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Lighten Engine Block (silly weight obsession)


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Ok first note I am not truly serious about this but am curious has any weight obsessed person done it?


My 1200 coupe that I race is a porker; its at 1656 (less my massive 140lbs) of which an overbuilt cage accounts for 130lbs. Note the body is still all steel as well.


An A series block with main bearing caps is 75lbs. So there are lots of protruding bits that aren't needed, especially on a car that is raced. So let's see; cut off that big chunk that is the engine identifier. No longer need the protruding bit that for the mechanical fuel pump. On the driver side of the block are the bosses for A/C mounting etc.


Now for really silly bits; so cut down the block breather and thin the boss that the breather tube presses into. Same thing could be done to the water pump area. On V8s the area behind the timing chain is milled down. Also could the area between the main bearing cap and oil pan mounting surface be thinned as well.


So if you managed to cut 20% off an A series block it would net 15lbs. Combine this knife edged crank and lightened flywheel and you drop the engine weight by a whooping 25-30lbs.


So has anybody suffering Chapman Syndrome gone this far?

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If you're racing the car, and blowing a motor is a possibility, I wouldn't waste my time. There are benefits to "grinding the basement" or inside of the crankcase, but that's to relieve stress risers and aid in oil flow.


Customers used to bring in blocks that they had ground and it broke my heart, every time they'd blow one up, and then realize what a waste of time it was.


Lightening a block for sake of weight savings...don't eat lunch before the race. That'll about cover the weight savings.

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Cut the extra crap off your roll cage. Also think think about heavy things in your car...battery, gas tank, dash, etc. you will see a benefit from getting these as low in the car as possible safely. Also getting weight in between the wheels and off the ends of the car helps too.


You could mod the pan and the crossmember to get the engine lower in the car too.

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On the race car I worked on last year, we had one motor(SB2) that had 40Lbs CNC'd out of the block. It made a noticeable difference when corner balancing the car. 

You make a good point. Though for a club racer, spending that amount of time could be better spent elsewhere. The pro team probably pays a team member to do such tasks as setting up and running a block in a mill.

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The only thing similar to this ive seen is sprint car racers machining the whole bellhousing mount off a sbc. Good weight savings but for a budget racer theres better things to spend that extra money on, like badass shocks.


Composite leaf springs for a 1200 would shed some weight, or one of those aluminum mini stock quick changes.

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@stoffregen you may have missed the part about my being 140lbs, at 5' 7" and so they'll be no skipping lunch. As noted I'm not planning on carving up the block for the exact reasons mentioned; milling a couple thou off a particular area, like one Nissan purposely beefed up to keep the crank from whipping itself in two, could well be playing Russian roulette.


@Scooter I won't be trimming anything off the overbuilt cage, it's overbuilt for a reason. Redoing the cage would be the only option for cutting weight while keeping strength but then it may result in a less rigid platform.


In my case I've weighed almost every component on a 1200 and know where the weight is. Things like the 280ZX calipers, the steel hood and wet battery result in an extra 40-50lbs. Some components are suprising; the H190 with alloy center and brake drums only weighs a pound more than the all steel H145 ( stronger diff and wider track easily,offset that pound). Hoosier Street TD bias ply race tires are 4lbs per tire lighter than the equivalent radial tire.


Back to the engine; my complete A15 including oil weighs 187lbs (complete as in clutch, starter alternator, carbs etc.) headers and flat slide carbs took a lot of weight off. There is actually a 2-3lbs that could be pulled off block without any risk but it's really a why bother considering the motor is putting around 105HP to the wheels versus a SCCA national level motor that would be 150 WHP.

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