Author Topic: MPG, Part 2  (Read 27145 times)

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #105 on: May 19, 2018, 04:11:27 PM »
Ok, sure these details all that useful to Chevy owners, but found out that apparently that 1984 Crown Vic 302 used a cam just slightly less than one I keep mentioning.  Oh and Summit sells a SEALED POWER CS1158R for 302 for $107 that is 194/204 at 050   That would be the bargain mileage cam for the flat tappet 302.  Only shown as mild performance cam for late 60s to early 70s Windsor engines.  Dont see it used in carb pollution engines or  the TBI or later computer engines.   Though that last 302 that was optional engine used in late 90s Exploders had a roller factory cam close to this.

I do have an old 83 Malibu fence row decoration out back with a 305.  Guy traded it to me in exchange for tuning up his ancient VW.  I dragged it home must be 15 years ago, never did anything except steal couple parts off it.  Never tried starting, knowing the guy, figured either engine seized or transmission shot.  Or perhaps it laid down a smoke screen for mosquitoes....  The other day did put a socket on the crank and wonder of wonders it still turned.  No idea if its still good enough to do a shade tree overhaul with new bearings/rings and lap the valves or not.  Not worth putting much money or time into it since I can get low mile Ford 302 or Chevy 4.3L for around $400 to $500.  Wait until I find a cheap rolling truck body/chassis that doesnt need body work, see what fits best in it.  Preferably a single cab long bed, but those in good shape getting rare.

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #106 on: May 20, 2018, 06:03:43 PM »
Not sure if i've already posted this, but read:

http://www.oldsmobility.com/old/carlife_apr67.htm


RPM is a big factor.
« Last Edit: May 20, 2018, 06:06:57 PM by Stewart G Griffin »

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #107 on: May 21, 2018, 06:57:53 PM »
Yes you did post that.   And it was interesting.  But on a pickup that is more truck than car, really cant see going higher than 3.2x  and probably more like 3.5x  rear.   Should be able to get pretty good mileage with 3.2x axle I think as maybe best compromise.   This being with non-overdrive transmission.  If I had an overdrive then I would something 3.7x to 4.11, somewhere in there.  I truly dont see point of an overdrive with a 3.2x rear axle  unless you are spending all your time driving high speeds on the interstate.   

Interesting looking Craigslist.   I found an 1985 C10 longbed in very nice condition, somebody had done body work and gave it new coat paint.  Very pretty. Also had 4spd transmission which is rare in 80s C10.  Said it didnt run, no other details.  Wanted $1200.  New tires.  Probably worth it if I was wanting a primary vehicle.  Very nice condition body for a 1985.  No doubt would most likely need an engine.  I mean seller be stupid not to put a little money into it and sell it in running condition if it was trivial problem, the body was that nice.

And found a 2000 F150 single cab long bed with blown engine.  $450 with solid body and paint still pretty good.  Thats a bargain if you are wanting something to stick a cheap engine into.  No emissions inspection in my state so not problem putting older engine/transmission in it.

But looking in my own back field there is my old 1976 Dodge D100 that I walk past most days and its just become part of the scenery.  I bought it cheap at auction back in 90s.  Drove it couple years until auto tranny started slipping.  Parked it where it sets.  so its set for 20 years.  Ugly but no rust to speak of.  I opened hood today and  could move crank pulley back and forth a bit, meaning take out plugs and put some ATF in the cylinders  and no doubt it would completely free up.  I had intended to put a 4spd in it but got busy with other things and it never happened.  Do have an old Dodge 4spd I got cheap at some farm auction for it, but never bought a bellhousing and flywheel, etc.  Anyway its still relatively solid old truck and I already own it so it would make ok vehicle to experiment with.  One neat thing about this generation Dodge pickup is that it has a rain gutter above the windshield and circling around above doors.  I have seen so many old Ford and Chevy trucks that the windshield seal at top leaks and water gets in and rusts inside the cab above the windshield.  Absolutely no rust above windshield on this old Dodge.  That alone made me smile and think this would be worthwhile project.

Anyway its still solid body.  No doubt need some tires that hold air and brakes gone through.  But be good test bed for testing carb fuel mileage.  Even if my state gets emission inspection, carb engine be no problem in it and its probably old enough they wouldnt even want to test it.

