4.9 tech

[hllon4whls]

This is damn close to 5.0 tech, so I'll give it a shot.

Why do most straight sixes from chevy, dodge and ford have the intake and exhaust port on the same side? It seems to have less performance potential this way. I cant see how it is any cheaper or easier to package because the timeframe for these engines were big trucks and big cars.

While I am at it, is the inline design of the six cylinder more conducive to create torque than a v8/v6 of similiar displacement and build?

Does anyone have any input?

 

[Michael Yount]

We modded the old 235 cubic inch 'stovebolt' six in my 55 Chevy years ago. Most of those in-line sixes (most inline 4's too) that didn't have cross flow heads have the cam and pushrods on the opposite side of the block from the intake/exhaust ports/manifolds. This means the designers can route all the ports (intake and exhaust) without having to work around the pushrods. Think about the intake side of your 5.0L - each intake port is constrained (width and shape/curvature) by where the pushrods have to run. In fact, back in the mid-to-late 60's Ford experimented with what they called a "tunnel port" 302 head. They simply made the port as big as they wanted in width and located it where they wanted, and created a 'tunnel' for the pushrod to pass through the middle of the port.

So in a way, having the intake and exhaust ports all on the same side did aide packaging - internal engine component and port location packaging. It's not optimum for performance, but very few American inline sixes were ever optimized for high performance applications

Chrysler offered hotter versions of the old slant six back in the 60's, and Pontiac offered an OHC version of the 230 cu.in. six in the sixties. As I recall, Car & Driver got a 67 Pontiac LeMans with the "Sprint" OHC six (230 cubes, 207HP w/4 barrel carb and 4 speed manual) to run in the 14's by bolting on a pair of small slicks, and stuffing 4.88 gears in the back. But in the days of cheap gas, big engine bays and big V8s - no one wanted a smaller displacement 'hot' six.

Look at many of the European inline sixes from years ago, and you'll find ohc or dohc engines with cross flow heads. Of course at the time, most didn't have access to big V8's or the engine compartment room to house them.

There's nothing inherent about the inline design that makes for better torque. In fact, the V8 is really just two inline 4's joined at the crank. But because of the engine architecture, usually the old sixes were oversquare - that is, they had a bigger stroke than they did bore. That longer stroke helped torque production especially at lower rpm. That's the main reason so many of the old sixes were so torquey down low - big, long strokes. 'Course, they didn't rev very high either - not much sense in taking many of them above 4000 rpm unless they're modded. There were some exceptions - Pontiac's OHC six was good for 6500 rpm - if the topend oiling problems it had didn't shut you down.

More detail than you wanted as usual from me....

 

[hllon4whls]

Actually about the right amount of detail. Thanks for the input. I had not considered the pushrod space needed in the heads.

Just a curiousity on my part. The 300 six seems to be begging for a turbo with all of the room, and having everything on one side of the block. Problem is that I will never do this because of budget issues.
C'est La Vive

 

[Michael Yount]

Big sixes actually respond really well to boost once you get comfortable with the notion that you needn't spin them high to make decent torque/power, and gear them accordingly. However, with any appreciable boost, aftercooling is required to optimize things. And since you've got to run plumbing to and from the cooler, a cross-flow set up might actually make for simpler plumbing and a more efficient cooler (pressure drop) assuming the inline motor is mounted longitudinally. Some of the modded SVO 4's are great examples of very minimal turbo plumbing because of layout.

But you're right - there's a whole slew of room on the sides....

 

[tjm73]

The Ford 300 I6 (4.9 litre) has a bore of 4.00" and a stroke of 3.98". It will quite easily handle 6000 rpm. It is a tough as nails engine. It's cammed for lo wend grunt though. A company called Clifford makes intakes, headers and cams for this engine that really wake it up. Hot rodded I6's have a unique sound that is definitly powerful, but different form the common V8.

 

[tjm73]

This is so intriqueing to me because it's not your average 5.0 build up idea. It got me thinking.

I looked up some specs on the 4.9/300 inch I6. It has rods that are 6.2097" long and a deck height of 10.000". The I6 layout is known to be very smooth. With low NVH. It's said they have some sort of natural balence.

As for boost, the ol' I6 should be well suited to the task. I don't think Ford ever really changed the 300 I6 much. It has 302 size rod journals and it has rather tall piston pin height of 1.757", so you could really put much longer rods in it with a 331 stroker piston. The 240 I6 (the "little brother" of the 300 so to speak) has very long 6.7947" rods that have the same rod journal sizing. It’d be a bolt in and be about .045” below deck height.

Because of the larger bore spacing and the no doubt higher heavy metal content of the block material and the inherently tough, over-built nature of truck parts, the I6 would yield impressive results from a blower or turbo.....IMO. Cylinder distortion would be less than in a 302.

The only bad thing is the exhaust port proximity to the intake port. The high heat generated by a turbo on the exhaust would likely, in part, transfer heat into the incoming air charge, somewhat negating the benefit of an intercooler. Same thing would happen with a blower, but it might not be as bad. Of course this is if absolute max power were being extracted. If a healthy boost in power for the street was the goal you could still get that easy enough.

The 300 also uses the standard small block bell housing pattern, so any tranny the fits the 302 will fit the 300.

