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MG MGB GT V8 Factory Originals Technical - Buick 3.8 V6 similarity to rover V8

Folks,
I was just reading the thread about the gearboxes and a guy mentioned the Getrag box. In oz for a short time the 5 spd Getrag box was used in tandem with the Buik V6 - 3.8 we have in our GM cars. Does anyone know how similar the engine backplates are? I believe the V6 is a variant of the original Buick V8 ( the rover) Will the buick V6 bolt to a rover V8?

Is this a future source of engine plates and gearboxes?

Many thanks
Allan

No- the Buick adopted a bolt pattern known in the US as the BOC- used on Buick, Oldsmobile, and Cadillac- in the mid 60's- the design does not bolt to the Buick aluminum V8 or the derivative Rover V8
greg fast

Thanks greg
allan

Greg,

I wasn't aware of the Caddy interchange. Around these parts we just call it the BOP bolt pattern.
Carl Floyd

If I remember correctly, the Pontiac bellhousing pattern is the same as Chevrolet, and Buick Olds and Caddy share a similiar, but different bellhousing bolt pattern (IIRC, 6 bolts, at approximately 9,10,11:30, 12:30, 2, and 3 o'clock.) The 10 and 2 o'clock positions are different. The BOC bells will bolt to the Chevrolet-Pontiacs, and vice versa, but will only attach at 4 places. There are adapter plates (1/8" steel, with welded nuts) to cross bellhousings back and forth.

I think BOP refers to the shared aluminum V8, used on these three model lines in the 60's. Being used on the Rover also, I refer to it as a BOPR
greg fast

All that I have read on the subject stated each division of GM built their own transmissions until 1964 when Buick, Oldsmobile and Pontiac were told to share a bell-housing pattern and that transmissions would come from an outside manufacture. The motor in question was produced by GM from 1961 until 1963 and having to remake the block of a motor that they had difficulty producing anyway to comply with the new bell-housing pattern could have been an additional reason to drop it. Buick introduced the iron V6 in 1963 using the same bell-housing pattern as the 215, but that motor they reworked to match the new BOP bell-housing requirement. For some reason Chevrolet and Cadillac were allowed to continue to use their same bell-housing pattern as before. Why they developed a new BOP rather than going to the Chevrolet pattern could have to do with the starter and oil pump positions. GM did cast the aluminum block around steel cylinder liners and there was shifting that ruined as much as half the motors and they would not know they failed until the motor was nearly complete. Rover was much more successful inserting the liners after the casting so was spared the horrible scrap ratio suffered by GM. Only successfully cast GM blocks were installed in cars so that need not be a concern when choosing Buick vs. Rover.
George Champion

Thanks George. I knew something like that had happened to the blocks. I wasn't aware that they were all caught during assembly.

Never heard of BOC. Its BOP - Cadillac always did whatever they wanted to do. Usually "slightly" different, but never a complete redesign.
Jeff Schlemmer

Would anyone know of the whereabouts of any dimensioned drawings of the various bellhousings (Rover/215/BOPR, BOP, & BOC) and respective bolt patterns?

Dom
Dom

This thread was discussed between 20/06/2005 and 28/06/2005

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