Driving Tour Of Elk Island National Park In A Flathead V8 Powered 1932 Ford Roadster! – @StrongsGarage

Driving Tour Of Elk Island National Park In A Flathead V8 Powered 1932 Ford Roadster! – @StrongsGarage


Excellent content from the guys at Strong’s Garage as always

Spring has Sprung in Sunny Alberta so we go for a spin in the Beautiful 1932 Ford Roadster that we just finished at the shop! Come along for a walk around tour of the car and then a Driving Tour of Elk Island National Park.

The Ultimate Pre-War Jalopy Shop Truck – Hot Rodding 101 @IronTrapGarage


More great content from Matt and the team at Irontrap

Our 1929 Ford Model A Roadster Pickup is styled as a pre-war hot rod, and one of our favorite builds. This jalopy is very reminiscent of the early shop trucks that could be found at Bonnevile, both racing and being used as support vehicles. Similar to the Pagoda City Coupe, this hot rod needs to be driven and is very bare bones. We can’t wait to drive this all over this summer!!

Customs Take Center Stage as the Highlight of the 72nd Sacramento Autorama – Steven Bunker @FuelCurve


For 72 years now the Sacramento Autorama has highlighted some of the best automobiles the West Coast has to offer. Nestled in the capitol of California, and what many consider the Custom Car Capitol of the World, the Sacramento Autorama gathered the West’s bests with others from throughout the country and shined the spotlight on traditional Custom cars this past weekend.

The lineup of awards dedicated to these custom creations are in memory of some of the best customizers in the world. Guys like Bagdasarian, Barris, Balion, and Bertolucci. Rod Shows calls them the “Big B” Awards, for obvious reasons. All four of the Big B Awards are selected by family members of those who have passed. Here are the 2023 recipients:

Bagdasarian Memorial Worlds Most Beautiful Custom Award – Ray Poletti – 1940 Lincoln Zephyr

Sam Barris Memorial Award – Jesse Orozco – 1956 Chevy 210 Sedan

Joe “Candy Apple” Bailon Memorial Award – Mitch Kelly – 1957 Chevy Bel Air

Dick Bertolucci Memorial Award of Excelence – Cesar Ruiz – 1936 Ford Roadster

But the annual top honor award that customs vie for in Sacramento is the Custom D’Elegance title. This year the trophy went back to the east coast after being awarded to Cody Walls and his gold ’49 Buick that debuted at the Grand National Roadster Show earlier this year in the Slonaker competition. Cody’s Buick edged out a strong field of six beautiful, traditional customs.

New for 2023 was the ARP West Coast Challenge competition which awarded $12,500 and a trophy to the Grand Champion, $6,500 to the runner up, and $3,500 to the third-place finisher. To qualify for the West Coast Challenge, vehicle owners needed to attend three of the four following events: Grand National Roadster ShowPortland Roadster ShowSpokane Speed and Custom Show, and the Sacramento Autorama. In Sacramento the judges did their final deliberating and awarded Jeff Hess’ “OldsSled” ’56 Oldsmobile as the inaugural West Coast Challenge winner – yet another major award for OldsSled after debuting at the 2020 Detroit Autorama, and later that year being crowned Goodguys Custom of the Year.

Read on

Unrestored, Undriveable 1970 Plymouth Superbird Sells for $203,000 – Daniel Strohl @Hemmings


Sale comes amid sharp jumps in Superbird prices

Estate sales and country auctions typically offer bargains for anybody willing to step away from the limelights of headline-grabbing auctions dedicated to collector cars. Then again, Mopar’s wing cars seem like they’ll sell for noteworthy prices regardless of the venue, as we saw when an unrestored 1970 Plymouth Superbird sold for more than $200,000 over the weekend.

According to Terence N Teeter’s obituary, the NASCAR and Mopar fan who lived in West Alexandria, Ohio, “could and would work on just about anything,” but with a CNC business to run, he always had “a lot of incomplete projects around the old homestead.” Many of those projects were vintage Hemi V-8s – he had at least eight Red Rams, 331s, and other first-generation Hemis in various states of assembly – though he also had a disassembled 383-powered 1966 Dodge Charger undergoing restoration as well as the Superbird.