 

[tjm73]

If you are thinking about a turbo 4.9/300 take a look at this.....

http://www.ford-trucks.com/forums/showthread.php?t=172939

 

[Michael Yount]

You can see how the 4" stroke is a torque-meister. Clifford Research is the company that specializes in inline 6 cylinder performance products - I used their headers and intake manifold on my Chevy six.

Inline 6's have primary and secondary rotating forces in natural balance. They are VERY smooth running just as V12's are (two inline 6's). Don't know about the rpm potential - although tjm seems to. Takes a special crank to survive at higher rpms in a big six. Because they're so long they suffer from torsional issues, and bending issues relative to the extra length. They're solvable - but you have to know what you're dealing with. tjm - do you know if it's a 7 main bearing crank? That helps quell the problems with the long crank. With boost and head/valve work, it could be quite a torquer at relatively low rpm (5000).

Packaging is usually the problem. It's deck height is comparable to a 460, and it's a good 10-12" longer than the 5.0L. Plus with all that height near the FRONT of the engine compartment - not sure how you'd shoehorn one in if that's what you had in mind. Now in old iron it would make a great motor.

My 55 through Clifford Research headers and duals/glasspacks (Thrush was hot at the time - I'm dating myself) sounded just like a GMC school bus -- a great resonance right around 3000 rpm. The reason for the similarity in sound is because many buses built in the early to mid 60's ran a 261 cubic inch version of the same engine.

 

[85_SS_302_Coupe]

I just thought i'd be a jackass and mention that the 5.0 is in fact actually a 4.9...so you're kinda in the right place

 

[IndyBlk5.0]

"You obviously have NO Idea what a 300-6 can do. 500-600 HP COULD be done fairly cheap (cheaper than a 302 can do it for)
Headwork with big valves, a good cam, STOCK forged HD crank, STOCK rods, and good forged pistons for a solid bottom end that would support 500-600hp. That setup alone would make ~275hp ~350tq (say about 1500$, but I build mine cheaper than that) Now get a T04B turbo and run 15psi boost and your at 550+HP and 700+ft-lbs torque, for another ~500$. If a person did all the work themselves you COULD build a 500HP 300-6 for UNDER 3000$" Whoa

 

[hllon4whls]

I just thought i'd be a jackass and mention that the 5.0 is in fact actually a 4.9...so you're kinda in the right place

Yes it is. 4.949 by my calculations.
300=4.917 liters
302=4.949 liters
306=5.015 liters
331=5.425 liters
347=5.687 liters
351=5.752 liters

1 ci = .01639 liters

 

[tjm73]

Don't know about the rpm potential - although tjm seems to. Takes a special crank to survive at higher rpms in a big six.

I tend to specialize in obscure info. To know what RPM an engine can theoretically handle you only nee to know this. The stand piston speed is 4000 feet/second. That assumes properbuilds with high quality parts and has been around for a LONG time. Modern engines can do more. Take 4000 feet/sec and multiply by the constant 6 (don't know where it comes from, just know it's the constant). Then divide by the engine stroke. There's you max safe rpm. The head on the 300 limits this without doing a bunch of porting, but it could probably be done.

Because they're so long they suffer from torsional issues, and bending issues relative to the extra length. They're solvable - but you have to know what you're dealing with. tjm - do you know if it's a 7 main bearing crank? That helps quell the problems with the long crank. With boost and head/valve work, it could be quite a torquer at relatively low rpm (5000).

The 300 I6 is a 7 main bearing engine.

 

[hllon4whls]

It is a fairly interesting thought. It would not be an easy fit in a late stang. Possibly a fairmont or early stang.
Surprised that this post got any attention at all. Great responses here.

 

[HISSIN50]

As I recall, Car & Driver got a 67 Pontiac LeMans with the "Sprint" OHC six (230 cubes, 207HP w/4 barrel carb and 4 speed manual) to run in the 14's by bolting on a pair of small slicks, and stuffing 4.88 gears in the back. But in the days of cheap gas, big engine bays and big V8s - no one wanted a smaller displacement 'hot' six.

i cant remember what i did last week and you remember stuff from 10 years before i was born.

 

[Michael Yount]

Yeah - my wife says I have an incredible memory for an infinite amount of useless information.

 

[HISSIN50]

Yeah - my wife says I have an incredible memory for an infinite amount of useless information.

LOL, i dont think so, Michael.
you have forgotten more than I will ever know, Guru.

 

[85_SS_302_Coupe]

Yeah - my wife says I have an incredible memory for an infinite amount of useless information.

Oh yea? WHAT is the land-air speed velocity of an unladen swallow???

 

[Michael Yount]

Certainly you can be more obscure than Monty Python.

 

[PNY PWR]

I had a FI 4.9 in my old 87 4x4. What a great motor, tons of miles, abused, brioken, and still went. I've heard about modding them and some hipo parts are made for them. It didn't rev real high but had gobs of torque.

Drain plug broke one time and I ran it quite a bit w/o oil. Just broke off a piston skirt and made a little noise.

 

[IndyBlk5.0]

Honestly I think they are good engines for what they are, but not for performance applications. This is due to the fact that a 302 aftermarket is huge, and a 300 I6 aftermarket is very small.