Educate me: Pontiac OHC inline sixes.

These have intruiged me since I first learned about them a few years ago. I know they were available in the mid size cars and the firebirds, and were considered really ahead of their time.

Any known specs on what kinda power can be made from one? I think it'd make a killer rat rod motor.

iirc the cam ran directly in the head, ie they did not have separate cam bearing journals, so a cam failure or an oiling system breakdown wiped out the head and made it a junkyard piece. google 'pontiac ohc' and i'm sure you'll find more info.

AngryCorvair wrote: iirc the cam ran directly in the head, ie they did not have separate cam bearing journals, so a cam failure or an oiling system breakdown wiped out the head and made it a junkyard piece.

And that's why you wont find many of them. A friend had that happen to his and he was very good with his maintenance.

There's a guy on the Bangshift forum building one here that may give you some inspiration:

http://www.bangshift.com/blog/Engine-Project-Spotlight-Getting-Started-on-a-Rare-1960s-Pontiac-OHC-Six.html

Not too familiar with it myself, but you may find some good info in that thread.

I'm pretty sure that they're really heavy.

I had one in a 68 LeMans. It was the Sprint 6 option. 10.75 to 1 compression, 4 bbl. carb 215 hp stock. I played with mine a little and it was about 250 hp and would pull to 7,200 rpms. I had that LeMans up to 135 until I spotted the trooper. He had a sense of humour and let me go when I admitted to over 120! Heavy motor and 30 degree valve seat on the intake. I bought it with 30k miles on it and had to do a valve job, but it ran like stink over 3k rpms.

AngryCorvair wrote: iirc the cam ran directly in the head, ie they did not have separate cam bearing journals, so a cam failure or an oiling system breakdown wiped out the head and made it a junkyard piece. google 'pontiac ohc' and i'm sure you'll find more info.

I've never actually seen an OHC motor that has bearings. They all run in the aluminum head, and if the Tin Indian ones failed, it would be an oiling issue, not a material issue.

Don49 wrote: I had one in a 68 LeMans. It was the Sprint 6 option. 10.75 to 1 compression, 4 bbl. carb 215 hp stock. I played with mine a little and it was about 250 hp and would pull to 7,200 rpms. I had that LeMans up to 135 until I spotted the trooper. He had a sense of humour and let me go when I admitted to over 120! Heavy motor and 30 degree valve seat on the intake. I bought it with 30k miles on it and had to do a valve job, but it ran like stink over 3k rpms.

Dad owned one in a LeMans too. Sprint edition like yours. Had a hurst shifter. He said he could do really well against small block cars of the same era. 215 hp stock is pretty damned good.

Too bad the cam design wasn't better. Dad mentioned he had a hard time keeping valve guides and rings in his.

In 1969 they increased the displacement a little (215ci to 230ci, I believe) and the rated horsepower for the Sprint option went up to 230hp as well. The camshaft is kind of the Achilles heel of those engines, they did have some oiling problems that could wipe out the lobes. Also, today it's hard to find a decent replacement cam for them - someone had a run of Sprint cams built a few years back, but I believe that was a one time thing and they were all sold.

I looked at a '67 Firebird with the Sprint option back in the early 1970s and thought hard about buying it, but the car was in really ratty shape so I passed.

IIRC, an achilles heel with these was the cam drive pulley: they either cracked and crumbled, or the center "disconnected" itself from the rest of the pulley, and blamo. My father had one in his LeMans, I recall him having oil leakage problems, from where, I don't know...but, for GM, they were ahead of their time... I'd imagine a good running one today would not be inexpensive, not unless they're simply being overlooked by their big V-8 brothers.

What, no hotlinks yet?

We had one of these in my old auto shop class that was essentially brand new, donated by a local Pontiac dealer back in the late 60's. It was awesome looking, and I wanted to steal it.

SilverFleet wrote: We had one of these in my old auto shop class that was essentially brand new, donated by a local Pontiac dealer back in the late 60's. It was awesome looking, and I wanted to steal it.

Yep. Me too.

so which one of you got it?

http://sohcsix.yuku.com/bsohcsix Forum deticated to the OHC six.