According to its fender tag and its broadcast sheet, the B5 Blue Superbird came from the factory with a 390hp 440 Six-Barrel engine, Pistol Grip-shifted four-speed manual transmission, 3.54-geared Dana 60, heavy-duty suspension, bucket seats, white vinyl interior, and black vinyl top. Of the 1,935 Superbirds built, 308 came with the Six Barrel/four-speed combination. At some point it had lost its fender scoops and had its nosecone molded to the front fenders, but little seems known about the car prior to when Teeter, then 22 years old, bought it in 1981 with 27,000 miles on it. He got to put another 9,000 or so miles on the odometer before parking it to take the intake and heads off the 440.

Photos of the Superbird show much of the car intact but in need of some work. Aside from the disassembled engine, the front bucket seats have significant rips at the seams while the hood is missing much of its paint. “We believe we have everything,” the auction listing claimed.

Teeter, his wife Susan, and their son Ben all died within two weeks of each other from COVID complications in December 2021, leading to this weekend’s estate sale conducted by Kirby Lyons Auctioneers in Greenville, Ohio. While chatter among the wing car community made it seem like the Superbird could sell for well below market value, hope for a bargain seemed to vanish once bidders filled the Kirby Lyons facility. Bidding opened at $50,000 and quickly ramped up to $170,000. Disbelief among the crowd seemed to start around the $185,000 mark, with the car ultimately selling for $203,000.

Read on



Having exhausted the alphabet for their different models, and after flirting with model numbers for a few years, Ford in the USA began referring to their cars simply by the model year of the initial design, starting with the 1937 Ford.

They produced the car in a range of different body styles; sedan, coupe, convertible, station wagon, pick-up and so on and also in two different trim levels; Standard and DeLuxe. Although each year it had a styling refresh and a few tweaks to keep things new, the ‘37 stayed in production through to 1940 after which, you guessed it, came the 1941 Ford.

Power came from a choice of an entry level 136 cu.in (2.23-litre) flathead V8, which generated 60 hp – or a 221 cu.in (3.62-litre) flathead V8 delivering 85 hp.

By 1940, the coupe had gained sealed-beam headlamps fitted further outboard and given bigger bezels. The bonnet was given a high, flat top and in DeLuxe spec the front grille was widened out with additional louvres to reach the fenders.

The combination of the legendary 221 cu.in flathead V8 engine and a fabulous body shape has made Ford Coupes of the ‘37-’40 era the go-to base metal for automotive alchemists looking to fettle, tweak and hammer their way to the ultimate custom car or hot-rod.

The example we have with us today was painstakingly built to be competitive in vintage and classic endurance rallies such as the legendry Peking to Paris event but largely due to Covid never taking part. As such it represents the opportunity to acquire an “out of the box” endurance rally car ready to compete in the post Covid 2023 vintage and classic rally calendar.

The Vehicle

Built for the 1940 model year, this left-hand-drive Ford Coupe DeLuxe was imported to the UK and registered with the DVLA in December 2014.

Handed over to Royal Kustoms of Poole in Dorset, at a cost of over £100,000, the Coupe was eventually rebuilt, with a 296 cu.in (4.8-litre) flathead V8 and prepared for endurance rallying organised by ERA and HERO (https://www.endurorally.com/) in time for the 2020 season. Sadly, we all know what happened in 2020. Although the car has undergone shake-down runs totalling less than 3,000 miles, it has yet to turn a wheel in competition.

With plans changing, the owner decided to sell the car and returned it to Royal Kustoms in September for a full service and check over.

Royal Kustoms estimate that the build today, excluding base car purchase, would exceed £200,000.

Royal Kustoms are highly regarded for the quality and ingenuity of their race and rally preparation. This car has been obsessively over-engineered – outside, inside and underneath – to the most exacting standards of build quality and craftsmanship.

Should they wish to do so – the new owners will just need some paperwork for the car, then they’ll be all set to compete in the pre-war class for notable endurance rallies like the Alaska to Mexico Marathon at the end of September this year.

