Drag car engines, battery storage, Celica's new heart - Morley's Workshop 435

By: Dave Morley

Presented by

new engine new engine

Twin-cam power for the Celica, long-life batteries, amazing facts about Top Fuel dragster action, a tribute to the role of the hammer and Cold Chisel, more red-motor blues



When I was a kid, my first decent car was a 1976 Celica RA23. My brother and I tuned it to a standstill, eventually breaking a con-rod and laying the engine to waste. This was lucky. How so? Because it introduced me to the joys of the Toyota 18RG; the replacement mill, a Yamaha-headed twin-cam lump of loveliness that turned the old RA23 into a genuine 120-mile-an-hour car.

And now, decades later, I have another ancient Celica with, you guessed it, an 18RG twin-cam under its homely little bonnet. The car, you’ve seen before in this fine, family publication when it was still sporting its original 18RC boat-anchor. You might also recall that I was contacted by a champion fella in Brisbane, name of Tim, who had an 18RG, salvaged from his own old Celica which had long gone to God. The engine was, Tim assured me, in good health having been rebuilt not too long before the car was decommissioned. Naturally, I jumped in the MBC tow-truck, collected Torrens on the way and drove from Melbourne to Brisvegas to collect on Tim’s generous offer.

Back in Melbourne I made an important decision. I could try to fit the 18RG to the car myself with a lack of gear like an engine crane and such. Or, I could stump up the bucks to get a mate of mine to fit the 18RG for me. When Tim (let’s call him Tim 2, to avoid confusion) reckoned he could do the job in around three or four days, the decision was even easier. So, yes readers, I paid to have a job done that I could have done myself. Workshop heresy? Nah, because if I’d stuck to the script, I’d still have a half-completed Celica lying around and you lot wouldn’t be reading this.

Anyways, here’s how the job panned out. I drove the car to Tim 2’s workshop, enjoying for the last time the breathless, gutless old 18RC rasping away under me. By this stage, I’d already delivered the RG to Tim 2 and he’d gone through the old girl replacing gaskets and crank seals that had sat motionless for about 18 years (according to Tim 1). We also stuck a borescope down each spark-plug hole but apart from a slight discolouration on a small patch of the bore surface on a couple of cylinders (the ones that had sat with a valve part open) everything looked beaut. We turned her over by hand a couple of times to make sure, checked the timing chain for stretch (none) and I left Tim 2 to have at it. Typically, the only things that gave us grief were the carbies. But it ran and drove, so I took it home to tidy up the fiddly bits. I then stuck it on a dyno to have it tuned by a local guru who took one look and told me to bring it back when I’d sorted the vacuum leak(s). Bugger.

So, I changed the old Bakelite carb spacer to a set of soft-mounts, checked and re-checked every nut, bolt and washer on that damn intake system and still, when I sprayed carby-cleaner anywhere near that bloody Celica, the engine revved up like I was leaning on the throttle pedal. Eventually, I did an internal search of the manifold and by pure fluke found a picture of it up-ended. And there, hidden up under the head, between the manifold’s main tubes and behind the twin return springs was a vacuum port that I’d never seen before. Maybe if you were standing on your head under the car, you might have spotted it. Eureka moment.

So I plugged the port (which still required removing one of the carbies) bolted it back together, hit the key and did the mechanic’s victory dance as that twin-cam brapped into life and immediately idled all smooth and even. A quick spray of carby cleaner did precisely nothing. Victory was mine.

So that’s where we’re at boys and girls. Next job is to take it back to the tuning shop and have the carbs finessed, but even as it sits now, I feel like it’s close to being `right’. And I tell you what, the first time I gave it a bootful in second and third with the vacuum leaks sorted, I suddenly remembered how good twin sidedraught Solexes sound and what a fabulous little engine these 80s two-valve twin-cams are. And I was suddenly 19 years old again.

I’ll tell you something else for free, though; my brother’s not getting near this one.


Air it out


Now the weather’s getting a bit better down here, a lot of older cars are hitting the roads for a Saturday gallop. But even if you’re not driving your car just yet, it’s still time to pick a nice, warm, sunny day and go out and open all the windows and let her air out. Even in a garage, air can get pretty stale and condensation (from damp winter air) can form in places you wouldn’t believe. While you’re at it, remove the floor mats and hang them up for a day or two. These are great for trapping moisture under them, leading to damp carpets and a musty smell. Open the boot, too (but don’t forget to take the globe out of the boot light or you’ll have a flat battery next morning).



