OK, we all know that steel is heavy, and we all want our rigs to be lighter so that they use less fuel. Has anyone considered boring or stroking an engine to make it lighter? For example, take the 351M/400 engines. the 400 has 49 cubic inces of extra displacment, so it must have that much less steel. By my calculations that would be 14 pounds removed. Now you may need larger engine internals, which could eat away some of the difference.

Also, yes, I know, fourteen pounds is nearly nothing on a truck this size. This thread is posted as "food for thought" only.

Discuss

 

but the 400 uses the same bore.

 

The 400 crank has a longer throw than the 351M and would probably be heavier. Has anyone weighed a 400 and 351M crank? The piston is aluminum and shorter so it would be slightly lighter. Overall the crank would more than outweigh the difference in pistons. The rods are the same. The block is the same.

 

Moved to appropriate forum.

 

I do think that stroking an engine, longer throws on the crank would result in a heavier crank. And as you point out, boring removes relatively little. But I have often thought of looking into whether there are other parts of the iron block that could be removed without compromising strength.

I think that weight saving is better approached by using headers, as opposed to cast manifolds, aluminum intakes as opposed to iron.

Overall, I think that the weight saving idea needs to be applied to the entire vehicle.

 

Yeah, this was just a little idea I had while daydreaming at work. It's pretty clear once you think about it that you aren't going to make any significant gains this way. Though it is worth thinking about the possibility of making an engine lighter by removing unneeded material. Of course, taking any metal away from the block could effect the cooling properties adversley (hollow castings etc).

 

The block and rotating assembly are not sources of weight savings. You can save weight on headers vs manifolds and having aluminum intakes. But the main source of weight reduction is switching from cast iron heads to aluminum heads, it saves about 50 lbs.

 

I have seen guys polish the lifter gallery for better oil return, and take a grinder to the outside of the block to remove the lugs used in the machining process but hte most I ever heard of anyone lightening the block was 12-15lbs range (don't remember exactly) but like mustang said the biggest weight reduction on an engine is in the heads. on a big block it's actually around 80lobs wieght savings (which BTW is still less than my stroker cranks weighs 83lbs without the mallory, never rewieghed it after balancing.)

 

Some of the aftermarket cranks are lighter also.

 

Any weight savings in the rotating assembly is helpful for performance of the engine and not for overall weight savings on the vehicle.

 

If you could find a way to get longevity out of magnesium pistons and aluminum rods
you would lighten the rotating mass and pick up some power. The problem is they don't stay together. The connecting rods used in the early Offenhausers were
forged round and bored so they shed weight. Seems to me I saw pictures
of connecting rods with a series of holes drill thru the web of the I beam.
All the ideas accomplish one end while giving up the other. I guess if we had unlimited budgets and didn't care about the engines life a lot of things could be tried.

 

A lot of racers use aluminum rods without incident. Perhaps the limiting factor is cost.

 

This is off topic but amusing just the same.
On a dirt bike forum a guy wanted to know how much weight he could save by using titanium fasteners (big bucks).
The overall consensus was to save his money and shave off way more weight by laying off the beer and chips between races!

 

i think the best way to save weight is either spend the money and buy the expensive parts that are lighter (wouldnt we all like to have a titanium block and heads) or lose the weight in the cab example: your nice leather seats prob weigh ton more then the cloth or at least as much as every is talking about losing in comparison to the original parts or the ton of tools everyone carries around and never uses or get rid of the "extra crap on your truck that you dont need i think everone whines about gas prices and trying to lose weight for fuel economy but they dont want to sacrifice the luxaries in there life well guess what gas is a luxary ya dont like it dont drive a v8 and whine about it

 

re post 14: Cars and trucks are our mass transit in the USA. When we are being ripped off by oil companies, we have a perfect right to complain. So don't try to be a tough guy and tell people not to "whine" as you put it. Many of us who work for a living carry a lot of weight, and it is things that we DO use often enough to justify carrying it. If I could stay home and make a liviing working in cyberspace I would, but the reality is I do a lot of work in a number of overlapping trades which require me to have a lot of tools on hand. It takes a lot of BTU's to haul it around.

Gas may be a luxury to you, but to most of us it's a necessity.







D