Bent Valve...

[MNLXi4D]

We bought our Accord LXi with a bent valve, or at least thats what the guy tells us. The timing belt broke, and it hit the valve and bent it. they didn't know that and when they put it all back together, it had a valve click, the guy drove it for about 500 miles and now, if you take it over 3K or have a load on the motor (Like floor it in 5 gear) it smokes REALLY BAD. How can we check if the valve is bent or if something else is wrong. The comression numbers were 150 cyl 2,3,4 and Number 1 was 120 (bent valve on that cyl). If it is the valve, how can we fix it?
Thanks guys.

[Lester Lugnut]

Unfortunately 3G engines are interference motors - break a timing belt - bend a valve or valves collide with a piston - same thing.

The cyl. head must come off. A machine shop will then need to replace damaged goods. It can get expensive, but there is no cheap way out.

If you're handy with tools you can save some $$$ by pulling/reinstalling the head. Machine services will vary in price, depending on what all has to be replaced.

[POS carb]

throw some oil in the hole and crank her over, if it seals now you need new rings or got a scratched cylinder.

[night]

a bent valve isnt gonna give 120.

ive broke belts and never bent anything. actually, i always check these engines for a broken belt by taking the cap off and checking if the rotor spins.

[rocky2]

120 psi is enough to suspect another problem besides bent valves maybe. Take off valve cover...inspect cam lobes,valve springs, bottom of spring surface,then check valve adjustment,could be way off ..then adjust and do another compression check,if there was a bent valve you would only get 10-50 psi

[MNLXi4D]

I just ran a compression test today on my Accord, and the numbers are
Cyl 4: 182
Cyl 3: 185
Cyl 2: 80
Cyl 1: 72
The guy said the bent valve was Cyl 1 but why is Cyl 2 so low also? Is there something else wrong with the car and not a bent valve?

[BensAccordLxi]

Does any one know if the b20a will bolt in to an 88 accord?
Some one said the only mount to change is the tranny mount. Is this true or is there more work involved?

[MNLXi4D]

Lets try keeping it on topic please.

[rocky2]

You could verify bent valves by putting compressed air into cylinder and listen at exshaust pipe/intake for air leaking though. And thats after cam is out with valves closed. Its also possible that timing belt is not put on right, and the head gasket could be blown between #1 & #2 cylinders. But its most likely bent valves from the timing belt breaking.

[monsonhonda]

hey rocky, couldnt he just put the cam at tdc for said cylendar instead of taking the cam off, all the valves are closed at tdc.

peace

fussell

[rocky2]

monsonhonda,


Yeah your supposed to do it that way, but when bigtime
work is suspected,you know for sure this way...with cam out the valves have to be all closed. plus even at tdc compressed air can push the piston down. Also with cam out you can look and see if the valve spring height are smaller on #1 and #2 cylinders cause valves are bent.

[monsonhonda]

alright, i see where your coming from, definately see the advantages in taking the cam out.

peace

fussell

[mike_fx_u]

my timing belt broke also. I took the head to a machine shop they pressure tested the head, resurfaced it, installed new seals, and replaced the bent valves(they provided) for $100.

[MNLXi4D]

Well, we pulled the head off, and brought it into a machine shop, they said the valves were all good. So we put a new headgasket in, and its still acting the way it is. Blowing alot of steeam out the exhaust and lots of blowby through the blow by tube off the valve cover.
We were thinking maybe the timing was off, because it feels gutless and won't go above 5500 RPM, but now we're thinking maybe a cracked block and thats why its steaming. Anyone have any ideas?

[rocky2]

Take your plugs out while engine is hot, then turn engine over.Look at plug holes when turning over for coolent. And take oil drain plug out for a second to see if water/coolent is the first to drain out of crankcase.,after it cooled down. Do another compression check. How did the cylinders look on the ones with low compression?

[MNLXi4D]

When we took the head off, the pistons were dark colored, but very clean we could read the codes on the top of the pistons.

[rocky2]

How about the walls of cylinders? Were they scored? And was there a ridge on upper cylinder?

[MNLXi4D]

Walls of the cylinders were great, no ridge on the top of the cylinder.

[dXsquared]

damn... thats a mystery. i think you should swap a B16 in! just kidding... just for coolant leaks into the cobustion chamber. thats all i can think of.
Travis