Re Use Head bolts, + question about MT

[Mishakol129]

I just got 2 questions. Is it okay to reuse head bolts for an engine that overheated? The bolts are new Victor Reinz (good company), only torqued down once, but the car blew its HG cause it overheated (probably warped the head too).
The OEM bolts are not TTY as I have heard and they CAN be re used, just if the car overheated, that's my main question.

2nd question, when i'm at the high rpms and try to shift into 4th from 3rd, the shifter won't go in gear at all. There are no grinds in any gears, its just like its frozen solid, just completely impossible to get into gear... Until that is my revs drop.


Thanks.

[reklipz]

Someone else will have to clarify #1, but I was of the understanding that the OEM head bolts were torque-to-yield, and therefor should not be reused.

As for #2, it sounds like the clutch isn't fully disengaging, or your transmission fluid is viscous enough such that even if the synchronizer was worn out, you're just not giving enough force to cause the teeth and sleeve to grind.

[Mishakol129]

Someone else will have to clarify #1, but I was of the understanding that the OEM head bolts were not torque-to-yield, and therefor should not be reused.

As for #2, it sounds like the clutch isn't fully disengaging, or your transmission fluid is viscous enough such that even if the synchronizer was worn out, you're just not giving enough force to cause the teeth and sleeve to grind.

I heard it the other way around, they can be re used.

I went to Victor Reinz website and saw an article about head gasket failures (very interesting pieces of information)

Link V

http://www.reinz.com/pictures/39-003...S-ND-e-low.pdf

I took a snippet about they said about re-using bolts.



So what do you think does this apply to our cars or not? My question is why the steel becomes longer but the aluminum threads in the block don't do the same thing. Can someone clarify for that? Doesn't make sense why aluminum threads would be that strong. They must be steel threads, there's no other way.


Btw I did use GM (Penzoil) Synchromesh for the transmission.

[Domesticated]

Someone else will have to clarify #1, but I was of the understanding that the OEM head bolts were not torque-to-yield, and therefor should not be reused.

As for #2, it sounds like the clutch isn't fully disengaging, or your transmission fluid is viscous enough such that even if the synchronizer was worn out, you're just not giving enough force to cause the teeth and sleeve to grind.

Torque to yield means that they are torqued to their yield strength. If you torque them below that they they likely won't yield, IE, be stressed past their elastic region. Assuming that the threads are still fine, you should be able to continue to use them. With that said, bolts are designed to fail at the threads, and after being properly torqued the first few thread yield and hold a majority of the pressure. Whether you reuse them or not is a preference I guess, but in the industry it's a rule of thumb to not reuse important bolts like that.

[oyajicool]

From ASE Study Guide

　Torque to Yield Bolts

With a regular head bolt a technician could torque a bolt to its yield point and it would return to its original form and length when removed. This is because of its elasticity, it is able to stretch and then return to its original form.

This is not so with a torque to yield bolt. There are two terms related to this phenomenon. The first is elastic deformation and the second is plastic deformation: Torque to yield head bolt.

1. Elastic deformation: This is the amount of force or torque where you haven't changed the shape or length of the bolt. At this point you are able to reuse the bolt as it hasn't changed its shape.

2. Plastic deformation: This is the point past elastic deformation where the bolt has changed its shape and length. At this point the bolt can not be reused and needs to be replaced.

For example an aluminum cylinder head will be torqued in a sequence say one to ten. The first pass would be a torque of 36 foot pounds. This is the elastic deformation point. The second pass would be a 90 degree angle or a quarter turn. At this point the bolt is going into plastic deformation. The third pass would be another 90 degree angle. At this point the bolt has changed its form and if loosened or removed it must be replaced with a new torque to yield bolt.

So you can re-use the standard head bolts, but when it comes to torque to yield bolts, if they have reached plastic deformation, they need to be replaced with new ones. Remember, a lightly oiled bolt should be easily screwed all the way in and out of the bore with only your fingertips. If there is excess resistance there is probably something wrong with the bolts threads. Always check with manufacturers specifications and TSB's when working with engine bolts, especially if you suspect them to be TTY bolts. TTY bolts are common and typically used to clamp cylinder heads on late model engines. Be careful, a loss of clamping force will ultimately lead to head gasket failure.

[Mishakol129]

Okay so they are not TTY then, so I can re use them even if they overheated? The bolts only have about 40,000 miles on them, they're newish. I feel dumb for letting my car overheat, but its no big deal.

I would like some more input on the 4th gear of my MT as well. I appreciate any and all help I can get.

[reklipz]

Torque to yield means that they are torqued to their yield strength. If you torque them below that they they likely won't yield, IE, be stressed past their elastic region. Assuming that the threads are still fine, you should be able to continue to use them. With that said, bolts are designed to fail at the threads, and after being properly torqued the first few thread yield and hold a majority of the pressure. Whether you reuse them or not is a preference I guess, but in the industry it's a rule of thumb to not reuse important bolts like that.

Someone else will have to clarify #1, but I was of the understanding that the OEM head bolts were not torque-to-yield, and therefor should not be reused.

Ah crap! Apologies on this one, I did not mean the first "not"; I was of the understanding that the OEM head bolts were TTY, and therefore should not be reused.

[Mishakol129]

Ah crap! Apologies on this one, I did not mean the first "not"; I was of the understanding that the OEM head bolts were TTY, and therefore should not be reused.

So what is it should I re use them?

[bobbycos]

So what is it should I re use them?

NO, get a new set Period

VICTOR REINZ Part # GS33407

[Mishakol129]

NO, get a new set Period

VICTOR REINZ Part # GS33407

What if im too poor?

[toycar]

What if im too poor?

Then your broke ass is going to be stuck on the side of the road when your new gasket leaks for no damn reason other than you cheaped out on headbolts and now you need to spend more money for a tow truck than the headbolts would've cost. By the way, that head gasket is now toast and the hours spent doing the half assed job were more or less wasted because you didn't want to pony up the dough to do the job right.

[cloudasc]

EDIT: ^^ What he said... in a nutshell.

If your ever planning on having the head off again in the future, just spend the money on the ARP Stud Kit.

I would spend the money on the new bolts instead of re-using the old ones, especially if I wanted to minimize the possibility of 'do it twice', unless you find replacing head gaskets enjoyable, or have an abundance of time to do so.

[Mishakol129]

EDIT: ^^ What he said... in a nutshell.

If your ever planning on having the head off again in the future, just spend the money on the ARP Stud Kit.

I would spend the money on the new bolts instead of re-using the old ones, especially if I wanted to minimize the possibility of 'do it twice', unless you find replacing head gaskets enjoyable, or have an abundance of time to do so.

Wth I though I heard people say you can reuse them no problem.

[ferenza]

You can reuse them . We dont have tty bolts.
HOWEVER, you overheated and killed the gasket and possibly warped the head.Meaning even though they are brand new they are more than likely out of shape. The last thing you want is to do a head gasket a third time.

[Mishakol129]

You can reuse them . We dont have tty bolts.
HOWEVER, you overheated and killed the gasket and possibly warped the head.Meaning even though they are brand new they are more than likely out of shape. The last thing you want is to do a head gasket a third time.

Out of shape? please specify. The heat might have damaged them but what specific way are you talking about? Not like it bent them. Perhaps they were stretched too much?