(first posted 1/13/2019) This was sitting outside a local video game store, and I had to stop and take a look. At first, I thought it might have been a GTO, which have been written about time and time again on oh-so-many different car sites that I wasn’t going to bother doing an article.
Until I saw the badge on the fender…
Huh. Interesting… This prompted a look around back…
…to find a LeMans badge! Now it was all coming together!
The Sprint Six was reserved for the LeMans and Tempest coupe as an option pack, while the big block was saved for the GTO. It was not a popular option, as it was dropped after 1969 to be replaced by the Chevy sourced 250 I6, to be used from 1970-1976 as the base engine.
I was happy to find this rare example of an interesting car that has lived forever in the shadow of its V8 brothers.
In the early 70, during my 1st enlistment in the Navy, a squadron mate had one of these. His was a twin to the red car in the ad. I had a 68 Mercury Cyclone GT with a 302 that I felt was a superior car.
Then, as more and more small cars made their way to the US with OHC engines I became more interested in these Sprints. As a fan of the unusual/oddball, they had an appeal to me with my ultimate Le Mans being a 4 door hardtop (or in a pinch, a wagon) with the OHC engine and 4 on the floor.
Yet aside from that red car, I think I have seen more OHC Firebirds in the last few years and even the Firebirds are fairly rare.
Someone in my area has, or had, a triple black 69 Firebird convertible, though I haven’t seen it in about 6 months.
Dropping this engine was a mistake, I know it had some issues but with some refinement the design seemed advanced enough to be a contender during the energy crisis 70s, if not just for Pontiac but as a corporate wide 6 cylinder. Could have given much needed life to a few notable models from that time (OHC 6 Vega/Monza anyone? How about a fuel injected variant for the original Seville?). Even a cut down 4 cylinder variant would have been feasible I would think. Rolling it out in the V8 60s was such a strange decision admittedly, but admirable that the brand only second up the Sloan ladder had the most advanced and worldly engine above the “standard of the world”.
I like the segmented vertical bar grille design of the Lemans more than the GTO for 67, other than the taillight panel the GTO had some really fussy detail changes I never quite warmed up to compared to the 66. Of note it’s easily forgivable that you initially mistook this for the GTO, I did too since it has the GTO hood swapped on.
A taller Chevy 6 wasn’t going to work in the Vega, and a 250 inch engine wasn’t going to be adequate for mainstream prestige cars in the 70s.
If the Vega were built around it or a 4-cyl variant to begin with is my point, though I’m not sure height mattered considering the excess height of the Vega 4 itself. Ford’s Pinto took an OHC in-line engine without much fuss as well and those have a comparably low hoodline. A 6 I certainly see problematic lengthwise in its compartment.
250 inch engine wasn’t going to be adequate for mainstream prestige cars in the 70s.
Well…
Matt ;
Those W116’s had a 3.80 Liter i6 with DOHC is gas or a turbocharged single OHC 3 Liter Diesel that really went, I forget how heavy these cars were but when they pulled up their skirts they really ran fast .
-Nate
Nate, just to clarify, there were no W116 with a 3.8 liter i6, the 280 SE or SEL (I don’t know if they were sold in the US) were 2.8, and as you say, DOHC. Depending on the year, they were available with different sizes of SOHC V8s. The Diesel model was exhasperatingly slow, though at its introduction time, at the end of 1977, it was the fastest Diesel sedan in the world. The 2.8 wasn’t particularly fast either.
Best
Rafael
It should also be noted that the 3 litre diesel was an inline FIVE. Yep, 5 cylinders, all in a row.
It was an outgrowth of the 2.4L diesel 4 cylinder engine. M-B wanted more power out of their diesel, but didn’t want the weight and bulk of an inline 6, so they split the difference and went with 5 cylinders. A balance shaft was added to smooth out engine operation. Originally, the engine was not turbocharged and there were applications that remained naturally aspired, but over its life, most of the 5 cylinder diesels that were made were turbo’d.
It didn’t help that a ’67 Firebird Sprint cost just about the same as one equipped with the 326 HO, which had a lot more power and torque.
+1, I agree, Pontiac OHC 6 would had been an interesting substitute for Buick and Olds when they dropped the V6 after the 1967 models to use the Chevy 250.
It might had helped Pontiac during the first oil crisis but the main obstacle would had been application for FWD vehicules.
