2312 lbs of torque

Thats what holds down a set of Small block Chevy heads. (34 bolts x 68lbs ea)

Its not too bad on an engine stand, but much more difficult leaning over the fender. I'm sure other cars are harder, but I am a wuss.

Looks like the Firebird won't be a challenge car anymore.

Jesus... See this is why I'm an ohc guy. My head has 8 bolts.

I use nuts to keep the marbles in place in my head. No need for bolts

I have single bolts requiring some 5400 lb ft here.

They big.

I opened this trying to figure out what dyno would hold that....

Pssst! Pounds ain't torque.

Seriously bro, do you even torque? If you tell us what the actual bolts are we can tell you the force though

In reply to RossD:

But you use a torque wrench set to ft lbs..that said im pretty sure its not multiplied, overall torque is still 68ft lbs just at multiple points so I guess what im trying to say is yeah your a whimp

RossD wrote: Pssst! Pounds ain't torque.

preach it brother.

Units are important! (said the engineer and physicist)

¯\_(ツ)_/¯ wrote: Seriously bro, do you even torque? If you tell us what the actual bolts are we can tell you the force though

Only if you know the K value for the friction scenario.

I am a fastener nerd.

tuna55 wrote:

¯\_(ツ)_/¯ wrote: Seriously bro, do you even torque? If you tell us what the actual bolts are we can tell you the force though

Only if you know the K value for the friction scenario. I am a fastener nerd.

Fair enough, but it'd still be a hell of a lot closer than assuming lb-ft=lbf

I always thought it weird all the bolts that chevy and ford use to hold down their heads.. being an import guy, I always liked how the Europeans do it.. 10 bolts.. two between each cylinder and 2 on each end.

Granted my saab uses 90 foot poinds and then 2 more 90 degree angles to stretch the bolts.. so a -lot- more than your whimpy 68

In reply to mad_machine:

Don't look at a flathead then!

Here i am with my F2T at a wimpy 900ftlbs.

tuna55 wrote:

¯\_(ツ)_/¯ wrote: Seriously bro, do you even torque? If you tell us what the actual bolts are we can tell you the force though

Only if you know the K value for the friction scenario. I am a fastener nerd.

Ask a helicopter guy about "the Jesus nut."

When your fancy flying machine becomes a rock.

so, foot lbs of torque gets multiplied by quite a bit by the pitch of the threads to turn into pounds right?

imagine putting a bathroom scale in a vice. You would register 200 lbs on the scale long before your torque wrench got to 200 ftlbs. I'd imagine it would be more like 20 ft lbs on the wrench = 200 lbs of clamping force...

So heads have to be held on by a giant clamping force. But remember, when that explosion goes off in the chamber you have a large PSI spike, and that PSI can be converted by the area of the combustion chamber (approximately the bore) to equal another very large expansion force. The clamping force on the head better be bigger than the expansive force during combustion.

In reply to rcutclif:

The bolts are very very very very stiff springs which must be able to absorb temperature changes (which can, depending on materials, mean that more or less initial cold clamping force is required), creep (pretty complicated) and the combustion pressures that you mentioned. Fasteners are amazing.

The extra Chev head bolt is a definite improvement over 4 per cylinder. How many Chev v8 head gaskets have you ever changed in engines that didn't involve blowers or nitrous?

tuna55 wrote: In reply to rcutclif: The bolts are very very very very stiff springs which must be able to absorb temperature changes (which can, depending on materials, mean that more or less initial cold clamping force is required), creep (pretty complicated) and the combustion pressures that you mentioned. Fasteners are amazing.

That sounds like the beginning of an interesting article. Maybe you can pitch it our dear overlords here in GRM land and add to the garage war-chest...

I would 100% read an article about fasteners. Good article to help us build faster motors and safer cars.

RossD wrote: In reply to mad_machine: Don't look at a flathead then!

I always liked the acorn nut look on a flathead.......