Does anyone have experience shimming the bell housing to fix Parallel Alignment? I'm pretty sure I'm going to have to shim to get it within spec. I'm going to check my readings one more time.

0 at 12:00
.008 at 9:00
.013 at 6:00
.003 at 3:00

I think this tells me I'll need to shim the 12:00 and 3:00 to get back into spec. Is that right?

Thanks
Bill

 

Yeah, some 0.007 dowel pins should take care of it. I used Lakewood locking ones. Basically you install them and then rotate them so you can locate the bell how you want and then lock them w the hex bolts in them. They were $150. I felt like they were really expensive for what they are but they worked well. I had similar readings and once I had the 12 and 6 reading the 3 and 6 fell into place really well. I have a quick time bell/t56 w a dual disk and it shifts awesome.

 

I'm not even at concentric run-out yet. I'm trying to check that the front transmission mounting surface is parallel to my engine block. Right now it is sitting at an angle.

Standard Automotive Bellhousing Alignment Specifications:
Parallel: +/-.001” or .002” TIR
Concentric: +/-.005” or .010” TIR

 

Wow, that seems pretty off. I haven't heard about any being that off. I'd check it a few times make shure its repeatable. I'd check the block to bell mounting surface and its relation to the crank. It should be good. Sometimes there's paint that needs to be sanded. If it's the bell that's that far off that would be an issue.

 

I'm pretty sure it is the oil pan causing the issue. I loosened the bolts but it still won't move back enough on the one side. You can see it protrudes pas the block just enough to be annoying. I bought one of the Hawks pans which technicallly comes out of the same factory as the Holley pans but I had alignment issues with the thing from the get go.

I have a few options...

1. Shim the crap out of it (Not doing that)
2. Pull the oil pan and enlarge the holes until it lines up correctly. (Don't really want to pull a sealed pan. I also just took this engine off the stand and onto a dolly to do the trans work)
3. Purchase a .125 transmission spacer. (That will make up for the crap aligned oil pan and will provide a flat surface for the bellhousing to mount unlike shims)

I purchased the spacer which should be here in a day or two. If it works, I can always make up the difference if need by shimming my throwout bearing.

My only worry is now the input shaft...However, I don't think 1/8in will matter.

 

I'm going to test the oil pan theory if a get a few minutes this morning. I'll throw a washer on each of the block-to-bellousing bolts and see if that corrects/improves the parallel issue. If it does, I know the oil pan interference is probably the issue.

 

Can take it to a real machine shop and have it trued up. Clamp the block side to the mill table and take a skim cut off the transmission mounting side. Ended up being as parallel as could be.

RBob.

 

Is this a LS engine.
I saw a youtube video that the oil pan protrudes where it interferes with the mounting of the bell housing.
Check that there is space between the bell housing and oil pan
They ground down the oil pan for clearance.

 

Well, I did the washer trick and my oil pan is interfering with the bellhousing as expected.

New Measurements with washers:

0 at 12:00
.004 at 9:00
.004 at 6:00
.001 at 3:00

Much better but still out just a bit. I'll also check with a second dial indicator.

 

It is an LS engine and it most certainly has the oil pan.

 

O.K...Parallel is dialed.

Concentric: +/-.005” or .010” TIR

So I took my measurements 3 times and my highest value was .010 which is technically in spec. (The highest value also fluctuated a bit between .009 and .010 between readings) .009, .0095 and .010.

I do have some .007 dowel pins but is it really worth messing with it at this point?


0 at Position 1
.0065 at Position 2
.010 at Position 3
.0025 at Position 4

 

I think it depends on the trans. My magnum t56 required 0.005 or less. I know it's pretty picky w that and other trans can handle different tolerances. It your trans can handle the 0.010 then your cool.

 

It is a TKX which has the same specs for alignment.

You can see at position 1 I'm 0 but just opposite at position 3 I'm .010. which makes for a .010” TIR.

If I just look at a single position (each one opposite the other), each value should be cut in half so position 1 stays 0 and position 3 becomes .005

So up and down I'm .005
Left to right I'm .0045

At least that is how I understand it....

 

Was there any interference between the bell housing and the oil pan ?

 

Yes there was...

I got it all sorted how and in spec...

 

Did you loosen up the pan and whack it forward a hair? My pan is a couple thou behind the block face too, I didn't notice it until I checked bell housing parallel. I'm using a steel SBC bell housing. Not sure if I want to disrupt the pan, or just machine the bell housing a hair. It does not bolt to the pan like an LS bell housing anyway.

 

My pan seems to be from the defect pile. I would've had to drill out at least one troubling hole to get it to line up correctly. I ended up getting a bell housing spacer which worked perfectly.

I should be able to make up the small difference with a throwout bearing adjustment.

 

That's actually a pretty good idea.

What pilot bushing are you running? I'm running the extended one because it's a sbc depth bell housing.

-- Joe

 

On the SBC setup I'm using the the small bearing. I have both the small and extended for the LS but haven't pulled the transmission out of the car yet to measure. For some reason I feel like the extended is the way to go if it fits. It seems like having the support further up the input shaft would be ideal but I have no clue what I'm talking about

 

I think the extended is the right way to go. I'm in the process of checking my bell housing runout, and need to measure my pilot depth. I ran into the same oil pan issue, but I might just mill a little bit off the bottom of the bell. The other issue I ran into is the 10mm flanged BH bolts don't work with the lakewood scattershield because the flange hits the bell. The recess is only machined 5/8" wide, so I had to order some 12 point 10mm bolts which effectively have a 5/8 round flange.

I was tempted to drill and helicoil the block 3/8-16 so I can use more common 12 point hardware but. I left it alone for now.

-- Joe