Long-life batteries!


Since there has been quite a bit of debate about the care and storage of batteries, I would like to give my input from personal experience about the batteries in my 1973 Porsche 911. I purchased two 12-volt batteries in 2006. I installed them in the battery storage areas which have flat metal flooring under the bonnet. After each run I have them constantly connected to a trickle charger. Incredibly after 13 years they are still performing well.

Jo Seeger,

JO, THAT’S an incredible innings for one battery, let alone a pair of them. Just goes to show what a difference a trickle charger can make, especially on a Sunday car like an elderly Porsche 911 that probably doesn’t see daily duties. I’ve been using those high-end C-Tek chargers for decades now, and I have one that was in use every day for about 20 years that still works perfectly.

Clearly, too, the batteries you bought were of a high quality and a known brand, because let me assure you, there are batteries and there are batteries. Buy the El Cheapo one and see how long that lasts. I guarantee you that even with a trickle-charger hooked up to it, it won’t be anything like 13 years. Meantime, some readers are probably wondering why you bought two 12-volt batteries for a car that should really only need one battery?. But it’s true, up to 1973, the Porsche 911 was fitted with a pair of smaller 12-volt batteries rather than one big one. Interestingly, it was all about weight, but not in the traditional way car-makers think about mass.

Rather than save weight, the idea of running two batteries was to actually increase the car’s mass. Specifically, to get more weight over the nose and try to balance out the crummy weight distribution that is a natural function of cantilevering the engine rearward of the back axle. By using two batteries, Porsche was able to send a bit more weight forward and by mounting one battery in each corner of the boot-space, there was better side-to-side weight distribution.

Did it make much of a difference? Not really, and as well as a lot of owners converting to a single battery on the left-hand side of the boot, the early 911 remains a widow-maker of the highest order. Lovely, but dangerous, just as in any good relationship with a loved one.

The other thing Porsche did on these early 911s was to fill the corners of the front bumper with lead weights. Again, the theory was simple, even up the front-rear weight bias. The problem with all of this, of course, is that while it makes the weight at each end (slightly) more even, whacking all that mass way out on the front extremity did precisely nothing for mass centralisation which can be just as important as fore-aft weight distribution.

Think about a ladder lying flat with a couple of buckets of cement hanging from the centre two rungs. Pick up the ladder horizontally, balance it and try to swing it around and then stop it. Now move those buckets to the very top and bottom rungs and give the ladder another twirl. Takes a lot more to control or stop the thing, doesn’t it? Well, that’s precisely what mass centralisation is all about. It’s not just the weight, it’s where it’s carried.


It’s the maths…again


The 18RG Toyota engine – Morley’s one true love

G’day Cobber. Regarding your recent brain-twisters on engine revs and pieces of string: Try the maths on how many revolutions a drag car does in the quarter mile…Bloody amazing!

Pete Dobe,

G’DAY YOURSELF, Pete. Yeah, this is amazing stuff. And from what I can gather, the answer to your question is – if you include the burnout of a Top Fuel dragster – about 900 times (540 times for the 400m run itself). And still these monsters manage to destroy themselves and their owners consider pistons to be `consumables’.

Of course, this whole issue of Top Fuel dragsters led me down another rabbit-hole of research, and I lucked upon a forum post (a computer-boffin forum, no less) by an Aussie bloke who goes by the handle of NickAu. Now, Nick obviously has a keen interest in this subject, and the list of kooky facts he posted had me fascinated. And I reckon you lot will love them, too.

There are factoids in Nick’s post that I have never heard before, and if you have a mate who doesn’t recognise the majesty of Top Fuel racing, get them to have a look at this. And, again, just for the record, this is all lifted from a forum, but if NickAu is a Unique Cars reader, I’d love to hear from him. Meantime, full credit for the following goes to the lad himself.

engine-2.jpgFour Buick motors could barely power the blower on a modern Top Fuel dragster

One Top Fuel dragster 500 cubic inch Hemi engine makes more horsepower than the first four rows at the Daytona 500. They have over half again as much horsepower in one cylinder as a Dodge Viper has in all ten. No one has ever successfully run one long enough on a dyno to get a horsepower reading. Current estimates are right around 6000 horsepower (2015).

Under full throttle, a dragster engine consumes about six litres of nitro-methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25 per cent less energy being produced.

A stock Dodge Hemi V8 engine cannot produce enough power to drive the dragster’s supercharger. The fuel pump alone requires more horsepower to turn than the average street car produces.

