Service replacement OHC6 Sprint engine

RJMiller · Veteran Member

Service replacement OHC6 Sprint engine

Beaumont4008 · Uber Guru

I had a 3.8 in a 67 Firebird sprint model years ago, great little engine. Would be neat to swap in a acadian. Is that the 3.8 or the 4.1 engine ?

RJMiller · Veteran Member

I am not sure, being a service replacement it could be either but it does need a rebuild and you could build it to either specs. Cheers :)

427carl · A Poncho Legend!

CdnGMfan · Canadian Poncho Superstar!

For '67 it would be a 3.7 liter or 230 c.i.d.; for '68 they changed the crank and it became the 4.1 liter or 250 c.i.d.

It looks as though it is a Sprint engine with the Quadrajet. It should have a 10.25:1 compression and be rated at 207 (3.7) or 215 (4.1).

The 3.7 shared the crank with the Chevy 230 but the 4.1, although it shared the stroke with the Chevy 250, used its own unique crank that would be safe for high revving combined with the longer stroke.

It would look nice with the correct silver paint, then add some polish to the aluminum covers.

Pontiacanada · A Poncho Legend!

They are cool engines!

Overhead Cam (OHC-6)

The OHC-6 design was adopted by Pontiac in the 1966 model year. The block was based on the Chevrolet Straight-6, but had block and head castings unique to the OHC. Both head and block were cast iron; only the large cam carrier/valve cover was aluminum. The engine featured a Single OverHead Cam and was the base engine in the Pontiac Tempest.

The Pontiac OHC-6 engine shared internal dimensions with the standard 230-cubic-inch (3.8 L) Chevrolet I6 block. The OHC head design put it in the avante garde of Detroit engineering. The single camshaft was supported by journals within the aluminum valve cover: no separate bearing shells were used. The cam was driven by a glassfiber-reinforced cogged rubber belt, instead of the usual metal chain, making it state of the art for the time - and very quiet. Valves were opened with finger followers (centered under the cam) that pivoted at one end on stationary hydraulic adjusters. The oil pump, distributor drive and fuel pump drive were not within the block, but were handled by an external jackshaft in an aluminum housing that bolted to the right side of the block. The jackshaft was driven by the rubber timing belt. The head had a single port face (exhaust and intake were both on the left side) and the valve stems were strongly tilted towards the left. This engine was used on the 1966 through 1969 Tempest and Le Mans and the 1967 through 1969 Firebird.

A high-performance version, called the Sprint, was an option. The Sprint featured high-compression pistons, a hotter cam, dual valve springs, a split/dual exhaust manifold, a better coil and utilized the then new Quadrajet 4-barrel carburetor. It was the first American high performance six cylinder engine since the demise of the Hudson Hornet.

The 250ci Engine (4.1L) replaced the 230ci (3.8L) from 1968 to 1969. The base engine produced 175hp while the Sprint versions that came with the automatic transmission were rated at 215hp. While the versions with manual transmission received a hotter camshaft which boosted the horsepower ratings to 230hp.
The Pontiac OHC-6 engine ended production with the 1969 models.

Like other Pontiac engines of the era, it was not available in Canada; Canadian Pontiac automobiles came with the Chevrolet OHV six instead.

Pontiac Overhead Cam Six engine

The 230 OHC-6 engine was produced in 1966 and 1967. Power output was rated at 165 bhp (123 kW) from a displacement of 230-cubic-inch (3.8 L). The high performance Sprint version produced 207 bhp (154 kW).

1968 Pontiac OHC 250 1bbl

Pontiacanada · A Poncho Legend!

The more I'm reading about these engines, the more interesting I find them!

DeLorean Banshee ...

http://www.pontiac-lemans.com/grafik/history/pdf/1964_ohc_banshee/1964_ohc_banshee.pdf

-- Edited by Pontiacanada on Thursday 20th of May 2010 09:25:51 AM

DANO65 · Poncho Master!

I wonder if 1 could be modified to fit in say a 67 Acadian????? Now wouldn't that just blow peoples minds. biggrin

427carl · A Poncho Legend!

I don't think you can put a Pontiac motor in a Acadian wink

CdnGMfan · Canadian Poncho Superstar!

Back in 1976 my older sister's highschool teacher owned a nice, clean 1967 Tempest Custom convertible with a 230 OHC six. It was that purple Plum Mist colour with a black top & interior. I believe it was sold new in Canada as a costlier import.

I'd love a Firebird Sprint from '68 or Lemans Sprint from '67. I'll bet most people didn't know that a Tempest / Lemans Sprint was offered through 1969 (back in '69 most enthusiasts were into large V8s but the insurance surcharges were just starting to break up the party).

-- Edited by CdnGMfan on Friday 21st of May 2010 12:33:12 AM