So interesting choices.  I should pull that Chevy 305 out of the Malibu and disassemble it to see its condition, as I have a Chevy 4spd and bellhousing and flywheel etc so be cheapest way to go.  I imagine however this 318 is in better shape even if parts bit more rare and costly.  And if neither engine is good, wouldnt offend me to put in a cheap low mile Ford 302 though I dont have a spare granny tranny for a Ford.

Oh I do remember when I was driving the Dodge before transmission started slipping, it never got better than 13mpg.  Course this is a pollution engine so sure a decent cam combined with manual transmission would get me into high teens.  People have said the pre-pollution 318 could get 20mpg.  I have just never seen one do that.
« Last Edit: May 21, 2018, 07:09:04 PM by Coasting2aStall »

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #108 on: May 23, 2018, 02:56:34 PM »
I maybe sorry on the Dodge, well if I keep the 318.  The carb pickups with this engine just were not known for great gas mileage.  Dont think the later "Magnum" roller cam fuel injected versions that great mileage either.  My 13mpg was pretty well par for the course with the carb V8 pickups.  Course lot Chevy and Ford V8 of this era similar.  One in great condition and geared 2.71 could get 16mpg hiway.  Little more, maybe 18mpg with lean burn.  I remember lean burn era for Chryslers, thankfully dont have that mess.  No idea of my rear axle ratio until I get the truck pulled out of its grave and tires that hold air put on it.  Hopefully tag still on the axle.  I have feeling its going to either be 2.91 or 3.21.   Hoping for the 3.21.  From memory and how it drove, really doubt it was lower than that though.

Only cam changes anybody mentions is to hotrod an older A-body and great love of something called the purple cam from late 60s 340 version of the small block.  Dodge pickup people dont seem to change cams much.  Seems odd since cam change from pollution cam be one of cheapest improvements possible.  Only two places selling aftermarket 194/204 at 050 for it and they are expensive.  Cheapest would cost $200 to get one shipped and you have to then buy set new lifters on top of that.  The 204/214 at 050 lot more common and lot cheaper.  Summit sells generic package deal of this more aggressive cam plus lifters for $117 but it requires a set of expensive special aftermarket valve springs.  Which in my opinion means its a more aggressive cam than those promoting it want to admit.  A mileage cam should be able to use stock valve train.  How much difference exactly for fuel mileage???  From all I have read, I still think the 194/204 is the mileage sweet spot cam for most older OHV engines.  And possibly one could advance the cam timing with adjustable timing set might even things out with that somewhat hotter cam?  I believe advancing the cam timing 4 degrees lowers torque curve by 200rpm.

No mention of recurving the distributor either.  Think one of those magic black boxes to change timing curve on the fly with a laptop would be way to go.  Lot more control than playing with springs.  Though if doing it on fly, be better to have a friend manning the laptop while you are driving.

Oh ran across this article on historical gas mileage improvements of pickups over the years:  http://www.trucktrend.com/features/1602-truck-power-and-fuel-economy-through-the-years/  They dont seem to want to talk about huge price increases and great increase in complexity to achieve very meager improvement.  Nor the big weight gains.

I did find a $70 318 clutch bellhousing.  Would need flywheel and clutch kit whichever engine I went with.  But this was bargain for a 318 truck bellhousing that will bolt to the granny four speed.  Anymore lot those old bellhousings seem to be made of gold way they are priced.  Lot of them up around $200+.  Separate bellhousings seem to ended in 90s when manufacturers went to manual transmissions with bellhousing cast as part of the transmission.  Now separate bellhousing either ancient factory stuff or very expensive aftermarket.

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #109 on: May 24, 2018, 11:33:57 AM »
i think cylinder deactivation may have a lot to do with it.

On one hand, yes i think there has been a large improvement in pickup trucks in terms of mpg AND power;   i rented a 4x4 crewcab with a 5.3 and the thing DID get 19 mpg highway according to the computer, which i think are pretty accurate.   Now, i've also got 19mpg highway in my own truck, but it was with the 4.3---so less power and i was probably lighter.

On the other hand, i was able to get 17 highway with a 350, carb and conventional (old?) HEI ignition in that same truck.  Power could be comparable to the 5.3 with a few mods with no mpg penalty.