Fully fettled and ready to go, the car starts, goes and stops as you would hope. The handling and balance are impressive, as is the power on tap from the stroked and bored, 4.8-litre ‘Flathead’ V8 offering around 170 bhp and excellent amounts of torque.

And it goes about its business to a barking, thunderous, roaring soundtrack of Wagnerian proportions that will have people diving for cover at 200 yards.

No expense has been spared, no corners cut, no compromises tolerated.

Every structural, mechanical, electrical or cosmetic component is the best that it could be.

The car has spent most of its life in the dry Southern States of America was sourced in New Mexico and brought to the UK in 2014.

The body, panels and wings are original as is most of the chrome work. That’s where it started now brace yourself.

Here’s the spec sheet…..


Original 1940 Ford Chassis converted with a custom centre section to accommodate 5-speed gearbox.

Fully step boxed the entire length of the chassis rails with added strength gussets.

Rear chassis crossmember converted to take 1939 pickup Parallel leaf-spring kit with custom rear crossmember.

Hydraulic bump stop brackets fitted onto chassis.

All chassis areas with either roll cage or suspension hoops fitted have crush tubes fitted into the chassis.

Front and rear tow hitches installed.

Suspension and Steering

Front: Original style transverse spring front suspension with custom-made front spring with new spring shackles fitted with poly bushes.

Royal Kustoms designed and made front shock hoops with removable strut brace.

Fox front shocks custom made and setup for exact weight of car. Fox adjustable hydraulic bump stops.

Front suspension wishbone has additional reinforcement.

Front anti-roll fitted.

Rear: 1939 Parallel leaf-spring kit fitted.

Fox rear shocks custom-made and setup for exact weight of car, fully adjustable for height.

Fox fully adjustable hydraulic bump stops.

Royal Kustoms top A-arm made with hi-acute off-road Land Rover centre ball joint.

Steering: Fully adjustable electric power steering unit connect to a GM525 heavy duty quick steering manual steering box via Borguson steering U/Js with added tilt adjustment.

Fully refurbished spindles with new kingpins fitted.


Ford Tremec T5Z Motorsport 5-speed transmission.

MDL dual-friction clutch disc and diaphragm clutch plate.

Wilwood external hydraulic clutch slave cylinder.

Mustang racing mechanical clutch release bearing.

Custom-made propshaft fully balanced with heavy duty U/Js fitted.

Ford heavy duty 9” rear axle assembly with Strange heavy duty half-shafts and 3.55 crown and pinion. Custom-made by Hauser racing.


Lincoln Bendix 12” Front drum brakes with re-lined road/race shoes and added air scoops on backing.

Ford 11” Bendix self-adjusting rear drum brakes with road/race linings.

Wilwood adjustable pedal box running Wilwood front and rear master cylinders.

Remote brake servo installed onto front brakes only, running a vacuum hold tank.

Brake proportioning valve and residual valves fitted. Braided flexy lines installed, front and rear.

Hard brake lines are Kniefer with a stainless outer spiral sleeving fitted through out.


296 cubic inch Ford ‘Flathead’ V8.

Ex-military block. Fully ported and polished. Heavy duty main caps. Engine block converted for oil filter system.

New Scat 4 ¼ inch stroke forged crank shaft.

Scat H-beam rods with 2.0 inch bearing size for modern rod bearings.

Ross Racing 3 5/16” forged pistons with Molly rings.

Custom Cam shaft with adjustable lifters, Isky racing springs correctly weighted, 1.6 Manley stainless intake and exhaust valves, 1 piece valve guides.

Mellings oil pump with baffled oil pan.

Edelbrock 75cc finned ally heads. Cosmetic head gaskets installed. ARP head bolts and complete stainless bolt set.

Twin Stromberg’s correctly jetted for engine.

Modern seal/bearing water pumps. K&N air filters.

Custom-made lightened flywheel. Engine fully balanced. Custom-made harmonic balanced front crank pulley fitted.

MSD electronic distributor with switchable on-the-fly twin MSD off-road epoxy racing coils with rev limiter.

Fuel System

Pro-Alloy 175-ltr custom-made fully baffled ally fuel tank.

Twin Facet Red Top electric fuel pumps. Twin Malpassi Competition fuel filter/regulators.

