C2 bell housing installation

[Steve D.]

There are two studs on the block to align the bell housing before bolting. I had always assumed that alignment was their only function. However, someone recently told me that shifting problems can result from the studs not extending out far enough. Does this make sense?. It seems to me that once the bellhousing bolts are torqued down, it would not matter whether the studs were even present or not.

Steve

[Paul Reynolds]

Re: C2 bell housing installation

There's more slop in those bolt holes than you may think. The dowels accurately center the bellhousing. The bolts just hold it on. Keeping the bellhousing accurately centered keeps the transmission input shaft centered. An off center bellhousing will cause undue wear on the input shaft bearing and pilot bushing.

Stock bellhousings are pretty accurate as opposed to aftermarket stamped/formed steel scattershields, which sometimes need offset dowels to get them properly centered.

[John H.]

Re: C2 bell housing installation

Steve -

The dowel pin holes in the block and in the bellhousing are VERY closely toleranced to the crank and transmission centerlines, and the fit of the exposed portion of the dowel pins is virtually line-to-line in the bellhousing holes, to ensure that concentricity is maintained even if the bolts loosen. I wouldn't depend on just the bolts to maintain concentricity - too many ugly things can happen to pilot bushings, clutches, and input shaft bearings.

[Joe L.]

Re: C2 bell housing installation

Steve-----

The dowel pins are critical for bellhousing alignment. As far as problems created by the dowel pins "not extending out far enough", it is possible for that to be a problem. Most, but not all, bellhousing alignment dowel pins have a taper on the end. If the dowel pin is pressed into the block too far so that it's full diameter section is completely below the rear face of the block and only the tapered section remains outboard of the block, then the dowel pin will be completely ineffective in performing its function and might as well not be there, at all. However, as long as some of the full diameter of the dowel pin extends outboard of the rear face of the block, the dowel pin will function perfectly and just as intended.