[chuckscott]

99 Ody EX, 235K mi - After pulling and reconditioning heads to replace bent intake valve on non-firing cyl 1, now have bent intake valve on non-firing cyl 5 and low compression on cyl 4. Here are the details.

Doing timing belt replacement. Also, pulled vtec solenoid, vtec pressure switch and solenoid/filter assy to replace o-rings. Hand-turned crank 6 times with new timing belt and saw rear cam was 180* off-time from front cam and crank. Removed belt, rotated rear cam back to TDC and re-installed belt. Hand turned crank again, watching belt-tooth position. All OK. When I started engine, it ran rough immediately, with valve chatter on rear head.

Warm engine compression test revealed:
- Cyl 1 - 0 psi
- Cyl 2 - 200 psi
- Cyl 3 - 205 psi
- Cyl 4 - 207 psi
- Cyl 5 - 205 psi
- Cyl 6 - 183 psi

Pulled both heads and sent to machine shop for reconditioning and valve job. Shop replaced stem seals and 2 valves: bent primary intake valve from cyl 1 (vtec intake valve OK); one exhaust valve (probably from cyl 6). Shop said they set intake valve lash at .008” and exhaust valve lash at .010”.

Put engine back together with new head/intake/exhaust gaskets. Hand turned crank with new timing belt, watching belt-tooth position. With plugs out, crank and cams turned easily, with no obstructions. But, when I started engine, it ran rough immediately, with valve chatter on front head.

This time, warm engine compression test reveals:
- Cyl 1 - 183 psi
- Cyl 2 - 182 psi
- Cyl 3 - 181 psi
- Cyl 4 - 130 psi
- Cyl 5 - 0 psi
- Cyl 6 - 185 psi

Valve lash after compression test:
- Cyl 4 - Both intake valves at .011”; both exhaust valves at .010”
- Cyl 5 - Vtec intake valve at .008”; primary intake valve lash too large to measure (bent valve); both exhaust valves at .011”.
- Cyl 6 - Vtec intake valve at .009”; primary intake valve at .024”; both exhaust valves at .025” - but compression is fine.

Plan to pull front head and replace any bent valves. I don't want to do this again, so I would like to understand the cause of these problems: low compression on cyl 4, bent valves on cyl 5, and large valve lash on cyl 6. Possible causes:
- Could be something with vtec system, since I removed/reinstalled pressure sensor and solenoid.
- I may have bent the cyl 5 intake valve when I set the front head. When I set the heads, the crank was at TDC, with cyl 1 and cyl 5 at the top of their stroke. Before I set the heads, I rotated the cams about 60* from TDC, so there wouldn’t be any fully open valves. But, the cyl 5 valves may not have been fully closed.

I would appreciate any advice.

 

[gregersonke]

The compression is about right for an engine of that kind of mileage. But seems wierd that it would get lower compression after head clean up. It sounds like the machine shop put in one of the bent valves instead of the non bent ones when they put it back together. The only other explaination I could think of is that the valve spring on the bent valve may be bad and caused it to hit. This time, I'd recommend replacing all the valves and replace the springs while you are there. Or, just get a low mileage engine as its usually cheaper than rebuilding heads.