Convert Degrees to Foot Pounds?

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Reply to
Jim Wilkins
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IIRC it depends on the design and what the makers say. The Rover K series engine uses torque angle method and the bolts can be re-used a few times provided the overall length doesn't exceed a specified length, the design does use long bolts though that run from the top of the engine through to the bottom ladder assembly which supports the crankshaft. Price can be cheap I recall the FIAT twin cam used torque to yield head bolts but they were quite cheap to get a set of them even from the main dealer.

Reply to
David Billington

The vast majority of TTY boltsm I encountered up untill about the early nineties were single use bolts according to the factory manuals at the time.

Reply to
clare

FWIW, the explanation on that site is not quite right. A bolt, or any piece of steel that has even a small amount of ductility, will continue to devel op more stress (clamping force) well after its yield point is reached. It i sn't practical to use that part of the curve for something like a head bolt for a couple of reasons, one of which is that different grades of steel ca n behave very differently after you pass the yield point.

What you get, with TTY bolts, is a reliably accurate and consistent clampin g force, combined with a small amount of elasticity that will keep the clam ping force very high even if the strain is somewhat relaxed, as when an eng ine cools down a bit after running hot.

But you can, as a technical issue, increase the clamping force by torquing beyond the yield point. It just isn't a practical thing to do in ordinary c ircumstances with normal bolts or studs.

Reply to
edhuntress2

FWIW, the explanation on that site is not quite right. A bolt, or any piece of steel that has even a small amount of ductility, will continue to develop more stress (clamping force) well after its yield point is reached. It isn't practical to use that part of the curve for something like a head bolt for a couple of reasons, one of which is that different grades of steel can behave very differently after you pass the yield point.

What you get, with TTY bolts, is a reliably accurate and consistent clamping force, combined with a small amount of elasticity that will keep the clamping force very high even if the strain is somewhat relaxed, as when an engine cools down a bit after running hot.

But you can, as a technical issue, increase the clamping force by torquing beyond the yield point. It just isn't a practical thing to do in ordinary circumstances with normal bolts or studs.

Reply to
Jim Wilkins

Reuben Geissler, my across-the-road neighbor, when I was 14, advised me that the way to find the correct torque on my 1948 Chevy head bolts was to "torque them 'till they break, then back off half a turn". I see no reason why that advise isn't just as valid today as it was then.

Reply to
Tim Wescott

Right. Depending on the alloy and the state of heat-treatment, most steels can be stressed quite a bit higher than the yield point, and they display more strength.

By that time, though, your threads commonly are going to hell. d8-)

Reply to
edhuntress2

The head bolts for my 1978 Honda Accord were so exotic looking that I bought one to study. The shank was necked down smaller than the threads and deeply roll-indented in a coarse spiral pattern, which I think was to selectively work-harden the shank where it stretched while the thicker threaded end didn't stretch enough to progressively strip the threads in the block.

-jsw

Reply to
Jim Wilkins

Wow, that's pretty fancy. I've never seen those.

At Wasino, we turned test runs of big-end bolts for Cosworth engines. They were a bitch; we had to use custom PCBN inserts to turn the threads.

Anyway, they had a *much* thinner shank, possibly because the threads were a weak point. The more accurate way to describe it may be that the threaded portion was intentionally oversize.

Reply to
edhuntress2

What do you give the odds of the replacements being installed correctly or the originals being reused? I've never seen TTY bolts, but I got out of the biz in '85. It's been a while.

I have, however, seen plenty of people who used a torque wrench improperly, trying to speed up the act of torquing bolts down. It _always_ resulted in too little torque being applied to the head- or main-bolts, sometimes with disastrous results.

Reply to
Larry Jaques

I've always -loved- that one. LOL! "Tighten it until it snaps, then _quickly_ back if off half a turn."

Reply to
Larry Jaques

The only time I tried to re-use TTY headbolts I had to replace them a few months later and it cost me a head gasket. When they break, you can'y easily remove them without pulling the head. They may have been compromised by not being properly torqued before, Undertorqued, they fatigue from stretching and relaxing with every heaty cycle. Properly totqued they basically don't move.

Reply to
clare

Ooh, bummer. Did you not know about their being TTY? Total cost was a set of bolts, another head gasket, and another gasket job. Both time- consuming and costly, right? Ouch.

UTI was a long time ago, but I don't recall ever hearing that an undertorqued bolt fatigued from stretching like that. I may never have learned about it.

Volkswagons are the leader when it comes to massive stretching of the head bolts. I've heard them going down the street, the heads bopping up and down on the cylinders. It heightens my disdain for the ugly, hissing beasties. The Cherman engineers should be shot for the noise + harmonics the engine and muffler produce. Give me fingernails on a chalkboard any day, over that monstrosity. Thankfully, the new Bug engines are all but silent.

Reply to
Larry Jaques

I bought two $300 high-mileage Beetles which were pretty quiet after I adjusted the valves.

This morning I addressed two other issues that might be of interest. I bought a used 120VAC starter to fit the Tecumseh HSK70 engine on my

20-year-old Toro 724 snowthrower. Running a 1/4-20 bottoming tap into the mounting holes in the block cut two more turns and let them accept 1/2" long screws. I've seen the shallow holes strip, possibly from using 3/8" screws.

I use Dell D820 laptops running Win7 as portable TVs and digital recorders. On one the screen started intermittently blanking which turned out to be triggered by the lid-closed switch, a magnet in the lid by the latch and sensor in front of the right touchscreen button. You can find the magnet with a paper clip. Holding a magnet over the sensor blanks the screen even if Do Nothing is set in Power Options. Apparently this is an APCI Lid driver bug in Vista, Win7 and maybe 10. The suggested fix is to replace (disable) it with the Volume Manager driver, which seems to work so far. Swiping a magnet over the sensor to simulate closing the lid still blanks the screen.

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--jsw

Reply to
Jim Wilkins

"Hmmm..." he distrusted. ;)

Ooh, that could be a lifesaver for many owners and repairmen.

Whatever _for_?

Only in a Mickeysoft product would it be possible for an audio program to control the magnetic screen driver.

Reply to
Larry Jaques

Don't expect me to validate your personal peculiarities.

I record mostly the morning, noon and evening weather reports instead of trying to remember them, because I need to plan my outdoor work and line-dried laundry for dry days and save indoor jobs for bad weather like this morning. The local radio is useless for weather and

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shows when it's time to stop and cover up because is about to hit, but not what it is, or the track and timing of distant storms. I don't pay for either cable TV or a smart phone plan.

PBS still runs concerts and some fairly decent science and history material and the commercial networks have been presenting live performances of Broadway shows featuring some of the Kelly/Astaire-class talent that Dancing With the Stars has attracted. I can't defend the rest of their programming.

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Derek's sister:
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The point is that they allow you to install a driver that occupies the space but doesn't do -anything-, good or bad.

--jsw

Reply to
Jim Wilkins

273.15K - 40C = -40F
Reply to
Good Guy

so that doesn't even take into account the thread pitch. you might advance 1 inch per turn. imagine that.

Reply to
Good Guy

Don't you mean Kelvin?

There are aps for your mobile for this sort of thing.

Reply to
Peter Jason

Unless I miss understand your use of terms, it can not be done. Degrees is a temperature measurement, OR a part of a circle.

Foot pounds is a measure of force.

If you are thinking foot pounds as the number of degrees that you must turn a nut, it depends on the wrench being used.

There is a rule of thumb that when you tighten a nut, you should turn it as tight as possible and then back off by an 1/8 of a turn. That sort of encompass the terms you used in your questions

Reply to
Keith Nuttle

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