Any advantage to TTY head bolts?

[Blown&Injected]

Interesting copy on TTY bolts. Since a cite was provided, nobody should have a problem.

Makes me feel better about one re-use on stock head bolts; I was told it would not work, but I did not have any issues with them :wink:

 

[49-blues]

I have a fairly new set i bought from gm for about $100. they were only torqued once. i was told you need to check to see how much they re stretched before you could possibly use them again. -i went to apr head studs-if interested in the bolts contact me.

 

[Ormand]

The TTY bolts give subtantially less clamping force than the ARP bolts or studs. TTy, torque to about 60ft-lb, per shop manual. ARPs all use higher torque, = higher tension. If head gaskets fail from the heads lifting, that would make the head gaskets less likely to blow. But if the head gaskets fail because the head deflects between bolts, as Nick suggests, then it won't make any difference. My GUESS would be that is a combination- some deflection, plus head lifting, and that the stronger bolts help, at least a little. But I haven't seen anything that would really verify my guess.
Another guess- GM used the TTY head bolts because they worked well on the assembly line. Anybody really believe they used them on race engines? I'm sure Robert Caruth is right as far as what Buick said, but then again, how much boost did they run? Their interest was in something that would make $$ for GM, with minimal warranty costs.

 

[Jerryl]

The TTY bolts give subtantially less clamping force than the ARP bolts or studs. TTy, torque to about 60ft-lb, per shop manual. ARPs all use higher torque, = higher tension. If head gaskets fail from the heads lifting, that would make the head gaskets less likely to blow. But if the head gaskets fail because the head deflects between bolts, as Nick suggests, then it won't make any difference. My GUESS would be that is a combination- some deflection, plus head lifting, and that the stronger bolts help, at least a little. But I haven't seen anything that would really verify my guess.
Another guess- GM used the TTY head bolts because they worked well on the assembly line. Anybody really believe they used them on race engines? I'm sure Robert Caruth is right as far as what Buick said, but then again, how much boost did they run? Their interest was in something that would make $$ for GM, with minimal warranty costs.

I would agree.
First off, I belief most in this community will agree that “re-torqueing is a good thing”. :smile:

Think about this from a MFG point of view; If non-TTY bolts such as ARP were used in the TR from the factory, who would re-torque them? From an assembly line / mass production point of view, the TTY bolts are the ABSOLUTE BEST choice for the automaker. (Show me the $)

From an enthusiast point of view, the ARP bolts make more sense.
Anytime you have a higher required torque value without subjecting the bolts to significant plastic deformation, the result MSUT be an increased clamping force.

Having stated that, everyone would agree that the GM head seal was/is bulletproof! They may have used some secret sauce as in the RJC kit.

Maybe heat cycled ARP bolts, re-torqued in combination with steel shim gaskets, AND the secret sauce would be the best combination?

Just my $0.02

 

[ijames]

If you gp yo ARP's web page they recomend retorqing all their fasteners 5cycles to get the proper bolt stretch???

No, it is to burnish the threads, the washer, and the underside of the bolt head smooth so that you get minimum and uniform friction. That way you get maximum conversion of torque into clamping force and closer to the same clamping force on each bolt.

 

[ThikStik]

Re retorking: I think that the steering shaft precludes the lower rear bolt on the drive side. So , I didnt retork my last build that used arp's and sealer...as it was, no problems at up to 21 psi.

 

[Marc87GN]

What confuses me is why does the ARP catalog state that the 6 point and 12 point do not need to be retorqued, but yet people constantly state to retorque them? I would think they know there bolts design better than anyone else and they have been thoroughly tested. I retorqued mine dry while the engine was out after a week, but it would be a PITA to do it now with the engine installed.

http://www.arp-bolts.com/ARP_2005CatFinal(p)work.id2.pdf

Page 41 incase it doesn't go right to it.

