What happens when your Timing Belt goes?

[newaccorddriver]

I've talk to a Honda tech about these cars & timing belts. He said that all Honda vehicles with a timing belt are interference design engines. So, if you don't have damage done breaking the belt, than consider it a plus. No debate here.

im assembling an engine within the next couple days or so, since ill be putting on the head and everything anyways, ill check it out

[Blkblurr]

This is such an old debate and their is always someone on here that says " They talked to a Honda mechanic or tech and they said it was an interference engine. Anyone on here that has replaced a timing belt or done head work and rotated the engine over several times without the timing belt in place knows that it is a NON-interferece engine no matter how many Honda techs say otherwise. Maybe if you've had the head shaved it would become interference or made valve/ piston mods but we are talking stock here.

[MessyHonda]

This is such an old debate and their is always someone on here that says " They talked to a Honda mechanic or tech and they said it was an interference engine. Anyone on here that has replaced a timing belt or done head work and rotated the engine over several times without the timing belt in place knows that it is a NON-interferece engine no matter how many Honda techs say otherwise. Maybe if you've had the head shaved it would become interference or made valve/ piston mods but we are talking stock here.

yeah on my uncles 89 lx the timing belt went...then they just put a new belt and it lasted another 4 years. till he junked it

[88Accord-DX]

There is allways someone that has "turned the engine over without the timing belt on" ... Never fails. I guess that Gates, Alldata, Chiltons, Mitchell, Honda techs & everything published saying it's Interference design engine forgot to "turn the engine over without the timing belt.

Here is an example of INTERFERNCE below. I've seen about 8-10 (3 gen. accords) on ebay being sold from bending valves.

Hello all I might as well introduce myself, My name is Josh I own a 1988 Honda accord lX w/ carb, I have owned it for over a year and whoever I baught it from decided to bypass the Cooling fans and I over heated the thing so it still ran ok (or so I thought) and I was driving and downshifted into second at 55 MPH (not smart) anyways the car died I started it back up it died again and wouldnt start back up, long story short I took it to a shop and they told me I just broke my timing belt and it could be replaced by the next day (Smart me didnt know that when 3geezs break belts it also bends valves) so I said go ahead and do it, well got 3 minutes down the road from the shop and it happened again took it back, the belt broke again!, turns out I had a melted camshaft so had the head rebuilt and about 3000 miles of drive it started smoking horibbly (Bottom end Fried! ) so I got a nissian maxima 93 nice car really was until started misfiring after only driving it 4000 miles, fuel injectors fried... Replaced them without replacing o rings, about 3 days later it burned up F***, but I still had the 3geez so now it is undergoing engine rebuild and much more.. will post pics next

[Blkblurr]

There is allways someone that has "turned the engine over without the timing belt on" ... Never fails. I guess that Gates, Alldata, Chiltons, Mitchell, Honda techs & everything published saying it's Interference design engine forgot to "turn the engine over without the timing belt.

Here is an example of INTERFERNCE below. I've seen about 8-10 (3 gen. accords) on ebay being sold from bending valves.

Try it yourself then. Stop trusting manuals we know to be wrong in that regard. Once you do, you will be on the other side of this ongoing and old debate.

[tuxdreamerx]

yeah when my timing belt went it bent the hell out of the valves dont take the chance....

[lostforawhile]

this has got to be proof there is a difference between the early bs series and the a20. I don't care what the book says,when I was replacing my valve stem seals, I was able to drop all three valves all the way down to the retainer groove at the top of the valve stem before it hit the piston. and the piston was at top dead center. the valve never moves that much in use,even if it was floating. as far as haynes and chiltons,they are not going to risk liability by sayings it's not an inference engine. I believe the other post about it breaking a valve and snapping the belt,if a valve should jam in there the first thing thats going to go is the belt,then the engine gets taken apart, someone sees the broken belt and bent valve,and assumes it all backwards,when it was the valve that caused the belt to snap. I'm just going by what i saw with my own two eyes. remember the books that are written for a bunch of different hondas have a lot of general info. and what about the guy who worked at the engine plant and said they aren't interference? I would think he knows.

[Blkblurr]

this has got to be proof there is a difference between the early bs series and the a20. I don't care what the book says,when I was replacing my valve stem seals, I was able to drop all three valves all the way down to the retainer groove at the top of the valve stem before it hit the piston. and the piston was at top dead center. the valve never moves that much in use,even if it was floating. as far as haynes and chiltons,they are not going to risk liability by sayings it's not an inference engine. I believe the other post about it breaking a valve and snapping the belt,if a valve should jam in there the first thing thats going to go is the belt,then the engine gets taken apart, someone sees the broken belt and bent valve,and assumes it all backwards,when it was the valve that caused the belt to snap. I'm just going by what i saw with my own two eyes. remember the books that are written for a bunch of different hondas have a lot of general info. and what about the guy who worked at the engine plant and said they aren't interference? I would think he knows.

That guys is me. The company I work for builds machines for the engine plant in Anna, Ohio. My job is to manage these projects from specifications to a finished working system. We also build test rigs for the engines and heads with valve tranes installed.

[lostforawhile]

all right do you know the difference between the bs series and the a20 series? my book shows minor spec differences internally between the two engines. could this account for the debate here? I know some of these cars were built in the US and some in Japan, mine is a japanese car. were there maby two different engines at the beginning of the production run?

