Balancer shaft belt removed - Unbalanced engine?

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08-04-12, 22:20
AlfaJack

Balancer shaft belt removed - Unbalanced engine?

I have recently removed the balance shaft belt and locked the front shaft so it is not turned by the bearing that the cambelt backs on to.

I have run it for a few miles now and the difference is very noticeable which is a shame as I have read that for some it is barely changed.

It definitely has less drag on the engine which is nice on the overrun - this is probably in combination with removing the AC pump too.

The difference is noticeable on acceleration only, mainly from 2K RPM to 4K. At a constant speed it is normal. I am yet to take it on the motorway though (a chance tomorrow).

Is it that my engine is basically worn and perhaps unbalanced?

Thanks,
Jack
09-04-12, 05:28
mpampis_

If your engine is in good health you won't have any problem. Any tuned car specially more than 260-280 hp must have removed this. The engine is still balanced but more aggressive which means it is not so "family" car any more. I remove completely the balance shafts and now I have 1 point more oil pressure
09-04-12, 07:22
Steve Webb

Sounds a little strange to me Jack, I would have thought that if the engine was unbalanced then you would have got the vibration regardless of whether you were accelerating on not.
Did you notice any vibration at these engine speeds before you removed the balance shaft belt?
Almost everyone else I've heard talk about removing the balancer belt has said that it just makes the engine a little more harsh, nothing about vibrations.

Does the vibration depend on how hard you accelerate?
09-04-12, 08:04
AlfaJack

Vibration is the wrong word. Yes it is harsh but I was hoping for no real effect as I had read that in some or a lot of cases it was unnoticeable. Will see how it is on the motorway today.
09-04-12, 08:20
Steve Webb

Quote:

Originally Posted by AlfaJack

Vibration is the wrong word. Yes it is harsh but I was hoping for no real effect as I had read that in some or a lot of cases it was unnoticeable. Will see how it is on the motorway today.

Motorway? Bank holiday Monday? Surely you won't get above 30mph :wink:
09-04-12, 08:54
jimnielsen

I did not notice any difference at all, after removing the balance shafts... but then again... I had the crank and flywheel balanced as an assembly before reassembling the engine...

jim..
09-04-12, 16:51
AlfaJack

Quote:

Originally Posted by Steve Webb

Motorway? Bank holiday Monday? Surely you won't get above 30mph :wink:

Hehe...no such problems. I didn't find it bad at all on the motorway, the harshness of it didn't cause me any problems and it runs really well, as I said the extra overrun makes it a nicer drive - I expect I am getting better MPG too.

@JimN...I think that would help do the trick...one day.

Anyway, we had a good run to the Horsham Piazza Italia in the company of a good few supercars like a Zonda's, Lambos and those other fast Italian cars. Also, there was what I think a Maserati Type 26B :cool: :clap:
10-04-12, 13:03
bussone

I also had the balancer belt removed before, the engine is more responsive after 3500 rpm without any noticable vibrations.
10-04-12, 13:37
Steve Webb

Quote:

Originally Posted by AlfaJack

Anyway, we had a good run to the Horsham Piazza Italia in the company of a good few supercars like a Zonda's, Lambos and those other fast Italian cars. Also, there was what I think a Maserati Type 26B :cool: :clap:

Get any pics?
10-04-12, 15:44
AlfaJack

Not many...there are a load of Alfaowner. I seem to have stopped taking photos at events....proably beacuse I walk away with the same set every year!

It was headline news though - this is my dad's Duetto, and himself (with his back to the camera) in the photo.
http://www.westsussextoday.co.uk/new...rain-1-3715703
10-04-12, 22:23
wrinx

Didn't Pavs do a trial removal and report that the vibration was noticeable?

wrinx
10-04-12, 22:33
AlfaJack

i think it just snapped on him soon after I fitted it and it does ring a bell that he mentioned that.
11-04-12, 07:35
Steve Webb

I guess it all comes down to if you can live with the extra harshness. Plus is there info about how to reset the balance shafts back to their correct location if you stick a new belt on.
11-04-12, 08:10
AlfaJack

Quote:

Originally Posted by Steve Webb

I guess it all comes down to if you can live with the extra harshness. Plus is there info about how to reset the balance shafts back to their correct location if you stick a new belt on.

Yes, I can definitely and will live with it.
Setting the balance shafts back to their proper setting is just like timing the cambelt up.