just... wow....

[InAccordance]

so i was driving home from work this morning, about a mile from the house, I hear a loud BANG, and the engine starts knocking horribly. Pulled into some random parking lot, popped the hood and the first thing I notice is the timing belt cover is destroyed, look further and for thr first time in my life I have ever seen this, the cam gear itself broke in 3 places. 3 of the arms of the gear literally just snapped. Somehow, it didnt break the belt so it may have not done any permanent damage, lets hope anyway.

I'll get a pic of the gear later, it's incredible.

[dacantu]

Ouch

[Dr_Snooz]

Nice! Definitely post pics.

[Legend_master]

Damn, any rust on the gear?

[2ndGenGuy]

It was common on early CRXs to have oiling issues on the camshafts, then the camshaft would seize up inside the head. I wonder if that's not what happened here... random bearing in the head wears out and grabs the camshaft and it stops... and the timing belt just twisted the gear apart.

[2oodoor]

just wow...
I wonder if the dizzy locked up, a siezed cam bearing would have been smoking and pushing smoke into the pvc and in the intake I would think, some warning there would have happend.
pics for sure..

[dacantu]

just wow...
I wonder if the dizzy locked up, a siezed cam bearing would have been smoking and pushing smoke into the pvc and in the intake I would think, some warning there would have happend.
pics for sure..

Wouldn't the rotary force of the crank be enough to turn a dizzy? I've never heard of a dizzy locking up but regardless would it have that much strength to break a cam gear? I think there is a different factor here.

So when this happened was the car still running after the noise? Or did it shut off when the loud bang happened? If it kept running that would eliminate the locked dizzy theory because that would mean there's still combustion.

I wanna guess something happened with the cam gear itself. Maybe something got passed the timing cover and actually is what caused the gear to break? Unlikely but possible.

[2oodoor]

Wouldn't the rotary force of the crank be enough to turn a dizzy? I've never heard of a dizzy locking up but regardless would it have that much strength to break a cam gear? I think there is a different factor here.

So when this happened was the car still running after the noise? Or did it shut off when the loud bang happened? If it kept running that would eliminate the locked dizzy theory because that would mean there's still combustion.

I wanna guess something happened with the cam gear itself. Maybe something got passed the timing cover and actually is what caused the gear to break? Unlikely but possible.

I know at the time I posted I was not able to picture the assembly, and I know I could be way off but since this is an unusual castastrophic failure I was thinking what is along the center of force most likely to have this effect on the gear ... the camshaft itself, that said, I doubt it was seized without some warning or symptom like a major compession loss at any given cyl where a lobe was cooked before it shredded the cam gear. My thought is distributor which is driven off the other end of the cam shaft, not the crank.
The belt, being rubber, would seem to be an isolator of such force coming from the crank assy, ya know, shredding teh center out of the cam gear?
If something locked up the crank in the combustion chamber, it would more likely do more damage to a valve stem, rocker arm, piston, hell rod bent etc.. so im stumped. So always leave room for factor X , lol... like a bolt or tool left under the valve cover that finally wandered over:nervous: Maybe the cam gear was way over torqued or had the key jammed behind it or missing al together and the gear was bent and wobbly the whole time before it disintegrated :dunno: but.. what your theory paints in the quote makes no sense at all to me, im sorry.

[lostforawhile]

just wow...
I wonder if the dizzy locked up, a siezed cam bearing would have been smoking and pushing smoke into the pvc and in the intake I would think, some warning there would have happend.
pics for sure..

none of these Honda's have cam bearings, the bearing caps are aluminum, the oil is the cam bearing. that's why they have such high pressure at idle, unlike a domestic V8 or something with just a few PSI, the bang and loud knocking almost sounds like sudden loss of oil pressure, the cam would have possibly seized up causing the timing belt to tear apart the cam pulley, those belts are extremely strong, the centrifugal force would have broken the cam pulley at it's weakest point, twisting it apart, i remember when a fram filter came apart and jammed the oil pump on one of my early civic engines, the pump didn't break, or it's driveshaft, which went through the engine into the pan, but it broke the pump drive gear on the cam, and twisted the cam, also broke the cam pulley key

[dacantu]

I know at the time I posted I was not able to picture the assembly, and I know I could be way off but since this is an unusual castastrophic failure I was thinking what is along the center of force most likely to have this effect on the gear ... the camshaft itself, that said, I doubt it was seized without some warning or symptom like a major compession loss at any given cyl where a lobe was cooked before it shredded the cam gear. My thought is distributor which is driven off the other end of the cam shaft, not the crank.
The belt, being rubber, would seem to be an isolator of such force coming from the crank assy, ya know, shredding teh center out of the cam gear?
If something locked up the crank in the combustion chamber, it would more likely do more damage to a valve stem, rocker arm, piston, hell rod bent etc.. so im stumped. So always leave room for factor X , lol... like a bolt or tool left under the valve cover that finally wandered over:nervous: Maybe the cam gear was way over torqued or had the key jammed behind it or missing al together and the gear was bent and wobbly the whole time before it disintegrated :dunno: but.. what your theory paints in the quote makes no sense at all to me, im sorry.

I'm very bad at putting the thoughts in my head onto paper (in this case type it out lol)

In mentioning the crankshaft I did not mean in any way that it was the cause of the cam gear breaking. I'm very aware of everything that could go wrong with a crank. I simply meant that the cam gear and cam arent driven by the dizzy, they are driven by the crank (combustion) so in other words I do not feel that the dizzy could "lock up" and create enough stopping power to over power the crank and cause the cam gear to break.