With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.

The 1.7:1 air/fuel mixture for nitromethane produces a flame front temperature of 7050 degrees F (about 3900 C).

Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw, burning hydrogen, disassociated from atmospheric water vapour by the searing exhaust gases.

Dual magnetos supply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.

Spark plug electrodes are totally consumed during a pass. After the run, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees F.

If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.

In order to exceed 300 mph in 4.5 seconds, dragsters must accelerate an average of over 4G’s. In order to reach 200 mph well before half-track, the launch acceleration approaches 8G’s. To put this in perspective; a top fuel dragster, parked next to a Super Hornet on the steam catapult on the deck of an aircraft carrier, would be in the water and sinking before the Super Hornet was halfway down the deck.

Dragsters reach over 300 miles per hour before you have completed reading this sentence.

The engine is entirely rebuilt every run, or every 900 revolutions. New pistons and rings, new rods, new rod bearings. Sometimes a new crank. The crew does this in about two hours between rounds.

Amazing stuff, no? A couple of other things I dug up include the fact that, on the hit of the throttle, a Top Fueller creates about the same G-force as the Space Shuttle taking off and that the average fuel consumption is about 18 gallons to the mile (call it 4300 litres per 100km). Got all that? Good. Now you know. And thanks again NickAu.


Keeping the faith

mercedes-benz.jpgThe W124 Benz still presses Morley’s buttons after all those years

I just happened to be browsing through my mag collection and picked up Car Australia July 1989. In a comparo between a BMW E34 535i and a Benz W124 300E, I noticed you picked the Benz. Good to see after 30 years you still regard it as a decent drive, as noted in Our Picks in last month’s Unique Cars. Been around a while now huh? Obviously still liking it.

I also noticed in the letters section of the Car Australia mag that a Mr John Ray nominated you for PM. I wonder how Australia’s motor industry would be today if you had’gone down that road.

On another note, I do a lot of night driving and I am absolutely buggered by the number of idiots driving around with only one headlight. Keep up the good work.

Philip Douch,

OH MAN, that makes me feel old. But you’re right, Philip; even though I was just a kid back then road-testing cars on a daily basis, I was very taken by the W124 Benzes and I still reckon they’re a thing of genuine beauty (in a Bratwurst-and-mustard kind of way). And yes, I’d have one today in a heartbeat. The one-headlight thing is, I think simply a case of people not paying attention to the condition of their own cars. Brake lights are another one. Torrens is always banging on about the importance of yearly roadworthies, but I’m not so sure they’d make much difference given that a bulb can blow on the drive home from the roadworthy station. Let’s not forget, too, that a lot of cars running about with blown lights are new enough to display a warning light on the dashboard to let the driver know there’s a light out somewhere on the car. So it’s not as if every driver would be totally unaware of the problem. And still they get ignored.

My own experience with this is that cars that I’ve resurrected after a long spell in a shed or paddock will, over the first 12 months of being recommissioned, systematically blow every globe, one after the other. My theory is that, somehow, minute amounts of moisture get into the globe over the years and builds up until it’s switched on the next few times. Anybody else noticed this?

As for me entering politics with a view to one day becoming PM, I honestly don’t think that would have played out too well, do you? Canberra might be a very different place. In fact, so would the rest of the country. You can back it in, for instance, that we wouldn’t be putting up with a whole lot of bullshit that minorities seem to get away with these days. There’d be no stupid speed limits, no ridiculous wire-rope barriers and I’d be making damn sure numpties would be getting booked for sitting in the fast lane. Driving while you’re off your chops on ice? Straight to the big house, pal.

I’d also make sure that young kids weren’t punished for having an interest in cars and I’d be doing something real about the road toll that wasn’t some complete load of horseshit with the words SPEED and ALCOHOL in capitals. You’d be taught to drive and develop the right attitudes while you were still at school and if you weren’t interested, you could keep catching the bus. That’s democracy, right there.

And I’ll tell you something else: If I had anything at all to do with it, we’d still have a car-making industry in this once fine country. Rant ends. Discuss.


Roadside repairs

Re-reading my July issue ‘Garage Gurus’ page 126 and Rob Blackbourn’s correct method for replacing a timing gear on a Holden Grey or Red Motor reminded me of my experience. Fortunately, it happened on a weekday during business hours, but on the road between Puckapunyal and Seymour, Victoria the timing gear in my Holden failed.

