what is the diameter of a small and large journal on the 2.8 v6?

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CMSII

 

i don't think the 2.8 motor had a large or small journal. They were probably all the same size. Smallblock chevys when from small j to large j (a difference of .1 inch) in 1969.

 

Actually (re: SBCs), they went from 2.30" main (2.00" rod) to 2.45" main (2.10" rod) in '68.

The 2.8 V6 (check with the V6 board here) IIRC uses the same size mains, what ever that is. Or are you asking about the main AND rod journal sizes?

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George P. Lara
1984 Z28
2001 SS #0391
SCCA, SCFB, SC3GFB

 

i was thinking it was when they went to 350s. but i guess your right, 350s really started in 68. For some cars at least.

 

Hey guys, I found my manual. For all you 6 bangers out there the 82-84 2.8 came with a "small journal" crank.its the mains that are small.2.4937" these cranks are junk, and impossible to find at even a junkyard, They went to the later style in late 84. the large journals hold up better, they are 2.6473" I didnt know what year engine i found, and couldnt find my book. the large journal block will take a 3.4 crank, and its one hell of a lot better crank

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CMSII

 

Actually, I think the large main crank started in mid-85. The small main journal cranks had the first and last journals sized the same as everything on the large journal crank.

Internal balancing of the 2.8's crank started in '87, meaning, you could change flywheels. Otherwise you either keep your old flywheel with your old crank, or have a machine shop externally balance the whole thing. All harmonic balancers were neutral balanced.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

I guess it dont matter cuz my machinist just told me to take that junk somewhere else, he quit diong small journals last year and had 2 large ones fail last month. no more. he dont do 400 small blocks or 290 fords unless you buy aftermarket heads. picky picky picky

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CMSII