JPrevost

Are the Vortec head bolts torque to yield?
I'm not convinced that they are. From various sources the best one has said that it is OK to re-use the bolts. Just because the torque specs require an angle does NOT mean they are tty.
I'd go to a dealer and ask but I'm afriad I can't trust anybody these days. Everybody is out to make a buck so I'm sure they would tell me that I need to replace them. Sucks having to spend so much time researching because most dealers are bastards .
I've put up a poll and would like explinations if you vote.

ede

not that i know much, but i thought the fact that you have a torque spec with a angle, or somethnig like 45 ft/lbs and a quarter turn does mean the bolts are torque TTY.

Z69

I used button head allens.
From what I've read, the stockers are designed to bottom in the hole to hold them in.

So who knows when you swap to aftermarket. Or if that is even true for that matter.

On my edelbrock intake the instructions said 11ftlbs and blue loctite.
11 on my torque wrench was not enough. And it felt off too if you have the feel.

I think I went to 13 or 15 and it felt better and looked better.
The intake was obviously all the way down against the
plastic carrier on the stock gasket. So that meant the carrier was loading up the bolt to put some tension on it.
I put about 1k on the 11 lb setting and the bolts would work loose very slightly in that time. I did a retorque after the first use too.
The stock gaskets are reuseable btw.

83ho86tpi

I would find out what type come from the dealer and from the parts store, or just buy a new set. I think autozones website has tourque specs for some headbolts, look up your year, make and model car the bolts came from and see what it says about tty, or look up the price of a new bolt set for your specific bolts on different sites. The instructions will tell you if the ones you just bought are tty. I dont know if the originals were tty or not, sorry.
IF it turns out they make both types of bolts for this I would not risk re-using the bolts you have.

JPrevost

Z69, I'm talking head bolts, not intake bolts. I know the intake bolts for certain will bottom out. It's a royal PITA because the intake gasket I got was an aftermarket and the intake was Edelbrock... bolts were ARP. Guess what, intake gasket failure because I couldn't get the bolts tight enough . Somebody doesn't have very good tolerances and/or I got a bad product somewhere with one of them.
Now back to head bolts.
Factory spec on the f-body 305/350's is 68ft-lbs according to my older (more complete) Chilton's manual.
http://www.sallee-chevrolet.com/Disc...html?975436095
That link is why I have a hard time with this. Somebody's gotta know, so who is that person and are they being bastards by selling out with a lie... that the bolts are infact NOT tty? It seems as if they aren't if they are to be tightened to 22ft-lbs and then 55-75 degrees. That sounds like it's close to 60ft-lbs. To yeild these bolts would be completely non-GM.
I'm going to mark where they are on the head, loosen, then re-torque until the mark lines up. Then I know approximately what they're torqued too and if it's close to 68ft-lbs I'm betting they aren't tty.

Z69

For some reason I had Jeremy in mind when I posted.
If the bolts look the same as regular old sbc head bolts and you torque them to 68....
Or are you trying to "find the truth"?

kdrolt

I say no.... but without proof.

IIRC the TTY bolts were used on LS1 engines first (for v8 apps), not on L31. On the LS1, I thought they were longer (to reach the block main web) and also designed with a necked-down region so that the yielded zone intentionallly occurs there, and not just anywhere on the bolt.

If TTY were spec'd for L31 Vortec head use, then it would say so in the FSM for the C/K/G trucks starting in the 1996 model year when the L31 was first issued.

Ask the FSM TTY question on the FSC forum -- someone there probably owns a FSM for a Vortec truck.

EDIT: ignoring the coolant direction (which should have no effect on a torque spec), from a casting viewpoint the L31 head are clones of the iron Bcar LT1 head. GM didn't use TTY bolts on the iron Bcar LT1 heads. So I doubt that they were used on the L31.

JPrevost

AutoZone lists the same head bolt part numbers for 87 and 97 suburbans... so I'm now 90% sure they aren't TTY. I'm betting this thread will be on Google in no-time.

DM91RS

JP...... I used std ARP head bolts both times I installed the Vortecs on an engine. Regular small block torque specs.

You have yours apart?