Sytec large metal pre-filter element fuel filter. Sytec anti drain back valves.

Cohline 2240 100% ethanol fuel lines fitted.

Electrical system

Complete new custom-made wiring loom fitted with reset trip-able fuses and heavy-duty relays converted to 12 volts.

120 amp alternator. Varley Red Top Racing gel pack battery. 12-volt power sockets installed under hood, inside car and also fitted in boot. Master cut-off key connected onto neg side of battery.

16” high CFM electric fan running with twin auto fan controllers set at different operating temps, also with a fan override switch and a river crossing switch.

New Classic instruments – fully electric gauge cluster.

O2 Lambda sensor and gauge fitted for AFR ratios. On-the-fly switchable fuel and ignition systems.

New electric wiper motor fitted with wash wipes.

Nav systems (GPS and wheel speed sensors) doubled up.

Ignition coils doubled up.

Body and Roll-Cage

Full restoration of body shell.

Original front sheet metal work. Custom-made hood with louvres and side panels. Custom-made floor with drop down boot area and removable trans cover panels enabling transmission removal from the inside if required.

Custom-made seat framework with lockable under-seat drawers.

Custom-made fuel tank framework with removable ally bulk heads and panel work.

Front and rear fenders reworked for higher tyre clearance and to place tyres in the centre of the fender openings.

Read on

Jeep Could Have Offered the First Crossover 30 Years Before Everybody Else – Daniel Strohl @Hemmings


Ask any longtime Jeep fan when the company started to lose its way, and the answers will vary. It could be 1979, when Renault gained a controlling interest in AMC; 1987, when Chrysler bought the brand and when the square-headlamp YJ Wrangler debuted; 2002, when the KJ Liberty replaced the XJ Cherokee and the 4.0L six-cylinder went away; 2007, when the transverse-engine MK Compass and Patriot debuted; or the early 2010s, when the Cherokee nameplate returned on a Fiat chassis and the brand once again fell under the control of a European carmaker.

Or, if things had gone a little differently, it could have been 1966 with the introduction of the Model H, a proposed vehicle that would have beat every other carmaker to the crossover segment by decades.

Nowadays, crossovers – sometimes called CUVs, sometimes called cute-utes, sometimes called soft-roaders – dominate dealership lots. Depending on how one defines a crossover, Toyota has as many as five in its current U.S. market lineup, Chevrolet as many as six. For some automakers, crossovers have entirely supplanted the conventional sedan and station wagon

How one defines a crossover and what models one considers to fall under that definition also provides a basis for when the crossover debuted. Using the generally accepted definition – a four-wheel-drive or all-wheel-drive vehicle built on a car platform rather than a truck platform – some have suggested the 1996 Toyota RAV4 as the first while others have pointed to the 1980 AMC Eagle or the 1972 Subaru Leone. Other likely candidates include the 1995 Honda CR-V and the 1995 Suzuki X-90. Which is all to say that Kaiser Jeep’s mid-Sixties collaboration with Renault on the Model H would have handily taken the title had it come to market.

For almost as long as raw, utilitarian Jeeps have been around, somebody has been trying to civilize them with fancy trim, plush upholstery, and automotive-style bodies. Plenty of servicemen during World War II tried their hands at itWally Cohn refined their attempts just after the war, an entire cottage industry dedicated to coachbuilt Jeeps sprung up in postwar Europe, and the likes of Raymond Ring and Brooks Stevens proposed postwar automobile designs using the Willys MB chassis. Kaiser even started to investigate softer Jeep SUVs as early as the late 1950s with its Malibu and Berkeley concept vehicles that tilted more toward station wagon than truck-based SUV.

While the Malibu went on to influence the 1963 Wagoneer and the full-size Jeep lineup, Kaiser still wanted a compact SUV better suited to take on the International Harvester Scout. Specifically, as Pat Foster wrote in “Jeep: The History of America’s Greatest Vehicle,” Kaiser wanted something that would appeal to customers used to buying cars, not trucks. “Factory air conditioning… arrived because Jeep’s customers were asking for it,” he wrote. “They considered the Wagoneer a passenger car replacement, not a work vehicle, and they wanted the sort of comfort and convenience features found in regular passenger cars.”

