Question : Cracked bellhousing?

[german_cargo]

In my 87 camaro 2.8 MPFI, 5 speed manual, we have broken two bellhousings. The car has a shaking problem that gets worse at certain rpms. We don't think the engine is out of balance... we've resurfaced the fly wheel and replaced the harmonic balancer and it improved it, but didn't cure it completely. We've been getting mixed opinions on whether or not the motor mounts need to be replaced as well, but many people have said neither the shaking or the mounts would be able to crack the housing.

Does anyone have any ideas?

[pocket-rocket]

I wonder if someone before you grabbed a flywheel for an older engine and put on it. 87 was the year the RWD engines went ton internally balanced instead of using the flywheel to externally balance it. If need be, Rockauto.com has them.

RHINO PAC Part # 167652
LT; Casting # 14100560
Sport; Casting # 14100560

$82.79

[german_cargo]

hmmm... yeah, that's certainly a possibility.

I read it on here yesterday but now I can't find it... how do you tell if its internally balanced again? Is it the one piece rear main seal? The tranny guy that put it in offered right away to get it fixed again for free and since there are so many different notions of if its internal or external on the parts websites, I thought maybe I could help him out and tell him for sure how to find out since I can't expect him to be a 2.8 expert.

Isn't there a specific number or letter in the casting number on the block as well?

[pocket-rocket]

About 1/3 of the way down on http://60degreev6.com/content/60%C2%BAV6_Family_Tree says this about '86s:

* Introduction of TBI (Throttle Body Injection) on S-10's only, which consisted of a 2 bore throttle body perched atop the engine much like a carburetor. One injector above each bore delivered fuel. Each bore measured 1-3/8"
* OBD I computer system introduced with TBI models
* Mechanical fuel pump is replaced with an electronic in tank pump
* Engines use a fully electronic ignition
* All engines now used large valve heads
* Engines on S-10's used a combination vee belt and serpentine setup. Water pump was still standard direction
* F-bodies now used a full serpentine belt system with reverse rotation water pump.
* Horsepower 125 (TBI only)
* Torque 150 (TBI only)
* Compression Ratio 8.9:1

And on '87s:

* Full serpentine belt system
* Timing cover and oil pan receive changes. There are no longer oil pan bolts in the timing cover. Oil pan gasket is one piece rubber.
* Water pump is now reverse rotation due to the serpentine belt system.
* Internally balanced crankshaft introduced. Cranks are all cast with reluctor wheel but the system is not used for spark delivery. Some engine still remain with external balance. Hit or miss across all RWD models

What sucks is on '85s it says this:

Switch-over year to larger main journal blocks mid-year main journals now measure 2.648in/67.25mm. Some S-Series vehicles still used small main journals and 2 piece rear main seals. All EFI engines like in the Camaro were large journal crankshafts with one piece rear seal.

which doesn't help identify it by a rear main seal since you are running an 87. As for a casting number, I have no clue, but I have bolded stuff that I think might be able to help. On the other hand, the last line saying that internal or external balance is hit or miss is kind of a kick to the groin for your year.