Re: stretch method for molnar/arp2000
[Re: mopar dave]
#2066559
05/03/16 03:26 PM
05/03/16 03:26 PM
|
Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
|
master
Joined: Sep 2014
Posts: 4,457
Washington
|
my rods are brand new. wont need sizing. You may have to size them to get your clearance where it needs to be.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
|
|
|
Re: stretch method for molnar/arp2000
[Re: MT-Tom]
#2066563
05/03/16 03:30 PM
05/03/16 03:30 PM
|
Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
|
master
Joined: Sep 2014
Posts: 4,457
Washington
|
The science behind the bolts is, bolts are nothing more than a very stiff spring and the spring must be stretched the proper amount to provide a certain amount of clamp load. While most of us grew up with a torque wrench in our hands and many people still rely on it, there are better and more accurate methods that can be used to tighten fasteners. The reason is, torque does not measure stretch, clamping or pre load and only measures the amount of friction that must be overcome to rotate the bolt. The type and amount of lube applied will effect the friction. When you add into the mix the surface of the spotface on the rod, the flange of the bolt and both male and female threads that can change with each tightening, it starts to become more clear as to why straight torque is not the most accurate method for tightening bolts. Over the years there have been rod manufacturers who would tell people to replace the bolts after 5 tightenings. This was not due to the bolts "giving up", it was because the friction level is a moving target and will change so much that an accurate preload could not be achieved by the simple torque method and it was easier (and more profitable) to just sell the customer new bolts. I heard all this same CRAP about TTY fasteners and how they would revolutionize fastener tech. All it was is a way for OEM's to do it cheaper. I'm with Pittsburgh racer on this. Torque the bolts, measure the bore and size it. Ridiculous.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
|
|
|
Re: stretch method for molnar/arp2000
[Re: mopar dave]
#2066705
05/03/16 08:49 PM
05/03/16 08:49 PM
|
Joined: Jul 2014
Posts: 42 Wedge Land
MBigBlock
member
|
member
Joined: Jul 2014
Posts: 42
Wedge Land
|
Back when I had a 120mph in the 1/4 N/A LS1 chev, we were told all the bolts are throw away after one usage. I reused my head bolts 3 times and just torqued to a flat ft/lb spec. Made 540hp with them, removed CNC heads, bolted on stock heads to sell car, used the same bolts, again!
Be weary of manufacturers wanting to sell parts. Not to say everything they tell us is lies, but some of it is a bit far stretched (pun intended)
Last edited by MBigBlock; 05/03/16 08:50 PM.
|
|
|
Re: stretch method for molnar/arp2000
[Re: mopar dave]
#2066812
05/03/16 10:43 PM
05/03/16 10:43 PM
|
crabman173
Unregistered
|
crabman173
Unregistered
|
Fixing something that ain't broke Lots of folks do it Lots of folks spend lots of cash doing it Can they beat your car at the race track?? Nah! Do they sleep better at night? Nah! Because they are busy thinking about and fixing other things that are not broken so the moral is... They are good for the economy!!
I have worked in lots of engine shops of all levels--after you build a life times worth of engines you figure out what is important to making them live and perform and what is Not The AVERAGE Joe messing around with a new bought angle gauge, rod bolt stretch gauge etc is just going to make a mess--LUBE the heck out of the fasteners with the correct lube as called for by the mfg--use any old torque wrench you can find and use a SMOOTH pull--You are DONE! That bolt will not fail because of anything you did or did not do--Period! Again I state-- that I have tested hundreds of torque wrenches with very expensive equipment designed for that purpose--many of the cheaper units perform as well or better than very expensive Snap Ons etc I had one shop that used a 1/2 in drive wrench for over 12 years--used it every single day--dropped it once or twice a week--used it in reverse --etc It was as accurate as any I ever tested and it was a $100 unit. yea yea I know they only measure friction etc yadda yadda--IT WORKS!!!
After hundreds and hundreds and hundreds of engines I can tell you that what you can get away with would simply amaze you and you would be unwilling to believe what junk parts put together by a knowing experienced builder can do on the race track in the hands of a winning driver--what is easier to believe is how poorly some very very expensive and over thought out engines and cars perform in the hands of folks with little experience. I applaud guys that want to do it well and do it right but if you want a picnic table use the plans from 1950 that make use of 8 equal length boards and a few nails--If you use plans by an "engineer" then plan on a truck load of lumber and a summer to build it with results that are sure to be no better at holding your burger, beer , and bum off the ground.
Last edited by crabman173; 05/03/16 10:44 PM.
|
|
|
|
|