While at least one four-door compact SUV on the CJ platform was proposed in house, Kaiser also looked outside of Detroit for something that would fit the bill. Specifically, the company turned to Argentina, where it had partnered with Renault for its subsidiary, Industrias Kaiser Argentina, starting in 1959. IKA assembled and sold Argentinized versions of existing Renault, Kaiser, Alfa Romeo, and AMC models under license along with the IKA Torino, which blended parts of the Rambler American and Rambler Classic with the Willys overhead-camshaft six-cylinder and new front sheetmetal.

Read on

How To Rebuild A Stromberg 97 Carburetor – Tips & Tricks


Today our resident Stromberg expert Steve is going to show us his step by step process on rebuilding Stromberg 97s. This step by step process can also be used with Stromberg 48 & 81s but there are some differences between the 3 models. Please comment below with any tricks that we missed!!

Reliving an epic 12000-mile adventure in a Ford Model A – Alastair Clements @Classic&SportsCar


It was 1962. My wife Jan and I had recently graduated in our respective vocations, her as a kindergarten teacher and me in architecture.

When we met, Jan had a ticket booked on a liner bound for the UK, but those plans were put on ice and it was marriage for us instead.

Before we got together I had done a fair bit of travelling, including a six-month stint in Japan, so seeing the world was high on the agenda rather than settling down, as a few of our friends were already doing.

Back in the 1960s, after graduating with some sort of degree or in a trade, youngsters in Australia (and many in Europe) seemed to gain the urge for adventure.

We were no exception, and began drawing up plans fairly soon after our wedding, but air travel proved prohibitively expensive. There were bus trips available to various parts of central Asia and India, and it was pretty basic travelling.

All on board would help to pitch tents and cook, yet it seemed a great way to see the world without having to look after your own vehicle.

But, having decided to go to Europe, we elected to drive and we chose a 1928 Model A Ford to do it in – after all, nearly five million buyers between 1927 and ’31 can’t have been wrong about these rugged workhorses.

We were living and working in Melbourne at the time, and after talking to other adventurous types it soon became clear this sort of journey was possible. Not easy, perhaps, but possible.

That was enough: the challenge was there and we were young, healthy and eager.

Decision made, although our parents were not so sure

On the Nullarbor early in the trip, on the way to Perth

Mutual friend (and fellow architect) John Dalton, was keen to return to the UK so joined us for the trip, packing his own one-man tent.

After a basic restoration of the Ford, our running around in Victoria prior to departure did little to indicate what lay ahead for the car.

We left Melbourne in late November 1962, with my brother and family accompanying us until our lunch stop. Jan’s sister, Sue, and a couple of friends were also present early in the morning to bid us farewell.

They were probably all wondering if they’d ever see us again.

Turkey’s Highway No 1 was under construction when the Hunters passed by in their Ford Model A

In Adelaide we met Jan’s elderly grandparents and two aunts, who all raised eyebrows at our chosen mode of transport, and on leaving the South Australian capital we happened upon a roadside weighbridge for grain trucks.

We drove on to the platform and were surprised to find that we weighed in at 39cwt, or 1950kg. Empty, the Model A tipped the scales at 21cwt (1067kg), so inevitably, as well as overheating, we had a few tyre problems.

We started with the best 450x21in rubber we could rustle up, but it let us down.

We bought four new tyres in Perth, and those then took us through to London, but compared with the vehicles of the many other fellow travellers we subsequently met, the Ford turned out to be relatively trouble-free.

We were really lucky to have decided upon the sturdy and simple 3.3-litre, four-cylinder Model A.

Even the ubiquitous Volkswagen Kombis and Land-Rovers were not immune to problems, generally with springs or clutches, and often because they were heavily overloaded.

We even spotted a Sunbeam-Talbot and a Morris 1100 – the latter was the first I had ever seen, and it wasn’t handling the conditions well

Some travellers had converted small buses into caravans, with youths and families going to Australia, and all too often they suffered from mechanical issues.

