Six Cylinder Engines

Today we see a lot of cars using a V6 design, in particular many great front wheel drive cars built by Mitsubishi, Acura, Honda, to name a few. There was a time when a six cylinder engine meant an in-line six and there were a few really interesting ones out there.

Jaguar had an exstreemly strong version in the sixties.  In the XKE it powered the two seater with such alacrity that it could hold its own with many of the muscle cars of the era and then out corner them.  It did suffer from the curse of Lucas.  The almost exclusive vendor of British car electrics was a company called Lucas.  Most owners referred to Lucas as “the Prince of Darkness”.  Whether it was the heater, the coil, or the light switch, Lucas electrics would be certain to let you down and sometimes in spectacular ways.  In the days of carbon spark plug wires Jaguar’s six cylinder ran them down between the cam covers where, as they aged, they could arc to one another providing misfires and frustration. 

Those were the days of points and condenser ignition.  It was odd to find cars designed for the British Isles would have a problem in damp and foggy environments, but they consistently frustrated their owners with “morning sickness” on this side of the pond.  There was a great story of a local mechanic, Al, who was called out one foggy Cape Cod morning to cure such a problem.  The owner was a wealthy man that lived in one of the more exclusive areas.  He had a multi-car garage and had several classic British cars in his stable.  The one he wanted to drive that day was an XJ-6 that refused to start.  All sowed up at the man’s house while the owner was still in his robe and slippers.  The man had planned to crank up the Jag and let it warm up while he had his morning coffee, usually a good idea.  So Al had him open the bonnet (hood) and then took a peek inside.  The owner, naturally curious stood near by to see what Al would do.  Al removed the distributor cap and pulled off the rotor.  “Ah ha”, said Al.  “Do you have a $100 bill?”  A bit flustered the owner of the Jaguar fussed about in his robe.  Al said,”never mind I have one,” and pulled one out of his wallet.  Then he took the bill and ran it between the points in the distributor.  He put the rotor back in, attached the distributor cap, and told the man to start it up.  He did and the engine immediately came to life.  The owner was monetarily grateful and would later recount Al’s magical genius to his friends and contemporaries.  The reality was that any piece of paper would have done the trick in wiping the moisture from the morning’s dew off the points, but Al’s showmanship was brilliant.

There have been a couple of notable six cylinder engines in the US as well.  Plymouth had the slant six.  It was a long stroke engine that designed so that the cylinders were at an angle, much like a bank of cylinders on a V8 engine.  This provided clearance for more conpact body designs and was offered in cast iron as well as aluminum blocks.  It was a strong dependable engine that could be had in as large as 255 cubic inches of displacement. 

Another six cylinder engine from America that never achieved the recognition that it deserved was Pontiac’s Overhead Cam (OHC) Six.  This was designed in an era when cams in American engines drove push-rods which acted on rocker arms in order to open and shut the valves.  The OHC 6 was revolutionary in that aspect in particular.  This offered it the ability to breath much better than the traditional six cylinder designs.  It came in a 250 cubic inch displacement and was offered with a four barrel carburetor in its “Sprint” configuration.  A friend had a 1957 Pontiac that came with a V8 engine that had a carburetor fire.   he repainted the scorched hood and replaced the bulky V8 with an OHC 6.  This took a lot of weight off the front end and allowed him to put in a transmission with over drive.  He ended up with a classic looking car that had great gas mileage and excellent power.

The straight six is not seen much any more.  It takes up too much space with its length and has a much tougher time passing emission requirements than the V6.  They were some great engines though.

 ohc6.jpg

About these ads
This entry was posted in Automobiles, Cars, Engines, Modifying Cars, Sports Cars. Bookmark the permalink.

33 Responses to Six Cylinder Engines

  1. mark says:

    Jim, You might also post on some of the more odd engine cylinder configurations to roll off the assembly lines. For instance, Audi had a straight 5 cylinder in the early 90′s. Subaru had that boxer 4, and now VW and Audi have a ‘W’ 12 with 3 banks of cylinders which allows a more compact fit. V10′s were started here by Dodge, originally planned for their trucks, and made famous in the early 90′s by the Viper. Ford followed with their own V10, with argueably less success. GM also has a straight 5 cylinder seeing duty in some trucks and SUVs today. You could probably dredge up something really historic, with a 16 cylinder….probably a Duesenberg. And then there is the Wankle with it’s rotors, each rotor being roughly equivalent to 3 cylinders in function, if not size. The RX-7 had two rotors, and a 3 rotor was reportedly in the works. Speaking of 3′s, I remember seeing under the hood of a late 80′s Geo Metro and asking “what the…?!!” when I saw the distributor with 3 wires on it. A 3 cylinder, 900 cc motor. Somewhere out there, I saw an article on a guy that welded two 350 Chevy’s together to make his own 700 cube V16…. 1,3,4,5,6, 12, or 50 cylinders, people with some “enginuity” will make a hot rod out of it.

