The Pontiac Tempest Le Mans Sprint needs more love.

"Jim Spanfeller" (awesomeaustinv) 12/04/2019 at 14:42 • Filed to: None

4

20

The Pontiac Tempest Le Mans Sprint is a somewhat obscure but very interesting and rare car. It was basically a Tempest Le Mans with a heavily modified hot-rodded inline six. The basic design of this engine was based on Pontiac’s regular inline six, but they added an unusual (for the time) belt- driven overhead cam, and modified or redesigned nearly every part of the engine. The least powerful version of the engine had 165 horsepower, which was not bad for the time, but with the Sprint option, you got stiffer suspension and around 207 horsepower. The output grew to 215 horsepower in ‘67, and as much as 230 by 1969, the last year of production.

Performance was on par with the competitive small V8s of the time, making it a pretty good sleeper car. As a nice bonus, the inline-six weighed less than the V8s it competed against, which is always a good thing. In a way, it was like the GTO of inline sixes. They weren’t without problems, though. The oil gallery returns were apparently too small, so if you drove the car the way it came from the factory for too long, the fancy overhead camshaft would suffer from inadequate lubrication and wear down. Enthusiasts say that you can fix the problem by drilling the holes larger, which makes the engine run much better. It seems that these cars are often overlooked because of America’s obsession with V8s, which is a shame, because here was a high-revving inline-six that could embarrass V8s. It’s a fascinating car with a fascinating engine , and I think it deserves more attention than it gets.

WilliamsSW > Jim Spanfeller 12/04/2019 at 14:51

1

Available in the Firebird, too!

From what I understand, getting parts for these engines isn’t easy these days.

slipperysallylikespenguins > Jim Spanfeller 12/04/2019 at 15:01

1

Very neat engine. The development was overseen by Mr. Delorean, he was going for a European feel for Pontiac. 

punkgoose17 > Jim Spanfeller 12/04/2019 at 15:06

1

Yes!

MoCamino > Jim Spanfeller 12/04/2019 at 15:07

1

TIL I want a Pontiac straight six to put in my El Camino.  If I could get the 230HP version, that would be a 50% HP increase over my current 305, and honestly would be plenty of power for me.  They were apparently 230HP and 255ft-lb of torque.  I’ve always loved the Tempests, and now I love them even more.

PartyPooper2012 > Jim Spanfeller 12/04/2019 at 15:28

0

Catch a murder charge pinned on ya??? No thanks

WilliamsSW > MoCamino 12/04/2019 at 15:44

1

Keep in mind that those were gross HP not net, like any pre-1972 engine, so your grain would be less. Still a neat engine.

Snuze: Needs another Swede > MoCamino 12/04/2019 at 16:03

3

I think Clifford’ s (inline 6 performance specialists) may still carry some performance parts for these. My buddy was looking for a “weird” (read: non-V8) hotrod engine and we took a look at these, so I learned a bit in the process.

They are unique but not necessarily “good”, at least by modern standards. They still use a uniflow head (intake and exhaust on the same side) which has a bunch of problems from a performance standpoint. It’s also an all cast iron, so while lighter than the iron V8's of the time, it’s still not “that” light.  But 230 HP gross isn’t bad, probably still over 200 net. And I think there’s still some power on the table if you were do some mods (bump compression, mild porting, header, revised intake or convert to fuel injection).  It certainly has the potential to be unique!

punkgoose17 > Jim Spanfeller 12/04/2019 at 16:04

1

What would be wonderful is to transplant an I6 Sprint into an early 60's Tempest to get the rear trans axle and IRS.

Snuze: Needs another Swede > WilliamsSW 12/04/2019 at 16:07

2

My buddy was thinking about sticking one in a hot rod earlier this year . They are out there and not crazy expensive, I want to say most of them were around $1,000 give or take, which doesn’t seem outrageous to me . They share some parts with the 230/250 inline engines so things like pistons, rods, bearings, and certain gaskets aren’t too hard to find. But I think some of the specialty stuff, like cam bearings, are harder or at least more expensive to get.