Citroën 2CVs seemed to put up with the tough conditions well, though, and later in Germany, shortly after waving to a 1928 Bentley that was broken down on the autobahn, one tore past us as we sat at a steady 40mph.

Read on

Turbocharged Prototype: The 1980 M81 McLaren Mustang – Ben Branch @Silodrome


This is the M81 McLaren Mustang prototype, it’s the first of a planned 250 cars that were built as a partnership between McLaren Engines and Ford’s Special Vehicle Operations (SVO). Just 10 vehicles were built in the end due to the high price, and today they’re among the rarest production Mustangs ever made.

McLaren Engines had been established in the United States in 1969 by New Zealand racing legend Bruce McLaren, also the founder of the famous Formula One team of the same name. McLaren Engines focussed on American racing series like Can-Am and Indy Car, and they consulted with many major American automakers.

Fast Facts – The M81 McLaren Mustang Prototype

  • The M81 McLaren Mustang was developed by Ford’s Special Vehicle Operations (SVO) with significant input from McLaren Engines. The car would be one of the fastest and wildest production Mustangs of its era.
  • In order to build the M81 McLaren Mustang a standard 1980 Fox Body Mustang was taken, steel fender flares were added along with front and rear brake ducting in the bodywork, BBS wheels, adjustable Koni shock absorbers, heavy-duty sway bars, heavy-duty springs, uprated brakes front and back, and a bolt-in roll bar.
  • The standard 2.3 liter turbocharged inline-four cylinder engine was taken by McLaren Engines and fully disassembled. The head was ported and polished, it was de-burred and blueprinted, and fitted with a new variable turbo that could produce from 5 to 11 PSI – adjustable from inside the car.
  • All of this work created one of the most memorable Mustangs of the time however it didn’t come cheap, with a sticker price of $25,000 USD in 1980, the equivalent to $91,576 USD in 2023. As a result just 10 were made of the originally planned 250.

McLaren Engines

McLaren Engines was founded by Bruce McLaren in Detroit in 1969. It was established to be the primary facility for the McLaren racing efforts in the United States, while McLaren in England remained focussed on the company’s Formula One racing program

The M81 McLaren Mustang was clearly a Fox Body however it benefitted from a serious styling revamp both inside and out, and it had a much more powerful engine under the hood.

Although today the name McLaren is most famous for its long history in F1, the impact that McLaren Engines had on the North American racing scene was immense. The company built engines for McLaren’s Can-Am cars, for Indy cars, and for countless other racing teams and series.

McLaren would win five consecutive Cam-Am championships, they built engines for three Indianapolis 500 winners, and they developed the turbocharged variant of the mighty Cosworth DFV engine that powered Indy cars for both Team McLaren and Penske Racing.

McLaren Engines was acquired by Canada-based Linamar Corporation and it remains operational today as a subsidiary, working with North American automakers on engine development.

Developing The M81 McLaren Mustang

The McLaren name was well-known in the United States in the 1970s thanks to the successes of Team McLaren in Can-Am racing. The team’s bright “Papaya Orange” cars had dominated for years, all powered by highly-modified American V8s.

This is the 2.3 liter turbocharged inline-four. It originally produced 131 bhp however after McLaren were done with it it was making 175 bhp, and was capable of more still.

The M81 McLaren Mustang was conceived as a sort of 1980s version of the Shelby Mustangs of the 1960s, now among the most desirable muscle cars ever made. Ford’s Special Vehicle Operations (SVO) unit was founded in the early 1980s and the M81 would be their first major project.

The M81 would be followed in 1984 by the Ford Mustang SVO which was sold in much higher numbers, with almost 10,000 made between ’84 and ’86. In the United States, and around the world, new emissions restrictions and fuel efficiency standards meant that the large-displacement V8s of years gone by wouldn’t cut it, and new engine technologies were needed.

For the new Fox Body Mustang Ford had developed the 2.3 liter inline-four with a turbocharger that made almost as much power as the 4.9 liter V8, with 131 bhp vs 139 bhp. In 1980 the world was turned on its head when the V8 was lowered in displacement to 4.2 liters, and the power output dropped – for the first time a four-cylinder Mustang was more powerful than the V8 version.