I’ve always thought that these motors were pretty cool. Just like the Pontiacs that they came in. Unfortunately in America the straight 6 has always been the ignored sibling once the OHV V8’s became common in the early 1950’s. The 6 was left for the cheapskates and the Grandmas. Buick had a progressive twin carburetor set up on their straight 8 back in the 1940s. Chevy used a multiple carb on the Corvette 6. Hudson had their famous dual carbed 6 in the Hornet. Of course the Brits and Europeans used the 6 as their top of the line engines so they were well developed. In the U.S. it’s not that the technology wasn’t there it just wasn’t seen as cost effective when a simpler V8 could more easily provide increased performance.
Most American sixes had very poor fuel distribution systems, with single barrel carbs with tortuous intake manifolds, often cast into the head. The exhausts were strangled into a exhaust header that was designed for production economy over any kind of performance. The Chrysler Slant six has a much better design for breathing and they were the most successful in racing. I’ve had Datsun and Jaguar sixes that were designed for performance and they are a delight to drive.
My ’70 Mustang had a 250 cid six that could have benefitted from some performance additions but the parts are quite expensive compared to V8 components. The famous AK Miller was very enamored with the light Falcon six and published several articles on hopping them up. There is a good on line forum dealing with this engine.
Yeah, the superior fuel distribution of the Slant-Six was the main reason it was such a good engine and what set it apart from the other inline sixes of the day. Although Chrysler’s claim that the 30 degree cant was for hood clearance, the real benefit was making enough room in the engine bay for the longer and more straight intake runners that made for a much more even fuel distribution than the archaic log-type intakes of the bolt-upright sixes. On the latter, the fuel mixture had to make a 45 degree right turn to get into the first and last cylinders and it was a severe impediment to both performance and longevity.
On top of that were the dreadful cast-in intake manifolds (mostly Fords) so it wasn’t even possible to use an aftermarket multi-carb set-up without a lot of torch and grinding work on the head. It’s no wonder the Slant-Six became the gold-standard of the era.
It’s always been my understanding that the main reason that the OHC 6 was discontinued was that it was deemed too costly to produce.
I believe there were some reliability issues as well. Pontiac went to great lengths to tell how durable the timing belt was (but what American car owner or service station mechanic had dealt with a timing belt before?) Were there some issues with the cam bearings?
I knew of a beautiful black, red interior, 4 speed Sprint 6 converted to a 400 in 1973, of course it was 7 years old by then…
Top-end oiling was a problem with the OHC6, and if one wasn’t attentive to regular (and fairly frequent) oil changes, the top end would gum up and starve for oil. This is what killed the OHC6 in my grandparent’s ’66 Tempest (that I subsequently owned and swapped in a SBC). I still have the valve cover hanging in my shop.
I wonder how the Pontiac OHC-6 would respond to modern synthetic oil (Mobil 1 made its appearance in the early eighties). Seems like it would be just the ticket to cure the gumming-up of old dino oil that would clog up and kill the engine.
As I recall, there were no insert bearing shells for the camshaft, but it ran directly in the aluminum. Corvair did the same, but submerged in oil at the bottom of the engine. Yes, on top not so much oil.
I seem to recall that the OHC 6 was developed at the behest of John DeLorean, who liked to push the envelope and liked European cars. But, like GM’s early turbocharging efforts, it was “too soon” for V-8-loving Americans and their cheap gas.
Americans generally weren’t quick to embrace new technologies in this period, either. Across the street at the Chevy dealer, you could buy a Chevelle with a 250 cubic inch OHV I-6 with 155hp that ran on regular gas, if you really wanted a 6. But mostly, Americans wanted V-8s.
Ah, the Pontiac OHC-6 or ‘the revenge of the Corvair’.
Delorean badly wanted a sports car. And why shouldn’t he? Pontiac was GM’s de facto performance division. There was just one problem: Corvette. Ed Cole was fiercely protective of the Corvette’s market and anything even remotely resembling the Corvette from another division was a non-starter.
And with his end-run around the 14th floor with the GTO, they were going to be watching him closely. Delorean wanted Pontiac to be the American Jaguar and that was really the focus of the OHC-6. Unfortunately, it would be tough to stuff a tall OHC-6 under the hood of a low-slung American car. The Pontiac Banshee
concept (which would ultimately be the 1968 Corvette) didn’t seem much like a Jaguar.
But the Jaguar-like OHC-6 got the greenlight, anyway, and went into the Tempest/Lemans and Firebird. As others have said, it was pricey and performance was no better than a run-of-the-mill pushrod V8. If not for the go-go V8 musclecar sixties, it might have had a chance.
Not to mention the irony that the cammer lost out to the cheaper V8s since Delorean’s GTO (and Iacocca’s Mustang) were major factors in the death of what was supposed to be GM’s other ‘sporty’ car, the Corvair with its revolutionary, rear-engined pancake six.
