tim73

92 f22a6, block is old 200k+, rebuilt head, new head gasket, new timing belt wp tensioners etc. when engine was on the cherry picker had compression175-180 all 4 cylinders. Install, test, went to150-120-120-0. Removed valve cover, aligned tdc mark on flywheel and cam sprocket appears off maybe 1 tooth. Could 1 tooth do that? I wouldn't think so. Ideas?

GhostAccord

Was this engine run yet?

If it was due to the one tooth, all 4 would be the same not just one.

Check you valve clearances for that cylinder.

Try running a leak down test on that cylinder and see where the air is going. Intake, exhaust or block.

Intake = valave issue
Exhaust = valve issue
Block = rings or piston issues.

tim73

Tried to start. Then tested. I'll try and air test in the next few days.

tim73

Has anybody experienced or heard of worn camshaft sprocket teeth? I havent had a chance to mess with it, but the more and more i think about it. the only thing it can be is a slipped timing belt. Ive done several timing belts of f22, so im pretty sure I have a good idea about what the tension should be. Plus, i rotated it several times via wrench on the crank bolt. Thansk!

holmesnmanny

If you have even one tooth off then the compression on all cylinders is going to be different. It's possible you somehow had too much slack so it jumped. The tension is set automatically via the springs if you allow the springs to do their job. There is no need to give it more slack or take slack away.

tim73

Leaking out of intake. And the valves are definitely closed. I double checked the timing, tdc mark is dead on and camshaft marks are perfectly inline with head. I'm truly stumped, because before I dropped in engine I compression tested it, and it was dang near perfect. When I get time I'll remove the head.

GhostAccord

Did you have a valve job done on the head?

If the air is coming out of the intake manifold that usually indicates that the intake valves are not sealing to the seats.

tim73

Yeah, the head was rebuilt from a professional machine shop.

tim73

So, I finally got some time to mess with it some more. I removed the cylinder head...and found a tiny piece of carbon/metal sitting in between one of the intake valve/seat. Just enough to where the valve was open maybe 1/16" of an inch. I fished it out.

At this point, I went ahead and replaced the a1 springs with the a6 springs. I was going to lap the valves...but the valve and seats all looked perfect. Not bent at all and sealing good, I would have liked to use some Prussian blue to test sealing, but I didn't have any so I just used a light test (No light would pass through any of them). So I went ahead and bolted head back on(With camshaft not installed) I did an air test, on cylinder 1&4, with #1 at TDC. A small amount of air could be heard coming out of the intake side. Not near as much as before...plus both cylinders were leaking the same amount. I was under the impression, the cylinders were tight...no leakage at all. But I am by no means an expert. I had my compressor set at about 60-70psi. I left it like this...I am thinking my next step will be to reset the timing belt and do a compression. Thoughts? Suggestions? Again....cylinder head was professionally rebuilt and tested...valves/seats look clean and smooth.

ej8

The valves should not leak. If the valve clearance isn't too tight, holding them open, and you still leak air from combustion chamber to intake, you have a bent valve, valve not sealing in the seat properly, or cracked head.

I would be concerned with the metal you found holding the valve open. Did it do any damage? Where did it come from? Is there more foreign metal objects inside your engine that can lead to further problems/damage?

tim73

I had thought about a cracked head too...but the head was professionally rebuilt(Has not been started up yet) Anyway, I took all the valves out...and rolled them...and looked for any sign of warbling...they rolled nice and true. I have another cylinder head...I may remove the intake valves...and install them. See if it seals up. I just wasn't sure if a small amount of leakage was normal...or should it be completely tight. Very frustrating.

GhostAccord

It is very rare to find an engine with a 0% leak result. 5 - 10% leakdown is very good condition. Also a 4 - 5% variation between cylinders is also acceptable.

ej8

Yes up to 10% overall on a leakdown test is considered in spec, but the pressure loss will be mostly through the piston rings. If I had a full 10% leaking past the valves into intake or exhaust I would be worried.

With the head off the car, the 'ole water test in the combustion chambers works well for testing valve seal (and also measuring combustion chamber volume with a little extra work) and if you have any leaking from this test it is considered "failed to seal".

tim73

So, I decided to just hook up timing and give another compression test. Test was good...I had 165 175 170and 160. I'm ok with those numbers. I will hook rest of intake up and try to start tonight.

holmesnmanny

Those numbers are fine. I really gotta wonder where that metal came from. Interesting.

ej8

Yes, I wouldn't worry about those numbers but the metal is a concern. I am very obsessive over making sure everything is 100% clean and free of trash before putting together a motor and I build it like I am in surgery. You should not have metal in the motor from machining etc. I am hoping it is not a broken piece that came apart while operating, instead of something that was accidentally overlooked at assembly.

tim73

So after a bit of fussing...setting timing, etc... she fired up. Had a couple of issues, surging idle(which I already fixed). But there was a taping/smacking noise coming from the valve train. This was concerning. So, I decided to reset valves(id done it already) but decided I'd double check it. But what I found was interesting and pretty much a lucky find. The far right intake valve rocker arm was missing its little spring. So it has axial slack and was smacking into the cam bearing cover.

I normally leave the valve train together when I remove it. But I guess a previous owner disassembled it, and neglected to reinstall the little spring. I have the old head so I replaced the spring. Engine is purring now. However there's a small coolant leak from a small coolant hose on the intake. I'll pick one up today. Plus change oil. Hopefully will road test in the day or so. Thanks for help guys!

holmesnmanny

Awesome man good to hear.

ej8

Great find Happy for ya!

tim73

Here's his car. It actually has 326000 miles. But body and interior are in really good shape.

ej8

CLEAN Gotta love old school Honda