I searched the the forum, read the FAQs, looked on YouTube, etc, but couldn't really find an answer to my question.

I'm wondering how tight--or slack--the slack side of the timing belt should be (meaning the portion on the water pump side). I followed the procedures in the FSM (six turns CCW, three teeth CCW, holding tension on crank pulley, tighten and torque tensioner pulley bolt).

All the other timing belt jobs I've ever done had hydraulic tensioners, and the belts were pretty tight. With the little spring on my DY18 engine, the slack side seems pretty slack in comparison. With just my index finger, I can deflect it about 1/4" to 3/8".

Is this normal? This is nagging at me, and I've put too much work into this Civic lately, and still need to replace the transmission, motor mounts, tie rod ends. I don't need to add a cylinder head rebuild on top of that.

I appreciate a quick response. Just waiting to fill it up with oil and coolant and be on the road.

Thanks.

 

the general rule of thumb I was taught is that if you cant turn the belt in the slack side more then 90 degrees then its good - grab the belt and try to twist it on its axis, if it does not turn more then 90 its good.

 

Thanks! I'll check.

 

Could only twist it about 75 degrees, so looks like it's a go. Thanks!

 

yeah I always time it, turn the motor just enough to take out all the slack, tension the belt...turn it over a few times and check my marks and that it is still tight...works everytime

 

Doesn't the FSM mention the amount of deflection you're supposed to expect? I'd be surprised if it didn't.

Edit. Not seeing it from the cursory look athe PDF.

 

not sure this info exists in the fsm. ive just gotten used to the right "feel" of the belt from doing so many of them. OP- sounds like you did it correctly.

 

Nope, the FSM specifies deflection for all belts except the timing belt - that just has a "how to do it" way.

 

What would happen if OP eased his fears by making the belt tighter?

 

Turn the crank 3 teeth forward to put tension on the front of the belt. This tugs the belt against the valve-springs, moving all the slack to the tensioner side where it's taken up by the tensioner spring. Now tighten the tensioner bolt while holding firm with the crank. That's how it's done.

 

Best case scenario, it'll be loud as ****. Worst case scenario, too much pressure against the cams = major valvetrain damage, possibly snapped cam. Bad things.

 

yep, belts too tight= always bad. over tightened accessory belts can cause major damage as well.

 

Premature bearing failure and possibly belt howl.

 

After torquing down to the timing belt tensioner pulley you should rotate the crank by hand and make sure the engine spins with no interference. Turn the engine by hand at least one complete revolution. This is done to avoid bending valves on start up if the belt is a few teeth off on interference engines.

 

You should really turn it until it gets back to TDC and check that cam(s) and crank are aligned

 

Thanks, guys. I followed the FSM exactly, but being my first timing belt job without a hydraulic tensioner, I was unsure about the "feel." I also figured there was a reason for not helping the spring with a pry bar, like some guy on YouTube did.

Car is running fine and the engine is quiet.