High torque engines

[NDIHC]

Agree again. I once had a ford pickup with an over square (4.36" bore x 3.85" stroke) 460. It also had very good low-speed torque, due largely to a very conservative camshaft.

Likewise, the Olds 394 had a bore of 4.125 and stroke was 3.6875. They were good for up to 345 hp and 445 lb.ft. torque. The earlier 371 was used in GMC heavy trucks as the 370. The Olds typically made their torque at around 2600-2800 rpm.

 

[Texasmark]

Agreed. Also, as far as I can tell, it's a myth that an oversquare configuration cannot make as much torque as undersquare. If you trade 10% less stroke for 10% more bore area, you trade 10% less lever arm for 10% more force (pressure times area) on the piston. The end result is the same twist. In other words, within reasonable limits, torque is proportional to displacement, regardless of whether the displacement comes from bore or stroke.

That must be the case as Ford had manufactiured a whole line of tractors for years based on that principle. Course thinking back about the Chevy 265 that premiered in 1955 with their first V8, they beat out Fords Y8 in drags due to its short stroke that could rev. up faster due to a shorter stroke.

 

[Texasmark]

Well my "over square" Fords make PTO RPMs at 1800. My CIH with "under square" engines make it at about the same RPM.

 

[Texasmark]

Well my "over square" Fords make PTO RPMs at 1800. My CIH with "under square" engines make it at about the same RPM.

I ve been impressed the 440 mopar over the hemi for street and track , performance

Back when I was growing up MOPAR was the hot dog. For many years they ruled drag strips. The MOPAR that was in the movies....orange General?????, was all engine with a very light chassis...perfect combination. I understand that the producer of that series had about a dozen of those to have one for the show while the torn up ones were getting fixed. I think the 2 door hardtop...forget the name....Charger???? is still built as I saw an ad just a couple of days ago.....another hot potato. I read somewhere, maybe it was the DeSoto, Walt Chrysler said that he wanted an engine that would go 250k miles. I don't know if he ever got it. Maybe one could ask the NYC police as they used a lot of Walt's products.

 

[olddavid]

560Dennis "I read somewhere, maybe it was the DeSoto, Walt Chrysler said that he wanted an engine that would go 250k miles. I don't know if he ever got it. Maybe one could ask the NYC police as they used a lot of Walt's products."

I think he succeeded. I had Plymouth Volare' slant six that went 215k and was still running great. I think it might have made 300k if the body hadn't rusted out.

 

[1948CaseVAI]

That Coronet had a 318 2 barrel but it certainly wasn't a slouch! Plain jane with rubber floor mats and vinyl seats, no ac. Driving on gravel was no fun because the dust would roll in like crazy. A hot day, no ac, had to keep the windows closed and vents off to try and keep the dust out. It only had a little over 30,000 miles on it when my grandpa gave it to my sister in the early 90s.

Well the police department started buying AC in about 73 but you are correct - plain plastic seat covering, no AM or FM radio, no cruise of course, rubber floor mats. But "taxicab package" radiators and tranny coolers and big alternators to keep the emergency lights running. Even with the big radiators had to release the hood latch and let it come up a few inches if youj were going to sit and idle in the summer. But I did love those Coronets!

Yes, they were really shot by 55000 miles or so and even the city traded them then.

 

[kencombs]

560Dennis "I read somewhere, maybe it was the DeSoto, Walt Chrysler said that he wanted an engine that would go 250k miles. I don't know if he ever got it. Maybe one could ask the NYC police as they used a lot of Walt's products."

I think he succeeded. I had Plymouth Volare' slant six that went 215k and was still running great. I think it might have made 300k if the body hadn't rusted out.

Back in the early '70s I was commuting weekly to NYC to work. Lots of cab rides from LGA to midtown Manhattan. Most cabs were slant six with Torqueflites. I talked with a few owner/operators during the rides and they usually needed an overhaul at around 175K. That's amazing when you factor in the run time versus mileage. Probably well over 300K of 'normal' useage.

The airline where I worked in the 60s bought a crew cab Dodge slant six with Torqueflite. It was used exclusively on airport property to transport mechanics and parts from our hangars to the terminal, a couple of miles away. 126 different drivers! When I left that job it has well over 125K and the engine and trans had not been touched. Tough!

