|04-05-2011 03:31 AM|
I was also considering the "grade 8 isnt required" argument, but then i backtracked mentally
A PROPERLY made grade 2 bolt would be one thing, but 1/2 the time that grade 2 bolt shouldn't even be classified that well. Sure the MATERIAL might be grade 2, but when its a factory crossthread or threaded off center, eeeeh.
nah, i think ill go buy some grade 8 bolts so they have 100% thread AND 2 years from now when i need a good bolt for some random repair project, thats a few more grade 8's i have to choose from in the bucket of bolts
Can never have to many high quality bolts laying around, that would be like having to much money in the bank.
|04-05-2011 12:30 AM|
|ductape&monkeywrench||maybe 'cuz' im young but a nice tie down strap between the exhuast lifts em' fine|
|04-04-2011 11:10 PM|
Oh, I know they are safe (reasonably?) to use.. I mean, I don't like them, and I wouldn't use one, but to each his own.
I thought we were just talking gr 2-5-8 bolts now?
|04-04-2011 09:46 PM|
|04-04-2011 09:33 PM|
I think what you are saying is that the tapped hole in the manifold will strip before the bolt strips or breaks.
Your analogy of the butter is ok.
So replacing the butter with aluminum the pull out strength in pure tension of the fastener if screwed in at least twice the nominal diameter will be pretty close to the fastener strength. It's really much more complicated than this.
Take for example a standard aluminum nut on a steel fastener assembled thru a steel plate. Were you able to pull in tension on the head of the bolt the aluminum nut would fail before the steel fastener. Now increase the nut size to at least twice the nominal height of the thread size. Now the shear value will approach the tensile strength of the area of the minor diameter of the bolt.
These plates would not be available if they were not reasonably safe to use.
As for the use of Gr 8 fasteners. I use Gr 8 on everything I can simply because I want no fastener failures ever and I buy them for about $3 a pound. A little more for certified ones. I see no reason to chintz on fasteners. In industry where we used hundreds of thousands of fasteners cost becomes a factor. Cost vs function then becomes the driver and the engineer is tasked with analyzing the situation to come of with a fastener that will do the job for the least cost.
In the shop anything that even remotely stresses a fastener gets a Gr 8 including nuts. Lifting anything gets the best equipment. You surely do not need to injure anyone due to faulty equipment.
The only application on the race car for deliberate fastener failure that I can think of is the blower attaching bolts. There aluminum studs are used with either a hole drilled thru and/or the body is thinned. These break off if the blower backfires preventing the blower from massive explosion and resulting shrapnel. You can see that even when aluminum nuts are used here and they seldom fail. Usually failure is from crossthreading and poor installation. A severe blower explosion will split the blower case, bust all of the blower bolts, cave the bottom of the manifold in besides popping the burst panel. The resulting fire will take care of the rest of the car but the shrapnel will be minimized.
I use them on my blower but I seriously doubt I could bang the blower hard enough on gas to split it let alone break the studs. They look cool and they were free.
|04-04-2011 06:48 PM|
It's like lifting a pound of butter with a stick jammed straight into the top. Doesn't matter if your stick is a toothpick, or a knife, the butter will yield first.
|04-04-2011 05:37 PM|
If you look at the chart I posted above you can see that Gr 2 1/4" bolts would be marginal at best. 1/4" Gr 8 will handle most any thing. 5/16 would be even better.
Don't forget that the load might not be evenly distributed. All of the load could be on only one bolt. Keep the plate tight to prevent this.
The rule of thumb is that in aluminum the fastener needs to be screwed in at least twice the nominal diameter. Steel it is 1 1/2 times the nominal dia.
|04-04-2011 04:15 PM|
|04-04-2011 02:50 PM|
There is a LOT of misinformation in this thread. I can't remember the numbers but I seem to recall grade 2 being sufficient.. But don't quote me on that.. I just don't understand why you would run out and buy grade 8 bolts to thread into aluminum.
|04-03-2011 09:55 PM|
I have pulled out a Hemi motor, 6 BBC, 5 SBC, & 1 SBF all with the same engine plate. Never had a problem. Out of all those motors 10 of them had the trans attached too. Best $ I ever spent on a tool, Engine plate.
|04-01-2011 06:05 PM|
|jessicafd||I had an adjustable crank bar,I hated it and got rid of it.Nothing but a real PITA to me.Got rid of it 2 years ago,I was installing an engine in a Chevy truck and had enough of it.I got so mad,pulled the engine out,removed the adjustable crank bar bolting a chain on and went in the scrap pile.A friend of mine took it out and I told him he can have it.I have plates (1/4 thick steel) I bolt to the cylinder head I made with holes which a chain can be hooked into.|
|04-01-2011 03:14 PM|
bolt qc ok
Bolt manufactures use SPC and sample testing, the problem is HOW GOOD ARE THE THREADS IN THE MANIFOLD ? how many times have the studs been removed and replaced for a spacer, etc,, I've seen too many bad threads in aluminum manifolds. The adjustable crank bar with 4 chains , easier to get an engine in a tight compartment, and safer.
|03-31-2011 10:42 PM|
Here is strength data on bolts.
I've used these for as long as I can remember and never had a probem. I also have one that attaches to a blower manifold that we use for the Funnycars. Even an all aluminum hemi is pretty heavy these days.
|03-29-2011 09:04 PM|
|jessicafd||I do on cast iron intake manifolds and have custom lift plates I have built.I have watched a 351 Ford hit the floor and dent the oil pan big time,one of my employees decided to use an engine plate and the threads for the carb studs were stripped.The intake was aluminum.Customer was not too happy and I ended up firing this guy that did this.I warned him twice to put a chain on it and never listened to me.|
|03-29-2011 08:24 PM|
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