Now the new pickup is probably 800-1000 lbs heavier than mine, but is 2 mpg really an improvement IF the mpg gains are mostly from LS engine---less friction, fuel injection vs. carb (maybe a 10% improvement), Distributor-less ignition and cylinder de-activation?    In other words, put the new engine in a square and you get roughly the same mpg increase?

So, there have been improvements, but there kinda haven't?

Go ahead and get into the new 4 cyl that will be in next years silverado, YES a 4 cyl.  i don't have time to discuss.
 

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #110 on: May 25, 2018, 09:56:51 AM »
I really dont understand why the fat half ton pickups.  Seems stupid for me.  Yea heavier vehicles if sprung correctly do ride better and theoretically could pull larger trailer without tail wagging the dog.  Its why luxury cars have traditionally been rather bloated.  I guess way they price new pickups now, that they are LUXURY vehicles cause only wealthy can truly afford them without a 30 year mortgage.

As to a four cylinder half ton.  Four cylinder engine was offered in 90s era second generation 2wd Ranger with extended cab that weighed around 3800 pound.  They discontinued offering four cylinder 4wd Ranger in the second generation because of the extra weight.   4wd extended cab Rangers weighed around 4200 pound!!!!!   So if you used an OHC 4cyl engine like that with a 5spd and you did gearing like 4.56 rear axle, then I think a four cylinder could push around an older full size truck in an acceptable way.  The 4.56 axle even with overdrive would limit speed, so gotta figure this wouldnt probably go over 65 comfortably.  You can even go to something like 5.71 axle but you would need an engine that could run comfortably at high rpm for that to work.  Europeans for decades used very small engines in cars we would consider too big for such, but they geared them low and made the engines turn high rpm.  One reason was that you payed higher tax for a larger engine in Europe.   American cars on other hand traditionally used big engines and high rear axle ratios.  They turned low rpm.

As engineer friend told me back in college, you can push around full size car with a 3hp lawn mower engine.  It would have to be geared so high that it would only move at literal snail speed, but it could do it.  200:1 ratio?

I vaguely remember somebody long ago mentioned in Popular Mechanics or Popular Science (think in 80s?) blue printed a Volvo 2.3L OHC engine and put it in a full size rear drive Caprice/Impala.  Anyway they made it drivable and it got a little better mileage than 6 or 8 offered.  Still four cylinder in a heavy car so no race car by any means, but usable, it could get up to hiway speeds of the time.  Think we still had 55mph limit?  Think they were trying to prove some point that vehicle manufacturers werent doing everything they could for fuel mileage.  And they were correct, except for fact GM simply couldnt sell a four cylinder full size car.  Its like current efforts to sell an electric car, few people want them especially at the price offered.  Time will tell if they can sell a four cylinder half ton pickup.

I guess you dont remember the earlier Cadillac 4-6-8 engines.  Sure it wasnt as sophisticated as current system but people went out of their way to disable it for drivability issues.  I think some arent pleased with this mandatory in current full size GM pickups???  Happens when car companies have to please EPA first/foremost and customers take what they can.
« Last Edit: May 25, 2018, 11:10:21 AM by Coasting2aStall »

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #111 on: May 25, 2018, 10:29:17 AM »
Made me look, the early 70s Dodge D100 like mine weighed around 3800 pound best I can find searching on web.  Just not too interested in making it a 4cyl, though for sure it would be unique.  Hmmm, might be interesting, definitely unique....  That 3800 pound was with a V8, so it would be even less weight with a 4cyl.  Might indeed work, would definitely want something like 4.56 rear axle though.  I think those extended cab Rangers with 4cyl were kinda dogs to drive especially with an automatic.  Lot weight for a 4cyl.

You know one best four cylinders ever offered in heavier vehicle was that Mitsubishi 2.6L.  The weakness was all the nonsense added on like balance shaft and 12valve cylinder head (cracks).  But will say it moved those 80s mini vans  which were around 3500 pound around pretty well with carburetor and automatic transaxle.  I never drove one of the rear drive Mitsubishi pickups with that engine and manual transmission.  The simpler version of this engine (8 valve and no balance shaft) used in Mitsubishi/Dodge D50 pickups did last pretty well.  Still see a high mile version show on Craigslist once in a while.  Always a 5spd of course.  Lot of the 2.6L in the minivans died because of oiling problems caused by worn bearing in the balance shaft.  Lost oil pressure and then the complex timing chain setup went to omaha...  Smart people put in kit to eliminate the balance shaft when they rebuilt the engine.

