What happens when your Timing Belt goes?

[njpeter]

consider the possibilities of a broken timing belt. it's not that hard fellas, maybe you'll need a trip to a friendly garage to bust the crank nut, but for cripes, anybody check the cost of towing recently? Not to mention the embarassment of causing a huge traffic jam.

I have timing belts and tires in the same class, change when questionable , and damm the expense

I busted a belt at 70mph, no head damage, and try to change belts at least once every 60-70k miles ( I've run some of em to 80-100k).

I believe the 89 engine for some reason can go 80k miles on a belt, pre 89's rated at 60k. Checking the fit of the belt on the top pulley reveals worn teeth, but typically oil contamination is a reason to change the belt, that crap seeps in everywhere in time.

My daily driver just turned 200k this week

[88Accord-DX]

I have got to bring this thread back! I see people looking at it & probably wondering WTF?

I'm pretty sure that the A20A1 & A20A3 is a "interface" engine. Meaning that the valves will contact the top of the piston if you break a timing belt. Or if you turn the crank with the belt off the cam.

[njpeter]

I have got to bring this thread back! I see people looking at it & probably wondering WTF?

I'm pretty sure that the A20A1 & A20A3 is a "interface" engine. Meaning that the valves will contact the top of the piston if you break a timing belt. Or if you turn the crank with the belt off the cam.

well sure or not, mine survived tossing some teeth at highway speed, so I guess I can color myself lucky. Had I ruined the head, I would have likely gone back to a big block v8 or something else.

Speaking of which, I've got a couple of complete accords and parts for sale, local pickup only. Hurt my back badly..and I'm pretty much out of the fix-it game for a while, so I'm selling off my fleet to any reasonable buyers ( except the daily driver 88-lx) Bergen country area.

[88Accord-DX]

I think I need to wait & see once I pull the head off & see if it has the recess in the pistons for the valve. A lot of pistons have the recess in the top of the piston to give the valve some clearance.

[Oldblueaccord]

I think I need to wait & see once I pull the head off & see if it has the recess in the pistons for the valve. A lot of pistons have the recess in the top of the piston to give the valve some clearance.

I was idling mine once without the damper on and the timing belt slipped off. I was looking for an oil leak near the front of the motor. No damage, BUT I wouldnt rule out it not happening.Best way is to clay up the motor and see what the distances are. Somebody here swore they milled a bunch off there block till the pistons where positive (above deck) and ran there motor that way. I dont think we have pop up(dome) pistons least from the pictures i have seen here so far.


wp

[carotman]

Our pistons do have the notches for the valves.

[Blkblurr]

by sean
"for the last fucking time the a20a is not an interfernce engine. i dont know when where or how it got around that it was but the bullshit stops here. put a belt on it youll be fine "


sorry sean i had too,peep's are confused again.

You are correct. It is a NON INTERFERENCE engine. I just called by buddy at the Anna engine plant here in Ohio and he confirmed it. Other things can cause damage that look like a broken belt issue. A valve can come loose and cause a piston crash. The load it puts on a worn or old belt can cause it to break. This type of failure would be diagnosed as a broken timing belt and since the valve hit the piston, it must be interference. I asked him to get me a list of engines Honda produces that are and aren't interference. He said he would try but no promises.

[Blkblurr]

I think I need to wait & see once I pull the head off & see if it has the recess in the pistons for the valve. A lot of pistons have the recess in the top of the piston to give the valve some clearance.

My A20A3 has recesses in the piston for the valves. I posted pics on this forum several months ago showing the tops of my pistons when I rebuilt my head and valve train.

[Blkblurr]

I found the pic but it didn't show up here. I'll try again.

[Blkblurr]

Hope this works

[ICEMAN707]

i still doubt the a20 is a non interferance engine. the pistons are at deck height on TDC. what makes you think there will be room there for an open valve? why do you think timing alignment is important when changing the timing belt? other than bent valves and destroyed pistons, you can also damage the engine by way of detonation when the compressed cylinder gasses shoot back into the open intake valve instead of out the exhaust valve into the exhaust manifold, and blow your intake manifold, valve cover, and head, etc. in any case, a snapped timing belt=damaged engine. just cus you could start it by way of luck, doesn't mean the damage hasn't been done. don't tell me the engine still purrs like kitten after that happens. LOL.

higher compression pistons, VTEC lobe, and mild to wild cam profiles certainly affect the way the engine is....certainly won't be non-interferance anymore, that's for sure.

[Blkblurr]

i still doubt the a20 is a non interferance engine. the pistons are at deck height on TDC. what makes you think there will be room there for an open valve? why do you think timing alignment is important when changing the timing belt? other than bent valves and destroyed pistons, you can also damage the engine by way of detonation when the compressed cylinder gasses shoot back into the open intake valve instead of out the exhaust valve into the exhaust manifold, and blow your intake manifold, valve cover, and head, etc. in any case, a snapped timing belt=damaged engine. just cus you could start it by way of luck, doesn't mean the damage hasn't been done. don't tell me the engine still purrs like kitten after that happens. LOL.

higher compression pistons, VTEC lobe, and mild to wild cam profiles certainly affect the way the engine is....certainly won't be non-interferance anymore, that's for sure.

The next time you replace your timing belt. put your engine at TDC, take the belt off and rotate the cam gear 360 deg. You will not hit anything. I have done it. This engine is a NON- INTERFERENCE engine. Did you see my post above? I got this from the plant that built the engines. I live in Dayton, Oh which is 40 miles from the engine plant in Anna. The company I work for builds equipment for them. Did you see the pic I posted showing the recesses in the piston? Do you think Honda put those there for fun?

