Harry Firth The XR GT and I “W

Be­fore his pass­ing in 2014, Harry Firth penned his rec­ol­lec­tions on the XR GT for the Ford and I oneshot mag­a­zine. Here Harry re­calls his de­mon Bathurst 1967 tweaks and out­lines his vivid rec­ol­lec­tions of how the race panned out.

Australian Muscle Car - - Immortal Muscle -

ork on the new XR GT was in progress as early as 1965. My role was devel­op­ing a ‘po­lice spe­cial’ as suit­able cam­ou­flage – Vic po­lice light blue and very stark trim and no em­bel­lish­ments such as chrome wheel trim and exotic dash. The eco­nom­ics of this was very sim­ple: 1000 GTs only would be ex­pen­sive to make and would tie up a pro­duc­tion line. But add to that base build an­other 2000 po­lice spe­cials and costs go way down. This is how the XR GT was put on the mar­ket at a very rea­son­able price. An au­to­matic ver­sion was run in the BP Rally and the Surfers Par­adise 4 Hour race for se­ries pro­duc­tion cars. It led the Surfers race in the dry, but fell back to sec­ond in pour­ing rain. Be­ing the driver, it was easy to put the lessons from this into the XR GT de­sign. I also did test­ing on You Yangs prov­ing ground, us­ing the 70,000 mile test cir­cuit, which was very sim­i­lar to Bathurst – so the sus­pen­sion, brakes and han­dling were com­pletely race and rally tested. The pro­to­type went around in two min­utes 39.5 sec­onds against the 200 cu­bic inch coupe’s time of 2m44.3s. It did 124mph down the road out­side ground, so it was a rea­son­ably de­vel­oped race pack­age in 1966 to early ’67.

“But some things that should have been easy proved dif­fi­cult. For in­stance, at You Yangs I was test­ing the pro­to­type XR GT and one of the rub­ber lo­ca­tors for the front sway bar came out – they didn’t have any re­strain­ing clips. So, no sway bar, and I spun it down the hill at about 120mph. Not good! I told the Ford en­gi­neer and he said: ‘nah, couldn’t hap­pen!’ All it needed was a small strip of steel to stop it com­ing out, but the en­gi­neer re­fused to ac­cept this. A month later, he’s driv­ing one him­self out on a high­way, and a rub­ber sway bar mount flew out, and he lost it! Very red faced, but they did put clips on it af­ter

that! Very sim­ple, but these peo­ple could be very dog­matic at times.

“Of course, there was no test­ing al­lowed at Bathurst as it was a pub­lic road. How­ever, a few did the oc­ca­sional moon­light flit at two in morn­ing and be long gone be­fore po­lice could make it to the moun­tain. Se­ri­ous of­fend­ers didn’t use Con­rod Straight as you could do that on any main road. If you did this on race week­end, the flag­gies camped on McPhillamy kept the soapy shower and washup wa­ter in four gal­lon drums on the side of cir­cuit and would spread this on the drift line for con­stant of­fend­ers. It pro­duced hi­lar­i­ous mid­night gy­ra­tions but never a se­ri­ous bend…

“The thing is that you’ve got to be able to stop. That is what held back the old Stude­bak­ers and other V8s at Bathurst, but they had other prob­lems too, like gen­eral un­re­li­a­bil­ity and ter­ri­ble han­dling – they were not good cars – and I made sure that that was not go­ing to be a prob­lem for us with the XR GT.

“Any­one run­ning an XR GT who elected to do their own prepa­ra­tion and not be ad­vised by us was mak­ing a se­ri­ous mis­take as I knew all the faults and fixes from all the test­ing we’d done. While the Geoghe­gans did elab­o­rate test­ing at Oran Park with Hardie Ferodo pads to try to go the dis­tance, I had made at Min­tex a new cooked base as­bestos sin­tered brass chip mix pad and rear lin­ings – M20 code so no one else had these. I elected to use them fully and change at half dis­tance. It was a sim­ple sum – one minute ex­tra on pit stop – two min­utes less on race time and no pussy-foot­ing on brakes at any time. We had full brakes for the last ses­sion – the Geoghe­gans did not.

“Very de­tailed work was re­quired on the 289 V8. This was be­cause the man­u­fac­tur­ing qual­ity was very poor. Core flash in the cylin­der heads had to be cleaned out or valve seats would dis­tort and en­gine would over­heat. It took 12 to 16 hours per head to fix this and re­mak­ing the valve seats gave me the chance to equalise the com­bus­tion cham­ber ca­pac­i­ties. The in­let and ex­haust ports at the valves were taken out to max­i­mum al­low­able size and the head was sur­faced to give max­i­mum spec­i­fied com­pres­sion ra­tio.

“Cylin­der bores had to be honed straight – .002 inch pis­tons and pins given proper clear­ance; the block was line bored for the main bear­ings to en­sure every­thing was straight. It was im­por­tant this was done, be­cause the crank­shaft off the pro­duc­tion line was very bad. It had to be ground – .010 inch mains and .030 inch big ends – to achieve cor­rect phas­ing and max­i­mum al­low­able stroke. Then it was as­sem­bled so pis­ton heights to the top of block could be mea­sured. I took the low­est one, and ma­chined the top of block to .015 clear­ance for that one and then took all rest to same deck height.

“Only af­ter these op­er­a­tions could you bal­ance the en­gine. The camshafts and lifters were good, and tim­ing cor­rect in en­gines. But the dis­trib­u­tors were com­pletely out. We fin­ished up do­ing an ex­change ser­vice on these with Ford – 12 at a time – be­cause I was the only one who had a dis­trib­u­tor ma­chine.

