I busted my harmonic balancer while doing a tear down on my motor this winter. and i been looking for alternative replacement for a harmonic balancer thats serpinetine driven since there is **** all for clearance. the two i came across is a ATI one made for a lt-1, ( my motor is a gen 1 80-85) i was wondering if it will fit the end of the crant shaft? http://www.summitracing.com/parts/ATI-917327/ Thats the one i was looking at. The fall back one is just the stocker style one street dreams by ross has for sale. http://streetdreamsbyross.m...le-harmonic-balancer I would like to go after market because it creates a better damping compared to the stock one that ross has thats just lathed down to spec for the crankshaft. Thanks alot. Prox.
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12:47 AM
PFF
System Bot
fieroguru Member
Posts: 12640 From: Champaign, IL Registered: Aug 2003
The LT1 balancers stick out WAAAAAAAAAY to far... they had to clear the opti spark.
The SBC/LT1/4.3 crank flange is the same as: Iron Duke... all varients marine, RWD and FWD and in the 2.5, 2.7 and 3.0 sizes Inline 6's: 194,215,235,250 2.8/3.1/3.4 60 degree V6 (and probably the rest of the 60 degree family)
The balancer street dreams lists is very similar to the single groove (double groove was also an option) balancer used on the marine 2.5's/2.7/3.0's and the inline six cyl 194,215,235,250 family... just with a wider groove for the more common wider v-belts. These older OEM applications came with a narrower V-belt. You can run either, just the stock fiero AC compressor clutch needs the wider belt, unless you want to swap out the clutch (assuming this is possible).
There are 6 rib serpentine balancers on the FWD 2.5's and 3.1's, but the 2.5's are more compact (the 3.1" require some additional machine work on the back side to pull them up as tight as possible to the SBC timing cover). But these probably will not fit within the framerails without some notching. Using the thinner streatdreams adapter plate helps get some clearance, but I do not think it is still enough to avoid notching with the SBC (unless running the F40 transmission and a 1/8" adapter plate).
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04:20 PM
3084me Member
Posts: 1035 From: Bucks County, PA Registered: Apr 2005
Is there in fact a "double groove" marine balancer that would work with the Fiero SBC V8 swap ??
I've always toyed with the idea of a double groove balancer (since I run AC and of course the alternator and hate that "little bit of belt rap" around the AC pulley. 2 belts may be a big help (if it's even possible).
Just curious.
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08:29 PM
fieroguru Member
Posts: 12640 From: Champaign, IL Registered: Aug 2003
Most of the balancers on the 250 were the double groove setup, but they are essentially twice as thick and will cause clearance issues with the passenger side frame rail.
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08:36 PM
3084me Member
Posts: 1035 From: Bucks County, PA Registered: Apr 2005
Was just out looking at the car and noticed the same thing... (Knew there was a reason I didn't look into that before).
I have the Archie Kit but replaced the engine adapter with a Street Dreams one after having quite a number of starter issues. Have a bit more room but as you mention... not enough. Thanks for the reply.
[This message has been edited by 3084me (edited 01-31-2011).]
That is the 3.1/3.4 balancer and has an extra 1/4" of material on the face, plus needs the back side machined down. I have used this balancer with the required machining a couple of times, but again it will not fit without notching the frame rail.
quote
Originally posted by fieroguru:
The balancer will be from a mid 90's 3.1 cavalier. It is a balancer/crank pully all in one and accepts the 6 rib style belt common with the 88 4 cyliner Alternator/AC compressor. The seal surface on the backside was turned down further to the front to allow it to be placed as close to the timing cover as possible.
quote
Originally posted by fieroguru:
The balancer is from a 3.1 from an early 90's cavalier. Mods to the balancer include: turned 1/4" off the front face of the balancer to reduce the overall thickness of the balancer (and to remove weight!), extended the seal surface on the backside to allow the balancer to suck up tight to the timing cover and used some emry cloth on the inside to help it go on (it was a snug fit). Here is a unmodified balancer next to this one:
It is from an internally balanced engine. While the 4.3 is an externally balanced engine, the balancer is neutral balance with the only external balance being on the flexplate/flywheel. Here is a pic of the 4.3 balancer (on the left):
I have known many stock car guys to delete the balancer on their race SBC's and only run the center hub (press the outer ring off. Also, the balancer (or should it just be a pulley) on the right is from an 88 fiero 2.5 and is OEM free from any damper. Maybe the theory of the shorter cranks not needing the dampner has some merit. This one is a 6 rib and also is compatible with the SBC/4.3 crank snout. I had it on a SBC for mock up several years ago, so it could be made to work as well.
If you want to go this route, then get one of the 89+ FWD 2.5 balancers, I suspect they will slide on w/o any machine work needed (test fitted an 88 fiero 2.5 balancer once - but it is just stamped metal and does not have the rubber isolated ring) and they are much cheaper... but you are still probably looking at a frame notch to use it. Here is a new one for $53 shipped: http://cgi.ebay.com/ebaymot...fPartsQ5fAccessories
Or a used on for $30 shipped... but I have a an ebay rule of never purchasing something there isn't a picture for... to many times the part the person thought they had wasn't the actual part they were auctioning: http://cgi.ebay.com/ebaymot...fPartsQ5fAccessories
[This message has been edited by fieroguru (edited 02-01-2011).]
I am pretty sure that is a 3.1/3.4 balancer. In unmodified condition (at least the one I have on the shelf), the crank snout is 1.53", but the face is surfaced a bit from the rough casting. In the picture it is difficult to see if the caliper is on the machined surface or on the rough cast portion. The rough cast portion would make it measure longer.
That balancer will not be tight against the timing cover and require more room at the frame rail. If you are running the plastic L31 timing cover with the crank sensor, it can not be tucked in as far.
Set the balancer on its backside and measure up from the table to the back side of the balancer. I can check that with the one I have to confirm.
[This message has been edited by fieroguru (edited 02-01-2011).]
Same as mine... that is a 3.1/3.4 balancer in unmodified condition. You should be able to pick one of these up at any junkyard that has FWD cars from the late 80's/early 90's.
