ungcobob

Hello Honda-Techers,

Goal: Refurbishing a stock Crx D15b non-vtec with MPFI 200k.
1. Had the cylinder head sent out to a machine shop for a valve job.
-Valves and seats were cut and cleaned
-Valve seals were replaced
-Valve guides were not replaced

Problem: After picking up the cylinder, all valves were still leaking
1. Found out they were leaking when i did a compression test
2. Did a leak down test, and found air blowing out the exhaust and intake valves. Cams/rocker arms off.
3. Took off the head and performed a water, gasoline test by pouring liquid into the intake inlet and exhaust outlet. And it leaked
-Brought it back to the machine shop. They were beating around the bush, first person i talked to tried to blame it on me, then second person said it should be okay after cranking the engine they valves should seat properly. I don't want to bother with them anymore because they seem like they had no intention or capability of fixing it.

Solution: Tried to learn all the techniques on how to get the valves to properly sit and seal
1. Lapping: Bought Valve grinding compound, applied it to the valve, then used a drill/hose to spin the valve into the seat to have a perfect mating surface. Using a hand lapper would take hours on each valve. I spent about 10 minutes on each valve with the drill spinning 150rpm and 10 second intervals

******************Questions*****************
1. Is 10 minutes a lot of time to spend on each valve for it to not leak?
2. Do I need to replace valve guides to get proper seating?
3. Does gasoline ignite better when under compression? I cranked the engine and heard no combustion. I thought the gasoline would still ignite even without compression.
4. Should i just find another cylinder head from a 92-95 Civic from the junk yard and slap it on? Would it be more affective than trying to lap all the valves myself?


Im trying to pass California smog without paying some shady character $300

*******************Update*********************
4/25/2014
Found the Solution to my Problem!!!!!!!!!!!

Skillwise

Just to make sure, when you bolted the head on... did you make sure your timing was 100% dead on? If so did you turn the engine over by hand a few times by hand prior to trying to start it? Those steps are crucial. I believe the machine shop may be thinking it wasn't timed properly and some valves hit the pistons. It happens more than you would think. Get a drill, put the drill in a vise. Put the suspect valve in the chuck of the drill. I think you will find that if you spin it by hand, you will see the head of the valve wobbling a bit off center. Check all the valves in the cylinders with low compression, or if you're like me, check ALL of the valves. Lapping should take around 1 minute per valve with a drill,...and that's being excessive. You should be able to see the area that you've just lapped, it will look freshly cut. If you have a micrometer handy, the seat width should be .040" in width. If you can't see the difference, use transfer paint. Too narrow and you won't dissipate heat, too wide and you'll build up carbon. Gasoline does not ignite with just compression alone, of course there are extreme cases but generally it needs an ignition source. Lastly, since you're already this far into it, just see what you have started through. You've already spent money on it, just finish it. Hope I've helped.

slowcivic2k

Cutting the valve seat will affect the valve stem height, reducing the closing force on the valve. Installed valve height needs to be checked and corrected for after a valve seat cut, regardless if the seat is new or used.

New guides should be installed to prevent oil leakage and marring of the valve seats due to excessive guide to valve stem clearance.

Of course, base engine timing needs to be checked to ensure the valve train is working in time with the crank.

Lapping valves does not take very long to perform, it only needs to be done to ensure an even seal from valve to seat and the results are evident if they seal or not.

To me, a "rebuild" on a head would include new valves, guides, seals, and seats, plus a valve spring test to ensure they are square and hold appropriate force.

What you have described is not really a rebuild, but a replacement of the valve seals and a cut on the seats. Were you having problems before?

ungcobob

Thanks @Skillwise for your response, it was very helpful. I'm sure my timing is correct, made sure to align all the gears in the appropriate position and installed the timing belt. Then hand cranked it a couple times to see if the tensioner adjust the belt correctly for all the gears to line up in place when TDC. I had another machine shop redo the valves and he tested the mating of the valves and seats concluding there was no leaks.

@slowcivic2k you make total sense, if this was a rebuild i wouldn't be using many used parts. I was hoping this would be a cheap and easy refurbish. Mixing old and new parts really doesn't cut it when trying to make old engines work. Response to your qustion "Were you having problems before? " Answer: I purchased this crx engine from someone, hoping i could use it to pass smog, it didn't have compression when i bought it but was able to crank. I've never done anything this extreme when it comes to cars. Never knew the smallest thing can prevent engines from working.

*******************Update*********************
1. Had the cylinder head valves redone, and it doesn't leak anymore. After installing it, a compression test was done and the results were 160,60,60,90. I poured oil into the cylinder and it boosted each cylinder up, 210,90,90,115. Originally when I measured the block cylinder bores (top, mid, bottom), they were close to their service limit, out of round, tapered. I was hoping replacing piston rings would be adequate, but i guess not.

2. I am looking to rebore the cylinders to the next size of 75.5mm and install new oversize pistons and rings in them. Probably get the crankshaft balanced and polished (not sure if that's really necessary)

Note for Next Time:
1. Start from the bottom (block) and do it correctly then move up towards the head. Would save so much time

ungcobob

****************************Update**************** ***************
CRX SI cranks but no start up. I could hear at least one chamber is igniting after a coupe of cranks.
What I've done
1. Replaced spark plug wires since they were old.
-Made sure they wires are correctly wired up
Firewall
Dizzy Bot - Top Row Cylinder
1 3 4-3-2-1
2 4
Front of Car

2. Took out spark plugs and poured a little bit of oil into the chambers and cranked it a couple times for rings to seat properly. Did a compression test, they were all showing 150 PSI probably cause there was oil still in it. Again cranked it a couple more times and all cylinders showing 90psi and holding.
3. Checked Timing for ZC single cam head with d15b block
-Cam side marking lined up to cylinder head, with Crank pulley lined up with marking
4. Tried running Engine with working PR3 ecu
5. Hook up another ground wire to the Engine

Assumption:
1. I believe it must be an electrical issue causing the no start. Even when all cylinders showing 90psi i feel like it should run but poorly.

FYI
1. The wire harness came off my running B16a ODB0
2. There isn't any CEL code being thrown.

ungcobob

I had an epiphany yesterday while driving home. My assumption that the root of the problem must be electrical. I've checked the ECU, Wiring harness, changed the spark plug wires and plugs, distributor igniter and coil. Then it came to me that the Rotor within the distributor can be mounted in two directions but only one side would be correct. I took apart the distributor and mounted the rotor in the opposite direction.

Guess what?!?!?!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

It fixed the problem, was able to start the car up easily like there was nothing ever wrong with it.

Thanks to everyone for your time, hope this thread helps you guys in the future