Timing Belt Broke

[85Skyhawk]

Hello,

Last Friday my timing belt broke on my 86 Accord LX-i Hatchback. The vehicle has 115K on it and I was planning to replace it but never had the chance. I had the car towed and pulled the valve cover this morning. From what I could tell the belt appears to have lost a few teeth down near the crankshaft but is not broke in two.

I pulled the plugs and slipped the belt off the camshaft gear. While I was cranking the camshaft around using the gear screw I felt no interference but just the camshaft wanting to turn to a neutral position. All the valves also appear to have the correct gap between the rockers as I take them off the lobes so I'm thinking none of them got bent.

They say these engines are 'interference' but I am not sure that is exactly the case. If anybody can shed some light onto this issue that would be great. I have read they say they are 'interference' but only if they are really carboned up which mine probably isn't.

I never had to do much work on this engine so if somebody can tell me what all is involved with replacing the timing belt that would help. I have done this job before but each vehicle is a little different. If there is something I need to pay particular attention to please let me know.

My water pump is bad so that will need to be done also. The other belts are shot so now is the time to get a lot of this done it appears. What do you think about the timing belt tensioner and lower crank seal at 115K?

Thanks for your assistance.

Regards,
85Skyhawk

[derolph]

These engines are "interference" engines. That issue was not eliminated until a redesign years after 3rd gen Accords. However, this does not mean valves will always get bent or worse damage occurs if a timing belt breaks. It depends on the factors surrounding the belt-breaking incident such as engine speed at the time, etc.

I'm puzzled by your comment about "the camshaft wanting to turn to a neutral position." Can you clarify what you mean by "neutral position"?

I believe the timing belt tensioner should be replaced, just to be on the safe side. Regarding the crank seal, I am not sure. I would look at all seals to look for signs of leaking.

[lostforawhile]

These engines are "interference" engines. That issue was not eliminated until a redesign years after 3rd gen Accords. However, this does not mean valves will always get bent or worse damage occurs if a timing belt breaks. It depends on the factors surrounding the belt-breaking incident such as engine speed at the time, etc.

I'm puzzled by your comment about "the camshaft wanting to turn to a neutral position." Can you clarify what you mean by "neutral position"?

I believe the timing belt tensioner should be replaced, just to be on the safe side. Regarding the crank seal, I am not sure. I would look at all seals to look for signs of leaking.

this is a big debate, plenty of people have broken belts with no damage, I broke one at 7000 rpm ,threw a belt on and it was fine. with the piston at top dead center, I was able to put a valve all the way to the keeper groove without it hitting, they never are that far down. the later engines are interference, it wasn't a matter of fixing things, nothing was broken, they went to more then one cam and more valves, so it became impossible to have a non interference engine, you should get the gates kit with the belt and tensioner, always replace both. Honda uses gates stock, so dont waste money paying dealer prices

[Dr_Snooz]

this is a big debate, plenty of people have broken belts with no damage,

Have we ever had anyone sustain valve damage after throwing a belt? I can't think of anyone.

[derolph]

this is a big debate, plenty of people have broken belts with no damage, I broke one at 7000 rpm ,threw a belt on and it was fine. with the piston at top dead center, I was able to put a valve all the way to the keeper groove without it hitting, they never are that far down. the later engines are interference,

so, if the 3rd gen's are non-interference, Honda took a step backward with later models? That's what I gather here and I'm surprised to learn it. I guess I was assuming 3rd gen Honda's were interference engines.

I once had a '84 CRX in which a timing belt broke. One or two valves got bent. But, that was pre-3rd gen.

[lostforawhile]

=derolph;1151299]so, if the 3rd gen's are non-interference, Honda took a step backward with later models? That's what I gather here and I'm surprised to learn it. I guess I was assuming 3rd gen Honda's were interference engines.

I once had a '84 CRX in which a timing belt broke. One or two valves got bent. But, that was pre-3rd gen.

it's not a step back, it's having multi valve engines, higher valve lifts etc, that makes them not able to be non interference, If the timing belts are changed it wont be an issue

[derolph]

A reference on this issue, Timing Belts: Is Your Engine an Interference Engine?, lists 1986-88 Accords as interference engines. No Hondas after 1998 are on the list.

[2oodoor]

1998? Vtec?

The Mazda/ford 2.0 and 2.3 are dohc used in dozens of models and are non interferance, just sayin...

Some people claim to have bent valves on their A20xx hence there's debate. Personally I think the valve reliefs on the pustons have been saving grace for many. Also just plain poorly seating valves could be mistaken as damaged valves IMO

Skyhawk it sounds like you got a good handle on the sitiation one thing cool with these cars is you can change the timing once the belt is on, without removing anything but the top dust cover. The tensioner bolt sticks out thru the lower cover and uss light spring tension that positions the tensioner for you. Just have to be carefull the belt doesnt slip off lower down, not really likely anything did though if he bekt slides back on the cam pulley.

[Dr_Snooz]

so, if the 3rd gen's are non-interference, Honda took a step backward with later models?

Well, on my '76 Accord, the front brakes were that infernal hub over rotor design that forces you to disassemble the front end and beat apart the front wheel bearings whenever you want to take your rotors in to have them turned. By '82, and through '89, they had fixed that stupidity. Then in my '93 Accord, they brought it back! Later, they went back to the inferior MacPherson strut suspension. And the styling turned ugly. At least for me, the newer Hondas are lesser cars.

it's not a step back, it's having multi valve engines, higher valve lifts etc, that makes them not able to be non interference, If the timing belts are changed it wont be an issue

Not necessarily. The 454 in my '86 GMC is interference. It threw the timing chain and bent all its valves. It's not high lift or multi-valve or anything. It's just bad design.