[ICEMAN707]

well, i did say "i doubt". which means im not sure. i still wouldn't want a belt break on me just to find out though, that's for sure.

[logic]

I can guarantee you guys the 86-89 accords are NON-Interference engines in stock form. All accords before 86 were interference engines so the timing belt MUST be replaced between 60k mi. and 80k mi. unless you want new heads. I don't have experience with 90 & later so I can't comment on those, however I would like to know before I get around to swapping my motor. There is no way I'm going back to an interfering motor!!!

The difference between Interfereing and NON-Interfering is simply wether the pistons will hit the valves if the valves are completely open when the piston reaches TDC. What causes an engine to Interfering or NON-Interfering is complex because it is derived from many different things. How close the pistons come to the top of the deck, whether the pistons have indentations in the top, how far the valves open, and how far they drop below the bottom of the head (if they do).

The reason I stated stock in my first statement is because modificatins can change that, if you change your cam to a cam that opens the valves farther than the stock one or if you mill your head & block more that a thousanth or two, use a thinner head gasket, change crank rods or pistons to increase stroke, or any combination of the above, you could make your non-interfering engine interfering...

[Blkblurr]

I can guarantee you guys the 86-89 accords are NON-Interference engines in stock form. All accords before 86 were interference engines so the timing belt MUST be replaced between 60k mi. and 80k mi. unless you want new heads. I don't have experience with 90 & later so I can't comment on those, however I would like to know before I get around to swapping my motor. There is no way I'm going back to an interfering motor!!!

The difference between Interfereing and NON-Interfering is simply wether the pistons will hit the valves if the valves are completely open when the piston reaches TDC. What causes an engine to Interfering or NON-Interfering is complex because it is derived from many different things. How close the pistons come to the top of the deck, whether the pistons have indentations in the top, how far the valves open, and how far they drop below the bottom of the head (if they do).

The reason I stated stock in my first statement is because modificatins can change that, if you change your cam to a cam that opens the valves farther than the stock one or if you mill your head & block more that a thousanth or two, use a thinner head gasket, change crank rods or pistons to increase stroke, or any combination of the above, you could make your non-interfering engine interfering...

Well put!

[system-f]

Hmm...so has anyone had any engine damage from breaking a timing belt? I still don't believe this is a non-interference engine. I am about to do a timing belt and oil pump and am going to see if I can get the piston to hit a valve...

[cardoc33]

I spent 14 years as a honda mechanic and have seen broken timing belts go both ways. Some people got lucky, others...well, "That will be $800.00 Ma'am."
My AutoData timing belt book says it's an Interference engine, so I wouldn't take chances. Do the belt and tensioner and seals.
If I remember correctly, Honda had an issue with timing belts in '85 or '86. Rated them for 90k, but they began to break around 60k. They issued a bulliten to re-rate them for 60k replacement. I think Honda ended up doing some free valve jobs over that one.

[Blkblurr]

The old engines in the second gen were interference engines. The post above does not state what engines are identified as interference! Just sizes. If the A20A3 for 89 is an interference engine, then someone please tell me how I can rotate the valve train 360 degrees or more with the cylinder at TDC and not hit anything??????? Of course the timing belt is removed.

[Blkblurr]

What happened to all you interference engine guys? Especially the ex Honda techs. What no answer to my question???

[NJC]

I can guarantee you guys the 86-89 accords are NON-Interference engines in stock form. All accords before 86 were interference engines so the timing belt MUST be replaced between 60k mi. and 80k mi. unless you want new heads. I don't have experience with 90 & later so I can't comment on those, however I would like to know before I get around to swapping my motor. There is no way I'm going back to an interfering motor!!!

I just had a t-belt break on an '84 Accord 12V 1.6L @ ~20mph. No damage.

[buds302]

well someone go outside and try it out!!!!!! cause this going back and forth is bullshit!!! just go out there take the belt off and crank the engine by hand!!! it it stops moving then it hits the piston!!!!simple as that!! common sense people! if you dont know try it out!!

[Soundy]

Kinda makes me miss my gold ol' GLC with its dual-width timing CHAIN. Now THAT'S heavy-duty!

[lamontlamont]

I tried to be a cheap skate and let my car go to about 90k miles with out changing the timing belt. The belt lost about six inches worth of belt teeth while cruising at 70mph. Right away i knew what the problem was. the only thing that upset me was that they towed my car and i had to pay 140 dollars for the tow. i installed a new belt and it runs fine. i would guess this is a NON interferrence engine just like the guy said. also, why would they cut the clearance marks into the piston if it is interferrence..... My tip is to just change the belt and dont be cheap. its easy to do it your self. you just need to get the crank pulley bolt off. i used a park bicycle bottom bracket lock ring tool to hold the pulley and a 18"breaker bar and a pipe to get extra leverage. Make sure u spray it down with liquid wrench first.

[cardoc33]

What happened to all you interference engine guys? Especially the ex Honda techs. What no answer to my question???

Just relating what my Autodata book says and my past expeirance. No need to flame.
Really, this is all just academic. Just change the belt if you think it's old and avoid the $140.00 tow bills and possibly more.

[w261w261]

gates.com has a list of timing belt applications. The catalog says the 86-89 accord is an interference engine.