New Zealand Classic Car - - Contents - Words: Ian Parkes Pho­tos: New Zealand Clas­sic Car Archive / Sup­plied


Cool­ing sys­tems in older cars are es­pe­cially worth your at­ten­tion. Some of them weren’t great to be­gin with. The bench­mark test in the early days ap­peared to be: ‘works most of the time’. Stop-start driv­ing in to­day’s traf­fic adds an­other strain; cool­ing sys­tems get gunked up over time, and the con­se­quences of over­heat­ing all con­spire to give them a high score on the cost– ben­e­fit ra­tio.

Over­heat­ing in­ci­dents, along with dodgy electrics, were prob­a­bly the most com­mon prob­lems with the cars that we drove in our youth, so, if it’s still an is­sue with your clas­sic car, this fea­ture is for you.

First, take a look at the ra­di­a­tor. Stuck in front of the engine with lit­tle pro­tec­tion, ra­di­a­tors can take a ham­mer­ing from low-fly­ing in­sects, stones, and other de­bris. Although they have some mar­gin of tol­er­ance, any dam­age to those flimsy cop­per fins will block air and re­duce their ef­fec­tive­ness, as well as make them look a bit sad. The big ques­tion is, what is it like on the in­side? But let’s start with a quick primer.

En­gines get hot­ter than boil­ing point be­cause spark plugs are set­ting fire to fuel in­side the cylin­ders, and all that metal rub­bing to­gether, even prop­erly lu­bri­cated, also gen­er­ates heat from fric­tion. But we can still use wa­ter to main­tain a good tem­per­a­ture by do­ing three things. First, we can pres­sur­ize it so that the boil­ing point rises and, sec­ond, add gly­col, which has a higher boil­ing point than wa­ter and ex­pands to fur­ther in­crease pres­sure. Fi­nally, we can cir­cu­late the wa­ter through a heat ex­changer — the ra­di­a­tor — which sheds heat through con­duc­tion to the out­side air so that we can send cooler wa­ter back into the engine to pick up more ex­cess heat.

The ra­di­a­tor com­prises tanks, tra­di­tion­ally at the top and bot­tom, joined by rows of nar­row tubes sol­dered to fins that dis­si­pate heat through the ac­cu­mu­lated mas­sive sur­face area. It is con­nected via hoses to the engine. Your ra­di­a­tor might be as clean as a whis­tle, but, un­less you have fol­lowed the ad­vice in our Septem­ber is­sue (No. 333) and spruced up your engine block, how do you know what’s lurk­ing in the wa­ter jacket (the

wa­ter-car­ry­ing gal­leries cast into your engine)?

Make sure you flush, acid wash, or even blast air through the wa­ter jacket on an engine block be­fore re­assem­bly. Auck­land’s Auto Ra­di­a­tors is one of the old­est names in the busi­ness, and owner Brad Ross has been on the tools for 30 years. Brad has had to field com­plaints about ra­di­a­tors that he had built re­cently over­heat­ing — in­clud­ing on a car fea­tured in these very pages — only to dis­cover that the ra­di­a­tor was blocked with dirt. The engine block, over­hauled else­where, hadn’t been flushed.

If your engine over­heats, or takes a sus­pi­ciously long time to reach nor­mal tem­per­a­ture, it could also mean that the ther­mo­stat is stuck and not do­ing its job of open­ing or cut­ting off cir­cu­la­tion to the ra­di­a­tor.

Is your wa­ter pump up to scratch? When was it last checked? Op­er­at­ing in gluey flu­ids in a broad tem­per­a­ture range, they have a lim­ited lifes­pan.

Time off the road or dis­as­sem­bled can also cause prob­lems. Brad says that peo­ple who have re­in­stalled an ap­par­ently sound ra­di­a­tor only to find it full of holes might agree that leav­ing it full of wa­ter would have been safer. He says that a dirty ra­di­a­tor left dry can kick-start cor­ro­sion.

Rob at Cap­i­tal Ra­di­a­tors says that pay­ing at­ten­tion to ra­di­a­tors is prompted by one of three things: leaks, over­heat­ing, or poor con­di­tion. Gen­eral con­di­tion is es­pe­cially rel­e­vant to clas­sic car en­thu­si­asts who have just over­hauled a mo­tor. “If you have a nice engine, you want to make sure that your cool­ing sys­tem is also good,” he says.