“When I ran the car along in lower gears to heat it up, I found the first and sec­ond gear shafts had no clear­ance and seized. So I had to ad­just the gears and make a spe­cial lube us­ing moly and lim­ited slip ad­di­tives Anglamol and Lubri­zol. Gra­ham Hoinville, my rally nav­i­ga­tor, was the lu­bri­cants per­son at BP so he was to mix up the gear­box oil es­pe­cially. We did some­thing sim­i­lar with the diff. The gear­box didn’t have a breather vent, so I made one by drilling a hole straight through one of the bolts that at­tached the out­put flange cas­ing.

“With the sus­pen­sion, you had to do about 3000 miles ini­tial run­ning to re­ally load up to sag the springs suf­fi­ciently. Ba­si­cally you’d fit the springs in a car and drive it around on rough sur­faces with four peo­ple in it. The sus­pen­sion mount­ings and points were all cor­rected and the hard­est rub­bers in spare parts fit­ted. The high­est of the run-in springs were put on the out­side driv­ers’ side of car, and the diff hous­ing was put in a press to give rear wheels a half de­gree of neg­a­tive cam­ber and 1/8 inch toe-in when as­sem­bled.

“I did have to ar­gue with the ARDC about the springs. I said, ‘Well, this is what I did. I ran it in over a course which in­cluded some rough bumps to re­ally make the springs work. You can’t say I’ve done any­thing to them. There’s no sign of heat treat­ment or any­thing on those springs, they look ex­actly the same as any other springs in the cars.’ We had done the same thing with the GT500. Also, as had been done with the GT500, ev­ery ro­tat­ing part of car was bal­anced.

“The ex­haust sys­tem joints were all checked for re­stric­tions and then re-welded. Noth­ing could be done to car­bu­ret­tor ex­cept to en­sure the cor­rect size parts were fit­ted. The en­gine wasn’t put on a dyno; it was tuned on the road out­side You Yangs cir­cuit and in­side.

“We made one red (Bob Jane and Spencer Martin) car, one white (for the Geoghe­gans) and one green car (Fred and me). All the rest were gold. They put 12 aside as press cars. On Sun­day morn­ing 9am on Bac­chus Marsh road (Gee­long to Bal­larat) I ran each one to make sure it did 125 mph. I was smart enough to tell the po­lice to come and see their new pa­trol cars so there was no ag­gro. These cars went to main race cir­cuits in each state: Calder, Ama­roo Park and Surfers Par­adise. I would test run them af­ter trans­port­ing and set a lap time. No journo broke this at any cir­cuit – even af­ter they swal­lowed their pride and had a few laps tu­ition.

“At Bathurst it took a few hours and slow laps to ex­plain to Fred Gib­son how to drive a tour­ing car at Mount Panorama and my way around the cir­cuit – he had only driven sports cars. But I thought he had the mak­ings and all he had to do was ex­actly he was told, not lis­ten to any mates – or think he knew bet­ter. Af­ter all, I had spent years find­ing the “way” and he had it on a sil­ver plate in ex­plicit de­tail. I said to him: ‘ap­proach Sky­line on the left of the road, look down­hill and see two peaks (hills) with sin­gle tree in mid­dle – aim for tree and go over top full chat. When you come to The Dip­per, go past be­fore turn­ing in – you can then take lip in straighter line, and not lift the in­side wheel and be go­ing quicker in straight line through next ess bend. Do­ing it this way, you will be 10mph faster down to For­rest’s El­bow. When you come to third hump (last) on Con­rod at 135mph, just tap brake on top of hump to keep nose of car down and air will not lift it air­borne. Then it’s just three hard presses on brake to Mur­ray’s. Give it a last press, and with the nose right down and still un­der brakes, give it a big flick into corner to swing tail and put foot hard on gas to fin­ish corner on power-steer and ac­cel­er­at­ing up Pit Straight. I never for­got the look on Fred’s face when he mas­tered all of this and found he was equal to Fatty Geoghe­gan, who was the lead­ing tour­ing car driver, whereas Fred, a young novice, could only get bet­ter.

“All the XR GTs had a carby surge prob­lem go­ing across mount when in high speed left-hand drift. But this was eas­ily fixed by rais­ing the out­side carby float 10mm. Of course, those who elected not to be told about such things and prepa­ra­tion in gen­eral promptly com­plained to Ford management about the lack of in­for­ma­tion – this in­cluded the Geoghe­gans – but Les Pow­ell of Ford quoted their ini­tial num­bers back. We had the job of mak­ing sure no one had any prob­lems.

“The start came and went, and the race went ex­actly to plan as far as we were con­cerned – clearly in the lead at half dis­tance and hav­ing an easy run. We had our own lap scor­ing and all knew ex­actly the po­si­tion. I left Fred in at last pit stop and all he had to do was as told on pit board. I let Leo nearly catch up (12 sec­onds) and then speeded Fred up a bit to 16-plus sec­onds – but to my con­ster­na­tion they gave Geoghe­gans the flag and we did 131 laps – one ex­tra!

“The mis­take was sorted out by 7pm and they had an­other pre­sen­ta­tion at Light Car Club of Bathurst rooms at the foot of Moun­tain (ED: ex­it­ing For­rest’s El­bow). It should never have hap­pened as oth­ers knew they hadn’t won – at one point they ran out of fuel go­ing up Pit Straight came through camp­ing park and back of pits to back into start of pit lane. This is where they were cred­ited with an ex­tra lap that they did not do. They should have been ex­cluded on the spot, but the in­fringe­ment was ig­nored by of­fi­cials un­der the ‘mates’ rule!

“Both my­self and Ford’s man­ag­ing di­rec­tor were not happy. Scru­ti­neer­ing the next day was no prob­lem and we just put car back to­gether and drove it home. Firth Mo­tors bought it off Ford for about two grand and my brother used it for about three years.”

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