 

[Destroked 450]

Well I do recall that Ford's rear end has a fancy drive train (forget what it's called).....at least my 3910 has such.

Does your 3910 have a column shift transmission, it should have a standard rear axle but it is different from the older 3000, 3600, 3610 rears, on the 3910 Ford swapped in the heavier planetary rear axle that was standard on the 4000, 4600, 4610 models
Your 3910 is much like the 4610SU model but with a smaller engine and less hp

 

[moresmoke]

Does anybody know what the warranty is on the newer turbo engines? Like the Chevy turbo or the Ford ecoboost? Some have a 10 year 100,000 mile warranty, don't know about those though. The ones I work on are 10/100k. But they aren't pickups.

Ford has mostly gone to a buy the warranty you want model. You get a really basic warranty with the vehicle, then you pay extra for more coverage if you want it.

 

[Texasmark]

Agree again. I once had a ford pickup with an over square (4.36" bore x 3.85" stroke) 460. It also had very good low-speed torque, due largely to a very conservative camshaft.

I had a 460 in a 1 ton with the overdrive tranny. Only vehicle I ever had where I could dump the clurch, with the engine at idle RPMs and move on out.......the OD tranny didn't have "grandmaw gear. It had the extra gear on the top end....overdrive.

 

[JMOR]

I had a 460 in a 1 ton with the overdrive tranny. Only vehicle I ever had where I could dump the clurch, with the engine at idle RPMs and move on out.......the OD tranny didn't have "grandmaw gear. It had the extra gear on the top end....overdrive.

Mark, we put a VERY warmed over 460 in a F-150 short bed and with slicks, it turned in the 12 sec range. Had a camper shell on it. A real sleeper on the street.

 

[buickanddeere]

History has taught us...er ah me, that under square (stroke longer than piston diameter) 6 cylinder engines (for inherent balance) were what's needed to provide high torque performance for heavy loads over the long haul. Many 500 hp, 450,000 mile between overhauls in OTR big rigs have proven this fact.

So here comes Ford with their semi-current (at least) square (4.2x4.2) to over square (4.4x4.2) and on up to their (4.4x4.4) and then I learn today that they dropped the stroke 0.2" back to 4.4x4.2 and installed a turbo on more recent, larger engines.

So having had Fords as my primary mover over the years, but not being a BTO, getting by with it satisfactorily, I was just wondering how they got away with it.

Its cold and wet outside and I have nothing else to do....goodie goodie...nothing is broken. Been in the house all day working jigsaw puzzles.

Easier to build in compression with an under square engine .
Room for larger valves with an over square engine . Hence the tendency for over square engines to be associated with high rpm and high HP .
With the same displacement and the same heads . The HP is the same under square or over square .

 

[Texasmark]

Easier to build in compression with an under square engine .
Room for larger valves with an over square engine . Hence the tendency for over square engines to be associated with high rpm and high HP .
With the same displacement and the same heads . The HP is the same under square or over square .

Well over square makes a point with more room for large valves. Since an engine is basically an "air pump" the more air you can move through it in a given time is what wins races.

My 2011 Silverado is 4.8 Liters but the air flow system is much larger and smoother than earlier basic pushrod Chevy small block V8s that I've owned. That engine just doesn't compare even to Chevy 350's in terms of performance. You step on the gas and it just wants to run......very impressive for just a basic V8 engine without any fancy hoop-la that has been popular lately. I know it has to make the RPMs to get its full rated HP but it isn't shy about going after it.

