Bill, points well made. As one who has build several Rover motors and
transmissions and is planning a Rover/MGB conversion with much preplanning, I
can
offer some responses. The B chassis has limits re the hp/torque that it can
handle. The late 4.6 Rovers if pumped up are probably more than is appropriate
for the chassis. The 3.5/3.9/4.2s are ideal in terms of hp/torque. A well
turned out 3.9 or 4.2 will make 225-250 hp with plenty of torque. The Rover 5
speed is servicable and long-lived if you don't feel a need to abuse it with
drag
race shifts. The major problem area is exhaust routing. There just is not room
for a proper system. Other options are the Ford V8, with additional power,
weight penalty, more fabrication to install, but a narrow V with more room, one
of the V6s, all of which have negatives, or a 90s 4 cyl which makes power, less
torque, and will be pricey, with more unaddressed problems to solve. The high
reving 4 is probably more in keeping with the character of the B and does have
appeal. I would ultimately like to build something that will capture that same
character--a 3.5 built to turn serious revs and stay together, less torque but
plenty of top end power, and it will have that one special characteristic that
no
4 or 6 can give.. It will sound like a hot V8. Hey, I missed out on southern
cal in the 40s and 50s, but still love the sound. John
WSpohn4@aol.com wrote:
> The purists need not read on nor comment - I can sympathise with the
> sentiments that have you view engine swaps with distaste, and in fact agree
> that it is a shame to do such things to cars like MGAs, which are now scarce
> and merit better treatment - I am talking here about swaps into MGBs,
> originally a half million potential donors, and arguably no loss if a few go
> the engine swap route. I would add that as the best candidates for a swap
> are the early cars, without the unfortunate suspension foibles of the Rubber
> Ducky set, and as the early ones are now starting to be a little thin on the
> ground, we will reach a point, some day, where the objections to using up a
> nice early car for such a project must be taken seriously.
>
> In any case, I was wondering about the common choice of the BOP V8 as an
> engine for such swaps. I understand that there are some things in favour of
> such a choice - the factory did it on the BGT, so there is precedent, and the
> techniques are well known, so it is a less scary road for the tyro swapper.
>
> In fact, though, aside from the weight, the BOP engine isn't that hot a
> choice, for several reasons. The output per litre is low (I know that they
> quoted 200 old gross bhp - do you have any idea what that equates to in
> modern terms?), unless you tune the engines, or locate a later version. The
> Rover SD1 versions are pretty scarce, and the injected engines don't lend
> themselves to tuning. The better versions developed by TVR, larger and with
> higher output, are likely almost impossible to locate and expensive if you
> can. Which leaves you with the original BOP versions, back before Rover spent
> all that money refining them and fixing some of the problems they had. Not
> the best of all choices, IMHO.
>
> There is no shortage of rather interesting donor vehicles out there, if you
> don't mind looking beyond the Rover. Many of the current Japanese stuff,
> going back a decade or so, if need be, is compact and has excellent power
> outputs - the carbon/kevlar bodied MGA coupe/choptop that was for sale a few
> years ago used a Toyota DOHC 4 cylinder - great stuff if you want 25 more bhp
> and another 1000 rpm on tap.
>
> The Honda VTEC engines are very interesting - the new one putting out 240 bhp
> in a sports car is just the latest example - how would you like that in a
> 2000 lb car instead of the 27-2800 lb vehicle that they installed it in?
>
> If you want to go bigger, or more American, there are several decent,
> somewhat old tech V6 motors around, including the 3.8 Buick, and even better,
> the little 60 degree 2.8 to 3.4 GM range. I use one of these in my Fiero,
> fairly highly modified and turboed, putting out around 300 bhp - imagine that
> in a 'B'. And the block on the V6 is no longer than the MGB block.
>
> If you attempt a new style of engine, you needn't be scared by the
> electronics. You can get a used engine complete with ECM (computer) and
> senders and you just have to make sure that all the senders get hooked up or
> tricked into thinking they are. You get the advantages of modern technology
> (you can even get an ECM that is customisable, and programmable from a
> laptop), with the attendant better running and lower gas consumption.
>
> I just thought I'd mention the possibilities and perhaps get a few people
> that might be thinking about swaps to examine some other possibilities,
> rather than automatically taking the well travelled road.
>
> Cheers,
>
> Bill Spohn
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