I have a problem with the timing belt gear on the crank shaft stripping on the inside then breaking the back porton of the keyway. The ballancer bolt was still tight and the ballancer and crank shaft is not damaged. The first time it happened the stock pulley, bolt, and timing belt came off I just thought the bolt was not torqued properly. I bought an ATI ballancer, crank gear key, timing belt gear, and bolt. Six months later I herd noise and notice the belt loosened up again nothing was noticibly damaged so I thought the threads on the crank might of been damaged. I applied red locktight and retorqued the crank bolt. One month later timing gear stripped out on the inside again I thought maybe the loose ballancer damaged it and replaced everything once more along ith a new head the valves contacted and pushed the cams out of the valve cover. Nothing was broke this time around except for the crank gear for the timing belt it self the keyway has slight wear on either side and it's been around 8 months. The olny reasion I found it because my ignition timing wouldnt set and the cam timing was off. The engine is a b18b1 ballanced everything done by Bill Ford in GA the cam duration is 256 at the cam 301 at valve .268" lift at cam .469" at valve Spring pressure is Seat: 1.400" @ 48 lbs / Nose: 0.950" @ 148 lbs / Coil bind: 0.710". I am using stock honda timing belt and components. Any help would be awesome I'm lost and tired of throwing money at the engine.

 

where is the gear breaking? any pics. Is it the same key you're using on these gears?

 

No pictures tonight sorry. I'm using a new gear and keyway every time it happens. The inside of the gear looks like the metal is too soft and parting like the red sea where the keyway sets. I can move the gear with everything on one tooth foward and back. The last one that I removed before this looked like the inside of a bearing that went out lots of melted metal and no notch for the key way the metal was at the same level all the way around. On the side where the timing belt rides it looks great.

 

no idea what going on...but u might want to remove and check your oil pump...something isnt right so before u blow ur engine do a check up...try running oem balancer...

 

Seems as though your crank bolt is not tight at least not tightening up correctly. In other words i think the threads on your crank bolt or crank are messed up causing it not to tighten the balancer. My buddy had problems like this with his 4ag motor in his corolla. The crank threads needed to be cleaned with a tap and a new bolt installed. After that there were no issues with it stripping it out. Before that he went through 2 gears within a couple weeks time.

 

I checked the threads and the bolt their both fine it didnt loosen up I used locktight red on it this time. Is there anyone one who makes an aftermarket gear? What does the extra belt tensioner help with? I do have to use more tension or the timing belt than a stock engine to keep the timing belt from jumping.

 

maybe the first time it broke it damaged the crankshaft, and it has too much clearance between the crankshaft and the gear.
change the crankshaft or add a lot of 271 loctite to the key and the inside of the gear and torque it to 130lb/ft

 

Going to Take everything to the engine builder and get him to fix it. I'm tired of messing with it. Knowing my luck the front of the crank is bent or something.

 

take ur oil pump out and change it

 

i broke my pump internally and u cant tell....when chunke get in the gear from the same pump it locks and snaps the timing belt if not the timing belt gear

 

take the pump apart and look at it

 

I had a full length keyway cut in the crank and a full lenght ket made to suit. It locates the crank gear and ati balancer together instead of two little keys.

 

Thank you for the replys guys ill change the pump and try a sinlgle key way. Who made the key way for you and is it brass or steel? I am running the valve lash a little on the tight side to try and keep the rockers from popping out would that affect it?

 

if it keeps breaking and everything is ok at the crank, have you considered that it is having to put way too much torque on the cams to keep them spinning?

 

The engineer who does my machine work made the key. It is steel.