[9K-sbc]

Here's the skinny, picked up a 350 sbc recently, was told timing is locked in at 34 deg because of a small nitrous shot, I checked the timing to verify the 34 deg advance and the timing marks on the balancer were nowhere in sight. After checking tdc, the ring on the balancer appears to be 180 deg off, (double checked with old non digital, non dial back timing light). The balancer is a mystery, I've searched the internet with the numbers from the balancer and came up with nothing. It looks alot like the Summit series "Bracket" balancers (clear coated, 6 tapered socket head screws around the outer front face and bolt holes for adding weights) so I called Summit with no luck. I know that a balancer ring can slip, but 180 degs exactly? I haven't put a piston stop on it yet to verify that it's exactly 180 off but it appears to be. Which leads me to the main question, are the 6 bolts around the outer front face of the balancer related to the ring? if so, can the ring be rotated 180 and re-installed? If not, I can Always just add some timing tape etc.
Thanks in advance for any replies.
Here's a pic from Summit

 

[woodz428]

I hate to be the one to ask...but...are you using the correct plug wire?? If the wires are not neatly run, you may have hooked up to the wrong wire. Balancers do get off after time, not all but some, usually it is no where near 180*. That's why I asked the cylinder # question. Something that far off should have telltale iundications that the bonding has failed and allowed it to turn.

 

[9K-sbc]

yes, right plug wire and did a quick "popping rag" test for tdc. I think I'll time off of #6 just to see if it shows the 34 deg that is supposed to be there, if it's on 34 deg then it's exactly 180 off. I've been out of racing for 30 years, so I'm unfamiliar with this type of balancer. I don't see how it could have slipped so much. I tried to find info or an exploded view of this type balancer but summit says they don't have one either and they actually admit that the sfi balancers they sell don't have any numbers stamped on them for identification. I guess I might just remove the 6 bolts in question and see what they do, Anyone ever do this?

 

[MT71c-10]

My guess would be maybe the timing pointer was installed on the wrong side of the engine. Like it was bolted on the passenger side and should be on the drivers side of the engine?

 

[9K-sbc]

maybe if it were 90 deg off, but not 180, you'd have to almost lay on the floor to read it.
Thanks for the reply

 

[ericnova72]

First off you are not 180° out on the firing order, checking #6 will give you the exact same results as you see now. #1 and #6 come to TDC at the same time, one is firing and one is on the exhaust/intake overlap, and the firing point is 360° crankshaft degrees apart, which is 180° only on the distributor because it turns 1/2 crank speed.

The scenario you describe of 180° off at the crank would only be 90° at the distributor.

Any chance the balancer has 2 keyways cut 180° apart for use with a blower, and it is just on the crank using the wrong keyway??

 

[9K-sbc]

That's what I'm trying to find out, I guess I could remove the balancer bolt and see if I can tell. Have you seen this before
Thanks

 

[ericnova72]

That's what I'm trying to find out, I guess I could remove the balancer bolt and see if I can tell. Have you seen this before
Thanks

Haven't see it before, but just pointing out info and possibilities.

If the balancer has a seperate hub section from a main body and ring section(like an ATI balancer does) it could be that it was assembled or reassembled incorrectly.

If it points straight down so you would have to read it from under the car when it should hit the tab at the normal SBC position of near 2 c'clock, then it sounds like the balancer could also be assembled 120° off, which is possible with a 6-bolt pattern.

 

[9K-sbc]

Well wouldn't you know it, the balancer bolt is tighter than dick's hatband, and yes, I'm hoping that it was just re-assembled the wrong way. I'm hoping to find someone who has had the 6 bolts out and is familiar with this. My bad on the #6 timing, how about #4.
Thanks

 

[9K-sbc]

I just talked to the guy that last timed this engine and he said that all was well when he did so, now I'm a little baffled, I can see the knuckles on this piston through the sparg plug hole and my timing marks are on the opposite side of the balancer from the timing tab. I'm sure I'm at or near tdc, even if I was at the top of the exhaust stroke, I should still be on the timing marks (0-60) not 180 off the marks. :drunk: I hope it didn't shear the key,

 

[SSedan64]

I usually put a socket on pull handle/breaker bar and wedge it against the frame then bump the starter. Loosens the balancer bolt easy.

 

[9K-sbc]

Thanks for all the replies, I pulled the crank bolt and washer off today and it appears that the ring has somehow slipped almost a full 180. The balancer key is at #1 crank throw but the 0-60 deg markings are on the other side. This must have happened within the last 3 or four runs at the track, I guess it didn't like 8 grand.

Thanks

 

[zap60]

Thanks for all the replies, I pulled the crank bolt and washer off today and it appears that the ring has somehow slipped almost a full 180. The balancer key is at #1 crank throw but the 0-60 deg markings are on the other side. This must have happened within the last 3 or four runs at the track, I guess it didn't like 8 grand.

Thanks

If that trully is the case, I would be quick to replace the balancer. First thing I would do is to establish actual #1 TDC of compression stroke with a piston stop and verify the distributor rotor is pointed to #1 plug wire. Now you can "re-mark" the balancer, to your pointer, and check timing with an adjustable timing light. If it does happen to be exactly 180deg off, I would tend to lean towards an improperly assembled balancer. Is it an aftermarket balancer?