Read on



Sources – Ken Layne @Motor.com and @RoadkillCustoms.com

Evaluating engine operation and pinpointing specific problems requires a comprehensive testing routine. Here’s how to do it.

Photo from Roadkill Customs

There’s nothing more basic than the fact that an engine is just a big air pump. It draws in air by creating a low-pressure area in the intake manifold and cylinders, compresses the air, mixes in a little gasoline, lights a fire, generates heat and pressure and finally pumps out the spent exhaust. Our preoccupation today with things electronic sometimes makes us overlook old-fashioned mechanical symptoms of problems and the mechanical test equipment used to troubleshoot them. Vacuum gauges are often in this category, but the insight that a vacuum gauge can provide is as valuable today as it was 30, 40 or 50 years ago.

Remember that engine vacuum is just air pressure lower than atmospheric pressure. The starting point to evaluate engine vacuum is the intake manifold. When you connect a gauge to a tap on the intake, you’re measuring manifold vacuum. Note that vacuum will vary in different areas of the engine, such as above or below the throttle valve and right at the intake and exhaust ports.

Vacuum drawn from an opening ahead of the throttle is called ported vacuum. Throttle opening affects ported vacuum opposite to the way it affects manifold vacuum. For example, at closed throttle, manifold vacuum is at its peak. But there is no significant vacuum at a port ahead of the throttle plate when the throttle is closed. Vacuum appears at such a port only when the throttle opens.

It’s important to remember that manifold vacuum is used to power vehicle systems that need a steady supply of low-pressure air under all engine operating conditions. These systems include power brake boosters, a/c vacuum motors and some emissions controls.

Ported vacuum is used to control vehicle systems in relation to engine load. These include old-fashioned distributor vacuum advance diaphragms and carburetor assist devices. They also include many emissions control devices and transmission shift points. Under some engine load conditions, ported vacuum may equal manifold vacuum, but it can never exceed it.

Get Out the Gauge

Most vacuum gauges are graduated in inches of mercury (in.-Hg) and millimeters of mercury (mm-Hg). Some also show the modern metric scale of kilopascals (kPa). For comparison, 1 in.-Hg equals 25.4mm-Hg, or about 3.4 kPa. For this review, we’ll stick to in.-Hg, or simply inches of vacuum.

Because engine vacuum is based on comparison with atmospheric pressure, it varies with altitude just as atmospheric (barometric) pressure does. The following table shows that as altitude increases, vacuum decreases about 1 inch for every 1000 feet above sea level.

Inches of Altitude Vacuum

Sea level-1000 ft. 18-22

1000-2000 ft. 17-21

2000-3000 ft. 16-20

3000-4000 ft. 15-19

4000-5000 ft. 14-18

5000-6000 ft. 13-17

Normal manifold vacuum at idle for an engine in good condition is about 18 to 22 in.-Hg. Manufacturers used to publish vacuum specs in service manuals, but this isn’t as common as it was years ago. Still, the physics of internal combustion haven’t changed in a hundred years, so the guidelines given here are a good starting point for vacuum gauge troubleshooting. Your best analysis based on vacuum readings will come from your own experience, however. As you use a vacuum gauge on different engines, you’ll learn what’s typical for one model compared to another. Some engines have reputations as low-vacuum motors; others are unusually higher than average. Experience is your best teacher.

Cranking Vacuum & Speed Tests

You can get a quick basic appraisal of engine condition by connecting a vacuum gauge to the manifold and a tachometer to the ignition to check vacuum and rpm at cranking speed. Warm up the engine first, then shut it down and connect your test equipment. Close the throttle and disable the ignition, or use a remote starter so the engine won’t start. Crank the engine for 10 to 15 seconds and observe the vacuum and tach readings.

Note that different engines produce different cranking vacuum readings. Some carmakers publish specifications; others don’t. Again, experience will be your best guide. What you’re looking for, most importantly, is steady vacuum and cranking speed.

If the cranking speed is steady (about 200 rpm) and vacuum also is steady (around 5 inches), the engine most likely is in good mechanical condition. If rpm and vacuum are uneven, the cylinders aren’t pumping equally. The engine probably has leakage past the valves, rings or head gasket. If the vacuum reading is pretty steady but cranking speed is not, you’re probably looking at a damaged flywheel ring gear or starter. If the cranking speed is normal or high but vacuum is low and slightly uneven, the engine probably has low compression or retarded valve timing. A jumped timing chain or belt is a common cause here.