 

[buickanddeere]

Way back when in a hot rodding magazine .
They built a Chev with a 3.75 stroke 400 crank, 5.7 rods and a 3.67 262 block . A cam , headers , intake and the best flowing head that would fit the small bore .
Then another short block with the 4.125 400 bore and a 3.0” stroke . Same compression ratio .
Cubic inches were within a few .
Dyno torque and HP results were identical

 

[Destroked 450]

Car Craft was my magazine so didn’t see that build
I can believe the equal results but would think the curves would be different with the longer stroke developing torque quicker

 

[Texasmark]

Way back when in a hot rodding magazine .
They built a Chev with a 3.75 stroke 400 crank, 5.7 rods and a 3.67 262 block . A cam , headers , intake and the best flowing head that would fit the small bore .
Then another short block with the 4.125 400 bore and a 3.0” stroke . Same compression ratio .
Cubic inches were within a few .
Dyno torque and HP results were identical

I had the 400 in a station wagon, 1971 model. I just had to have it. There were 3 of them on the lot in Dallas. I test drove all 3 and they were "big block" dogs (396 upgrades.....er. ah......downgrade. But that type/size vehicle was what I needed for my family and our play toys. Never thought about a Surburban "truck" station wagon......didn't like the only door on the curb side with none on the driver's side to get to the back seat anyway in later observations.

One of the things that chapped me was the size of the air inlet on the air filter housing. It had the quadrajet and those openings were much larger than that inlet hole. Flipping the top over gave air access 360 to the quadrajet....another dog part of that thing. Then there was the door rattle...close the door and it took 15 minutes for it to quit rattling. At one point I removed the interior panel on the driver's door and stuffed the area full of foam. That helped.

Then the seat vinyl was tighter at the left driver's corner than the rest of the seat.....made you feel like you were sliding off the seat all the time. Then I installed a trailer hitch and I had this squeak while driving. Finally had wifie drive and I dropped the "disappearing" tail gate, while going down the road, looked up under the rear end and the hitch was contacting a piece of sheet metal making the screeching noise.

Then I wanted more fuel filtering than that little thing on the Quadrajet fuel inlet so I put a large fuel filter in the hose leading to the fuel pump. Hot summer afternoon, AC running full blast, dragging the boat with all the kids and all our vacation gear and the engine just quit. Pulled over on the side of the road and let it sit for half an hour, started right up, ran for a few more miles and did it again and again and again. Apparently the fuel pump sucking on the filter was drawing a partial vacuum and the fuel vaporized in that area killing the engine. It goes without saying how my wife felt about this interruption on our way home.

 

[RedMF40]

I had the I-300 in a ‘67 F100 which was badged as a Mercury. Found it in SLC, Utah and drove it back east with my girlfriend. Well-used truck but at highway speeds it was about as smooth as anything new on the road, albeit a little louder. Gearbox was three speed on the tree, don’t remember if top gear was overdrive but I feel it was. Always liked that year and body style. Would have kept it if not for the rust which was more than I could deal with. Can’t speak to its torque, never did any heavy hauling with it.

 

[olddavid]

I had a '61 short bed half ton 235 six-cylinder Chevy that I had about a ton of gravel on. I had to go up a fairly long grade on a curve and thought I might have to down shift on it but it walked it right on up. I think it had a 3.90 to 1 rear end. The 235 had a 3.56 inch bore and a 3.94 inch stroke.

 

[TerryfromSWIowa]

I had the I-300 in a ‘67 F100 which was badged as a Mercury. Found it in SLC, Utah and drove it back east with my girlfriend. Well-used truck but at highway speeds it was about as smooth as anything new on the road, albeit a little louder. Gearbox was three speed on the tree, don’t remember if top gear was overdrive but I feel it was. Always liked that year and body style. Would have kept it if not for the rust which was more than I could deal with. Can’t speak to its torque, never did any heavy hauling with it.

Those early 300 were 170 HP and about 265 torque.

 

[dhermesc]

Those early 300 were 170 HP and about 265 torque.

That was "gross HP", net they were around 145 or so HP. I saw an excellent build on an old old 300 6 that had been on a generator.

In original form they got 88 hp and 170 ft#s torque. Then they added headers, intake, roller rockers, carb and electronic ignition

Just the headers gave it 93HP and 226 ft#s torque. The intake, carb and electronic ignition brought it to 166 hp and 277 ft#s torque.

The roller rockers were a simple bolt on and brought it to 169/280.

100% stock internals and 60+ year old pistons and lower end.

Then they got crazy and put a new rods & pistons, and all kinds of other stuff that 99% of people would never do:

270 hp and 337 ft#s torque.


Then they added a turbo!!!!!!!!!!!!!!!

497 horses and 575 ft#s torque!!!!!