There also was the MerCruiser 4 cylinder 3.0L (181).   It was a stroked Chevy Nova 153 engine from 60s.  Lot simpler than the Mitsubishi engine.  No experience with one in a car though.
« Last Edit: May 25, 2018, 10:42:37 AM by Coasting2aStall »

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #112 on: May 25, 2018, 02:07:26 PM »
I kinda need to know condition of the 318 before I go farther.  Pulled plugs and none were oil fouled, but looks like it was running bit rich.  All were uniform thinly coated with black, neither fluffy nor oily. Hmm, could been wrong carburetor, one jetted bit rich.  Or automatic choke wasnt working quite right.  Pulled a valve cover and rockers clean, no sludge.   Actually just way it is, probably could start it up with bit work.  Just as it sets.  I did put some ATF in cylinders and turned engine over with socket on the crank bolt.  It didnt put up any fight, so was just bit stuck from setting 20 years, not rusted or anything.

I will play with it some more, then try to start it as it sets and then do compression test.  I think its still pretty good ole engine.  If I were sifting through a junkyard looking for cheap bargain core engine to use, this one would go home with me as a likely gamble.  Not thrilled that it will cost like $260 for cam and lifters I want.  But if I am going for mileage, thats a necessity to test my theory that bad mileage is mostly from pollution era cam.  Oh and it has two piece rear main seal.  Those are just painful to change out anytime.  Big plus for the Ford 302 same vintage that it used a one piece seal.

Trying to think back 20 years ago.   I know I took apart the 2bbl Carter carb just to get it home.  Some idiot designed the thing so one piece internally could be installed backwards and previous owner had done just that.  These were ok but not great carburetors. Reversed that and it ran ok.  Had to replace left front lower ball joint.  Thats about it.  The truly annoying thing is that the ignition modules kept burning out.  After couple long walks home I learned to carry a spare.  This was back before I knew you could just mount a GM four prong module to chunk aluminum and it would work fine with nearly any magnetic triggered pre-computer era distributor.  With GM module could use either standard coil or GM-HEI/Ford-TFI remote coil. And without a ballast resistor.  That four prong GM HEI module was very robust design and the better mouse trap.  Only thing it didnt like was heat.  So you wanted to mount it remotely on chunk aluminum preferably next to radiator by front grill and use the thermal grease mounting it to the aluminum.  I used them on Volvo, Ford, Nissan, and probably some others I've forgotten.  Never had one fail whether GM or a clone.

Offline Coasting2aStall

  • Newbie
  • Posts: 15
  • Newbie
Re: MPG, Part 2
« Reply #113 on: May 28, 2018, 03:58:42 AM »
For anybody not familiar with old CJ jeeps, it was about as hard getting good fuel mileage out of them as a full size pickup.  Despite them being significantly lighter weight.

Anyway here is thread on Jeep forum about mileage of CJ with AMC 304-8. http://www.jeepforum.com/forum/f8/gas-mileage-amc-304-a-1296215/   Really interesting posts by "JeepHammer".  He goes on a bit soapbox style, but he does get how things work together as a system.  Some good info in his ..um speeches.  Tells how he gets 20-22 in his CJ with the 304.  Apparently he custom tunes jeeps for a living?

 I never owned an AMC 304 in anything, but did have couple of the 1970s era full size Wagoneers (one was a 2door Cherokee Chief) with FULL TIME 4wd and AMC 360 and TH400.  I actually really liked them.  One got 14mpg and other got 16mpg, amazing mileage with full time 4wd, quadratrac I think they called it.  Yep from the late 70s so pollution era. 

Another bit interesting info on my 318.  Seems Chrysler used a "203/203 at 050" cam in their bigger 360.  Same LA block so using this stock 2bbl 360 cam in the 318 is a cheap upgrade.  I can get this cam and set lifters new for under $100.  Its a single pattern cam but I dont think be worth the extra $100 to get my preferred  aftermarket "194/204 at 050" cam.  Just really cant see there being that much difference.