  2. mark says:

    Jim,

    Good post. Another aspect might be discussion of less conventional engines. We are used to 4, 6, 8 cylinder configurations. Audi had a straight 5 cylinder, and VW and Audi now have a “W” 12 configuration of 3 banks of 4. Ford and Dodge both have V10 offerings, although Dodge has done the better job through the vipier program. Mention of the Wankle rotary in the RX7′s of the past bears mention. I remember lifting the hood on a late 80′s Geo Metro and asking “What the…” at seeing 3 plug wires on the distributor – yup a 3 cylinder 900 cc motor. In the diesel world, detroit built a lot of variants of the ’71′ series motor, ranging from the 2-71 to the 14-71. These were 2 cycle, supercharged motors where the first number indicated the number of cylinders, and the second number indicated the cubes per cylinder. The 4-71, 6-71, and 8-71 variants were often the early sources for hot rod superchargers.

  3. Travis says:

    Hey do you know how much the 250cid ohc six would cost and where to get one?

  4. Travis says:

    I found a nice 1968 ohc 6 and i was wanting to know what transmission to put on it? Do you know how much they cost?

  5. jimsgarage says:

    Tough question to answer Travis as there are several choices. They range from an automatic with over drive to a five speed manual.

  6. Stefan says:

    Jim,
    I like straight six. I have an XKE.

    I have always wondered which is smoothest. Steraight Six or Boxer Six? Any idea were I can find the answer and explanation?

    Regards Stefan

  7. jimsgarage says:

    Stefan -

    Your question deserves a reply. I have actually been doing some research on it! Once I’ve done my work I will reply to your question in a post rather than just a comment.

    My bet is that the stright six is “smoothest”, but we’ll see what the facts support.

    Thanks for the question.

    Jim

  8. Retro says:

    Who doesn’t love classic cars? Seems everybody does and hollywood has jumped on the bandwagon too. You see them in just about every movie and TV show now.

  9. Miguel says:

    would a 250 straight v6 fit a 2000 dodge stratus

  10. jimsgarage says:

    You talk about a straight six 250 (cubic inch?) in terms of it also being a v6. The stratus comes in a v6 configuration. If you are trying to put in a straght six there will never be enough room. As far as another v6 goes it is far more likely, but a lot of work and expense.

  11. w says:

    The W-12 motor has 4 banks of 3 cylinders.

  12. Al Cortes says:

    Where can I find an aftermarket 6 cyl. distributor to replace a Bosch distributor used on the early sixes BMWs . Want a point distributor

  13. jimsgarage says:

    Al -

    I don’t know of any such distributors. You might want to try the various BMW owner forums that deal with that era six cylinder car.

    Jim

  14. john says:

    anyone know where the story is about the guy who welded two 350 engines together and made a V-16 that ran???

    thanks

  15. Jamie says:

    Al, Why would anyone want a point distributor? I had an old (1972 F250 4X4) Ford pickup. I built a 300CID straight six with Clifford headers, an Offenhauser dual port manifold fed by a 390CFM 4bbl Holley. I also added electronic ignition and an electric, in-line fuel pump. That engine came to life and had torque to spare. I always dreamed of fitting that engine with TB fuel injection, but the carb worked so well that I never got around to it. That truck is for sale today, if anyone is interested.

    Jamie

  16. Chuck Crawford says:

    Where can you get an overhead cam six complete?

  17. jimsgarage says:

    Chuck -

    Their might be some Pontiac forums out there that could help you locate one. Other than that I would suggest craigslist.org or maybe even eBay.

    Jim

  18. Fred says:

    I have bought four OHC6 Pontiac motors on ebay in the past year. One is a 1967 Sprint motor with a four barrel carb and 230 cubic inches. The others are one barrel carbs and 250 cubic inches. Cliffords sells manifolds and duel exhaust systems.

