The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by Michael_e, Mar 13, 2011.
I seem to recall a magazine article from way back when that detailed a Pontiac six swap into a Jag.
It's quite possible that somebody may have
have swapped a Pontiac OHC-6 in, so I'm,
not saying you're wrong - but likely, the
OHC-6 you saw in that Jeep pickup was a
OHC Jeep 'Tornado-6'. Jeep beat Pontiac (and
every other North American manufacturer,
by several years too) to the punch by coming
out with an OHC-6 in 1962. Besides having an
overhead cam, unlike the later Pontiac OHC-6
that used inline valves and conventional
wedge-shaped combustion chambers, the
Jeep engine used inclined valves in a cross-flow
layout and hemi combustion chambers too! The
Jeep OHC-6 engine didn't lasting in North
American production - only until the end of the
1965 model year in civilian Jeep trucks and
Wagoneers - and through 1969 in Jeep
military trucks. But it continued in production
in Argentina, in refined and much upgraded form
through 1982 in Jeep trucks and AMC/Renault
'Torino' passenger cars. Apparently, in Argentina,
there's still good 'high-performance aftermarket'
support for this engine with cam upgrades and
4-bbl and triple-Weber carb installations being
i have a buddy that has a 66 4bbl ohc, call him it is probably for sale ,
One of my uncles had one in a '68 'bird that he bought new..
Old thread. I know. Sorry. As the king of buying $500 late 90's cars with 250,000+ miles (one a Taurus wagon with 286,515 on it) I stumbled across a solition for poor oil flow due to sludge & etc in small capillaries of already ran engines. Valvoline premium blue diesel oil + 1 quart 30w valvoline conventional.
The government cracked down on diesel and the API created a new fleet spec diesel oil without ZDDT , maybe ZDDP. The stuff of debate from old dudes worried about flat tappet mechanical lifters and pre-mature wear.
Anyway the secret is in the oil itself, they engineered the molecules to attach to sludge and thus turned the oil itself into a filter. I ran it thru a 3100 GM 30° v6 for 3k & it ate the varnish that made the lifter stick when cold. I ran it from here (WI) to south Indiana and back in a 1990 dodge ram with a 318 which was quite neglected in oil change parameters. After that 1000 mile run I drained it, filter felt like 10 pounds.Half my engine was inside it. Clean as a whistle now under the rocker covers and the PCV works agian (dodge has a test where you place a stiff piece of paper over the breather grommet and allow a minute for suction at idle to pull on the paper.
When I was a kid in my dads bread truck he served bait shops where the drunks were shad tree mechanics who would 'help' the owner by draining his oil and running 5 quarts of diesel to clear sludge for about 5 minutes before changing the oil. I think it was stupid. Was a lot of smoke.
The pontiac OHC-6 is its own inique desigs the only interchange parts with yhe chevy 6 are main and rod bearings. The head is cast iron with an aluminum cam housing this is sometimes mistaken for the cylinder head itself. the block shares no parts with the chevy. production was from 1966-1969 they were dropped due to the cost of producing them and the issue with not clearing the hood on the new for 1970 firebird.These were prety advanced for the 60's but with the big V8's available they didnt realy catch on. The bigest issue with them was a problem with wiping out cams thsi was solved in 68 with modifications to the lash adjuster oil feed to reduce presure. all in all they are a nice engine capable of producing 250-275 hp without much work. I am currently building one for my 31 pontiac coupe
I was in High School with a guy who had one of these engines in a Sprint (LeMans?). It was a 4 speed car and he used to bet any takers that he had a 6 cyl that could get rubber in all 4 gears. He was right and he cleaned up on a regular basis at the races before school.
I once had a base '67 Tempest---not even a Tempest Custom, just the cheapest Tempest available---with a Sprint OHC 6 and a 3 on the floor. It took a terrible beating and kept on ticking. I never had a tach in it, but I wish I had; it would be interesting to know just how far I wound that poor thing. I eventually swapped in a Saginaw four speed and sawed the Y pipe in half and ran dual glasspacks on it; it sounded like an old XK140 Jaguar. Even with 3.55 gears, it got very good gas mileage when I drove it like a sane man, which wasn't very often. Although they shared almost nothing with the Chevy sixes, I do remember reading about guys dropping 292 Chevy cranks in them along with special stroker pistons.
are those clouds and does he have a jacket on burr must be winter in AZ
So when the belt breaks do various valves meet their death in the tops of pistons with all the destruction that implies?
Or is it a non-interference engine like many modern cars that don't break every living thing when the belt pops?
one of my buddies had a Four barrel version with a four speed in his 48 Chev Pickup. That thing went like stink but he finally blew it up and put a 427 in the truck.
A lot of the ones I saw when I worked at two different Pontiac dealers in the 70's lost number five piston due to overheating.
Is that with 5.13 gears or in the rain?
In the mid 1970's I bought a low mile rusty 69 Lemans Custom S Sprint with the 4BBL OHC6 and T350. Put the entire drivetrain in a 64 El Camino, It looked factory installed. I used the interior too, buckets, carpet, console, seat belts. Even used the arm rests and door panels after trimming off the tops. I added Pontiac Rally II wheels and a GTO hood tach.
