wt. of engine
 

Why is the 911 engine so heavy?
Despite extensive use of light alloys it weighs about the same as a small block Chevy V-8.
Some of it may be the chains & tensioners instead of a rubber cog belt for the valve train, but that can't be all of it.

Thoughts?

This was rehashed a number of times before on this board. From my admittedly biased view, I recognize that the Chevy SB is a "great" engine design, ...different of course from the Porsche flat six, ...but an elegantly simple design nonetheless. Car and Driver magazine seems to think so too when both motors were voted among the 10 best ever.
The Chevy has a short skirt / short deck design employing thin-wall casting techniques...pretty nifty around 1955 when they first appeared.
---Wil Ferch

How much does a P crank weigh? And yes, I know it obviously depends on the size, but any weight to size reference would be on interest. Don't forget, its the 930 engine that is equal to a stock SBC. You must use aftermarket Al parts to get near the 911 engine's weight. The amazing thing is that a BOP/Rover weighs in at a little more than 315lbs!

LS1 engines (Corvette for the Chevy ignorant) ready to run aren't that much lighter than a simple Al headed SBC either. Remember that although Al may only weigh 1/3 of iron (roughly, you engineers) it requires more of it to gain rigidity. Rigidity is important in holding the crank still. Chevy's still have less main journals to do this though.

Luke

The things that come to mind are:
Chevy SB has one fewer camshaft, one fewer timing chain (and a shorter one at that), no layshaft, none of those big long throughbolts in the block, no headstuds, and probably 200 fewer o-rings :)

I think all these things must really add up. I was surprised how heavy 24 head studs are.

The Mg-cased engines weighed around 385 - 400 lbs, 3.0's in the 419-442 lb range, and 3.2's weighed 483 - 485 lbs ...

Not until the Turbo, at 530 lbs do you approach the 525 lb of a SB! Ford SB 289/302 is significantly lighter than the Chevy!

So how much does a 993 twin turbo engine weigh?

You also have to consider that the SBC would weigh a bit more if you included the weight of the radiator and coolant. Though 12 or 14 qts of oil, the dry sump tank and the oil coolers add a bit of weight to the 911 also.

SB Chevy's...depending on how much auxiliairies are included...can weigh 420-450 lbs ...cast iron block with aluminum heads. Radiators/alternators and such add weight , which makes the comparison to 911 engines at nominal 450 lbs interesting since they include the cooling system ( fan /shroud, alternator, etc)..

Still, the SB is remarkably light and compact for its displacement...

--Wil Ferch

Don't worry, but
 

This SBC weighs 489 pounds wet and fully dressed! Aluminum heads and other light-weight components. It dyno'ed at 420hp at the flywheel.

Don't worry; it's not going in the 911 - it's for another project TDB. It was just a hell of a lot of fun to build! I still like to threaten the local Pelicans, though - it makes for lively conversation.

I just installed a [fairly] virgin 2.7 in my car - only 40K original miles on the engine since 1977. THAT took some work and a lot of refresh!, but I'm pleased with it. BTW - according to the freight bill, (OK, how accurate do you think THAT is?) the 2.7 weighed 417 wet with the pallet, no exhaust. That's 72 pounds and 250 hp lighter! But that's not really the only consideration, is it?!

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