Triumph TR7

Chris fi­nally gets around to fit­ting elec­tronic ig­ni­tion to the TR7 – the im­prove­ments are star­tling

Classic Car Weekly (UK) - - Contents - CHRIS HOPE FEA­TURES ED­I­TOR

The TR7 has bro­ken down twice in the year or so I’ve owned it and on both oc­ca­sions it’s been as a re­sult of worn points and con­denser. I be­lieve that re­plac­ing them is straight­for­ward, but on the TR7 the po­si­tion of the dis­trib­u­tor can only be de­scribed as lousy, ob­scured on all sides by the engine man­i­fold, cylin­der head and bulk­head-mounted bon­net re­lease. In each case, th­ese break­downs re­sulted from at­tempts to ride my luck; ‘It’s an awk­ward job’, I thought, ‘I’ll put it off un­til next week­end.’ The next thing I know, I’m sta­tion­ary in a layby on the A47.

A few weeks ago I de­cided that there wasn’t go­ing to be a third breakdown and after tak­ing ad­vice from Si­mon at Rob­sport (01763 262263, rob­ booked my TR7 in to be con­verted to Lu­me­ni­tion elec­tronic ig­ni­tion.

There are myr­iad ben­e­fits to elec­tronic ig­ni­tion (which I’ll get on to later), but my pri­mary aim was to re­move from the ser­vice sched­ule some­thing I saw as be­ing in­con­ve­nient – chang­ing the points and con­denser shouldn’t be as fid­dly as it was prov­ing to be.

With the TR7 once again in Rob­sport’s work­shop, me­chanic Jake be­gan by po­si­tion­ing the pis­ton vis­i­ble with the oil filler cap re­moved at top dead cen­tre, achieved by turn­ing the engine by hand at the crank with a ratchet wrench and a chunky 38mm socket (I need to buy one for my tool set). He then re­moved the dis­trib­u­tor from its sunken po­si­tion in the engine bay and set about re­mov­ing its in­nards.

The TR7’s dis­trib­u­tor is a Delso unit with a ro­tor arm that sits on top of a disc – this is re­tained, with a mount­ing plate for the op­ti­cal switch at­tach­ing to the breaker plate and a plas­tic ‘chop­per’ (a fan-like disc with four tabs to disrupt the in­frared beam be­ing sent by the switch) at­tach­ing to the main­shaft, un­der the ro­tar arm. Break­ing the beam is what trig­gers the ex­ter­nal power unit to fire the coil – this mo­d­ule needs to be lo­cated in the engine bay, so there is some drilling re­quired (Jake at­tached it to the in­ner wing in this case). This form of op­tronic ig­ni­tion re­tains the dis­trib­u­tor’s vac­uum and me­chan­i­cal ad­vance mech­a­nism, en­sur­ing that engine tim­ing is as per the orig­i­nal man­u­fac­turer’s spec­i­fi­ca­tion.

With the Lu­me­ni­tion kit now in place, the fi­nal job for Jake was to re­place the dis­trib­u­tor and turn it by hand, us­ing a tim­ing light to en­sure that it was in the cor­rect po­si­tion. It was then taken on a quick test-drive to make sure that all was work­ing as it should, while I had a play with one of the cars Rob­sport had for sale – a Triumph Stag pow­ered by a Ford V6 engine. Read all about it on page 57.

Leav­ing Rob­sport and head­ing back up the A1 to the CCW of­fices, I was amazed at just how much the Lu­me­ni­tion kit had im­proved throt­tle re­sponse, par­tic­u­larly at cruis­ing speeds. It’d prob­a­bly be over­stat­ing things to sug­gest that it’s im­proved per­for­mance, but the engine does seem to run notably smoother than it did be­fore and is most def­i­nitely more com­fort­able at higher revs than it was on the old con­tacts breaker set-up. What’s more, on a morn­ing the TR7 is now far hap­pier start­ing. Be­fore, the four-pot would churn sev­eral times be­fore it awak­ened. Now it fires al­most in­stantly.

I’ve been as­sured that I’ll see bet­ter fuel econ­omy now too – I’ll let you know the next time I fill up whether there’s been an im­prove­ment, but even if I don’t see a dif­fer­ence, I’m still thrilled with the re­sult.

Owned Since April 2016 MILEAGE SINCE LAST RE­PORT 429 TO­TAL MILEAGE 100,547 LAT­EST COSTS £160 (Lu­me­ni­tion kit)

Back in the work­shop, this time to be con­verted to elec­tronic ig­ni­tion.

can you see it? with the dizzy cap off, it’s ob­vi­ous that there are few worse places to lo­cate a dis­trib­u­tor.

an op­ti­cal switch and ‘chop­per’ disc re­place the points and con­denser.

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