[gyates93]

I don't know if it's bad engineering/design to manufacture a device that could be damaged if proper maintenance procedures (ie replace timing chain at xxx xxxkm) are not followed.. It just means that the operator/maintainer needs to be conscious that a potentially catastrophic failure could result from not following maintenance schedules specified by the manufacturer.

[lostforawhile]

I don't know if it's bad engineering/design to manufacture a device that could be damaged if proper maintenance procedures (ie replace timing chain at xxx xxxkm) are not followed.. It just means that the operator/maintainer needs to be conscious that a potentially catastrophic failure could result from not following maintenance schedules specified by the manufacturer.

it's not bad engineering if they warn that major damage may occur if you dont follow maintenance instructions

[Dr_Snooz]

I don't know if it's bad engineering/design to manufacture a device that could be damaged if proper maintenance procedures (ie replace timing chain at xxx xxxkm) are not followed..

it's not bad engineering if they warn that major damage may occur if you dont follow maintenance instructions

Okay smart guys, what is the timing chain replacement schedule for my truck? For that matter, what is the timing belt replacement schedule for our cars? If you need help, the maintenance schedule is in the owner's manual in your glove box. There is also a maintenance schedule in the Honda manuals freely available here. There's a few there for you to choose from. Go ahead and find the replacement schedule, then tell me what it is. Feel free to include any warnings about engine damage from failure to replace the timing belt or chain at the required interval. Just post whatever you find.

[dieselgus]

Timing chain replacement schedule depends on a couple things. The first being guide wear (if it has guides), and the second is actual wear/stretch. Yes. Chain does wear and stretch. A good rule of thumb would be to measure the deflection in 2 planes if it is above 200,000km. There shouldn't be a hell of a lot of side to side slop in it at all. For the price and peace of mind, change it anyways. Think of it as preventative maintenence.

On our cars I would say the 80,000 mile (120,000km) interval is about right. Chances are either the cam or crank seal or waterpump is seeping at that point anyways. J series are 160,000km belts, and dollars to doughnuts the belt isn't the issue, it is the tensioner that is going to shit the bed. For a few hours of time and less than $60 in parts, no sense waiting until the very last moments of expected service life to change it. These motors are probably light interference types with little chance of catastrophic damage if the belt does break.

Storytime:

Used to be heavily involved in the VW Tdi scene. We always heard of horror stories of folks not changing the belt at the 160,000km interval as it is not a cheap job ($600ish in parts, some specialized lockdown tooling and a good solid 8 hours of time), only to have it break at 165,000km. Diesels are defiinately interference engines. The pistons will certainly hit the valves and bend them. They will also snap the face right off and hammer it around on the top of the combustion chamber. You may get lucky and only have to replace the head at $1500 for a reman. You may get really unlucky and also have to replace a piston (or 4 as they only come in matched sets). Or win the big prize of a bent connecting rod (used to keep one on the counter that was bent in 2 directions and had 4 really good valve marks in the top of it). Moral of the story? Replace things at the reccomended intervals. If that interval is not clear, ask the dealer. If you buy a car with uncertain history, make the timing belt the first thing you change and check that off the list of things to worry about.

I haven't had a head off one of these motors and done any extensive measuring to see if they are at all a break a bunch of shit when the timing belt breaks type of motor. But really, at the price of the parts and simplicity of the job, who cares if it has to be replaced at even 80,000 miles. Should be checking the valve lash at that point anyways.


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[derolph]

But really, at the ... simplicity of the job, who cares if it has to be replaced at even 80,000 miles.

"simplicity"? For people who have never done it, even though they might be mechanically inclined, I don't believe replacing a timing belt is generally perceived as a simple task.

[vteckiller]

Untitled Document

List of engines being interference.

[derolph]

Untitled Document

List of engines being interference.

Your list does not agree with the source I previously posted. Without knowing the source of your list, I'm inclined to trust my reference over yours.

[vteckiller]

So apparently i'm automatically wrong lol. You realize that ain't a complete list right?

[derolph]

You realize that ain't a complete list right?

You mean your list, right? Yep, I agree it's not complete. It contains no info on 3rd gen Accords, which is the focus of this forum.

[2oodoor]

Okay smart guys, what is the timing chain replacement schedule for my truck? For that matter, what is the timing belt replacement schedule for our cars? If you need help, the maintenance schedule is in the owner's manual in your glove box. There is also a maintenance schedule in the Honda manuals freely available here. There's a few there for you to choose from. Go ahead and find the replacement schedule, then tell me what it is. Feel free to include any warnings about engine damage from failure to replace the timing belt or chain at the required interval. Just post whatever you find.

Im going to interject here, I dont care if I spelled it right... Ive seldom ever heard of an American v8 bending valves or breaking a timing chain. Unless its solid lifters or like a Ford Cobra jet 428 THE nylon coverd gear breaks off teeth and is the more common failure in that area and they do jump time but just dont run, new gear and chain and tbeir fine.
on that big block truck 454 I would say that was burnt valves which is hellova lot more common bcause those motors run on the hot side. Not sayin it didnt happen but that is apples to watermelons to the topic here.

[lostforawhile]

you know there are aftermarket gear drives that replace a lot of American V8 timing chains, and they have that cool gear whine sound,