The first step if your engine over­heats is to check the wa­ter level. But if you have lost wa­ter, top­ping it up is not go­ing to solve the prob­lem — it will hap­pen again. The next step is to do a pres­sure test. “You have to find out if there’s a leak,” says Rob. And look un­der­neath for tell­tale signs.

Over­heat­ing can be so frus­trat­ing that spe­cial­ist help will usu­ally pay div­i­dends. Spe­cial­ist ra­di­a­tor work­shops can re­pair or re­man­u­fac­ture parts to an orig­i­nal pat­tern, or they may know of some im­prove­ments that over­come a known weak­ness or de­sign flaw. Ex­pe­ri­ence counts here.

Mike Hope of Town­row and Sanko Ra­di­a­tors in Hast­ings cau­tions that the first thing to ap­pre­ci­ate when re­con­di­tion­ing or re­build­ing a ra­di­a­tor is that the price of cop­per, brass, and sol­der have shot up re­cent in years.

“A re-core that might have cost $200– $300 20 years ago could now cost $1500,” he says. “Sol­der costs us $1K a roll.”

He has had cus­tomers who have spent $20K on a hot rod engine say that “they just want some­thing to go in the hole”, but the cool­ing sys­tem is not the place to cut cor­ners, and it’s quite in­volved.

He is cur­rently re­build­ing the ra­di­a­tor on a Model A Ford, dis­as­sem­bling the three-piece top tank. “I’ve quoted him eight hours but I know it’s go­ing to take 20,” he says.

It also takes skill. Even a sim­ple re­pair is rarely sim­ple. “You’ve got to have fine con­trol of the flame and heat, or, as you

“Qual­ity alu­minium ra­di­a­tors are fine, but if you ex­pect a cheap one to last as long as the orig­i­nal in your 1980s Corolla, well, it’s not go­ing to hap­pen”

close one leak, you open an­other and dis­lodge 20 years of crap.”

Mike says that you can buy cheap alu­minium ra­di­a­tors, but they can be toast in­side a year: “Qual­ity alu­minium ra­di­a­tors are fine, but if you ex­pect a cheap one to last as long as the orig­i­nal in your 1980s Corolla, well, it’s not go­ing to hap­pen.”

Brad Ross in Auck­land says that if cus­tomers ask for an alu­minium ra­di­a­tor he al­ways asks why. He says they look ‘bling’ and are lighter, but they are much more likely to cor­rode and the ser­vice­abil­ity is much lower. “And if you want a qual­ity alu­minium core, man­u­fac­tured in Aus­tralia or Europe, the cost of im­port­ing them means that they are not much cheaper,” he adds.

“If some­one has in­vested a lot of time and care in a re­build, I want the fin­ish on my part of it to re­flect the qual­ity, and to be the best it can be”

Brad also ques­tions cus­tomers who might want to re­place engine-driven fans with elec­tric al­ter­na­tives. “If the engine’s run­ning, the engine-driven fan’s work­ing, and, if it has a shroud, it will also be very ef­fec­tive.”

Alu­minium ra­di­a­tors can also suf­fer elec­trol­y­sis. Brad re­calls EA Fal­cons had early alu­minium ra­di­a­tors. Fal­cons were a com­mon choice for taxis, and their ex­tra lights and me­ters would cre­ate stray elec­tri­cal cur­rents, “and your ra­di­a­tor be­comes a bat­tery,” says Brad. “The sparky would say [that] he’d done it right, and he had — for a brass and cop­per ra­di­a­tor.”

Hornby Ra­di­a­tor Shop’s Greg Ged­des says the ex­pec­ta­tion that “ev­ery­thing comes from China” makes for a tough mar­ket. The full range of work comes through his work­shop, from sim­ple re­place­ments of stan­dard equip­ment to one-offs, and it’s in­tri­cate work.