I swear researching fuel mileage for carburetor V8s is quite the challenge.  So many conflicting views and lot liars.  No one single magic bullet, thats for sure.  I would love to break the 20mpg barrier, but mostly just want to prove to myself I can get better mileage out of a carb V8 pickup than the 16mpg hiway I get with my fuel injected Ranger.... without making it unpleasant to drive.   Even 16mpg isnt bad in a full size V8 pickup, so thats enough of a goal for the Dodge, to at very least match that and hopefully beat it.  Only ran across one guy claiming to regularly hit 20mpg in stock  Dodge  pickup with carb 318.  He had a manual 3spd.  Unfortunately didnt give any more details.  I'd of said he was exaggerating if he had automatic, but if stars were all aligned when his truck was put together or he has very good mechanic that can tune it within a gnats eyelash of perfect, then suppose its possible.  That egg taped to bottom of his right shoe probably helps too....

Getting into hot summer weather so not sure how much progress on Dodge over summer, but no hurry.  The Dodge is more curious hobby than a necessity.   Least like to get it to point it can start and move under its own power around the yard. 

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #114 on: March 08, 2020, 09:07:23 PM »
Part 3:

i decided to rent a truck for a while---since i'm still working on the trans in the usual truck as you may know.

'20 Ram 2500 crew cab with 6.7 cummins diesel, single rear wheels
Not sure what trans, but automatic
Not sure what rear, but i would imagine 4.10?

438.5 miles/21.00 gallons = 20.88 mpg    Computer said around 20.3, but i think it's averaging everything, not just last tank?
$2.699 per gallon diesel at mobil,  $56.69 to fillup   i did not fill up all the way because i was returning the truck.    Also, i drove more than 438 miles, but i was only measuring mpg for the last tank.

i'm pretty impressed with the mpg considering the size of the truck which i feel is TOO BIG----i usually have to take up 2 spaces.

If you're not picky about brands, this is a nice truck.  Very quiet.  i did tow a little and it did good.

Of course, i only buy gm generally.  But if i wasn't brand loyal, yes i would buy one.
« Last Edit: March 11, 2020, 05:52:23 PM by Stewart G Griffin »

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13299
  • Family is not an important thing. It's everything.
Re: MPG, Part 2
« Reply #115 on: March 08, 2020, 09:19:14 PM »
for the longest time the cummins was paired with 3.55 ratio. i think a few years ago it did change to 3.73
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #116 on: March 09, 2020, 07:01:25 PM »
Well whatever rear end ratio it had, it's a pretty impressive drivetrain----IF you can afford it all.

i've not driven a duramax or powerstoke yet, but i imagine  they are on par with the cummins?

Offline fitz

  • Senior Member
  • ****
  • Posts: 2064
Re: MPG, Part 2
« Reply #117 on: March 11, 2020, 06:48:25 AM »
  I had the privilege of driving a 2019 F250 powerstroke / 4 door / 8'bed truck for 4 months last summer / fall (the truck on the right).  In 4 months I put 15k on it.  The dash computer says it averaged 18.6 mpg's.
  It was an Enterprise Rental courtesy of Ford while they processed the paperwork to buy back my 2019 F250 under the lemon law (the truck on the left).  My truck had the 6.2 gas motor and averaged 14.4 mpg's for the 2,800 miles I owned it.
  I enjoyed driving the diesel,  but I think maintenance would be expensive as the truck gets older.

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #118 on: March 11, 2020, 05:52:55 PM »
Yes, i rented from Enterprise as well.

Offline Stewart G Griffin

  • Senior Member
  • ****
  • Posts: 3284
Re: MPG, Part 2
« Reply #119 on: March 18, 2020, 09:36:39 PM »
Part 4:


i've joined the LS club:

'11 colorado crew cab
5.3 LS (LH9)
4L60 trans (which, i think, is a renamed 700R4?)
4.10 rear, but still rpms decently on highway----1900-2000 @70mph  because of OD.
Not sure what the front diff is.

339.6 miles / 16.16 gallons = 21.01 mpg
$2.439 per gallon regular  Exxon   $39.42 to fillup.

i'm not giving up on the square at all.  i'm just very busy these days and don't really have time to really mess with it as the primary transportation----it was down over one month because of the trans.   Plus, i felt i needed another car anyways.