David:
Think of the cross-flow head as the basis for a dramatic change in B series
engine potential. Do they live up to any of their claims? It depends on
who is writing the marketing blurb, and what your expectations are.
If you take the cross-flow head out of the box, bolt it on an engine, then
bolt on some kind of carburetion you are probably going to feel ripped off
for all the money you spent. Either that or you are going to go out of your
way to justify the expense to yourself when the improvement isn't really
there and the engine still runs badly.
On the other hand, if you spend a bit of time cleaning up the production
ports, do a bit of smoothing. Determine the correct carburetion for your
driving needs. Increase the compression a bit. Install a correctly timed
cam to match the rev range and increased flow potential. You will end up
with an engine that performs far better than any modified siamese port
headed one could. The engine will have more power and be far more
tractable, both major pluses for street use.
I think the best A-B comparison was done (I think) in MG World a while back.
They took a fully modified hill climb/vintage race MGB running a DCOE Weber
and ported head. Road tested it and ran it on the dyno. They then bolted
on a crossflow head (out of the box) and a pair of DCOE Webers. The result
was a power increase, but more importantly much, much better low end
tractability on the road test. The peakiness of the race engine was gone,
but the power remained.
Is it worth it?? Anytime you move from stock, figure on cubic $ to make
minor improvements. Personally I think a nicely tuned stock MGB is a very
fun economical car. It's going to take a lot more than just bolting a chunk
of alloy and bigger carbs on the car to make it a better car. It's going to
take an investment in love, time and technical expertise. That tends to
always pay for itself.
Me, I have two of the heads and can't wait till I get a chance to play
with them. I think they are the niftiest thing to happen to the B Series MG
since sliced bread, but then, I'm a nutter and think twin DCOEs are v. cool.
As can be seen by the attached link. I just had to see if the twin DCOEs
would fit in a Magnette.
http://www.mgcars.org.uk/mgccz/Pictures/monthly2000/flowhea4.jpg
In answer to your question about the 2L conversion. I am not a big fan of
this. I think you are better off by using the +60 piston which was designed
for the engine and has adequate safety margin. I picked up an SCCA over
bored cheater motor some time ago that ended up failing due to corrosion in
the water jacket penetrating the cylinder wall. Once you have to replace
every wear part and a block due to water contamination, you don't want to do
it again.
Hope this helps and has proved interesting
Kelvin.
>
> Folks,
>
> Do the aluminium cross-flow heads for MGBs live-up to any of their
> claims? Are they an upgrade, or an expensive placebo?
>
> Also, does a 2L engine really do much more than using the
> +060" pistons
> for 1868cc's?
>
> Thanks,
>
>
> David Randall
> '66 MGB-GT
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