On the face of it it’s easy if you want to make your Triumph
Herald hotter – just drop in a GT6 or even a TR6 engine! That’ll certainly do
the trick, but there’s a lot more to slipping in that straight six than you’d
credit – we’d sooner find a Vitesse and enjoy the other benefits this car has to
be frank. Also with some selected mods you can make the Herald as quick and a
lot nimbler plus it would make a better candidate for certain motorsport
classes; Heralds were pretty capable rally cars in their day, winning the Tulip
Rally outright. Here’s how to make yours well and truly blossom.
Triumph Herald
1200 design was by the Italian stylist Giovanni Michelotti, and the car was
offered in saloon, convertible, coupé, van and estate models.
Before You Start
First things first; ensure that your car is solid and safe.
The chassis is prone to rust but the good news is that you can weld in sections
or even buy new frames and riggers. Mechanically (apart from a Morris Minor)
you can’t get a simpler car; the forward-hingeing bonnet allows magnificent
access to the engine and front end and parts availability is excellent. The
main concern is that old Triumph foible of crank thrust washers and these need
to be okay before you tune; naturally an engine overhaul would see these
replaced with the latest aftermarket types as a matter of course.
Hotting Up
The engine first started out as a ‘Standard’ unit of just
803cc and ended up almost double the capacity! It’s a simple, sturdy unit with
plenty of potential; eclipsed by the A-Series but extremely popular in the
States. Discarding the 948cc unit, you’re best off starting with the 1147cc
‘1200’ or best of all 1296cc ‘1300’ unit. While they all share the same 76mm
crank throw, you can’t bore the engines out to their next respective sizes
without hassle. And while the blocks look similar, the early 1200 flat chassis
cars differ in engine mount fittings.
Triumph Herald
1200 Race Car Engine - 1500cc Spitfire decked block
That said, you can overbore a 1296cc unit by 40 thou and
some have even stretched the 1500 by as much as 60 thou to 1604cc using TR6
pistons – but seek expert advice first as this employs custom roads and liners
from the USA and they don’t come cheap!
Some engines (made from 1961-65) featured weaker con rods
and are not suited for dramatic tuning, so be warned! One of the reasons why
specialists hark on about the 1296cc unit, apart from its larger size, is the
far more efficient eight port cylinder head used. Sadly, this can’t be fitted to
the smaller units as the stud pattern is different.
Pre 1296cc engines featured a Solex carburettor with an
integral inlet/exhaust manifold and the only mods you can carry out is either fit
a Weber carb (you may strike difficulty finding a manifold or adaptor) or fitting
the twin carb set up from a Spitfire or Herald S along with the exhaust
manifold. Bear in mind that if you don’t go the full Spitfire tune then the
jetting will be wrong but these are easy enough to revise.
One peculiarity is that the 1200 Herald head features larger
valves than the ‘sportier’ Spitfire! This means that it already has more scope
for further modding, although without a Spitfire camshaft (usefully made racier
when the Mk2 Spitfire was released) and distributor (advisable to fit electronic
ignition), the gains will be moderate but worthwhile nevertheless for road use,
especially if you raise the compression ratio by having 40 thou skimmed off the
head. Incidentally, fitting a camshaft with the engine in situ is quite easy as
it can be pulled out at the front once the grille rad and head are removed,
while you may need a Spitfire downpipe to mate with the stock exhaust. Better
still use the factory Mk2 Spit tubular extractor manifold if you can find one,
that can at least be made to fit to most systems.
Rear suspension
always needs attention at all stages of tunes
The 1300 engine is regarded by most as the best and this
alone in an earlier car will give a useful power gain. If you don’t find a less
rev happy but lustier engine, then the single carb 1500 engine is a good pick,
gives Spitfire-like pace and looks completely standard.
With a fully modded head, racier cam and a single Weber DCOE
carburettor (can’t use twins due to Siamesed inlet ported head) you can muster
up to 90bhp or so from a 1200.
The 1300 unit saw up to 130bhp in full race tune in its
heyday but it will be a pig for road use; aim for a milder tune on Webers and
you’re still looking at over 100bhp or say 80-90bhp if using the standard
1.25in twin SU carbs. Webers are expensive instruments so the twin 1.5in Stroms
found on Vits, GT6 & 2000 saloons are a useful upgrade if you can find a
suitable manifold, but speak to your tuner as some advocate using 1.5in SUs
which fit much more easily and give much greater needle selection.
Moss sells Triumph Tune and Piper cams catering for road,
fast road and Race for around $302.51 incidentally, and a range of cylinder
heads in the region of $1,512.53 as do some specialists like Moordale.