 

[rodman99999]

What confuses me is why does the ARP catalog state that the 6 point and 12 point do not need to be retorqued, but yet people constantly state to retorque them? I would think they know there bolts design better than anyone else and they have been thoroughly tested. I retorqued mine dry while the engine was out after a week, but it would be a PITA to do it now with the engine installed.

http://www.arp-bolts.com/ARP_2005CatFinal(p)work.id2.pdf

Page 41 incase it doesn't go right to it.

The thought there is that when your head expands from heat, and the bolt doesn't stretch(as in ARP), your head gasket will have to take up the pressure(get crushed a bit). When the engine cools, the gasket is still compressed, therefore relieving a bit of torque. I've heard a bunch of varying opinions, and hope I can get away without retorquing my ARP headbolt, OEM GM HG combination.

 

[ijames]

What confuses me is why does the ARP catalog state that the 6 point and 12 point do not need to be retorqued, but yet people constantly state to retorque them? I would think they know there bolts design better than anyone else and they have been thoroughly tested. I retorqued mine dry while the engine was out after a week, but it would be a PITA to do it now with the engine installed.

http://www.arp-bolts.com/ARP_2005CatFinal(p)work.id2.pdf

Page 41 incase it doesn't go right to it.

I've read that page twice now and it doesn't say that. It says that the smaller bolt heads make it easier to retorque because you don't have to remove the valvetrain components.

Here's the text from page 41 (bolding mine):

CYLINDER
HEAD BOLTS
HIGH PERFORMANCE SERIES
High Performance head bolts are available with a reduced wrenching
hex or 12-point and wide area flanged head that eliminates the
need for valve train removal to facilitate cylinder head retorquing. All
High Performance Series bolts are 180,000 psi (which is 15% stronger than
Grade 8) and kits come complete with hardened parallel-ground washers.
PROFESSIONAL SERIES
All Pro Series bolts are cold-forged to ensure molecular integrity, heat-treated prior
to thread rolling and machining, and are rated nominally at 200,000 psi. ARP Pro
Series head bolt kits are application specific – designed for use with typically competition
only components. These fasteners deliver superior strength and meet the ARP
“ZERO defect – ZERO failure” quality standard. Hardened and parallel-ground
washers are included with each kit to ensure even load distribution and accurate
torque readings. All Pro Series head bolts have a reduced wrenching 12-point head
and wide area flange to eliminate the need for valve train removal for cylinder head
retorquing and permits the use of larger diameter valve springs. Most applications
have undercut short bolts that can help eliminate head gasket failures through providing
more “stretch” to compensate for the additional compression of gaskets.

 

[Marc87GN]

I've read that page twice now and it doesn't say that. It says that the smaller bolt heads make it easier to retorque because you don't have to remove the valvetrain components.

Here's the text from page 41 (bolding mine):

CYLINDER
HEAD BOLTS
HIGH PERFORMANCE SERIES
High Performance head bolts are available with a reduced wrenching
hex or 12-point and wide area flanged head that eliminates the
need for valve train removal to facilitate cylinder head retorquing. All
High Performance Series bolts are 180,000 psi (which is 15% stronger than
Grade 8) and kits come complete with hardened parallel-ground washers.
PROFESSIONAL SERIES
All Pro Series bolts are cold-forged to ensure molecular integrity, heat-treated prior
to thread rolling and machining, and are rated nominally at 200,000 psi. ARP Pro
Series head bolt kits are application specific – designed for use with typically competition
only components. These fasteners deliver superior strength and meet the ARP
“ZERO defect – ZERO failure” quality standard. Hardened and parallel-ground
washers are included with each kit to ensure even load distribution and accurate
torque readings. All Pro Series head bolts have a reduced wrenching 12-point head
and wide area flange to eliminate the need for valve train removal for cylinder head
retorquing and permits the use of larger diameter valve springs. Most applications
have undercut short bolts that can help eliminate head gasket failures through providing
more “stretch” to compensate for the additional compression of gaskets.

Good Point! Reading > Me. Could be why I have an Accounting degree and wasn't an English major. I still refuse to pull that passenger side valve cover off unless it blows the gasket.