[Blkblurr]

The interference tag has been put on the engine because the valves extend into the piston area but the pistons have cresent dishes in them to stop the damage. None of the Accord engine are damaging interference engines from the factory as built. If you modify the engine by changing pistons or valves you can cause damage. This is why Honda calls them interference engines. Anyone that has had a valve bent has had this happen due to other causes. I milled my head by .008" and the valve still does not hit. It is not possible to end up with a good unbent valve during a timing belt break if the engine is a damaging interference engine. If you understand the physics of the valve trane and the lower piston/ crank trane you would know that at any normal operating speed, the valves will hit the piston if the timing belt breaks if the engine is a true damaging interference engine. There are four possibilites of valve damage per engine cycle and the engine cannot stop fast enough to stop it from getting through many cycles before it comes to a stop especially manual trannys. If the engines were damaging interference engines, you would have nearly 100% failure during a timing belt break. I have rebuilt the top end of my engine and performed the very test I mentioned before. I wish I had recorded it when I did this so I could post it. Maybe then this debate would end.

[lostforawhile]

thank you !! somebody please make this a sticky,thats the most common sense answer i've heard yet. I forgot any engine that has the valves go into the piston area is an interference engine,even if clearance has been milled for the valves.

[Civic Accord Honda]

ok i am not reading 3 padges of posts but i will tell you this
in are 1987 Accord Hatchback Dx we broke the timing belt in it 2 times and the car was fine did need a tow truck tho lol

[Estimated Prophet]

Well all is well that ends well - who wants ice cream?

[RamThis]

Those "little cutouts" or "crescent cutouts" are technically called Valve Reliefs.

If you can put a piston to TDC, and turn the camshaft, and the valve face does not contact the piston face, it's non interference, period.

As for whether the A20A is or is not, I have no idea. I will know eventually when I get back into my resto project and start rebuilding my A20A3 engine. This is something I'd like to know about the engine really. Would be nice to know if I need to be really concerned about belt replacement intervals or if it's not that major of a concern.



I hate to ask it, but does anyone know if the B18C1 engine is interference or not? I have that engine in my 96 Integra GSR and am soon to replace the timing belt. The belt might have been done at 75K, might not, we dont know what the dealership did at that service interval. But the car has 140K on it and I worry about it every day until I can get that damn thing changed, wondering if it has 65K on it or if it has 140K on it. BIG frickin difference LOL.

[88Accord-DX]

I had a couple days to think about why some people are bending valves even though these motors are labeled "interference". I can agree with it being non-interference with rebuilding mine & seeing the valve releifs. Generally, the releifs on tops of the piston are for compression, not so much for a valve releif.

To me, looking at the top of numerous pistons with high milage on them. I think that the valve releifs are being filled in with carbon deposites along with a good amount on the bottom of the valves, causing bending on valves.

[Blkblurr]

It's possible. Could also be mods to the engine such as a cam with more lift, a shaved head from having too much warpage, a broken valve spring or a seized valve due to no lubrication.

[lostforawhile]

what also could be causing a lot of this are retainers that have broken, if the valve gets bent a lot of times no one will be able to tell if the retainer broke or not. if it breaks the valve drops down into the cyl. always replace your retainers when rebuilding. also when you are done with the cyl head work,hit the top of each valve stem(lightly) to see if the retainer is seated,this can also help set it.

[DDRaptor]

sorry to revie an old thread mine broke while driving an i had no idea what had happened. i stepped out the car and i checked oil, trans fluid, msd coil, dis, plug wires, plugs and i tried starting it 2 times and i saw something moving from the spark plug holes, luckly after about $450 I got a new belt but i think my timing is off i'm still tring to figure out how i can check it

so i lucked out i thought my valves had bent would have been a nice way to get new valves, springs, and seals outta my dad. but shes so slow now i can't even beat a 4g stock which i used to do real easily.

[Blkblurr]

Sounds like your timing is off. Do you have a timing light? Maybe take it back to the shop that did the work and have them check it. take a copy of the manual with you that describes how to check it. Is it carbed or FI? Carbed timing is 24-26 degrees and FI is 15 degrees

[DDRaptor]

carb and how much does a timing light go for,

is it possible that the belt was loose and it just advanced itself until it finally broke???

even if was able to check the timing and all that is'nt that really hard to do, i know how to do ign cause easy to reach.

cause i'm not going back to that shop they used the wrong freaking spark plugs, and also broke the tip of my msd causing me to buy a new one.

[Blkblurr]

Once the new belt was put on the timing was set by how the new belt was installed. My timing light cost around $60 but that was a while ago.

[DDRaptor]

how much of a difference does does 1 tooth off make???

[Blkblurr]

Big diff. You need to be on the money with the belt.

[DDRaptor]

so if used to keep/pass 4th gen with ease they stock around 120 and i have a carb 98hp-19years of aging. i would mean that i had to be at least running 110-115 before the belt was changed and that guy had a stick i have an auto, so i defintly have to invest in checking my belt.

what are the tools needed to adjust tooth??
since you said the timing for carbs is within 24-26 what's the safest/most agressive timing that can be placed, and is listed somewhere on the car.

thanks alot sorry for the all the questions.

[Blkblurr]

Take the valve cover off to check timing. Put piston #1 at TDC. Check flywheel timing mark to make sure it's at TDC. I take the plugs out to make it easy to rotate the engine. You can get to the crank through the drivers side wheel well after taking off the tire and rotate the engine using a socket and extention and a ratchet or breaker bar. Rotate it CCW to get to TDC on piston 1. I use a piece of wire to make sure the piston is at the top of it's stroke. Now look at the cam gear and make sure the line in the gear is lined up with the top of the cylinder head. See manual. If it is you are on the correct tooth / belt position with respect to the crank and cam shaft.