Bellhousing alignment help needed

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duster360

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All 7 bolts are in the housing and tight. I took a video of the bellhousing alignment. Looks like the side to side bore has an issue or am I looking at it wrong. Where do I go from here?
 
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First I would use an ID mike to check the roundness of the hole that the indicator is sweeping. If the hole is "dead" round then on to step 2.

Is the magnetic base mounted on the back of the crankshaft??
 
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Center of the flywheel
That will work. If the hole is "dead" round then you need to make sure that the back surface of the bell is parallel to the back of the block. If the back surface of the bell is not parallel to the block then the bell might have been machined improperly which will make the hole in the bell indicate like an oval. You already have the set-up, just move your indicator to the back surface of the bell to check for parallelism. If the "back" bell surface is parallel to the back of the block and the hole is round go to step 3.
PS - Make sure that you don't have any end play in the crank when you check the back surface of the bell, if the crank moves axially it will give you a false indication.
 
At the moment I don't have a mic to check the hole roundness. I will see what I can round up. I will check the back of the bellhousing for squareness tomorrow.
 
At the moment I don't have a mic to check the hole roundness. I will see what I can round up. I will check the back of the bellhousing for squareness tomorrow.
Good luck, we have seen FABO members who have found that the back of their block is not perpendicular to the crank bore, hope yours is not that way???
 
That looks typical of some of the engine/bell combos I have indicated.
For a one time install, I just take out the pins, loosen the bolts slightly, tap the bell into alignment and torque the bolts. It may be 120,000 miles or 20 years before you have to go back in there.
But on a car you may be taking the trans out 5 times in one summer (yeah I did that; three times in one week even), well then you need to get the alignment pin kit and do it right.
 
If I'm thinking right (it's early) I not sure you have a major issue side-side. Does .007" down and .002" right, from where your dowels are now toward this indicator direction make sense? Red being the target ...…
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That what I was thinking, just needed a second opinion. If that is the case, I am within spec. My Motors repair manual calls for .008” or less to be within spec.
 
That looks typical of some of the engine/bell combos I have indicated.
For a one time install, I just take out the pins, loosen the bolts slightly, tap the bell into alignment and torque the bolts. It may be 120,000 miles or 20 years before you have to go back in there.
But on a car you may be taking the trans out 5 times in one summer (yeah I did that; three times in one week even), well then you need to get the alignment pin kit and do it right.
I have .014” offset dowels in at the moment.
 
I would install it without dowels and only 3 bolts just to see if you can tap it around until it centers up???
 
May try that. I am gonna try readjusting and will report back here with video. Once this part is sorted out I will be checking the parallel also.
 
I forgot the video. But I got it down to .005” tolerance. The parallel measurement is .004” off on one side. Would this be acceptable?
 
I forgot the video. But I got it down to .005” tolerance. The parallel measurement is .004” off on one side. Would this be acceptable?
.004 (parallel) is really good on the back face of the bell!! If you got it within .005 on the concentricity you're probably as close as your gonna get. Did you have to remove the alignment pins??
 
At first I did do that. Tried this and that. Put them back in turned them a little bit different than what they were to start with and it all came together.
 
I would install it without dowels and only 3 bolts just to see if you can tap it around until it centers up???

That might work for a very small discrepancy, but you still will need to remove the bellhousing to install the flywheel and clutch. When you reinstall the bellhousing you might be in a different location.
 
I had the dial indicator on the bellhousing when I was tightening all the bolts. I had all of the bolts in. Every time I would tighten a bolt the indicator would move.
 
I thought that once u got it in the exact right spot u would drill two or three 1/8" or 1/4" alignment holes to b able to reposition it during final assembly. You install it then stick a 1/8" or 1/4" rod through the holes and go to town. That way u know you'll have it as close as possible to the right spot?? You could also (once you get the dowels in the right spot) drill and tap a 1/4" set screw into the threads of the dowel to hold it in place (radially). I couldn't find a pic of how stake a dowel pin (using a set screw) to keep it from rotating but I did find a pic of how to "stake". Being a machinist we used to drill and tap the space where the pin meets the casting with a small (1/4") set screw and lock tight to keep the pin from rotating. Once you get your pins rotated into the best possible position you can drill and tap from the back side, install a set screw then you can be sure that the dowel pins will be in the exact correct position when you install the bell.


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