However I do agree after thinking about it that there was something occuring towards the center of the cam gear. Like you said there had to be something that seized the cam, or gear but I do not think it was the dizzy. Your theory of a bolt or tool doesnt seem out of the question. :dunno:

I do hope to find out very soon what the real cause of this issue was.

[dacantu]

sounds like sudden loss of oil pressure, the cam would have possibly seized up causing the timing belt to tear apart the cam pulley, those belts are extremely strong, the centrifugal force would have broken the cam pulley at it's weakest point, twisting it apart

This also sounds very possible.

Hmm I'm getting curious.

[lostforawhile]

the way the dizzy is designed, it would have broken way before the cam gear ever did. I believe the pin at it's base is actually a shear pin to prevent this from happening. the two tabs that go into the end of the cam would have broken well before the cam pulley

[dacantu]

the two tabs that go into the end of the cam would have broken well before the cam pulley

My thoughts exactly.

[AccordEpicenter]

swap heads and check your oil pressure. there is somthing else going on here, you might have oil pressure probs either way i bet the head is trashed

[MessyHonda]

pics of the damage and under the valve cover

[InAccordance]

my camera battery is dead of course, so while it charges, here's some more info.
When that bang happened it still was running and had power, normally if an engine blows or things of that nature, you lose power.
The belt didnt break or slip, no teeth were torn.
the cam still moves just fine as well as the crank.
No obvious rust on the gear itself, it's been under the plastic cover its' entire life.
The cam seal isnt leaking either.
I really just think it was a freak metal fatigue failure.
I'm going to tackle it friday and pull the head to see if there was any internal damage. Externally, the timing cover was destroyed, a small piece of the valve cover was chipped away and it scored the head itself along its rotation.
The key holding the gear in place is fine. The gear itself came right off when I removed it, key wasn't jammed in the cam or the gear.
I've never taken the gear off the cam on this motor and when I did remove the gear after this incident, the bolt came loose with a fairly short breaker bar so that rules out over-tightened.
I'm just as stumped as to what caused this as anyone, i've never had a gear break like this and not do damage to anything else other than cosmetic.

[2oodoor]

yeah Lost i know there is no cam bearing so to speak but there is the bearing surface for the cam which is what I may have been visioning.
The pin in the dizzy makes sense, like I said I was not totally seeing it in my head as I was multitasking at work ;)
Now , Accordance what your last post says just bafffles me even more...
Ever hammer the pulley on the cam? just wierd place for fatigue like this...


oil pressure can be lost from the seal kit inside the oil pump, pretty common thing for these. Not even the pump is at fault when those go out , its like a heart valve in a human, the muscle is fine and pump blood but the valves fatigue from infections etc.. and wont allow proper pressure per cycle. The seal kit is less than 20 bucks but the lower timing cover has to come off to remove the pump separate it and install the new seals.

Still loss of oil pressure , seems like something bearing more energy on the crank would have failed first.

[stat1K]

lost it's funny that you mentioned that situation because the first thing i was going to say was i bet it was a fram rofl!

[lostforawhile]

lost it's funny that you mentioned that situation because the first thing i was going to say was i bet it was a fram rofl!

the only reason it had a fram was the oil filter gasket had failed, and the only filter i could find in stock was a fram, i was waiting on another filter to come in, it was on there literally a day when it did that much damage to the engine. I put in another cam, replaced the pump and drive rod from my spare pats and drove it another 5 years

[stat1K]

no i meant his car probably had a fram.

every car we happen upon in the junkyard with either broken camshaft / cam gear or a hole in the front of the block, the first thing we notice is the bright orange glare of the fram filter.

[Dr_Snooz]

Still need pics.

[Ichiban]

I bet it blew up for fun!

[86dxhatch]

Damn, after reading these posts about fram filters I better go buy a wix asap.

Did you get her going agian?
Any pics yet?

[lostforawhile]

no i meant his car probably had a fram.

every car we happen upon in the junkyard with either broken camshaft / cam gear or a hole in the front of the block, the first thing we notice is the bright orange glare of the fram filter.

new quote :bowrofl:

[lostforawhile]

no i meant his car probably had a fram.

every car we happen upon in the junkyard with either broken camshaft / cam gear or a hole in the front of the block, the first thing we notice is the bright orange glare of the fram filter.

[AccordEpicenter]

fram oil filters suck ass! They are just pitiful, seriously.

[MessyHonda]

http://home.freeuk.com/jrknight/smileys/postpics.gif

[Grinder_1]

I'm reviving this thread just to bitch about reading so many posts that say pics to come.. and never any pics... Don't say your gonna post the pics.. just do it... Ffs.

[InAccordance]

Lolwat..
Sorry mr grumpy gills.
I can say that it ended up being a chunk of the block broke off breaking the mounting point of the side engine mount and said chunk of iron about the size of a dime went in between the cam gear and head breaking 3 spokes of the gear, shredding the cover and chipping the valve cover. That valve cover is the one on my current 3g in fact. I can get a pic of the damage on it if you want.
The old engine was trashed because the actual block piece broke off and not just the mount.

[InAccordance]

https://i.imgur.com/tLDrWRwl.jpg

Chunk broke off valve cover. Didn't crack it or anything, just took a piece of it out.

[Fixedit]

Damn what a crazy break. Just another thing to overthink and worry about on long trips now lol

[InAccordance]

Amusing part was the timing belt never broke. It was still running when I pulled off. Threw the hood up and saw the cam gear wobbling side to side. I had a spare gear at the time so I figure I'd just replace it and get a new belt, but when I was taking the lower cover off, I found the bits of iron and found the mounting point broken.
That engine also still had the upper and lower covers on it so it wasn't like something got in there and caused it break.