[DML] Re: B280 heads on B28 engine

["content22207" <brobertson@xxxxxxxxxxxx>]

I envisioned Robert trying to swap heads as complete units, in which
case they would have everything to do with valve timing. Speaking of
which: are you sure B28 cam lobes interchange with B280 valves and
springs? They definitely differ from B27 (are higher and longer duration).

Everything I've read online pegs B280 displacement at 2.85 liters --
same as B28.

Compression was bumped all the way to 10.5:1 (taller or flatter pistons?).

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, wingd2@xxxx wrote:
>  Bob,
>  The heads from either engine have nothing to do with the valve
timing. It's 
> the camshafts that control valve timing. And the camshafts from
either engine 
> will fit either set of heads, so you could take the B280 heads and
put them on 
> a B28 engine by using the B28 cams. The cam bearing bores and
centers and all 
> the valve locations and rocker arm spacing is the same and the parts
will 
> swap from one head to the other. The timing chain sprockets will also 
> interchange. You are correct, the intake ports are different between
the two sets of 
> heads, and the intake manifolds cannot be swapped. So a B28 intake
will not 
> directly work on B280 heads.  A few other problems with this head
swap are - the 
> cylinder diameters ARE different between the two blocks, both ID
bore and OD 
> sleeve size, so gaskets and mating/sealing surfaces are different.
The B280 heads 
> have bigger combustion chambers, which will lower the compression
ratio if 
> installed on the B28 engine. The B280 heads also are not machined to
accept the 
> ignition distributor from the B28 engine nor are they machined to
accept fuel 
> injector nozzles from the K-jet system. The head bolt pattern is the
same, 
> along with the valve cover and timing cover bolt patterns. The
exhaust ports are 
> also the same bolt pattern. So you could physically bolt a set of
B280 heads 
> onto a B28 block, but installing B280 heads on a B28 engine will
not, in itself, 
> give any performance gains. Just a lot of work to have something
"different." 
> 
>   Marty
> 
> 
> [Non-text portions of this message have been removed]




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