    Punch in 1968 Pontiac motors on the ebay search. I checked almost daily to find mine. I had to go pick up each motor from the seller. Average price ran $400 for a complete motor assembled. All need to be rebuilt. My Godson is putting one in his 1955 Pontiac Catilina coupe.

  19. jimsgarage says:

    Fred -

    Thanks for that information! The OHC6 was quite and engine and way ahead of its time. Years ago a friend of mine had a 1957 Pontiac that had had an engine fire. He pulled the V8 and replaced it with the Sprint OHC6. It took at least a hundred pounds off the front end and he ended up wiht a much stronger engine.

  20. rogerwilcox says:

    I have a delco remy distributor off of an omc inline 6(gm?) in my boat (1973 reinell). part# 1112942 4j6. All thats wrong is the springs broke inside the distributor. I used too long of a screw when changing the points and condenser and it broke the springs. I cant seem to find anything on the dist# and I can’t find a cross referance for a new part even at delco’s website whats my best option? Thanks!

  21. jimsgarage says:

    Since the distributor is used in a boat all part numbers will be unique. This is because everything must be certified for marine use if insurance is to remain in force. You can probably find an automotive equivalent in terms of springs. I would check with hot rod web sites or supply shops. Replacement springs should still be available. You may have to check with a marine supply shop.

  22. Fred Barnes says:

    Jim:
    The Pontiac Owners Club has a chapter dedicated to the OHC 6. There is also a web site entirely devoted to the Little Cammer that Could.

    I just picked up a 250 cube Sprint motor with the four barrel carb. It was in a 68 Lemans and ran fine. Started right up blipped the throttle a few times and it settled down to a nice idle. Got the motor, 3 speed trans and the radiator for $4oo. I just love these guys that take the SBC crate motor route. Had to drive 400 miles round trip to get it but what the hey. I’m up to 5 motors now. It’s all the excuse I need to buy that 47 Pontiac sedan I’ve been looking at. I mean a motor has to have a home ….right?

  23. jimsgarage says:

    Fred -

    That sounds fantastic. Such a deal! Putting it in a ’47 Pontiac sedan is a great choice, too. I hope you take photos of the process.

    Jim

  24. al hummel says:

    I am in the process of picking up the necessary parts for a 49/50 chevy project and would like to know if there are any out of the ordinary problems associated with using the 250 ‘cammer’ and o.d. auto. I will be using a Morrison chassis so at least it is up-to-date . I love the sound that is unique to a straight-six with “pipes”. Thank you

  25. jimsgarage says:

    You may or may not be able to get away with using the engine mounting points with the 6. My experience doesn’t that chassis. If you do have to fabricate some engine and transmission mounts be aware of the pinion angle and keep it neutral or to a minimum.
    I couldn’t agree more as regards the sound of the straight six and some free flowing exhaust. Let us know how your project turns out.

  26. Hi, this is jimmy Great points. Thanks for sharing that info , where i can find OHC6 pontiac aftermarket distributor Not everyone knows instinctively that the best Auto body car shap in Washington, DC, but if you own a car, something is to know.
    Thanking you

  27. alex schellenger says:

    Jim, I own a 96 MB S320. It’s the smoothest engine I’ve ever run. It looks like the European Straight 6 may be headed for the history books. They were arguably The best engines BMW, and Porsche produced as well. Any tips for keeping this baby running forever

  28. jimsgarage says:

    Alex -

    The MB six is another great engine. Don’t give up on the Euro straight six yet. As I understand it, BMW is moving away from the V engines and looking to turbo charging in the near term, especially for their M cars.

    In terms of getting the most mile out of your current straight six it will depend upon how it is driven and keeping up with regular maintenance. I expect that you change your oil and use a high quality oil and filter. Do a compression check at least once a year so that you can spot any problems with the valve train or rings. An oil analysis for each change can be helpful as well. If you have an experienced mechanic – experienced with that engine – he or she can let you know what the typical weak points are and you can keep ahead of problems. Often overlooked are things like engine mounts and the cooling system. Flush your cooling system at least every couple of years and have your engine mounts inspected for cracks and failures.

    That engine should be good for a very long time.

    Jim

  29. LARRY MYERS says:

    Can you direct me to a source for a Pontiac OHC six cylinder engine?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s