Stage 1 block with stock front cover

[FreddieWilliams]

I have a couple of questions to ask:

1.) I have heard of the requirement of "on center" stage 2 motors needing to have a stock front cover milled ~ .120" to allow the cam sensor drive gear to align properly.
Is this the same for a "off center" stage 1 block using a stock front cover?


2.) The issue I ran into today was that my BMS balancer interrupt ring is hitting the front cover and also bottoming out into the crank sensor.

My cam sensor drive drops right in and looks to be aligned dead center. I'm using a stock front cover gasket (very thin compared to the paper Felpro unit).

I determined the balancer needs to be shimmed out by ~0.125" to clear the cover and sensor. This of course pushes the crank pulley too far forward.

I figured instead of shimming "all" the other pulley components to get it to line up with the new crank pulley position, to just mill the pulley face down on the balancer by the shim amount (.125"). This will bring the crank pulley back in alignment with all the other pulleys without any further mods.

What do you guys think?

 

[TurboDave]

I don't know if it's thick enough in your application, but did you put the oil slinger back onto the crank nose before installing the front cover?

 

[turbodave231]

I ran into the same problem with my motor S2 offcenter block with a stock front cover. I wasn't hitting the cover but was bottomed int the sensor. I machined .140 off the crank sensor base. I made a spare while I was at it.

Dave

 

[Jeff Rand]

Freddie, lining the key with the keyway on the balancer is very difficult to do(the key is hidden by the timing chain cover) if you have a tight fit as BHJ recomends. It is easy to miss the key or have the key get pushed back on the crank. I had to have another keyway placed on the front of the crank to get the correct alignment .
Jeff

 

[FreddieWilliams]

TurboDave,

Good point about the oil slinger as most people leave this out. In my case I do has one installed. Thanks for checking. The slinger is probably about ~.060" to .070" thick if I were to guess. Without it and the use of a non-stock front cover gasket, things would be worse.



turbodave231,

Had your front cover been milled before and what balancer were you using?



Jeff Rand,

Yes it is a very tight fit. I have about 3 keys installed along the crank snout. I pulled the balancer off and on about 4 times now and it is definitely lining up on the key.

 

[turbodave231]

Stock cover no milling. Buick MotorSports balancer. Correction: I milled .150 of the base of the crank sensor not .140 as previous post indicated.

I installed the sensor and balancer on Sunday. I found that I had to grind a small flat spot on the cover just in back of the plastic body of the sensor. I also took the plastic sensor body and carefully filed the back flat to remove a small amount of the sensor case down to the potting material. I am using a Standard brand sensor. I gained just enough clearance to properly adjust the sensor. No big deal 10 minute "custom adjustment"

Dave

 

[FreddieWilliams]

For the sake of other searching this topic in the future, I will comment on what I found.
I talked to Kenny Duttwelier the other day about this problem and he said it is a well know issue when using the older neutral balanced BMS balancer.

Kenny said when this balancers first come out long ago, they could not get a motor to start. They later found the interrupt ring was too far into the crank sensor and it never saw the gaps to trigger the spark sequence. They fix was to shim the balancer out so that it cleared the crank sensor (and in my case the front cover too). In my particular case, I needed to shim the balancer forward 0.125”.

A list member e-mailed me personally and told me that a spacers could be purchased at Jays GN Parts. I have not verified this to see if this is the correct spacer needed since it would require a woodruff key slot to be cut in to the I.D. of it.

Now that the balancer is pushed forward, the crank pulley will be out of alignment not be able I forgot to ask Kenny what he does to align the crank pulley after shimming the balancer forward. I however, decided to have TurboJoe mill 0.125” off the face of the balancer (pulley mating surface) down so when I bolt the pulley back on, it will line up with the water pump pulley again.