Blueprints for the BOPC, early Pontiac and Chevy bell housings

[Todd McCreary]

Chevrolet - specced from back of engine block



pre-1964 Pontiac - specced from front of trans, starter is driver side


I was wondering of any of you fine gents would have the blueprint for the Rover / 215 bell?


Here's the BOPC bell from the Speedtalk forums.  I know youns machinists like to get all fancy dancy with your dimensioning, but what kind of a goomba doesn't reference the centerline of the crank to his reference point?  Maybe I'm blind, but I'm just not seeing any dimensioning arrows going to either the vertical or horizontal axis of the crank c/l.

[MGBV8]

Couldn't find anything on the 'net.  Many years ago Dan LaGrou displayed the actual GM blueprints for the 215 engine.

Here's the Forum to ask:

http://www.cnczone.com/forums/general-metalwork-discussion/72914-cad.html

[BlownMGB-V8]

That Pontiac pattern would be the old BOP that the smallblock Buicks used. 300 Buick and early Buick V6, I think the Mark I and II  engines.

Jim

[Todd McCreary]

That Pontiac pattern would be the old BOP that the smallblock Buicks used


No, the starter is on the driver side, it's Pontiac ( you'll notice that the print mentions 389 and 421 ) specific.  That's why I made a point of noting that, the Buick / Cadillac starter is on the passenger side and is NOT oriented the same as the O / P starter so you can't just flip the pattern 180 degrees through the vertical axis and make it work.

That's why dual pattern bells have starter kickouts on both sides of the bell.

( got rid of some inaccurate info that Joe hit me with a clue bat for )

[joe_padavano]

The Pontiac drawing above is the old, pre-1964 Pontiac bellhousing, NOT the BOP bellhousing.  All of the 1964-up motors have the starter bolted to the block, not the bellhousing.  Only the FWD TH425 (Toro/Eldo) trans has the starter bolted to the bellhousing, and that's only because the design of the trans precludes the use of the normal block-mounted starter.

Also, only the Buick V6 motors through the 3800 Series I family use the BOP bellhousing.  All Series II/III motors use the 60 degree metric bellhousing (yes, even in RWD applications) that was originally used on the Chevy 2.8L V6 motors.

[Todd McCreary]

That's good information Joe, thanks.

Don't suppose you'd have the Rover or standard BOPC patterns, would you?

[Todd McCreary]

Here is one of the BOPC bells ( kickouts for both starters ) that I was talking about.  This would not be considered a 'dual pattern' bell, because it does not have holes in the bell pattern to bolt it up to a Chevy block.



You can clearly see both the difference in starter clocking that I was talking about as well as the fact that there are no holes for starter attachment on the bell that Joe was talking about.

[BlownMGB-V8]

There is also one which only has the starter bulge on the right (as in photo above) for Buick engines such as the 300, 340, 350, 400, 430, 455 and early V6. The double bulge bell can be used in an MGB by sawing off the bulge on the left, as we did in the MG-Roadmaster. If desired it can then be closed off by TIG welding a plate over the gap but is not required by any means. These bellhousings can generally be picked up for somewhere around $50-$100 and are pretty common. The early V6 also has a cable operated clutch version, I believe the cable comes in from the front which means that the pivot bolt would be on the opposite side. That might be useful for a slave cylinder mounted back beside the transmission.

Jim

[mgb260]

The 75-80 H body cable V6 bellhousing with slave is what Mike Moor did on his. Very nice setup, a lot  like the Ford version.

[mgb260]

There are dual pattern Chevy/BOP bellhousings. 76-81 GM midsize and Camaro with Buick 3.8.  The bottom 2 bolts and dowels are the same. Transdapt has inexpensive adapters to go back and forth also. The GM 2004R also has the dual pattern. Here is a pic of the 2004R, can't find a pic of the manual one but have seen it.

[Todd McCreary]

That pic is mislabeled, Jim.

I know for a fact that it's the Chevy pattern that uses the two holes directly above the dowels where your pic has them colored Blue and asserts them to be BOPC.

It is correct for the upper sets of holes.

Here is a pic of a Chevy 350 ( L ) and a Buick 350 ( R) side by side:

[mgb260]

Todd, You are right. The 2 above  the dowels. Colors are reversed.

[Todd McCreary]

Got authorized into the Speedtalk forums and picked up the BOPC pattern.  Added to first post.