Rumbly Engine in '89 Civic

I have an 89 Civic LX sedan that needed an alternator and I got a good deal
on one from Ebay but it was actually for a '93 civic and is in very good
condition and not a reman. I'm wondering if the fact that it is 70amp
alternator and my car only requires a 60amp if it is causing the engine to
idle a little lower than normal and possibly overcharging the distributor.
It bolted right up of course but the pulley was too big but even the belt
used in my civic works well with it because the grooves on the belt line up
fine with the 1st 2 grooves on the bigger pulley and the tensnsion is tight
enough for it not to flop around. Anyway the engine rumbles a little too
much I noticed while at red lights with the car in drive. Does anyone think
the bigger alternator could be causing that? Let me know your thoughts.

-jeff

 

I think it could be your engine mounts. The sound guys put in upgraded
alternators to power their systems, so that's not likely to cause the engine
to rumble.

On a side note, typically the brushes on the alternator go bad, a $30 part
from the dealer.

 

I doubt the extra capacity is a problem, and it won't be overcharging the
battery unless it is defective. Look at the belt when the engine is idling,
and when you open the throttle a little. If you see the belt "whip" (flop
back and forth) more than about 1/2 inch, especially if you see "S" curves
flash in front of your eyes, you need to do something about it. Tightening
beyond the usual tightness won't help, either. Lord knows I've tried! ;-)

I presume from your description this is a V belt rather than a serpentine
belt. Most sizes of V belt come in a premium version (I think Gates calls it
"green stripe") that dramatically cuts down on whip. You may have to go to a
premium belt, perhaps even a cm or two longer to accomodate the larger
diameter pulley. I once had a car that was supposed to take a "green stripe"
belt but I could only get a regular belt at the time. The belt whipped so
badly it broke in less than a week. By then I could get the green stripe
belt and had no more problem.

Mike

 

It's running fine. The car has been through alot. What's amazing is how
interchangable parts are on civics over different years. I think the the
extra amps is really not a bad thing anyway. Thanks for everyones advice.


-jeff