Do you need new head bolts......
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Do you need new head bolts......
According to Chevy dealer, they use new head bolts when reinstalling the heads. Is this true?
Also, the head bolts final torque spec is 80 degrees ---- not foot pounds of torque. I recall reading about a torque angle meter. Anyone know about this?
Also, the head bolts final torque spec is 80 degrees ---- not foot pounds of torque. I recall reading about a torque angle meter. Anyone know about this?
Race Director
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
Re: Do you need new head bolts...... (95-383)
I know people who go 2 or 3 rebuilds with arp head bolts before they get new ones.
Melting Slicks
Joined: Nov 2000
Posts: 3,388
Likes: 1
From: X
Re: Do you need new head bolts...... (95-383)
Pete...They are replacing the heads on your plane..(single engine) They want to know if you want the head bolts replaced. BTW...You have to take the plane out for its test run when they finish...what do you do? The bolts are only a couple bucks each... :crazy:
I know people who go 2 or 3 rebuilds with arp head bolts before they get new ones.
I know people who go 2 or 3 rebuilds with arp head bolts before they get new ones.
Burning Brakes
Joined: Aug 2000
Posts: 984
Likes: 1
From: Cincinnati OH
Re: Do you need new head bolts...... (JonM)
I believe there are two kind of head bolts. One type is like a "normal" bolt that you torque normally and can reuse a number of times. The other type is meant to stretch, and therefore has a rotation angle in the spec. You cannot use a simple torque reading on these since you are in the "plastic deformation" (i.e. bolt mangling) strain range. For the same reason you cannot reuse these, they are permanently stretched once you torque them down.
Advanced
Joined: May 2001
Posts: 65
Likes: 0
From: Phoenix, Arizona
Re: Do you need new head bolts...... (Vince Ivanc)
So how do you know which type of bolts you have, normal or stretchy? I have an LT4, with stock head bolts, and currently have the heads and intake at the shop getting valve job, port matched and CNC'ed intake. I had planned on using the same head bolts when I put it back together. Do I need to get a new set of head bolts? What have the other LT4 owners done?
Thanks,
Chirs - 1996 LT4
Thanks,
Chirs - 1996 LT4
Melting Slicks
Joined: Aug 2000
Posts: 2,009
Likes: 1
From: Springfield MO
Re: Do you need new head bolts...... (crt)
I learned the hard way. I was told that I could re-use the stock bolts. Snapped one right off. Luckily I could use an easy out to get the broken one out. I went down the parts store and invested in some ARP's. And I certaintly didn't have a problem with spending the extra dough for their reputation. That was the last time I tried to cut corners while working on my car. Good luck on your project :seeya
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Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Do you need new head bolts...... (AS84)
I checked the Helm manual last night and did not find mention that the head bolts should be used only once. The dealer mechanic said that was the case.
The manual did say all the bolts needed to be first torqued to 22 ft. lbs. then torqued to 80 degrees for the long and medium ones and 67 degrees for the short ones.
I guess I will buy new ones and try to borrow/rent a degree torque wrench.
The manual did say all the bolts needed to be first torqued to 22 ft. lbs. then torqued to 80 degrees for the long and medium ones and 67 degrees for the short ones.
I guess I will buy new ones and try to borrow/rent a degree torque wrench.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Do you need new head bolts...... (JonM)
Thanks, I will.
I am now trying to determine if the stock head bolt are in fact "torque-to-yield". This type is not reusable since they stretch slightly (a few thousands of an inch) and may break or not provide enough clamping force.
During my research, I have found a number of good sites that explain the differences and advantages.
See http://www.federal-mogul.com/felpro/...ing_force.html
or
http://www.autotruck.net/ms/archives...599/599gst.asp
or
http://www.autoweb.lycos.com/garage/...op/ency01g.htm
Pretty interesting stuff.
I am now trying to determine if the stock head bolt are in fact "torque-to-yield". This type is not reusable since they stretch slightly (a few thousands of an inch) and may break or not provide enough clamping force.
During my research, I have found a number of good sites that explain the differences and advantages.
See http://www.federal-mogul.com/felpro/...ing_force.html
or
http://www.autotruck.net/ms/archives...599/599gst.asp
or
http://www.autoweb.lycos.com/garage/...op/ency01g.htm
Pretty interesting stuff.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Do you need new head bolts...... (Cam Potter)
Heads already off and being ported as we speak. Decided to take the intake manifold off to reseal the ends then couldn't stop myself. Nothing radical, just pocket porting, gasket matching, cc, flowed, etc. I did the intake manifold.
See---its your fault. I needed a project now that the garage is down to a nice temperature and you have not brought the 1990 over yet.
See---its your fault. I needed a project now that the garage is down to a nice temperature and you have not brought the 1990 over yet.
Safety Car
Joined: Aug 1999
Posts: 4,862
Likes: 118
From: Texas
Re: Do you need new head bolts...... (Mez)
Excellent, glad to see you are putting some extra beans in that LT4. I have been working on the ZR-1 and the '71 the last couple of weekends. I still have a few odds and ends to do. It's all stuff that I was putting off until it cooled down. Are you goining to the Texas' Fastest Vette Showdown out at the Motorplex Saturday.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Do you need new head bolts...... (Cam Potter)
Well, I had to do something. But you know I will never be able to catch you or Joel (if he ever get his car back).
Sorry but will have to miss the Fastest Vette event. I am going out to Texas Tech Saturday to see the A & M football game and see the kids. Our once a year trip to beautiful Lubbock.
Sorry but will have to miss the Fastest Vette event. I am going out to Texas Tech Saturday to see the A & M football game and see the kids. Our once a year trip to beautiful Lubbock.
Thread Starter
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Do you need new head bolts...... (Mez)
I ordered the complete set from Scoggin-Dickey for $27 including tax and shipping. Worth the piece of mind.
Confirmed with the shop that new head bolts is manditory as is the torque angle routine. No short cuts. Glad I did the research now rather than assume I could use the old bolts and have to possibly change blown head gasket down the road.
Website for the bolts is: http://www.sdpc2000.com/cart.asp?act...id=525&pid=650
Confirmed with the shop that new head bolts is manditory as is the torque angle routine. No short cuts. Glad I did the research now rather than assume I could use the old bolts and have to possibly change blown head gasket down the road.
Website for the bolts is: http://www.sdpc2000.com/cart.asp?act...id=525&pid=650
