How to dial in bellhousing/scattershield - Lot of pics

[scherp69]

So this is one step that I found really frustrating. One reason is there wasn't a whole lot of info or pics on how to do it. I took a ton of pics and thought I would create a thread to show how I did it. If anyone finds anything wrong, or wants to add to this...please feel free. Mods...if this is all BS...please just delete the thread or if you think it will help many..please make it a sticky.

What you are doing with this step is centering the scattershield with the center of the crank shaft. If you miss this step, you may wear out the pilot bearing and have clutch engagement issues.

From what I have read, this step needs to be done if you are using a stock GM bellhousing or a Lakewood scattershield (which is what I have). There are some differences with McLeod scattershields so make sure you find out what else has to be done.

There are other ways to do this, this is only an idea of the way I did mine. Here's what you will need to do it this way
- a dry erase marker
- a dial indicator
- a magnetic base to mount the dial indicator
- ratchet and sockets

Make sure the magnetic base is an adjustable one. Even better if you get a fine tuning one.

Dial indicator and magnetic base. You'll notice and On and Off switch. This is to turn the magnet on and off. Comes in handy when trying to put the magnetic base through the scattershield.





The dial indicator that I have goes from 0 - 100. What I did to make things easier was to mark one side of my dial indicator as positive and the other as negative. I didn't clue in until later how much easier this would make things. With the + and -, now if the dial goes to the right, you know you have a + number and if it goes to the left, you have a - number. That will make a huge difference knowing that. Here's what I mean. I used the dry erase marker so I can wipe it off later.



If you are using a scattershield, you need to mount the motor plate. Also attach the flywheel



You will notice there is one bolt missing from the flywheel. This is where you are going to mount the magnetic base. Here is a pic of how it mounts without the scatter shield on.



The one thing that I found while doing this was that my magnetic base would not fit completely between the flywheel bolts and was sitting on a bit of an angle. Also, it was hitting the lip of the crankshaft where it came though the flywheel. These were giving me false readings. The easy fix I found was to grind down the parts of the magnetic base that were hitting.



Now that the magnetic base in sitting properly, put the scattershield on and mount the magnetic base the same way it was before



Here's a couple of pics of how it is sitting against the flywheel





The important part here is make sure that the dial indicator can make a full 360 degree turn without hitting any part of the scatter shield. There was a weld on the inside face of mine that it was hitting, so I had to adjust it accordingly. You also want to make sure the dial indicator is as flat as possible.

This is how NOT to do it. This will give you false readings.



This is how you want it to sit. This part may take a bit of time and playing around as you will need to make several adjustments with the magnetic base to get it right.

[scherp69]

Once this was done, I made 4 marks on the face of my scattershield marking each of the quarters...12, 3, 6 and 9 o'clock.

Now what you want to do, is using a socket on the balancer bolt, turn the engine over until have the dial indicator pointing to 12 o'clock. Zero in the dial indicator and with the dry erase marker, write 0 on the scattersheild. With mine, I just had to turn the face of the dial indicator until the zero lined up with the dial. There is a nut on the side of mine that allows me to set the face in place.

Now, to make the next step easier, take out all the spark plugs so there is no compression making the engine harder to turn over.

Turn the engine over until you get to 9 o'clock. With the dry erase marker, write down the reading from the dial indicator on the face of the scattershield. Do the same thing for 6 and 3 o'clock.

Now you should have 4 readings on the face of your scatter shield. My quarter readings were: .010 at 3 o'clock, 0.041 at 6 o'clock and 0.031 at 9 0'clock. You now need to take the difference between the opposite sides to find out what offset dowels you will need. With my readings, I took the largest number, .0041 and then the opposite number, which in this case would have been 0. This left me with .0041. If I took the 3 and 9 o'clock readings, the difference was .021. The larger number is obviously the .0041 so that is the number I needed to choose an offset dowel.

For runout (largest difference between two sides) of .009 in. through .020 in., use a .007 in. offset dowel set.
For .021 through .034 in., use a .014 offset dowel set.
For .035 through .050 in., use a .021 inch dowel set.

Since mine was .0041, I needed the .021 dowels. Ideally, your eventual goal is to be able to turn the dial indicator 360 degrees and not have the dial go above + or - 10. You will still be okay if the difference between the two numbers is less than 10. That is the approved tolerance.

Now to the most important tip I can give in this thread. DO NOT buy the type of dowels that look like this



I got mine from Lakewood. They are junk. They say that once they are in the block, you can turn them with a screw driver....YOU CAN'T.

Here's what you want to get. These are from www.robbmcperformance.com When I talked to Robb, he mentioned that ones that Lakewood sells like these, are actually ones that he has sold to them. Again...GET THESE TYPE OF DOWELS.





Once you have the offset dowels, you need to take the scatter shield off and take out the stock dowels. I found they came out very easy, although I have a new engine so that probably helped. I used a bolt and tapped them out. Sorry for the blurry pic.





Once the old ones are out, you need to make sure the dowel holes are clean. Then get some never-seez and coat the holes. With the RobbMC dowels, you will probably want to take out the screw and lightly tap the dowels into the hole until it is in far enough where the offset will move the scattershield. When you look at the dowels up close, you will be able to see where the highest point is. You will notice the bottom part is centered, and the top part is offset. When they go into the block, you want to make sure the offsets are pointed in the same direction. In my case, both towards 2 o'clock as that's the way I wanted to move the scatter shield. The nice thing about the RobbMC dowels is that the offset runs parallel to the flat parts where you can put a wrench. So basically you want the flat sides on the dowels to be facing the same way on both sides so they are parallel. I don't know if it's the same on all, but I found the highest point on my dowels were had a stamp on the top of the dowel. You can see it in this pic.



Here's the only pics I have the dowels in. Note the pics are with the dowels not to use. Imagine the proper ones in there.





Now that the dowels are in, you want to put the scattershied back on, put in all the bolts and torque them down. Mount the dial indicator back to the flywheel, put it to 12 o'clock, zero it and wipe off all the old readings. Turn the engine over again and write down your new readings at 9, 6 and 3 o'clock. I always wrote 0 at 12 o'clock. With your new readings, it's time to keep adjusting the scattershield. You need to have patience for this step. You want to find out where the biggest difference is and move it in the right direction. In the next pic, my readings were 0, 14, 12 and 6. The difference between the 14 and 6 was 8, so there I was okay. The difference between the 12 and 0 was 12...so I still had to make some adjustments. In this case, I needed to move the highest point of the dowel towards the lower number. I needed to turn the offset towards 12 o'clock to pull the centre that way. Keep in mind you won't be turning the dowel all the way to 12 o'clock, you need to turn it a bit, then test again and so on. The other thing to keep in mind is that when you move the dowels, it will change your other readings so may have to keep adjusting until you have it right. Like I said...you need to have patience during this process. Here's the pics of my readings.



As I already said, you want to get the difference between the opposite numbers to be 10 or less. These were the final readings that I ended up with when I called it good. This is also when I finally clued into marking the numbers as + or -.



So now that I was okay for tolerance, I held the dowels in place by using a 9/16 wrench and tightened up the center bolts. You want to hold the dowels in place with the wrench so they don't turn after all your hard work. Now that you have this done, you can mount the clutch (as long as you have checked the clearance on that) and throwout bearing and bolt the scattershield on for the final time. Then go the fridge and grab a cold beer and be thankful that process is over with