If a cus­tomer hasn’t got an ex­ist­ing ra­di­a­tor to work with, it’s vi­tal to get the num­bers of tubes and rows, ca­pac­ity, and pitch right when spec­i­fy­ing a one-off core from spe­cial­ist man­u­fac­tur­ers. Greg says that New Zealand man­u­fac­tur­ers make top-qual­ity cores, but the ma­te­ri­als and work in­volved make for high-value items. Even vin­tage-pat­tern hon­ey­comb cores can be re­man­u­fac­tured here. But if a ra­di­a­tor doesn’t work, the ra­di­a­tor shop will bear the cost, so ex­pe­ri­ence and crafts­man­ship is in­te­gral to the busi­ness.

“We get as much in­for­ma­tion as we can,” says Greg. “There’s quite a bit in­volved, and you have to work care­fully through it.”

Greg says that they usu­ally fabri­cate the tanks them­selves, and they can some­times save cus­tomers money by us­ing spares that they can cut and join — “[t]here’s al­ways a way around it if you know what you are do­ing.”

Rob from Cap­i­tal Ra­di­a­tors says that re­plac­ing or re­man­u­fac­tur­ing ra­di­a­tors will be the best op­tion for sys­tems in poor over­all con­di­tion but it de­pends what the cus­tomer wants. He can do any­thing from pro­duc­ing a cus­tom sys­tem to leak re­pairs, and, with more than 40 years’ ex­pe­ri­ence in the work­shop, he can tai­lor so­lu­tions to give the best value for any bud­get.

Re-cores for small cars like a Dat­sun 1200 will ob­vi­ously cost less than a four-row ra­di­a­tor for a Chevy Im­pala. “It’s down to time and quan­tity of ma­te­ri­als, but it could cost as lit­tle as $400,” he says.

Rob men­tions that their ex­per­tise with tanks and pipes also ex­tends to fuel-tank and fuel-sys­tem re­pair and re­con­di­tion­ing.

Auto Ra­di­a­tors in Auck­land also re­con­di­tions fuel tanks, and Brad says that they line theirs with a spe­cial flex­i­ble com­pound that stays flex­i­ble, un­like most other types avail­able — so, “[y]ou should never have an­other prob­lem.”

Brad echoes the com­ments about crafts­man­ship in ra­di­a­tor work: “They are all black and square. They are all the es­sen­tially same but a bit dif­fer­ent, and you have to pay at­ten­tion.”

And he takes pride in his work, say­ing “I make the ex­tra ef­fort to make the fin­ish as good as pos­si­ble.”

He’s of­fended by sol­der­ing “that looks like it has been dropped by a seag­ull”. It takes very lit­tle ex­tra ef­fort to make it tidy, he tells us, adding that “[i]f some­one has in­vested a lot of time and care in a re­build, I want the fin­ish on my part of it to re­flect the qual­ity, and to be the best it can be.”

Greg Ged­des says that New Zealand man­u­fac­tur­ers make top-qual­ity cores, but the ma­te­ri­als and work in­volved make for high­value items.

Singing in tune

If its tem­per­a­ture is sta­ble but your car won’t purr along as ad­ver­tised or ac­cel­er­ate cleanly, sus­pi­cion often falls on the car­bu­ret­tor. But check a few other things first. Check the com­pres­sion on each cylin­der, that the ig­ni­tion sys­tem is up to scratch, that the spark tim­ing and ad­vance curve are cor­rect, and that there are no man­i­fold leaks — re­con­di­tion­ing your carb is not go­ing to fix those is­sues.

Any im­prove­ments to an engine’s breath­ing will also af­fect car­bu­ret­tor per­for­mance. A dif­fer­ent ex­haust or man­i­fold, port­ing and pol­ish­ing or shav­ing the cylin­der head; a dif­fer­ent cam pro­file; or even a dif­fer­ent air cleaner will all have some ef­fect.

Brian Win­gate of the Car­bu­ret­tor Ser­vice Cen­tre has worked on carbs since the mid ’70s. He says that if you are over­haul­ing an engine on a clas­sic car you should also get your carb over­hauled: “It’s me­chan­i­cal like an engine, it’s done the same miles, and parts wear.”

Carb kits, with seals, gas­kets, and di­aphragms, are avail­able, but they won’t fix wear or their symp­toms. “British cars start to run rich and run out of ad­just­ment,” says Brian. “Ja­panese cars run too lean, and, when cruis­ing, they stum­ble or hunt.”

