well im not the bigest honda tec, but i can work on cars and i just replaced my ac and alt belt and took the covers off the timeing to inspect the timeing belt and i noticed a pice of belt hung up in the cover so i pu,lled the crank off and found out that it was what was left of my balance shaft belt, there is nothing belt wise on either of the 2 balance shaft gears so i have nothing driveing the balance shafts . the car is running just fine might i add, i do recall a few nights ago on my way home i hear something odd but didnt feel anything change just a sound , and that might have been the belt breaking , but how important is this balance shaft belt? i have my own made up idea of what it is and does but i honestly dont know the real reason other than to help balance the motor vibration wise, will i be ok without the balance shafts working or do i need them working to prevent major damage to my car?

 

well i checked another fourm and it came to my attention that many people cut or remove their balance shafts anyhow to lighten their car by a mere 8lbs and to reduce strain on their motor to free up a little bit of hp, with no damageing affects, some report major vibrations and many note no noticeable vibrations, so i guess i will take my chances without the belt, and im posting this responce so others with the same problem will have an idea of what they should do as well


and i personaly have no noticeable vibrations and i can put up a video (not real good quality) if someone wants to see the motor running on someone elses car before they go and do something on purpose

 

My understanding is that all the balance shaft does is to balance the secondary imbalances inherant in straight fours. For many years there was a practical limit on the capacity of four cylinder engines because as they got larger these imbalances would cause unacceptable vibration, making the car uncomfortable for the occupants. This is why for so many years you'd be hard put to find a 4 banger bigger than 2 litres. Then Mitsubishi invented the balance shaft, and now quite a few manufacturers (including Porsche) have used or are using this design under licence from Mitsubishi (who own the IP) for inline fours up to nearly 3 litres. Now we can have large 4 cylinder engines as smooth as small 4 cylinder engines (still not as smooth as a bent eight or straight six, which is the smoothest of all along with a bent twelve cylinder).

That's probably enough history lesson that you probably didn't want to hear anyway!

In theory the only consequence should be some increase in vibration without the shaft operating, though it sounds like it must be so slight that in your case you can't even feel this. Perhaps very soft engine mounts have something to do with this? I have a sneaking worry though that the counter balance shaft might possibly have some protrusion that could concievably come into contact with the crank if the balance shaft stops in a certain position??

It probably doesn't, but such things can be a consideration with some engines, e.g. some Fiat Twin Cam motors can self destruct if the vestigial camshaft is fitted incorrectly (these twin cam motors being based on an older pushrod block but still used the 'old' cam shaft to drive the oil pump, and the eccentric cam that was used on the old cam to drive the fuel pump could contact the crank if the two shafts were not 'timed' to miss each other as they rotated). Something like this could conceivably be an issue with a balance shaft, I doubt it but the consequences coud be serious if it is.

 

very informative, atleast i know part of the purpose of the shaft. and as far as someting comeing in contact with the other i dont belive that is a worry in my app. the front shaft has about 2inches all way around and the rear mesh gear has about 3/4 - 1 1/2 clearence ...

but thanks for all that info[sm=thanx.gif]

 

Won't cause any problems besides some extra (minor) vibration. You might actually get a slightincrease in oil pressure from it.

 

I'd be surprised too if crank /balance shaft contact were a danger, Imentioned it just in case! I've never had a Honda engine that far apart, so just didn't know for sure.

If the balance shaft isn't rotating you will in theory gain some additional torque at the crank (not steady state torque, but when accelerating) and engine response, because the balance shaft has inertia and does take some power to drive and is parasitic in this respect. The affect would be similar to lightening the flywheel, though just how much of a gain is likely I don't know, not much I'd think.