The friendly Seymour Holden dealer kindly lent me the necessary harmonic balancer puller and provided the replacement timing gear. As a good RMIT engineering student, my toolbox included a manual metal shaper and calibrated knockometer (AKA cold chisel and ball-pein hammer). So, off with the radiator, harmonic balancer, and timing case.

Hmmm, interference fit timing-gear boss, but an obvious keyway. One judicious application of cold chisel to steel, adjacent to keyway, and, presto, off came toothless timing gear. New timing gear, inside diameter of boss and teeth liberally coated with oil, teeth aligned, brass drift and hammer gently persuaded new gear on to camshaft. Other parts reassembled, ignition timing checked, mobile again. Could not do that with a late model Holden-or, indeed, any other late model. But the good news is the family Mazdas now have long-life timing chains.

Claude Palmer, FRMIT, CPEng,

I’M TIPPING that little episode happened quite a few years back, Claude. But nice work and it just shows how practical the average bloke in the street was back then. These days, the same young fella would probably grab his phone, take a picture of the engine bay (once he’d worked out how to open the bonnet) and post it on the internet for his `friends’ to discuss.

Somehow, despite the bazillions of kliks I’ve covered in red-motored Holdens, I’ve never had the dreaded stripped timing gear problem. Mind you, it always crossed my mind, and the first thing I’d do when the engine didn’t want to fire was flip off the dizzy cap and check that the rotor was still doing laps of the cap. If it wasn’t, you could bet your timing gear had just bundied off. And maybe part of my luck was to do with the fact that whenever I had a red apart for whatever reason, it always went back together with the GTR-spec alloy timing gears.

And here’s proof that some of us never grow up: The lump on my engine stand right now, this instant, is a red 202 that’s getting a jazzed-up cylinder head and a big cam (for my hillclimb car). Oh yeah, and a set of alloy timing gears.


No bearing on the result


Tried and trusty Holden red motor with timing gears still doing the business

Re: Undersize bearings in Red Motors. Again. I can assure you, Morley, that it’s a fact and not a theory. I first struck it in a brand-new HR station-wagon that had not even been sold. The rear-main oil seal was leaking badly and I was given the job to fix it.

It was during this strip down to replace the seal which, incidentally, had been put in with half the seal back to front (they had a two-piece neoprene seal) that I spotted this phenomenon. Anyway, when I was putting the crank back in, I dropped a bearing cap and the bearing fell out. This is when I noticed it was oversize (luck or fate?).

I struck it again a couple of years later on a HK taxi I was doing a quick rings-and-bearing job on and Greg from True Bores on Parramatta Road in Burwood measured the motor and said we would get away with standard rings and bearings. While I was assembling the motor, I remembered my previous problem and a quick check of the old bearing shells soon found another example of a 10 thou oversize big end bearing. Had to get Greg back to measure all journals so that we could put an oversize in the right place.

Geoff D,

YEP, I’VE heard enough stories like this one, Geoff, that I have no doubt there was a bit of mix-and-match engineering going on when Holden was building the red motors. So here’s my next question: Did Holden have the same problems with its 253 and 308 V8s?

These were a lot less common back in the day, so maybe the tooling stayed more accurate over the years. But then, the pistons for both sixes and V8s were probably cast and machined on the same tooling, so maybe there were similar `challenges’.

And what about Ford and Chrysler? Did their engines display similar idiosyncrasies? Anybody played with enough old Falcon or Valiant six-cylinder engines to offer an opinion?



Strike me pink


A bloke is driving home from the pub, three churns in and a bit wonky on it. He swerves to miss a pink elephant and finishes up upside-down in a ditch. He’s trapped. The car following, driven by Mr and Mrs Smith, stops to help. So does the next car, driven by Mr and Mrs Ball. Luckily, the bloke was pulled out by the Smiths.

Flukey fit


Speaking of Toyota 18RG twin-cam engines, I’m reliably informed that pistons are getting pretty hard to find for these engines. Along with timing chains and guides, apparently. But some bright spark has grabbed a set of verniers and worked out that the piston from a Yamaha SR500 motorcycle makes a perfect replacement. Could a piston from an air-cooled, 500cc single cylinder engine fitting a water-cooled four-cylinder ever be a thing? Or is it something to do with the bike’s maker, Yamaha, also being the company that built the 18RG’s cylinder head? Anybody?


Write to Morley c/o uniquecars@bauertrader.com.au or Unique Cars magazine, Locked Bag 12, Oakleigh, Vic 3166


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