WilliamsSW > Snuze: Needs another Swede 12/04/2019 at 16:17

1

  Yeah, the engine shares a lot of design/ dimensions with the Chevy 230/ 250 but I have no idea what parts from the Chevy fit it, but the basic stuff you mention ought to.    C ertainly anything related to the cam will be hard to find.

That would be a sweet engine in a lightweight hot rod!!

Jim Spanfeller > WilliamsSW 12/04/2019 at 16:30

1

Dang it! I knew they were available in the Firebird as well and was going to mention it, but I forgot. Thanks for the reminder! The sources I used for this post said that there are still a couple companies making parts for these engines, so while parts aren’t super easy to find, it’s not impossible. They’re out there.

Snuze: Needs another Swede > WilliamsSW 12/04/2019 at 16:31

2

Agreed, cam parts are one of the harder things to find . The accessory drive is pretty weird, too, bunch of stuff driven off a jackshaft.

My friend ended up going with a different engine for 2 reasons. One was the cost and difficulty in finding some of those sorts of parts. Two was, honestly, while this engine was great for it’s time, it’s still not all that great. It’s all iron so it’s still a hefty boy, and the cylinder head design is atrocious. We’re both engineers so we obsess over stupid stuff like that. But it’s all iron which limits it’s heat transfer capabilities which in turn limits compression, and it’s a uniflow head (intake and exhaust on the same side) so the ports suck and you get a lot of intake heating, which again, hurts compression.

We ended up with a Volvo 2.3L turbo Inline-5  and a head from a ‘ 98 V70, and we’re swapping the turbo for an Eaton M62 supercharger! It’s going to be... interesting

Jim Spanfeller > punkgoose17 12/04/2019 at 16:33

1

That would be interesting. Aren’t the older ones lighter too?

Jim Spanfeller > slipperysallylikespenguins 12/04/2019 at 16:34

0

It seems he succeeded, with authentic E uropean reliability as well ;)

WilliamsSW > Snuze: Needs another Swede 12/04/2019 at 16:35

0

Neat! Some posts on that build would be fantastic!!

And yeah, almost any American engine from that era is an iron pig. The 6 as considered lightweight, but that was comparing it to the monstrosity that  was the Pontiac V8. Cool in many ways, but not the best way to go fast, considering design issues, weight, and parts availability.

WilliamsSW > Jim Spanfeller 12/04/2019 at 16:39

0

Yes, they are. And with the rear transaxle and the “ half of a 389" slant 4, they had 50/ 50 weight distribution, too.

A lighter, modern engine would be sweet in a 1st gen Tempest, but the rope drive and transaxle can’t take a lot of power, IIRC.

Snuze: Needs another Swede > WilliamsSW 12/04/2019 at 16:53

0

I posted some junkyard pictures when we pulled it a couple weeks ago . I think right now it’s just sitting in his garage on a stand. We both work full time  and are also both going to grad school. But I know this Friday he’s going to get pickup a bellhousing for it (you can use a Volvo 960 RWD automatic trans bellhousing, cut a hole in the side for a hydrualic throwout, and get an adapter to mate it to a Mustang T5 manual). Over the holidays I’ll have some free time so we’re going to get together and clean it up and start mocking up the blower mount, intake, and the exhaust system. I’ll make sure to take more pictures.

MultiplaOrgasms > Jim Spanfeller 12/04/2019 at 17:08

1

Obvious shoutout to the IKA Torino 380 , which was basically a Rambler with a itali anized body, built in A rgentina and powered by a modified 230ci Jeep SOHC Straight six. These engines made something along the lines of 215hp in their hottest production form with triple W ebers , although I can’t tell for sure what measuring standard they used. Apparently racing engines made up to 350hp. These are by sheer accident also the last front-engined, rear wheel drive passenger cars built by Renault.

Jim Spanfeller > MultiplaOrgasms 12/04/2019 at 17:32

0

I had no idea that Italian-bodied Jeep-engined Ramblers were a thing. And now I want one.

punkgoose17 > Jim Spanfeller 12/04/2019 at 18:38

0

Yes the older cars are smaller and unibody. Apparently the newer ones were larger and ladder frame.