Chevy guys would scratch their heads when looking at that car.
I'd always say "I dunno, I think it's Canadian or something"
It was a good running engine and snorted for a 6cyl.
Sold it after a couple years.
I bough a 67 Lemans that had the 230 cu.in. 1-bbl 3 on the tree,it used oil & one day on the way to work going down a hill it started slowing down,I shut off & it stopped real quick,I knew what it was,checked the poil & yes,none showed on the stick.So I went & bought a couple of quarts,put them in & went to start it & it was so tight it wouldn't crank fast enough to start,finally someone stopped & we pull started it man it smoked really bad.
So one the way home I stopped @ a gas station got a gallon of used oil dumped in it for the 15mi trip home & it smoked so bad I couldn't see thwe cop car trying to stop me to tell me my car was smoking (I told him I noticed & was just trying to get home)
Found a '68 250 1-bbl put in it & that ran like stink,used to beat a bro in-laws new 302 Torino (he was pi$$ed)along w/alot of other cars.
I never heard of anyone losing valves due to timing belt failure on OHC sixes.....and where did you get the idea that many modern cars have noninterference engines? A lot of the ones I come in contact with are the opposite.
Are aftermarket camshafts available for these things? Supposedly a 300 hp version with three Webber two barrel side draft was made for race homologation, but abandoned when GM banned multi carb set-ups. Does anyone know if that thing actually had 300 hp? If so, was that on 100 octane or something more readily available?
Some modern engines are non-interference (also known was freewheeling) others are not. With emissions and fuel economy requirements it is necessary to use a carefully shaped piston, increasingly compression ratios above 11-1, sometimes as high as 14-1, are used. Almost all new engines have four valves per cylinder. All this makes it rather difficult to have a non-interference cam profile while still maintaining decent lift.
10-15 years ago, some guy cast up a run of OHC 6 camshafts, but I think that he sold them all and that was that.
cams are available both stock and HP versions, most of the hp versions are made on reground cores this reduces the base circle of the cam which requires milling the cam tower or shimming the lash adjusters and using longer valves to compensate for the reduced base circle
Whats were your times & MPH with this?
Going out on a limb here, seems with scrap prices so high around here, lots of the desirable parts for these are now next to impossible to find. I've decided to fab up my own intake and exhaust system for mine as I can't find any speed equipment around my neck of the woods. Still, there's something about these mills that just adds a cool factor to your build !!
I was just looking at a Kanter Auto Parts catalog and the list "New Production" cams specifically for the OHC 6 Pontiac motor with the 4 barrel, also known as the Sprint 6. There is nothing about having to turn in a core, so it looks like those of us that want to add a little punch to their base-model OHC 6 motors can now do it a little easier. Now, if someone would just do headers and intakes for them again!
Bought a brand new 66 Tempest Sprint for $2400. It had a 4 speed, posi, and an AM radio....bottom of the line 2 dr post body. It held the AHRA J/S F6 record at something like 85 mph as I remember.
Engine had NO cam bearings, the cam tower was align bored and the cam rode in the aluminum housing. The "lifters" were actually made to pump up to keep the followers against the cam. Engine ran really well at high RPM, the Saginaw has a 3.11 first gear and my car would leave two black tire marks from a standing start thru second gear using old bald tires (hard rubber). Car would out run a typical 283 Chevelle 4bbl.
The engine had an accessory drive on the side of the block which was belt driven by the timing belt. The accessory drive drove the distributor AND the oil pump. If you decked the block or milled the head (I had a milled head), the timing changed because of the belt....and the timing marks didnt align anymore.
The engine revved to well over 6 grand....like a 2 stroke bike, it liked being "on the pipe" and ran well at higher revs.
Mine never used any oil.
I have a 1967 Firebird Sprint with just under 60,000 original miles on it.
230CI with 4 speed, 4barrel, split manifold dual exhaust, 3.55 posi, dual traction bars, hood tach, deluxe interior and convertible to boot.
I am the third owner and have had it about 7 years. It has been a fun car with great torque, but not a speed demon by any means.
Pontiac was going all out for the performance image at the time. They wanted to give people something the others didn't have, even in the six cylinder bracket. The idea was the person who could only afford a six cylinder car could still be a little proud of his car.
In practice it was an excellent engine. Better performance than the typical six and better mileage too. Basically, small V8 performance and six cylinder economy in a light car like a Tempest. Most people who bought them were happy about it.
Their downfall was that not many people cared about performance six cylinders back then. Performance enthusiasts bought V8s. Thrifty six cylinder buyers were into economy and nothing else, they wanted the cheapest engine and the OHC wasn't it. So it go replaced by a Chev pushrod six.
The design was well thought out with some ingenious features. If it had stayed in production until the oil crisis hit it might have stayed around through the seventies. But in the late sixties the demand was not there.
ive never owned one but i have an original 1966 gm engineering manual on the ovh6 pontiac for sale in the classifieds if anyone is interested
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