in brake cleaner and make sure it doesn't seep out.

i think your valves are fine. i'd leave it alone. every honda valve problem i've ever had was a chipped valve.. every time i've done it it was due to holding the car floored longer than a smart person would. i chipped 2 valves at once trying to break 120 in a 89 civic. i chipped 6 of 8 exhaust valves holding the car floored in 3rd around a 4 leaf clover ramp with 5 people in the car. (young and dumb/steep learning curve)