The cranking vacuum test also can provide a quick test for PCV restrictions. Perform the test and note the average vacuum reading. Then pinch the hose to the PCV valve closed with your pliers and repeat the test. If the PCV system is clear, vacuum should increase. If it doesn’t, check the PCV system closer for restrictions.

What Idle Tests Can Reveal

From Roadkill Customs

You can zero in on several basic mechanical problems by taking a quick look at manifold vacuum. Warm the engine to normal temperature-get it really warm-and connect your vacuum gauge. Make sure you connect to a manifold vacuum tap and not to ported vacuum. Connecting a tachometer also is a good idea.

Just to be sure that the evaporative emissions system doesn’t interfere with vacuum testing, disconnect and plug the canister purge hose and its manifold port. If you’re testing an OBD II car, check for evap-related DTCs when you finish testing to be sure none set.

Run the engine at idle, low cruise (1800 to 2200 rpm) and high cruise (2500 to 3000 rpm). Note the vacuum readings, and any fluctuations, at each speed. Next, hold engine speed steady at about 2500 rpm for 15 seconds and read the gauge. Now release the throttle and watch the gauge as the speed drops. The vacuum reading should jump as the throttle closes, then drop back to its normal idle reading. If vacuum doesn’t increase at least a couple of inches when you release the throttle, you may be looking at worn rings, cylinders or valves.

Idle vacuum for most engines is about 18 to 22 in.-Hg, but some may produce only 15 to 17 inches at idle. (Remember what we said about experience.) If vacuum is steady and within these ranges, the engine and fuel and ignition systems are operating normally.

If vacuum is steady at idle but lower than normal, the ignition or valve timing may be retarded. Low compression, an intake leak or tight valves also can cause low vacuum at idle.

If the vacuum reading fluctuates within the normal range-the gauge needle bounces around a lot-uneven compression (broken rings or leaking valves or head gasket in one or two cylinders) is a likely culprit. An uneven air/fuel mix, erratic ignition timing, a misfire, misadjusted valves or a manifold leak near one or two cylinders also are possible causes.

If vacuum drops intermittently at idle, one or more valves may be sticking open or dragging. Higher-than-normal vacuum at idle is a common clue to overly advanced ignition timing, while low vacuum can indicate retarded timing.

Low vacuum also can be an immediate clue to a plugged exhaust. To check further, run the engine at about 2500 rpm for about 15 seconds. If vacuum drops during this period and does not increase when you close the throttle, you’re almost certainly looking at a restricted exhaust.

Vacuum Fluctuations & Power Balance

Several of the guidelines in this article have distinguished between steady vacuum gauge readings and fluctuating readings, where the gauge needle bounces up and down erratically. This may seem secondary-almost inconsequential-but it’s an important distinction. A steady but abnormal vacuum reading indicates a problem common to all cylinders. Things like incorrect ignition timing or an old, tired, high-mileage engine affect vacuum equally for all cylinders. A bouncing needle, however, usually indicates that the problem is localized to one or just a few cylinders. Here’s where power balance testing enters the picture.

Compression testing on many late-model engines is flatly impractical from a labor standpoint for a quick engine evaluation. That’s especially true on some of the weird vans for which removing and reinstalling spark plugs is a two-hour job. It’s relatively quick and easy, however, to connect a vacuum gauge to the manifold and your engine analyzer to the ignition system.

If your initial vacuum tests produce gauge fluctuations, you have a definite indication that the problem is limited to just one or a few cylinders. In these instances, a power balance test can help you pinpoint those cylinders and the condition they’re in. Does the engine need a valve job (fluctuating vacuum) or a complete engine exchange due to universally worn rings and cylinders (steadily low vacuum)? Combine modern power balance testing with traditional vacuum analysis and you’ll have the answer.

The author would like to thank the staff members of The DMV Clinic in Santa Cruz, California, for their help with this article.

Motor Magazine