Aluminum head; just putting in holes & letting the aluminum be the bearing surface is pretty common with OHC.
I’m guessing that it was cam lobe wear, getting enough oil to the lobes.
These also had hydraulic lifters sneaked into the mechanism.
The entire head isn’t aluminum, just the camshaft carrier. It did have hydraulic lash adjusters, though, which was a real novelty for an OHC engine at the time.
Here’s hoping that Poncho still has the Sprint Six instead of the dreaded, almost inevitable, 389/400 conversion.
Leaned to drive in my Dad ‘s ’66 2 door Sprint (3 on the floor Hurst shifter). He traded in a ’63 slant 4 Le Mans, so the 207hp seemed peppy, and the white stripe on the black body (with black interior) made it look faster than it was.
http://phscollectorcarworld.blogspot.com/2017/08/the-1966-67-ohc-6-and-sprint-tempests.html
The Tempest 4! When better paint is shaken. Was that to prepare customers for the later odd-fire Buick V6?
The Bordners next door had a series of GTOs for the Mrs. To drive starting in 1966. In 1967 Mr Bordner brought home a LeMans Sprint 2 door hardtop in light metallic green with a black vinyl top. I know it had a stick, probably a 4 speed. I remember the unusual exhaust note, which sounded unlike anything else on the street.
With a 66 GTO in one half of the garage and a 67 LeMans Sprint in the other half, my next door neighbors must have been John Delorean’s personal focus group. ☺
My only experience with the Pontiac OHC six was in a ’67 Firebird that belonged to my college roommate. It had the “Sprint” engine with a 4 bbl and 2 spd auto. I borrowed it for a weekend to visit my folks, 100 miles distant, as my ’66 Mustang was in the shop. Once it was rolling it ran quite well and I loved the sound of the secondaries opening up combined with the sound of the six.
My Mustang (289-2v & Cruise-o’ Matic) would beat it off the line but wouldn’t keep up with the Firebird at speeds above 65 mph.
To be fair, the small-block Ford V8 was the least peppy of the breed. The flip-side is it was also the most narrow (the reason it was chosen to go into the AC Ace and Sunbeam Alpine). So, the OHC-6 with a 4v carb would be a good match for it, especially if it was a low-performance 289-2v. But an LA-series Mopar or SBC wouldn’t have much trouble beating the Pontiac Sprint 6.
Friend of mine had a 69 Mustang Grande 302 2bbl 3sp on the floor, raced a 67 Lemans OHC 6 4bbl at Northstar drag strip in Minnesota and beat it. Actually trophies as these 2 were the only ones in their class (N/Stock)
T comment about maintaining this engine is something that I remember from a friend’s wife’s aunt’s husband who was toying with the engine in The Catskill Mountains in 1970 and remarked to me that it required extra maintenance. He liked the pep of the engine. I find this article interesting as I read it today because I remember Avery fooling around with the engine with the valve cover removed.
People wanted a V8, 6s were kind of outcasts. GM went all out on the motor with tons of advertising for once to no avail.
A sad foot note to when the Engineers were trying so hard to give the public what they wanted .
After tooling up for it I’d have expected GM to keep offering it across all lines as it would have made a dandy choice for all i6 powered vehicles using the cheaper thinwall i6 engine.
Light trucks too could have made this very popular once the word got out .
-Nate
“A sad foot note to when the Engineers were trying so hard to give *Bob Lutz* what he wanted.”
There, I fixed it for you. 🙂
I had 66 lemans 4 speed sprint in 66. There was no 283 or 289 2 barrel that would beat it. Top end “raced” a 283 chevelle and was slowly pulling away at 120 mph. Crazy back then. I took it to the strip once with another sprint and a 273 barracuda 65 maybe and a 64 impala 327/250 4 speed convertible. I got the impala 1st and lost .I had high 16’s to the chebby 15.5’s The other sprint beat the 273 with another high 16 run. So the that sprint raced the impala with the same times and results. To this day I think the impala was lying and either had a 275 h.p. or 300 h.p as it did have a 4 barrel.
I would have challeged with a 50$ teardown fee but I had no extra $ at the time. The fact that my sprint and the 2nd one were both running 16.9’s told me that was it for the quarter. Then I read an article a the1966 car mag.that had taken a 3 spd and “tuned” it to go 15.5’s in the quarter.I think the mag. was Motor Trend. hmmm? But I did get mid 20’s mpg which was important as a 17 year old even with cheap gas. Great sounding engine. Even my 350 h.p. 350 C.I. chevvy with street headers doesn’t make me smile like that LeMans .