98TAauto

iTrader: (2)

ok whats the big difference. I already got GM head bolts here that i ordered, but I hear that ARP's are much better. But they run like 90bucks I think?

whats the pro's and cons? Should I send my GM ones back and get ARP's? Heads arent going on untill the first of June so I have some time.

Is the trouble worth it?

AG Formula

I looked into ARP vs GM, one draw back is you have to retorque the ARP after the first heat cycle.

99 TA

iTrader: (1)

Why is that? I have never heard about that. I just put my heads on today with ARP bolts and it was very easy. I just followed the directions on jmX's site and it was easy.

Stu

If ya wanna get rid of the GM bolts I will take em from ya..........Just in case.

98TAauto

iTrader: (2)

Stu, if you want them email JTSS on efa man.. goooooodddd deal on those suckers!! Thats why i got them.

I just didnt know if ARP held up better or had some other benefits. If i gotta re torque them then that blows

AG Formula

I looked on ARP website and found this http://www.arp-bolts.com/pages/tech/images/fasttorq.pdf and http://www.arp-bolts.com/pages/tech/fastener.html

Here is the number I called: 800-826-3045

I would be interested hearing if someone else receives a different answer from ARP or the reason to check torque after a heat cycle.

robertbartsch

The parts manager for the Chevy dealer in my town claims the service department has always re-used the original factory bolts...I know this because I asked him why he did not stock the replacement bolts when I went to buy mine...

...apparently, they have had no problems with re-using torque-to-yield bolts in many years of their warranty work...

No flames, please - I did not suggest this was a good idea, I'm only stating what he told me.

He said ALL bolts stretch and twist and that it is just bunk to replace them!

I bought new ones but would be interested in knowing if anyone else re-uses theirs?

BIG PD

omg...a dealer guy told you that...wow...that's just idiotic. if you ever do a crank pulley swap measure your old center bolt and then measure your new one...hell look at them and you can tell the size difference. never reuse head bolts...well...i guess if your car didn't run and you took them off and put them on again...but no wait just don't...lol

1999_SS_M6

No flame intended, but torque to yield bolts ARE NOT re-usable, period. Bad advice is best when free, and it sounds like that mechanic has plenty in stock!

ARP is going to instruct you to re-torque after you heat cycle the engine any time you use aluminum heads. The reason is becuase of the expansion charateristics of aluminum, and its' tendency to "walk". Honestly though, I have done it both ways and had no trouble with either.

I can see their point when installing aluminum heads on an iron block, due to the fact that the two materials will expand and contract at different rates. IMHO, this is a hold-over policy from the early days of aluminum, and the sealing problems that came with them. I had a 5.0 mustang with a set of Edelbrock RPM heads that I finally SOLD cuz I was so tired of changing head gaskets. I don't think that's the case with the aluminum motors. I've been through this on a half dozen LS1's and have NEVER re-torqued the ARP bolts.... no problems to report.

At the end of the day, you gotta do whatever you feel comfortable with. Ask all the questions you can, get all the advice you can, and try to check with some of our sponsor shops that do tons of installs... then make an informed decision you're comfortable with.

malibu350

The bottom line w/after market fastners is that they are stronger than stock, and you can reuse them. So if you plan on doing some head swaps in the future...or changing lifters, blowing head gaskets, then the ARP is what is for you. If this is just one head change to give you a little more performance(which a little is never enough) Then you should be fine with stock replacements...BUT DO NOT REUSE THE OLD ONES!!!!! Hope this helps!!!!

98TAauto

iTrader: (2)

thanks for the info everyone.. im just gonna go ahead and use the replacement GM ones anyway since I got them.. but i dang sure aint using the stock bolts i just took out!!!

Terry Burger

iTrader: (4)

I reuse LS1 head bolts all the time. Forget the torque to yeild BS, just use a torque wrench and go to 70 #/ft.

robertbartsch

Terry:
I'm glad someone here can back me up that re-using the old bolts has been done before and works.

In addition to what the Chevy dealer told me about their constant re-use of torque-to-yield bolts over the last six years without a single problem, I also asked an engineer what he thought.

He said torque-to-yield bolts are bull. They are made of high tensile steel just like all other bolts. He also said all bolts stretch when torked and not to worry that a new bolt is not as tall as a used bolt.

I'll use new bolts with my H/C swap, but I feel the torque-to-yield thing is largely a ploy to sell new bolts...

BIG PD

that's really bad advice imo...i went to NASCAR technical institute. if you they ever saw you putting old bolts back in a head, you'd pry get kicked out of the school. they pounded on us to never reuse torque to yeild bolts. why would they being trying to make us buy more bolts. well maybe nascar doesn't know anything then i guess.

CAT3

iTrader: (9)

OK. Point here is GM Head Bolts or any other bolts are just as good as the after-market (period).

Now, tell me, has anyone ever taken an APR head bolt, or crank bolt out and mic'd it after install to torque spec's? I bet they mic over the New Unused one! It is true to fact that anytime you place torque on a bolt you will stretch it. Now the ARP will not stretch as much as it is made to withstand more stress, but the point being htat it still stretched.

I doubt NASCAR would reuse an old bolt, even if it were ARP. Why? Well, one have the sponsorship, then the whole multi-teear down, and then the actual punishment those engines are made for and fianlly there prolly is a little propaganda concerning "NEVER reuse a torqued bolt, buy After-Market" etc.....Do you treat your car like it were NASCAR?

