Title says it all. I heard someone say that they stretch and have to be replaced once used. I cant find anything in my service manual about this, and I cant find the post where I seen this. Thanks for your help.

 

All I can say is I've always reused head bolts without any trouble. :seeya

 

No, you really buy new head bolts whenever you remove them. Mainly stock bolts, ARP ones can be reused.

 

OEM bolts are torque to yield. Everything I have read is to never re-use them. It can probably be done, but it is not recommended. I would think that you won't get the right torque/stretch when re-installing them since they were torqued to the yield point from the first install.

 

I re-used mine... no problems so far.. 5k and counting.. I'll keep the fourm updated as the years go by..

 

I once pulled the head off of a ford escort, and it had the bolts that are one time use only but the service manual said so. I just cant imagine why it would be left out of the factory service manual.

 

Cost of new parts to r&r cylinder heads (less labor)....$500+

Cost of new ARP head bolts...$60.

When in doubt it seems like a no brainer to me.

I recall reading in the '96 Service Manual it said to not reuse the OEM bolts.

 

I would never RISK reusing a head bolt. Just not good practice. :lurk:

 

oppsss... :blueangel: hope they hold

 

:iagree:

In the old days when it was torque to XX lb/ft, it was fine to resuse them... Now they are stretched with the TTY method... I don't think anyting in the last probably 20 years has been reusable... :confused:

 

What is the tourqe angle used on a LT1 head? If they're TTY, they would have to be torqued, then an angle meter installed, and the bolt turned to the correct angle. All bolts on LS1's are TTY and cannot be reused.

I've reused stock headbolts on l98 and LT1 heads many times without issues.

 

The spec for oem bolts is 22 ftlb first pass all bolts, then 80 degrees 2nd pass on the long and medium bolts, 67 degrees 2nd pass on the short bolts. You won't get as much stretch out of the shorter bolts, hence the smaller angle.

 

Ditto for the LT4

 

Well, that settles it, LT1/4 headbolts are NOT reusable. A small price to pay in headbolts, rather than new headgaskets later. Thanks for the info. :cheers:

 

Ok, Im not trying to argue here, Im just trying to understand so please stick with me on this. In my 93 factory service manual, in the specs section, it states to torque heads to 65 foot lbs. I cant find anything in there stating to torque to xx lbs, and then tighten to xx angle, such as I seen on the escort that I worked on. Is it possible that the older LT1 were torqued differently then the newer version? Also, since I dont want to take a chance with it, Im going to order the ARP bolts, but with these, what torque procedure should be used and are they reuseable? And thanks to everyone for their input. :cheers:


Ok, I came back on this post with a edit. The following is out of my 93 service manual page 6a1b-34 titled cylinder head assembly
Install or Connect
1. New cylinder head gasket (82)
2. Gasket (82) over locating pins, with yellow side of tab on outboard side facing up.
3. Cylinder head assembly (34) over locating pins and gasket (82)
Coat threads of cylinder head bolts/screws (81) with sealing compound (GM P/N 1052080 or equivalent).
4. Cylinder head bolts/screws (81) finger tight.
Tighten Cylinder head bolts/screws (81) in sequence and in three passes to 88 N.m (65 lb.ft.) (figure 51).
5. spark plugs
6. Engine coolant air bleet pipe and bolts/screws.
Use a backup wrench on pope fittings when installing bolts/screws.
Engine coolant air bleed pipe bolts/screws to 41 N.m (30 lb. ft.).
spark plugs to 15N.m (11 lb. ft.)

Now that is all I can find in my service manual about it and I typed it the best I could (poor typist) word for word.


[Modified by 93 ragtop, 5:54 AM 2/11/2004]


[Modified by 93 ragtop, 5:56 AM 2/11/2004]

 

If I remember right my 95 Helms listed the torque at 65. My 96 Helms shows the torque to yeild method. So they may have changed for the 96 year. When I did the heads on my 95 I replaced the bolts and used the 65ftpnd. For the 40-60$ after spending so much more on other things when the heads are off I think it's peace of mind to just replace them.

 

I confirm that the 1996 LT1/4 Helm manual says TTY bolts.

Here is my experience.

I did research via the web to understand the whole TTY bolt thing. In simple terms, the bolts are designed to "stretch" slightly to provide the best clamping solution for aluminum heads. My guess is since aluminum heads expand and contract with heat cycles, the engineers designed bolts to help compensate or so my theory goes. But after the bolts go thru an installation/removal/reinstallation cycle, some of the bolts may be OK but others may have stretched too much and won't really provide the necessary clamping force as they continue to stretch with less force. Kind of like pulling tafy, if you know what I mean.

So when I got my heads ported, I went with the stock GM head bolts. Bought them for $27 including shipping from Scoggin-Dickey Chevrolet in Lubbock Texas. They are cheaper than the ARP bolts but not by much. I recall ARP was $46+shipping for the basic head bolt set.

But I had to buy a torque angle guage from Autozone for $12, so the cost between the two types was about $10-15.

Using the torque angle guage was a big pain to use. It was difficult to reach some of the bolts with this huge gizmo on the end of your 1/2 drive wrench. Next time, I will probably go with stock ARP bolts. Go visit their website for more information on head bolts.

 

Ragtop, The manual never tells you to replace head bolts. The bolts do stretch. I would replace them. If you Alum Heads you should always replace the head bolts. :seeya

 

I agree that it is probably a good idea to replace the bolts. But after a little more research I have found in a haynes manual, they show torque specs. for 92 to 95 with the standard lb. ft. ratings. Then the 96 is shown as the torque to yeild version. So IMO I believe it is always a good idea to replace the bolts in a 92 to 95 and it is absolutely necessary to replace them in a 96. I do appreciate everyones help on this.

 

Hmmm. Interesting. I was looking in my 96 book when I posted the specs above. Never thought to look in my 93 book to see if they were any different.