Want to Build Ultimate MPG Motor

[mschilling]

Hey Marc, the local crankshaft shop does cam grinding as well. Reportedly it is actually cheaper to have them regrind a cam to your specs than to buy it new. And you get to keep your gear mesh as is. I still think that a stock 36hp engine would be the best bet for mileage and power, after all how much hp do these exotic combos put out anyway?

[Marc]

I've had very good results from cams (and lifters) reground by Delta in Tacoma WA. I think a large part of it is due to the surface treatment they do after grinding, Parco-Lubriting (a manganese-based phosphating process).
http://www.deltacam.com/camshaft%20grinding.htm
Bear in mind, though, that as a cam is reground its base circle becomes smaller, which makes the lifters hang further out of their bores and could necessitate the use of longer pushrods. Whenever I have a high-performance billet cam with a lobe that's just starting to pit I take it to Delta and have them regrind it to a "smaller" grind, like a W-100, which they can do and still retain a decent-sized base circle - those have proven better-than-new for me.

Have you ever driven a 36'er? In a lightweight car with a 4.43 or 4.37 R&P they'll push you down the highway OK provided there aren't any hills or major headwinds...I drove my `56 back & forth from San Francisco to Seattle every weekend for a year, took 14 to 14½ hours and two full tanks + 2 gallons each way (that was averaging 65 or so, sometimes at 40MPH up mountains and 80+ coming back down). I would NOT want to try that in a 2000lb car or one with any taller gearing. They're getting rather hard to find parts for these days, too. A big-bore 40HP (1385) would be easier/cheaper to build and about the smallest I'd want to live with on the freeway.
I had an acquaintance years ago who built a ~9:1 1600-based 2-cylinder, he got almost 50MPG on Premium with water injection - but the driving experience took me back to the 36'er, OK around town but a little too slow to be safe in highway traffic.

[72_square]

Do these two cylinder engines work ok? Which cylinders do you use, 1&3?

What's the score with water injection? How does that work and what does it do?

[Marc]

You use 1&3 if you want heat, or 2&4 if you want manifold preheat
If you want to make a self-propelled air compressor you can do this:
http://mywebpage.netscape.com/alphahr/volksair.htm

Water injection will allow higher compression for a given fuel octane and can gain a little mileage too - when it flashes to steam you get a little extra pressure. The trick is getting it set up just right, difficult to do for all conditions. At first my friend merely rigged a water bottle to the vacuum advance port on his carburetor which made it pull the most water under light-load/cruise and that wasn't ideal; he was constantly fiddling with it, I don't know what he finally settled on.

[mschilling]

That would be neat to be able to run on two or four cyls depending on conditions, sort of like the new Mercedes engines.

[johnwalklett]

I blue printed a stock 1957 1200cc that was fitted in my '57 Karmann ghia.

On a run a could average 44 mpg but the engine was only producing 36hp.

Sadley I no longer own the car.

John

[CHAZAVW]

That would be neat to be able to run on two or four cyls depending on conditions, sort of like the new Mercedes engines.

or like the new chrysler hemi 300 it turns off four cylinders when cruising.

[Guest]

You might want to look up beetlemex on the web. They are based in mexico and sell parts for the modern beetles whos production just ended. They had a modern closed loop fuel injection system and oem electronic ignition distributor. Last time I was on their website(quite awhile ago) I e-mailed them asking if they sold complete F.I. sytems. They e-mailed back saying they did but didn't give any prices. I was thinking the most modern technology might make the best mpg. You could possibly make an adventure out of it and go on an auto wrecking search in mexico.

[the.fordhams]

One trick from the racing guys is to address the driveline losses - roughly 20% - 30% of engine power is lost here. They use special oils and low friction coatings in the gearbox and final drive to reduce the losses. Don't overfill oil levels as pumping the oil is a big waste of energy and one of the primary sources of heat.

Go for a tall final gear ratio to drop those rpm's on longer runs. Cogbox will be able to help with any or all of this.

Use a rebuilt carb and maybe something like aircooled nets SVDA to get a few more mpg's.

Make sure pre-heat on the manifold and the air filter is working ok avoiding gassing it constantly to pick up the rpm's when half warm.

Ovoid the high capacity oil pump in the engine as this is (potentially) wasted energy - pointless pumping oil through the bypass valve.

Smaller cooling package / fan but make sure the tin etc is all present and correctly fitted. Use the thermostat too as this will help get temperature quicker.

Rolling road for best tune-up and settings and / or a fuel mixture sensor to get best jet settings. Talk to the rolling road guy about what you want to achieve.

Good luck - I know how much petrol is in the UK and so all the mpg helps.


Thx,

Al

[James2]

77mm bore, 69mm stroke, small turbo, low boost. Fuel injection, power pully.

[Hank Winning]

For my two cents worth
a dash mounted vacuum gauge will really help you get better gas milage IF you drive by it--and not letting the pointer go below 10 inches of mercury
you are not going to win any stop light Grand Prix's but your mileage will go up!
We have vacuum gauges on all our gas powered cars

happy trails
hank

[j-bro]

You might want to use a grooved cam gear such as a Berg. Less energy put into squishing oil beetween gear teeth. I also hear karman ghias get better mileage because of the improved aerodynamics. Beetle aerodynamics are terrible.

[Keene]

This is a topic which is bound to come up more and more...

From what i have gathered, here are some of the things to aim for, in theory:

- as high a compression ratio as possible, without detonation, of course.
- low average piston speed (again, theory)
- the most free-flowing exhaust as possible
- low cam overlap
- free-flowing, but rough (casting) surface in intake

There's a book "power with economy" by David Vizard, which outlines most of this.

F.I. can really help, if the engine is built for it, and tuned for economy.

there's apparently a difference between "milage " end "efficiency", and sometimes they meet, sometimes not.

Hoping to learn more, keep us poste, keene.

[Keene]

This is a topic which is bound to come up more and more...

From what i have gathered, here are some of the things to aim for, in theory:

- as high a compression ratio as possible, without detonation, of course.
- low average piston speed (again, theory)
- the most free-flowing exhaust as possible
- low cam overlap
- free-flowing, but rough (casting) surface in intake

There's a book "power with economy" by David Vizard, which outlines most of this.

F.I. can really help, if the engine is built for it, and tuned for economy.

there's apparently a difference between "milage " end "efficiency", and sometimes they meet, sometimes not.

Hoping to learn more, keep us poste, keene.

[1961bluebug]

One "mileage motor" concept uses a small (77mm, from a 1300) bore and a mild stroke (76mm) for a displacement of 1416cc

What problems will I face when bilding this combo? I have a 1300 DP engine longblock and want to try this. Will I have to use some custom 77mm stroker short skirted pistons, will I have to make some cylinder spacers (how thick they will be?).

I dont´have probelm in machining etc., but we dont have much experience in stroker engines here...