Ok so how do you know if you have damaged valves from a broken timing belt. I removed the valve cover and nothing looks bad unless there is something special i should look for... Anyone???? Is it something obvious or do you have to actually remove the head or anything like that? I need an answer as soon as possible. Thanks guys!
you won't be able to see the valves very well from just removing the valve cover. the valves are pointed downward into the combustion chamber, and will not be visible.
you might be able to tell if they are bent or shattered by turning the motor over manually (via the crank pully bolt) and looking in the exhaust ports with a flashlight pointing inside.
since you probably won't be able to tell much from that, the next best bet is to pull off the timing belt and remove the head. its definetly a PITA, but if you think you damaged your valves/pistons, its the going to happen eventually anyway.
good luck to you, and if you need any help along the way, the shop manual at www.pauldesign.ru is invaluable.
EDIT:
http://www.a20turbo.com/features/chr...1/IMG_0417.jpg
this picture shows the angle you will need to try to look for.as you can see, all you really can see is SORT OF the top of the valves, you wont get to the see the face of it until you pull the head. but you might be able to tell if stuff is REALLY messed up.
Last edited by bobafett; 05-22-2006 at 03:41 PM.
well it wont tell you if you bent valves or windowed a piston but me personally i always do a compression check before i go any further. Im sure you now how to do that. Pull a spark plug, screw in a compression tester and record the values in each cylinder after you crank you engine over. I usually let it crank 4-5 complete revolutions on each cylinder. A little sidenote. you obviously dont want the engine to strat so be sure to pull the coil to cap wire as you dont need spark down there. If you have a certain value way lower or all are below id say 150 id pull the head from there
Incidentally, I believe the general consensus is that our engines are non-interference, which means a broken timing belt will not cause valve train damage or piston head damage, unless you've had milling done to the head.
a compression check will def tell you, if it's low,squirt a TEASPOON of oil into the cyl,then repeat the check,if it goes up it's bad rings and you've got worse problems. if it's still low it's the valve train or a crack in the head. the oil seals the bad rings temp. you can also check the height of each valve tip with a height gauge. all the exaust should be about the same,and all the intake should be about the same. any valve that is sitting lower then the others indicates it's not sitting correctly in the seat. it's probably bent or the seat is damaged. a lot of carbon buildup can also cause this. eithier way any valve that is off means the head will have to do the same.
i say a cylinder leakage test should tell you whats wrong and wether you have bent valves or not.
You won't be able to tell if the valves are bent with the valve cover & timing belt off. Since you probably off on TDC marks on the crank & cam.
The best way for putting the cam back at TDC is to take loose the cam bearing caps, then move you crankshaft & camshaft back to #1 TDC. Then install your timing belt. After that, then do a compression check. That is the closest way to seeing if you bent a valve without removing the head.
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Hey thanks for the info guys! One more question... I tried to turn the engine over with a large ratchet at the cam bolt but it only moves a tiny bit. Is it just really hard to turn or do you think somethings wrong?
nope your supposed to use the 19mm nut o the crank pulley. if you pull the drivers tire or at least turn it hard left you can get a 1/2 inch wratchet in the with a 6 in extention. you should hopefully be able to feel the compression strokes and it should turn past that. Since its already past a section anyways I wouldnt worry about causing any further damages
if you pull out the spark plugs you wont have to fight engine compression, but you will still have to fight valve springs and the mass of the engine. i can turn mine over with only a slight struggle with a regular 3/8 ratchet with 19mm socket and 6" extension. if you turn the wheel you can get a small rachet in there, if you remove it, and use like 1-2' of extension, you can get a huge breaker bar in there.
be careful of the cam gear bolt, mine was all rounded from using it too much, so i bought a new one.
EDIT:
turn COUNTER CLOCKWISE, like you are trying to remove the bolt. that is the direction of engine rotation, just fyi...
Last edited by bobafett; 05-23-2006 at 10:22 AM.
what I was saying is anything that distorts the valve will change the way it seats and change the installed height in the head,they have to fit the seats perfectly
Yeah, that is the BEST way to see if you have bent valves, but most people don't have a compressor & leakage tester.Originally Posted by newaccorddriver
Anyhow, pull the spark plugs out as mentioned to ease up the compression. Personally I would take loose the camshaft caps to let the valves come to the top. Just my $.021
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EDIT- Double post.............
Last edited by 88Accord-DX; 05-23-2006 at 05:43 PM.
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OOPS forgot to mention remove the rocker assembly from the head before checking the height, sorry
I wouldn't be too worried about bent valves. Sure, it's possible, but unlikely. The only time to really worry about valves is in a zero-tolerance motor, like some domestic 4 bangers. If you're unfarmiliar with the term, what happens in a zero tolerence motor is scary. When the timing belt fails, the valves drop from the head into the cylinders while they're still turning. Pretty nasty, but it happens.
89 accord LX
A20A1 (carbed)
Slowly dying.... catastrophic ignition failure
91 Prelude Si
B21A5 MPFI out and apart, coming together.
Just because I use an old distributer cap as an ashtray does NOT make me a redneck!
I forgot to mention removing the distributor when taking loose the camshaft caps to let the valves come to the top.
Also, when the timing belt breaks, most of the time the rocker arms aren't going to ride on the highest points on the camshaft. One other thing to take in respect is the pistons have valve releifs in top of the piston. Your chances of bending a valve when the timing belt breaks is about 25 percent.
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I have never had a problem turning a motor without taking to rocker assembly loose. If you feel that the engine is held up then i turn the cam in one direction or the other. then everything works out good. if you get the timing belt back on and you try to turn it over twice by hand and it slips a tooth on your timing belt with the tensioner set then you have a vavle problem. I was working on a h23 with 2 bent valves on the intake side. I tried and tried and tried to get that stupid timing belt on without it skipping a tooth. but it did everytime. grrrr
- Col Jack O'Neal - Stargate sg-1."If you were paying attention DANIEL you'd know the Nintendo's pass threw everything!"
Working on cars everyday, taking loose the camshaft caps is a precaution that I was taught with any Honda motor that has a timing belt broke. With carbon buildup on the piston & valves, it is better to be safe that sorry.
I called Honda, & they said all their motors that have timing belts are "interferance" design. When the timing belt breaks on these 86-89 accords, the chances of bending a valve are 1 out of 4 roughly. The pistons have valve releifs & the rocker arms aren't going to ride on the highest point of cam lobes when it breaks most of the time
If your going around 5,000 RPMs when the timing belt breaks, the little valve float might be detrimental.
Last edited by 88Accord-DX; 05-30-2006 at 01:00 AM.
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huh.....that's wierd because there's a thread where they debated wether the engine is interference or not, and someone who lived near the town where they're built knows someone who works at that plant, and they told him it was non-interference.
It only matters if your belt breaks, which shouldn't happen if you change it every 60k mi. like the maintenance requirements dictate, but if you do break one it sure would be nice to know for sure one way or the other.
There is always a debate whether or not it is interference. It depends if you can get out of the box and call sorces such as the Honda dealer.
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That is weird, cause I think we need a poll. Everyone call their local Honda dealer & ask if 86-89 Accords are NON-INTERFEANCE or INTERFERANCE....
Like most people would tell the truth cause it is hard to think outside the BOX!
Last edited by 88Accord-DX; 05-30-2006 at 07:10 PM. Reason: there=their
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