Not an LS1, but on other BowTie engines I have indeed reused every nut and bolt, with the exception of the rod bolts and nuts. I never had a problem with a crank bolt letting go, or head gaskets/bolts. Oh yeah, one time I installed headers on a 64 Nova, and I used header bolts over manifold bolts cuz they were easier to get to.

The difference between the ARP guys and the Re-Torque guys is: The guys that Reuse know there is an option, and the risk they MAY take and they do not care if You ARP guys buy new bolts or not!

robertbartsch

My heads are off right now... ...and just to prove a point, I am tempted to re-use the old factory head bolts... ...I'm confident they would work fine.

Question: Why does ARP recommend that their head bolts be replaced each time but their head studs can be re-used multiple times? I would bet their studs and bolts are made from the same high tensile steel. ...great stuff, no doubt from me.

NASCAR?? ...My street motor does not run on race gas at 15 to 1 compression at 10,000 RPMs for hours on end... ...OK if I was building a NASCAR engine I would not re-use ANYTHING!!!!

sawedoff

iTrader: (3)

Okay, Okay! There's a big difference in grades of fasteners, guys. The grain structure of the ARP is probably alot denser. The threads have no microbursts or burrs. The studs distribute an even clamping load over the entire head. All head fasteners will stretch, when run through a cycle, that's why you retorque. ARP caters to high end performers and racers, that take the time to retorque. So, that's just their standard procedure for what the sell. The bolts that come on your stock motor, are designed for just that, a stock motor. They are manufactured in lots, from the lowest bidder. GM delivers the contract to the fastener manufacturer, and there you go. They have an average level of quality and are designed to a minimum standard for the engine. The bolts do make service, repair, and manufacturing easier by reducing "time to install." This lowers costs for GM and it's dealership base.Now you may get away with not retorquing the fasteners on your heads for the street, but in a race situation, you would definitely retorque, for added precaution. If you have a choice, always take the studs over bolts any day.

parsonsj

I don't post here much, but I think I understand a little bit about the torque-to-yield GM head bolts and why GM recommends that you shouldn't re-use them.

Bolts (metallic objects in general) have two critical points to remember when tightening them. The first critical point when tightening a bolt is where the bolt reaches its elastic limit. Prior to that point the bolt will return to its original length and properties once it is loosened. Once the elastic limit is exceeded, the bolt is permanently stretched. That is called its yield point. GM head bolts are torqued past this point at the factory and therefore don't return to their pre-tightened properties. Past the yield point, there is a fairly uniform period as the bolt is tightened further where the clamping force doesn't change very much until the bolt reaches its failure point. The failure point is where the clamping force diminishes rapidly as the bolt is tightened even more until the bolt actually breaks.

So in-between the yield and failure points of the stretching of the bolt there is a nice area of consistent clamping force. This is good for factory assembly of engines: all thread surfaces are new and the bolts can be quickly installed and there is no need to check for torque later, since the clamping force is somewhat independent of the torque in this area of the torque vs clamping force function.

Compare this to conventional Chevy head bolts used until the LS1. There the bolts are not torqued to their yield point and so will retain their original properties when removed. So they can be reused over and over again. In the pre-yield area of a bolt's performance (torque vs clamping force), clamping force is very sensitve to torque and therefore ought to be checked once the engine has gone through a heat cycle ... since the parts can move around a little bit. Also keep in mind that clamping force in this area of a bolt's performance is actually a function of the stretch of the bolt, not the difficulty in turning. Since the stretch can't be measured directly, we measure it approximately using the difficulty of the effort to turn the bolt ... aka torque.

The ARP bolts and studs are not torque-to-yield and so they recommend checking the torque readings once the engine has gone through a heat cycle; something they've recommended for all their head bolts and studs for years. In fact, GM used to recommend the same thing. The torque-to-yield technology is a direct result of research into a couple of problem areas: 1) the pita of having to re-check the torque readings after the customer has driven the car away, and 2) the only approximate way torque measures stretch.

You guys that re-use yielded head bolts are probably fine as long as you don't torque the bolt down to the failure range. Perhaps 70 ft/lb is safe for that. Sure seems to be, since there are many reports of successful re-use of them. My preference would be to use new bolts, or ARP studs, but I won't be tearing my engine down more than once every few years or so (hopefully ).

John Parsons

1999_SS_M6

hey, you guys really have the wrong idea... Nobody here, ESPECIALLY not myself is telling you that YOU HAVE TO do it "my" way... Do what you like.. At the end of the day, it's your engine, and your wallet.

However, IMO, freedom of choice doesn't make re-using torque to yield bolts a good idea. It's a matter of tensile strength. A fastener's tensile strength determines its' resistance to stretch. The higher the tensile strength, the less succeptability to stretch the faster will have, and subsequently, the more safely re-useable it will be. Eventually, ALL fasteners to reach their "maximum stretch" and who is to say how many re-torques will be safe before that occurs. To me, it's a matter of cost vs. risk.

Don't come into a forum asking a question hoping to hear someone give you the answer you want to hear. These forums are for advice, opinions, and information sharing. Take that advice and use it, or ignore it, it's completely up to you.

Myself though, you'll never find me risking a time-consuming tear-down to save 60 bucks in bolts.

JurisAg02

so you can reuse ARP head bolts?