The sim­plest way to check your mix­ture is to pull the spark plugs and in­spect the tips. Sooty plugs in­di­cate an engine run­ning too rich; white or light grey plugs, too lean. The right mix is in­di­cated by straw-coloured plugs.

If en­gines haven’t been run for a long time, seals can per­ish, and the works can get gummed up as the volatiles in mod­ern fu­els dis­si­pate. If your car is go­ing to sit idle for a time, Brian says it’s worth adding a fuel-treat­ment ad­di­tive (stocked at chain­saw shops) and run­ning it through the carb to avoid fuel in the carb turn­ing into glue.

Brian has also no­ticed a re­cent trend of carbs com­ing in from cus­tomers who have run older cars on higher oc­tane fuel con­tain­ing ethanol, often for less than three months. “Ethanol doesn’t agree with old rub­ber,” he says.

A car­bu­ret­tor has a sim­ple job — to de­liver a mix­ture of at­om­ized air and fuel at the right ra­tio, 14.7 parts air to one of fuel — to get the clean­est burn, which con­sumes all the fuel and all the air in ev­ery cylin­der.

The ideal fu­elling mix and the rate at which it burns, re­gard­less of engine speed, are con­stants, but ev­ery­thing else is vari­able. Am­bi­ent tem­per­a­ture and air pres­sure vary; engine tem­per­a­tures vary enor­mously. Throt­tle open­ings change, and you need to deal with the fact that fuel is thicker than air. Car­bu­ret­tors don’t even use a fuel pump to push things along; it’s the vac­uum cre­ated in each engine cylin­der that drives them.

They use the Bernoulli prin­ci­ple — the same one that al­lows aero­plane wings to stick to the sky, and yachts to sail to wind­ward. It’s the prin­ci­ple of suck­ing, although We­ber Spe­cial­ties’ Mur­ray John­son in­sists that there’s no such thing as suck­ing — it’s sim­ply the high-pres­sure side push­ing. “I use the word ‘physics’ a lot. There are laws of na­ture; they are not sug­ges­tions, and you can’t al­ter them be­cause you want to you. That’s why they’re called ‘laws’,” he says.

The cylin­der sucks (cre­at­ing a low-pres­sure area); the nar­row waist in the car­bu­ret­tor bar­rel, the ven­turi, ac­cel­er­ates the air, which also draws in a spray of fuel through the main jet noz­zle, and the at­om­ized fuel and air heads to the cylin­der. How much gets through is con­trolled by a but­ter­fly valve across the bar­rel, op­er­ated by the ac­cel­er­a­tor pedal, hence the term ‘throt­tle’. Press­ing the pedal sim­ply opens the air­flow to the engine.

A car­bu­ret­tor, though, is much more than a sim­ple ven­turi de­vice. Car­bu­ret­tor de­sign­ers had to add other sys­tems to over­come all the vari­ables. These in­clude a by­pass sys­tem, which pro­vides a fuel-air mix at idle, when the pres­sure dif­fer­ence in the ven­turi is low. You can ad­just the idle screw with­out af­fect­ing the rest of the carb’s per­for­mance. The choke, man­ual or au­to­matic — typ­i­cally an­other but­ter­fly valve — makes the mix­ture richer for cold start­ing. An­other sys­tem, a sec­ondary jet or booster mech­a­nism, adds fuel when the throt­tle is opened. With­out an ex­tra shot of fuel, the mix­ture would im­me­di­ately go lean, caus­ing the engine to stum­ble ex­actly when you want more power.

As de­mand for power in­creased, twin carbs be­came com­mon on per­for­mance en­gines. Un­til fuel in­jec­tion took over, per­for­mance­ori­ented mo­tor­bikes had one car­bu­ret­tor per cylin­der. How­ever, in larger (car) en­gines, the con­tin­u­ous draw pro­vided by mul­ti­ple cylin­ders helps over­come the fuel-in­er­tia prob­lem you get in a stop-go sin­gle­cylin­der sce­nario.

We­ber be­gan de­vel­op­ing twin-bar­rel carbs in the 1930s and also patented a de­sign for dif­fer­ent-di­am­e­ter bar­rels. The smaller one fu­els light run­ning; the sec­ond, larger, bar­rel kick­ing in when power is called for. In 1965, in the US, Rochester de­vel­oped the first four-bar­relled carbs for V8s. They usu­ally op­er­ate as two dif­fer­ent-sized pairs. Once again,

“It’s not worth do­ing un­less you do it prop­erly. Car­bu­ret­tors are del­i­cate and in­tri­cate, and they have to be set up right. They only have to be a lit­tle bit out and you have prob­lems”

de­mand for more power led to twin-carb set­ups, or ‘dual quads’.

