Tremec Alignment Question

[Rebird]

HOW DO YOU CHECK FOR ALIGNMENT (CENTERLINE OF CRANK vs. TRANNY) WHEN INSTALLING A MANUAL TRANSMISSION? I HAVE READ IN THREADS ABOUT TREMEC'S AND OTHERS THAT VIBRATE AND HARD TO SHIFT WHEN THE ALIGNMENT IS NOT CORRECT. THANKS IN ADVANCE.

[sporter]

Lakewood Bellhousing Alignment Procedure

Go here and open the pdf titled "Lakewood Bellhousing Alignment Procedure"



Its the 3rd up from the bottom.

[Hurst - Jeff]

This is what we include in our kits:


Bellhousing Alignment Instructions
Important!
Before installing your new Tremec TKO transmission, it is important to make sure that your bellhousing or scattershield is properly aligned with the centerline of the crankshaft. The alignment process is called “dial indicating”. If using a stock GM bellhousing or a Lakewood scattershield, dial indicating is necessary before installing your transmission. If you are using a McLeod scattershield and your motor has not been line bored, dial indicating is not necessary as these scattershields are pre-aligned by McLeod from the factory***. A bellhousing that is not centered with the crank can result in poor shifting, clutch engagement problems, worn pilot bearing, as well as accelerated wear on the transmission itself.

Unfortunately checking the alignment can be a tedious task, especially if the engine is still in the car. To check for proper alignment, you will need a dial indicator, some basic tools, and a bit of patience.

Checking bellhousing alignment
1. Making sure that dowel pins are clean and free from dirt and/or paint, securely mount bellhousing to the engine block, and torque all bellhousing-to-engine bolts to specification. If you are using a scattershield, make sure the block plate is installed.
Note: Make sure your stock dowel pins protrude out far enough to let the scatter shield and block plate fit on the flat part of the dowel and not the tapered part. If the scattershield is resting on the tapered part this can cause inaccurate measurements. It may be necessary to tap the stock dowels out far enough to allow this. Moroso makes longer straight dowels for this purpose. If you need to new dowel pins, we recommend Moroso or Precision Products Performance Center brand dowel pins due to quality and fit. Moroso pins come in .007”, .014”, and .021” sizes (http://www.moroso.com/default.asp). PPC’s are available in .005”, .010”, .015” and .020” sizes (http://pppcenter.com/).

2. Install dial indicator base on the flywheel and adjust plunger to contact the inside edge of the register bore of the bellhousing (Fig. 1). If you need to create space for the dial indicator base to sit flat on the flywheel, remove two of the flywheel bolts that are directly across from one another.

3. With the dial indicator mounted correctly, rotate the crank 360* and note the indicator readings. Using an inspection mirror to read the gauge as it rotates is helpful. Mark your readings at the 12:00, 3:00, 6:00, and 9:00 positions (Fig. 2). This will give you an indication of which direction you need to move the housing - if necessary. Make sure to double check your readings. The total travel of the needle, divided by two, equals your reading – this reading is the amount of misalignment between the crank centerline and the bellhousing bore. Tremec specifies a maximum misalignment, or “runout” of 0.005". If you have more than .005” runout you will need to correct this by using offset dowel pins. If your reading is 0.005” or less, your bellhousing is within tolerance and you are finished with this process. If you have between 0.005” – 0.040” misalignment, you can correct it by using the correct offset dowel pins (proceed to step #4). If your misalignment is greater than 0.040” you have either measured incorrectly or there is a problem with your bellhousing and it will likely need to be replaced.


Bellhousing alignment procedures
1. To correct misalignment, you will need to use offset dowel pins. These dowel pins come in the sizes mentioned above. Select the offset dowel pin pair that is closest to ½ of the runout reading (i.e. if runout is .016” then ½ of .016” = .008”; in this instance you would select .007” dowels). Pick the brand of dowels that has the size you need. If your runout is .014” you would buy the Moroso, .007” dowels. If you are at .010”, you would buy the .005” PPC’s. Offset dowels have screwdriver slots so you can turn them, thus moving the position of the bellhousing.

2. Start with the indicator at the 12 o’clock position and turn the engine 360 degrees (one full turn). Mark the locations where the reading is highest and lowest. These readings may cover a large area but will help determine which direction to move the housing to correct misalignment. Now put the indicator in the center of the area of the LOWEST reading and ZERO the indicator (for example, if the lowest reading was between 7 and 9 o’clock you would put the indicator at 8:00. Now rotate the engine until you get the highest plus or positive reading – in this example it should be somewhere near 2:00. If the reading is .014” you would need to move the housing towards 2:00 by .007”. If it were .020” you would move it .010”. After the initial learning curve you will understand how this process works. Remember that all readings are divided by two. This can be a frustrating process. Have some patience and use a notepad to record your measurements, not the face of the bell housing as it will get full of measurements quickly. After your dowel pins are in you can turn them as needed to get the required alignment.

3. To install offset dowel pins, first remove the stock dowel pins by driving them through from the back with a brass drift or by using gripper pliers. Properly clean engine block dowel pin holes and lightly coat with lubricant.

4. Lubricate dowel pins and install them into engine block. The slot of the dowel pins DOES NOT indicate the direction of maximum offset. You must find the high spot on the dowel with the dial indicator and mark it so the dowels can be installed parallel to one another and in pairs (i.e. both 0.007”, both 0.0014 etc.).

5. Install bellhousing and torque bolts to specification. Re-mount the dial indicator and recheck runout by repeating step #3. Small corrections can be made by loosening the bellhousing bolts and turning the dowels with a screwdriver to bring the bellhousing within limits.



Congratulations – you have completed an important step.


*** If you choose to check alignment of your McLeod scattershield, do so without the silver register ring installed in the register hole – checking alignment with this ring in place will give you a false reading.

[Rebird]

Wow, Thanks For The Help!!! Very Informative!!!

[MarkM66]

Do you just use a magnetic based dial caliper? If so, how would you ever know if it was directly centered on the crank shaft/flywheel?

[CFster]

Doesn't have to be.

No matter where it is on the crank/flywheel, it will always be the same distance from the center if you have it mounted securely. So as you rotate the crank the arm will be always going in a perfect circle.

At first you adjust the arm so it's well within the hole on the tranny side of the bellhousing, then adjust it further out until it's just touching the edge. Then you can zero it out and begin turning the crank and taking measurements.

Think about it...

Anyway, what jeffmort said about it being a frustrating process is an understatement. Sometimes it can be downright maddening. You change the dowel pins to what you think is the right offset and the measurements will come out completely opposite. Having the torque off on one of the bellhousing bolts can throw things off as well.