Alternator belt tightening - too tight?

Scott560 · Post by **Scott560** » Mon Jun 15, 2020 8:46 am

So after having fitted new belts a month or so ago, I decided the alternator belt needed a little tweak - it would make occasionally a chirp sound on startup which to me indicated the belt was not tight enough.

So I slackened off the 12mm and 14mm nuts that hold the alternator in place, put an extra few turns clockwise on the front 10mm adjuster nut to tighten the belt, tightened the mounting bolts back up and started it. Horrible droning noise, quite loud, sounded like a supercharger.

Loosened it all up, slackened the belt back off, started it up. Start to get some screeching if i put on the electrical load, but i still get the droning. So that's too loose, but I still get the droning noise.

I'm starting to think i may have done in the alternator bearings? it only ran for approx 10 seconds at the too high a tension, but I guess they are approaching 130k miles and that could easily finish them off.

Anyone done similar? I don't fancy the idea of replacing the aircon compressor (the droning persist with aircon engaged or not, so i don't think it's that).

Eurocarparts alternator is about 150quid, but its lucas branded

. Honda still stock front and rear alternator bearings (about 37quid each, i'm sure cheaper alternatives could be found).

Post by **RattyMcClelland** » Mon Jun 15, 2020 11:47 am

I tightened and loosed my alternator belt to hell when I was supercharged as it uses the alternator to tighten and loosen the belt, I had it super tight or very slack. Mine made the same noise eventually but the alternator had started to fail. Cooked the internals with high exhaust gas temps and it being a mm away next to the header. Universal alternators rebuilt it.

Scott560 · Post by **Scott560** » Mon Jun 15, 2020 11:53 am

I still have the alternator from the h22a5 which I'll assume is the same. Perhaps I will swap that in to confirm actually.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Jun 16, 2020 5:14 pm

Immediately getting the droning noise is odd... If you had damaged the bearing, I wouldn't expect that to have happened during the tightening and to instantly cause a problem like that? It is possible, but unlikely...
Lucas branded alternator isn't anything to worry about, tbh.
Worth swapping with the one from your A5 though, definitely - if nothing else, it will help to eliminate something.

Scott560 · Post by **Scott560** » Tue Jun 16, 2020 8:16 pm

given that the weather is either too hot, or tipping it down, i went for a new lucas one from eurocarparts, its always a false economy to fit second hand parts.

Perhaps it has been on its way out for a while. At cold idle you got an inconsistent metallic sound, light and bearingy, so perhaps they were on their way out. Also realised that any play in the bearings would reduce the grip of the belt on the pulley, so hopefully i'm right. Should be here tomorrow and will fit at the weekend.

It should be easy to feel and play in the bearings when the alternator is removed, the spare one spins and feels beautiful when you pick it up by the pulley (you can feel the weight pivot around the shaft with ease), i suspect the one on there wont feel as good.

If its the aircon pulley/clutch, then the car can just go to hell , time for a new one lol.

Post by **vanzep** » Tue Jun 16, 2020 11:34 pm

yes new parts - lovely

hope this sorts out the droning and stuff - could be your lude complaing about not been driven in vtec for a while

a good run(if you can) and some music to drown out any worrying or unpleasant noises always did the trick on my BB4

Scott560 · Post by **Scott560** » Wed Jun 17, 2020 8:15 am

I'm already using the radio to drown our the rear silencer heatshield which has decided to come loose

Its been driven enough, the noise started the second i turned the key after tightening the belt, my own stupid fault. Its hard to check the tension because of its location (the PS belt and engine mount is in the way) and its hard to get a perpendicular force on it to measure the deflection at said force (as specified in the manual). Had a quick search on ebay for tension guages but didnt see anything. I don't mind buying tools for some reason - even if its a bit pricey or im only going to use it once, it pays off down the line when someone needs a favour.

I have to admit, the service manual was actually quite lacking in its description of the process. Normally everything is explained over several pages with pictures and warnings, but this part is quite sparse. I consider myself reasonably competent DIY mechanic so i'm annoyed i over tightened it. If its the aircon pulley ill be really annoyed with myself because i dont fancy replacing that.

When the new one is refitted, i will leave the PS belt off whilst I check/adjust the tension of the alternator belt, which is what i should have done first time around (instead of fitting both belts, run for 10 mins, then try to adjust tension).

Drove the wifes car yesterday for a quick work meeting, so managed to get a bit of vtec turbo action (not quite the same but still moves OK - '17 civic sport 1.5 turbo). It does make you consider getting a new car lol. Whilst its a touch slower, it has plenty of torque, CVT ruins the driver experience but makes it lovely to drive day to day. Has all the assists and comforts, and the chassis is actually pretty bloody rigid and even the slightest steering inputs you feel the whole car begin to move. Id go so far as to say it probably has more mechanical grip than the lude. I bet the manual is a hoot.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed Jun 17, 2020 6:41 pm

Yep, no doubt it hasore mechanical grip etc but... Modern stuff just doesn't have the excitement, I find.

Scott560 · Post by **Scott560** » Wed Jun 17, 2020 7:57 pm

wurlycorner wrote: ↑
Wed Jun 17, 2020 6:41 pm
Yep, no doubt it hasore mechanical grip etc but... Modern stuff just doesn't have the excitement, I find.

Yep - it has 0% exciting engine/intake/exhaust noise , the cvt is a slushy change over (even in sport mode with flappy paddle shift nonsense). And the hazards flash when you brake moderately. Interestingly, the CVT has an odd trait. Floor it from the line, it wont loose traction as the revs rise. As soon as it decides to lower the ratio (at about 40mph), some kind of internal intertia is dumped into the drivetrain and it breaks free. Very odd power delivery. Fine day to day, but i wouldn't feel comfortable hooning it around too much cos you don't know when your going to get this massive surge in torque. Its not turbo lag, its gearbox related...

Alas, this is not the place for a review of the wifes car lol - Its quite decent in all respects if a little larger than needed (no kids, mostly used just by her). Nothing about a jazz or even the new to be released jaxx hybrid seems attractive though, even though its probably a better fit for the needs. Honda has a pretty bland line up. Most of the big manufacturers offering many models and sub-models, but honda is pretty limited and safe options at that (type r excluded of course).

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu Jun 18, 2020 11:08 am

CVT shouldn't have any gear change at all, in reality (it should continuously adjust the 'ratio' and during acceleration, hold the engine at constant revs/peak torque/efficiency) - it's 'fake' gear changes that manufacturers have programmed in, because people don't like to have an engine that's sitting at constant revs (it doesn't feel 'normal').