On car­bu­ret­tors, it’s often the spin­dle shafts, and some­times but­ter­fly valves, that wear, says Mur­ray, but he’s also seen carbs over­tight­ened on man­i­folds, which have dis­torted the bar­rels. “We had to ma­chine one out 2mm over­size,” he says. He hasn’t seen any wear on jets us­ing clean fuel, just on air-col­lec­tion jets that have op­er­ated in very dirty air.

Auto Trail’s Paul Mor­ris says that while the Hamil­ton com­pany stocks carb kits and parts for peo­ple who can do the work them­selves, the only carb ser­vice they of­fer now is a full re­con­di­tion.

“It’s not worth do­ing un­less you do it prop­erly,” he says. “Car­bu­ret­tors are del­i­cate and in­tri­cate, and they have to be set up right. They only have to be a lit­tle bit out and you have prob­lems.”

Brian Win­gate, whose ser­vice cen­tre is based in Nor­manby, South Taranaki, agrees. If a car has sat for a long time, seals and di­aphragms can go hard, crack, and start leak­ing, but you have to ad­dress wear if they are go­ing to per­form as in­tended. Brian says that some own­ers are sur­prised when a carb is re­stored to full func­tion; they didn’t know their carbs could be that good.

He knows the foibles of most carbs and where to look for is­sues. Wher­ever they come from — and they come by courier from all over the coun­try — he gives ev­ery carb a re­fresh­ing acid bath. That gives him a solid base for any ma­chin­ing, bush­ing, or resur­fac­ing. “It also makes them look brand new,” he says.

If cus­tomer par­tic­u­larly wants that look for an as-new restora­tion, Brian also zinc plates all the steel bits; then, he says, “they look brand new, they per­form like new, and the steel stays pro­tected against rust.”

Auto Trail’s re­con­di­tion­ing also in­volves strip­ping and clean­ing, re­plac­ing any worn parts, and set­ting them up prop­erly. “They come back as good as new, or bet­ter than new, ac­cord­ing to some peo­ple,” says Paul.

You only need to set the idle and mix­ture screw and, on Hol­leys, the float level.

We­ber’s Mur­ray John­son says that he’s seen peo­ple give up on clas­sics that don’t run well, but, like Brian, he says that some peo­ple don’t re­al­ize what they are miss­ing with a worn carb.

Some peo­ple aim to fix lack­lus­tre per­for­mance with mod­ern cams, but there’s a cau­tion. He cited cams for Valiant Charg­ers (which run triple We­bers), de­signed re­cently, in the era of highly re­spon­sive pulse-type fuel in­jec­tion. “You can try any­thing, but they just won’t run right.” Carbs work with con­tin­u­ous flow, and cams de­signed for that sit­u­a­tion are sim­ply more ap­pro­pri­ate, he says. Even the stan­dard cam will work bet­ter. “It’s sim­ply horses for cour­ses.”

An­other tip: “Fuel-pres­sure reg­u­la­tion is crit­i­cal,” Mur­ray says. Some brands of re­place­ment reg­u­la­tors sim­ply don’t work. “We test them and they are do­ing noth­ing,” he says.

It’s not al­ways about be­ing stan­dard. Mur­ray tells us that a strong side of his Auck­land busi­ness cur­rently is re­plac­ing the worn-out and en­ergy-sap­ping emis­sions gear on ’80s and ’90s Ja­panese utes with down­draft We­bers. “That works re­ally well.

In all cases we achieve more torque for the same or less fuel use,” he says.

Wayne Lip­pert says that word of mouth is per­suad­ing peo­ple car­ry­ing out restora­tions on clas­sics or cars that have stood for a long time to seek out his work­shop at Car­bu­ret­tor Restora­tions in Dunedin. He has also seen skin-deep restora­tions.

“But,” he says, “I find more peo­ple are pre­pared to spend money on fuel and ig­ni­tion sys­tems now. If you’ve got an early Land Rover, a Willys Jeep, or a Wolse­ley 6/10, you know that parts will be hard to find, but we can do it.”

