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Re: Engine swap 1147>>1500

To: Scions of Stanpart <triumphs@autox.team.net>
Subject: Re: Engine swap 1147>>1500
From: Andrew Mace <amace@unix2.nysed.gov>
Date: Wed, 16 Aug 1995 11:07:17 -0900 (PDT)
On Wed, 16 Aug 1995 CWNicholls@aol.com wrote:

> In a message dated 95-08-16 00:06:16 EDT, Killjoy@aol.com writes:
> 
> >Recently I acquired a 1500 engine and 4 speed gearbox (and many other parts)
> >from a '72 Spitfire, and I'd like to put the engine into my '67 Mk2 while
> 
> This 1300 (the '72 was a 1300cc engine, 1500's start in 1973) is the worst of
> any Spitfire in terms of power.

True. The first of the U.S.-spec. low-compression Spitfire engines, 
rated at something like 48 net hp. That said, though, it's not the worst 
thing in the world. I've helped take care of a good friend's 1972 for 
years, and that engine has never given him any trouble beyond needing 
occasional tune-ups!


> >First:  Are there any tricks I need to know about dropping the 1500 engine
> >into the engine bay?  No cutting required, I hope.  (Because I'm not doing
> >any.  If it needs cutting, I won't do this little project.)  Standard motor
> >mounts will work, won't they?  Will I need a custom exhaust manifold, or
> will
> >a standard production unit work here?
> 
> Goes right in, no problem!

You could probably get away just fine using a Mk.3 or Mk.IV exhaust 
system, or at least the headpipe from either and whatever you like beyond.
> 
> >Second:  Assuming that the first has easy answers, are the transmissions
> >different in any significant way?  Or will the (weaker) 1500 engine bolt
> >right up to the gearbox of the 1147?  How about clutch, slave cylinder,
> etc.?
> > If I change, am I asking to have a new driveshaft made?
> 
> May need to change the throwout bearing, arm, etc. to the 1500 setup.  Check
> them visually, it depends on the clutches.  If your 1147 is really a MkII,
> this probably won't be neccesary, but maybe better safe than sorry.  I think
> the slave is the same.

If the "new" gearbox is in fact from a 1972, its outward appearance 
should be identical to that of your Mk. 2. There are two important 
differences: a. you gain a synchro first gear with the later box; and b. 
you'll need to swap the u-joint flange on your present driveshaft for 
the larger one that comes with the 1972 (did you get a prop shaft or the 
rear axles from the 1972? Any of those flanges will work.
 
> >Third:  Is it worthwhile/advisable/possible/crazy to exchange the
> >differential units for the year or so that I will be running the 1500
> engine?
> > I'm not at all concerned with performance issues, I only want to make sure
> >nothing gets chewed up in there.  If I can leave the original there, that's
> >all the better.
> 
> Don't bother

Absoutely right, Clark! You could open up the proverbial "can of worms" 
here. The 1972 uses the same 4.11:1 ratio, in a unit with stronger inner
axles, bearings, etc.  Simply swapping diffs won't work, though. The
later one will bolt in, but it has only four threaded holes on top, for
mounting the later-style swing spring. Of course, you could use the
complete driveshaft, diff and half-axles from the 1972 in your Mk.2,
along with the fatter front sway bar. It all bolts right in.

If, though, your ultimate goal is to keep your Mk.2 "stock," by all 
means don't bother with anything more than the engine swap, or at worst, 
engine and transmission with the u-joint flange from the later 
driveshaft on your present driveshaft.

> 
> >Fourth:  Anything else?
> 
> If you use the 1500 transmission, the rear flange bolt pattern is larger, so
> your driveshaft won't bolt up.

Right, as noted above. The early 1500s (1973-74) in the U.S. continued
the use of the three-rail, all synchro transmission introduced with the
Spitfire Mk. IV; they all have that larger output flange. It was around
1975 in the U.S. that we got the new-style transmission, which bolts up
but has different splines on the input shaft. 

> >I got this engine for a pittance, and would like to put it to use this way
> >before I find a car to install it in.   I think that this should be an easy
> >exchange, but I thought I'd seek higher wisdom before I open my toolbox!

Bottom line: it is, and it isn't. It is pretty much all bolt-in and 
easily reversible. Toughest part is probably coming up with a linkage 
from gas pedal to carb, about the only area that isn't absolutely "bolt-in."

If you're at all unsure of the components you have, run the serial 
numbers of the bits by me and I'll be glad to help you identify them.

Andrew Mace
10/Herald/Vitesse (Sports 6) Consultant
Vintage Triumph Register
amace@unix2.nysed.gov



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