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Harmonic Balancer on a Iron Due 120?

billv45

New member
Hi All, almost finished a teardown on a Mercruiser 2.5L on a 1985 Peterborough, fun stuff. So far I've collected about a pound of peanuts and birdseed. Hopefully it'll go to the machine shop tomorrow for a slight boring. The crankshaft pulley is rusted beyond salvation and I was wondering. Would installing a real harmonic balancer from a 3.0 be a good idea or not, and why? Wouldn't it smooth it out a bit? Definitely would look so cheesy with that wimpy pie pan pulley but don't want to screw anything up.
Iron Duke not Iron Due, first post, nice job...
 
The harmonic balancer I'm considering is [h=1]MerCruiser 2.5L 3.0L Harmonic Balancer Crankshaft Pulley New 55045T[/h]on amazon. Seen it numerous places and they all say 2.5L/3.0L but most all posts research I've done indicates the 2.5L just has a simple pulley
61bMVo1TWzL._AC_SX466_.jpg
 
Ayuh,.... It's NOT an iron duke, but a Chevy based motor, that does Not use a harmonic balancer,.....

The iron duke is a pontiac based motor, at 151 cid,....
Yer motor is a chevy 153 cid,....
 
Right! Owned at least three of them over the years.

Betcha don't know the 2.5/ 3.0 Mercruiser started life as a Chevy six with 2 cylinders lopped off. GM was looking for a cheap and quick powerplant for their new boxy Chevy II. In their wildest dreams, the engineers involved in that never dreamt the motor would still be in production 60 years later!

Jeff
 
Re: Harmonic Balancer on (not) a Iron Duke 120?

The iron duke is a pontiac based motor, at 151 cid,....
Yer motor is a chevy 153 cid,....[/QUOTE]

Wow, there are a lot of misinformed folks out there. Thanks for educating this one! So I do NOT have a Iron Duke engine, crap, I was going to enjoy saying I did. I will enjoy telling everyone I have a Iron Duke's Daddy in the back, that might even be a good name for my boat. The stock version of my IDD does not have a harmonic balancer and just a chinsy, thin, easily rusted out pulley. As mine is rusted out and before I spend too much money on used version of what already rusted out (at least once) on my boat, can I upgrade tot a new HB made for a 3.0 140 Mercruiser? Will it fit and will it be better and do no harm?
Cheers,
Bill


[FONT=&quot]As part of the decision to build the new L-4 engine, a review was made of recent General Motors engine designs. This review revealed a 2.5 Litre (151-cu.in.) L-4 engine was being produced by General Motors do Brasil. This particular engine had started life as a version of the early 1960s Chevrolet II 153-cu.in. L-4 which is currently produced by General Motors of Mexico. General Motors do Brasil had reduced the stroke from 3.25" to 3.00" and increased the rod length from 5.70" to 6.00" to reduce the vertical shaking forces inherent in an L-4 without counter-shafts. At the same time, they had increased the bore from 3.88" to 4.00" to maintain the displacement. Pontiac's analysis indicated that this engine had significantly reduced secondary vertical shake versus either the 153-cu.in. engine of the aluminum 2.3 Litre (140-cu.in.) engine then being used in small General Motors vehicles. In addition, since the 2.3 Litre was currently being produced by Chevrolet, the 2.5 Litre, being slightly larger, fit well into Pontiac's marketing plans.[/FONT]
 
As mine is rusted out and before I spend too much money on used version of what already rusted out (at least once) on my boat, can I upgrade tot a new HB made for a 3.0 140 Mercruiser? Will it fit and will it be better and do no harm?
Cheers,
Nope,..... It'll alter the crank balance in a bad way,.....

You need a pulley only,....
 
If you are worried about the rust, get new/lightly used one, and get it powder coated...if you want to go a bit wilder, get an aluminum one and get it anodized...
 
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