If a carb is still on a car and is sus­pected of caus­ing poor run­ning, Wayne will also go out on-site to check other things — like tim­ing, dis­trib­u­tors, and leads — be­fore re­turn­ing with a carb for over­haul. He’s a qual­i­fied auto elec­tri­cian, so he can sort elec­tri­cal prob­lems out too.

Wayne’s first job, at age 15, was work­ing on carbs, and he knows his way around most of them. He also man­u­fac­tures parts if he has to, but he also knows which parts are com­mon be­tween dif­fer­ent mod­els, so he can some­times find parts in spares.

His main sources are lo­cal but also the UK and US. While this might push the turn­around time out to two or three weeks, that’s usu­ally not a prob­lem when the rest of the car is also get­ting a makeover.

Auto Trail also has an­other string to its bow. Staff can make up new HT leads on­site for cars whose poor run­ning isn’t — or isn’t en­tirely — due to a sub-par carb. Still be­hind the dash­board, Auto Trail of­fers a speedo re­con­di­tion­ing ser­vice as well, cov­er­ing ev­ery­thing from faded graph­ics through damp­ing, gear­ing, to new ca­bles. Paul says that they can re­cal­i­brate speedos for dif­fer­ent gear­boxes or wheel sizes, or re­set mileages in re­place­ment speedos to match the orig­i­nal.

The fu­ture of fu­elling

Fuel-in­jec­tion sys­tems be­gan to re­place car­bu­ret­tors on pro­duc­tion cars in the 1980s, although they date back to the vin­tage era in com­pe­ti­tion cars, and in avi­a­tion. Diesel en­gines have al­ways used in­jec­tion sys­tems, but, for petrol en­gines, carbs were sim­pler, cheaper, and worked bet­ter over­all un­til this era.

Petrol in­jec­tion has some ad­van­tages — bet­ter cold start­ing and idling; less sus­cep­ti­bil­ity to tem­per­a­ture and pres­sure changes — but it was its abil­ity to run leaner through greater ac­cu­racy that won the day. Clean-air reg­u­la­tions drove the change, and cat­alytic con­vert­ers need clean ex­haust gases to op­er­ate ef­fec­tively.

Mod­ern fuel-in­jec­tion sys­tems are mas­ter­minded by ECUS (elec­tronic con­trol units), but the sys­tems in the early years were all much more com­plex me­chan­i­cal sys­tems.

There are sev­eral vari­ants. Fuel is pres­sur­ized with a pump and then in­jected into the man­i­fold (sin­gle-point fuel in­jec­tion), or into in the in­let tract just up­stream of each in­let valve (mul­ti­point fuel in­jec­tion), or di­rectly into the cylin­der head (di­rect in­jec­tion). The Bosch di­rect-in­jec­tion sys­tem in the iconic Mercedes-benz 300SLC that Stir­ling Moss drove to vic­tory in the 1955 Mille Miglia had in­jec­tors in the spark-plug holes in the ex­ist­ing block. The spark plugs were moved to the cylin­der head.

Mod­ern com­mon rail sys­tems use ex­tremely high pres­sures, up to 26,000psi, and highly re­spon­sive piezo­elec­tric in­jec­tors that can fire mul­ti­ple in­jec­tions per cy­cle. Note that these pres­sures are dan­ger­ous. A me­chanic can ap­par­ently suf­fer a ‘ hy­po­der­mic jet-in­jec­tion’ of fuel at any­thing over 100psi.

Next month is our spe­cial Targa is­sue, and we’ll take a look at what it takes to set up a street/track com­pe­ti­tion car.

In­tri­cate work - Re­build­ing an orig­i­nal ra­di­a­tor is time con­sum­ing and costly, but well worth it

Art pro­vid­ing mo­tion - on a Fer­rari V12 engine

A Fer­rari V12 boasts 3x twin choke We­bers

Triple We­bers pro­vide a highly re­spon­sive engine

Right: Four-bar­rel car­bu­ret­tors are gen­er­ally used for high-dis­place­ment V8 en­gines

A fully re­stored Mercedes Benz 300SL Bosch di­rect-in­jec­tion sys­tem

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