BHJ dampner and trigger wheel clocking

[Alky V6]

What is the deal with the trigger wheel being clocked to 3.5 degrees advanced of TDC?

Can someone explain what stock is and why 3.5 degrees is now prefered? This is how BHJ has been doing it for quite some time and they couldn't explain why they do it except to say that some time ago some big wig Buick fellas came to the conclusion that this was how it should be so BHJ mounts them this way.

Is there any special adjustments that would need to be done to compensate for this new trigger wheel clocking? Or is this a bolt in and don't worry about it deal?

 

[ijames]

I don't know anyone who prefers it this way and have no idea who told them that. The guys with FAST or other aftermarket systems just adjust their base timing to compensate, the guys with stock ecms pull the rings off and press them back on in the correct position. Most that I've heard of were more like 6-8 degrees off, not 3.5. John Estill has posted on this a couple of times with pictures that show the stock hub alignment. If you just bolt it in and ignore it, then obviously your timing will be 3.5 degrees different than you thought it was .

 

[d90dan]

Don,
I have two BHJ balancers. One is offset ~3.5 degrees, the other is right on. I could never figure out why, other than poor quality control

 

[Alky V6]

BHJ told me that they can install the trigger wheel like factory if that's what I want, but by far the more common practice is to install the 3.5 degree deal. They actually have a special jig to set up the wheel with the 3.5 setting.

 

[A2000RICH]

i measured one for someone today and the interrupter ring was 2.5 degrees off and the outer ring was 4 degrees off--------i have measured dozens of them and haven't seen two alike-------i really can't imagine why they don't make them correctly or at least all alike............RC

 

[turbofabricator]

I have heard them to be as far off as 12*, too. I have one I am going to install soon. I will use a known good stocker, and build a jig to verify the clocking. I have had to do this before on a BMS balancer, too. The car owner just eyeballed it and figured it would be OK. It wasn't. It was fortunately retared 26*. If it had been the other way..............

 

[Alky V6]

Wow. I guess I'll be getting the ring and installing it myself. Thanks for the heads up everyone.

 

[A2000RICH]

guys here is the fixture that i made to measure these darn balancers------i have shown it actually on a GM and BHJ balancer------the GM of course is correct and this particular BHJ is 2.5 degrees off--------they reference from the keyway in the crank and display degrees-------i had to make two different ones since the BHJ inside diameter is slightly smaller than the GM and i wanted to be able to measure them without sizing------there is a similar fixture to measure the outside ring timing marks as well------a plus is that this measuring fixture doubles as an assembly press............RC

 

[Alky V6]

Is that made from brass?

 

[turbofabricator]

Nice fixture. All I did was lock the crank down on a engine and then install a stock balancer. I bolted a bent up piece of 1" steel strap and layed it against one of the cut-outs on the ring. Then remove the stock balancer and install the aftermarket one, and verify the placement of the interruptor ring. I would just tap the ring in the needed direction to re-clock it. I then tack welded it, to prevent future movement.
You should sell your fixture to BHJ, so they can do it right everytime.

 

[A2000RICH]

Is that made from brass?

its made from aluminum................RC

 

[KILL4PEACEUSMC]

Thats a work of art brother!

 

[SuperCPA]

That is ingenious.

WOW!

 

[Alky V6]

I think I figured out what BHJ was referring to. If you pick a line of sight off to the side of the stock crank hub and rotate the hub normal engine rotation, the reluctor window will open, what appears to be 3.5 degrees before getting to the TDC mark on the crank hub. I used some crude measuring, but it does appear to be 3.5 degrees. Is this the general consensus?

The keyway doesn't line up with either, but I do understand how you can use the keyway to check the alignment of both the TDC mark on the dampner and clock the reluctor wheel. Assuming the crank manufacturer and/or dampner manufacturer was accurate in placing the keyway groove.

 

[A2000RICH]

guys----about this damper issue------i sort of got sidetracked by BG last week (it was great for me by the way) so i didn't have a chance to finish showing the damper measurements--------here is the fixture measuring the outer timing ring which is the one that you would normally use for things such as cam, distributor and cam sensor timing------on the GM balancers it is off quite a bit (looks like about 7 degrees) and they are all the same------the BHJ is off a little (about 4 degrees)-------is it supposed to be off?????------don't really know but i know at least i can measure it accurately-------shame i dont' know what it means at this point------could it be a correction for the cheesy plastic timing indicator????---------if so i would think that the BHJ should have the same "error" as the GM but its about 3 degrees off from the GM????-------i am going to "refine" my fixture and build a device that allows me to measure the position of the crank throw relative to the crank keyway------stay tuned..........RC

 

[HighPSI]

That is an amazing tool! How far off are the tabs in relation to each other. I am concerned about the timing on other pairs of cylinders.

 

[A2000RICH]

That is an amazing tool! How far off are the tabs in relation to each other. I am concerned about the timing on other pairs of cylinders.

as indicated on the round hubs the tick marks are 5 degrees apart----ie 72 of them in a 360 circle------if you would lilke to borrow this fixture let me know and i can send it to you for a few days-------i would love for someone to explain to me what this all means since the more i measure the stuff the more confusing it appears--------i really don't see how we can have accurate timing if we don't know where "0" is------i personally have 3 BHJ balancers and all three of them are different-------at least the GM units are closer but not perfectly identical------while it is easy to move timing around it shouldn't be necessary to change the mechanical "0" reference point from engine to engine................RC

 

[HighPSI]

Richard,
With an aftermarket computer, it doesn't really matter where the signal comes in. We just put a timing light on the car and tell the computer where the crank signal is coming in at (this is called the crank referance angle). This way the timing matches what the computer is telling it to be.
My concern is that we set the timing based upon #1 cylinder. Since it uses the same tab on the balancer as #4, we know the timing is correct for those two cylinders. If the other tabs aren't EXACTLY 120 degrees apart from the #1, #4 tab then the timing would be diferent for the other 4 cylinders. I have checked a couple cars using a dial back light and the other TDC points on the balancer and they "appear" to be right. I was wondering if you had seen any balancers where the tabs were NOT 120 degrees apart?
Thanks for offering to let me see it, but if I got it, I wouldn't want to give it back This would be a great tool in the hands of someone like Dan Strezo (probably already has one)

 

[A2000RICH]

i realize that with an aftermarket ecm that it is possible to move things around a given point of rotation--------kinda makes things difficult with the old timey stocker but i guess by the time someone puts a BHJ on a car its gonna have a FAST as well--------but it just seems to me that there ought to be an agreed reference -------how hard would it really be to stick to a simple standard-----------at any rate i can say that as far as the consistency of the three interrupter taps on the ring they seem to be really close-------i have used this fixture on over 20 GM balancers and about 8 BHJ dampers---------with this unit i can easily discern less than 1 degree of error and i have seen no variation in any of the units from either source-------what i have seen in the BHJ dampers is the length of the interrupter tabs is sometimes not exactly 50/50 with the open areas--------probably not a issue as long as they don't vary between each other............RC

 

[turbofabricator]

I was going to design and fab up an adjustable crank sensor bracket to allow the adjustment of initial timing. Then, the MAF Translator Plus came out, and negated the need to adjust initial timing. Maybe I should have developed it anyway.
At what RPM does the BHJ balancer really start to work. Most aftermarket balancers start to work around 6500 with the sweet spot in around 7,000-7200 rpm. Most of us never rev past about 6200. Has anyone analyzed this?