DM

JPrevost

It's not apart yet but the engine only has 35k miles on it. GM head bolts... why waste them if they're perfectly good? Seriously though, I find it hard to believe the vortec heads would get TTY so I'm going to measure them when I remove them and use a torque wrench to tell me what the final torque is using the 22ft-lbs + angle.
There is a guy on e-bay selling head bolt kits for vortecs saying that they are TTY

Fast355

iTrader: (2)

If you read the note on the bottem of the page on the Autozone computer, it says "Manufacturer Requires Replacement of Headbolts Upon Removal" or something real similar. They are TTY bolts. The 1997 G1500 that I put a 350 Vortec into were TTY per what the GM dealer told me. I used a set for a standard old school 350, torqued them to spec, and they are doing just fine.

Fast355

iTrader: (2)

If you read the note on the bottem of the page on the Autozone computer, it says "Manufacturer Requires Replacement of Headbolts Upon Removal" or something real similar. They are TTY bolts. The 1997 G1500 that I put a 350 Vortec into were TTY per what the GM dealer told me. I used a set for a standard old school 350, torqued them to spec, and they are doing just fine.

Why skimp on a new bolt set, $40.00 gets you a NEW set of bolts.

JPrevost

I don't consider it skimping when for years the small block chevy has been non-TTY bolts... and like my first post, I think the dealers/GM are just being bastards trying to push the product on the consumer.
So now let's talk about the Autozone quote. Does it make sense that the "Manufacturer requires replacement of headbolts upon removal" when the part numbers match that of an older small block chevy? Using my 87 engine rebuild manual it says I can re-use the head bolts so long as they aren't stretched (past yield). So who's right? So far it appears clear that these are infact not TTY. Another reason might be that GM doesn't want to be deal with the liability of telling somebody that it's okay to re-use a part. Seriously, do you honestly think that they changed the way the bolts are being made when they have never had a problem in the past? It all seems to filter down to a no-trust situation between dealers/GM and the consumer.
I've heard of people re-using the vortec head bolts and not having any troubles. I'm whiling to save my $40 just in spite of them. If I do end up having to replace them I'll only be out an extra $40 (have an extra pair of head gaskets and intake gasket is re-usable... or is it ).
The only other thing I can think of is the type of head gasket. I know the vortec head gaskets have their own part number and I know for a fact that they are slightly thiner than traditional (bette quench ). With that being said, it might be the case although it's unlikely.

DM91RS

GM PART # 10105117
CATEGORY: Engine Cylinder Head Gasket
PACK QTY: 1
GM LIST: $18.75
OUR PRICE: $13.12

FYI this is the GM composite .028 thick gasket.

GM also sells a std sb headbolt "kit" with sealer installed for around $20.

I have reused the GM Vortec intake gasket twice

DM91RS

Another FYI........

GM PART # 12495499
GM LIST: $27.46
OUR PRICE: $19.23
DESCRIPTION: BOLT PKG

Supervisor42

Well since this is a poll, I'll add my
They are not TTY but need to be replaced when a shop is working on a customer's engine.
Why replace the bolts?
1. Erosion of the threaded part of the bolt that extends into the coolant. Anybody that has pulled down many SBCs has seen this.
They damage the block threads bad enough on the way out, a few more trips and the threads in the block strip during torqueing.
2. Heads are commonly pulled for replacement that have been overheated to the point of "glowing", bolts included. This destroys the tempering of a hardened bolt. If you don't think this is important, try torqueing a grade 2 bolt to 68 ftlbs.

Don't you wonder why the torque spec is this silly 22 ftlbs and so many degrees? Instead of the good old 68 ftlbs?
There are 2 reasons:
1. How GM assembles the engine at the factory. The machine puts all of the bolts in at once and spins them down with a high speed low torque motor. Then a low speed high torque motor turns the sockets tightening the bolts a certain number of degrees in order. They just want the same thing done during reassembly.
2. Allowance for torque resistance during torqueing. This means if a bolt thread or hole is fouled or damaged and the bolt takes 5 ftlbs to turn it on the way down to the surface, it will have 5 ftlbs less clamping force if it is torqued to the same ftlbs as one that spins freely. If the bolts are turned a certain number of degrees after contacting the head they will have exactly the same clamping force.

JPrevost

Supervisor42, I'm not sure what your point is.
Are you telling me that GM/dealers don't trust that their mechanics can tell if the head bolts are stretched or damaged? That seems to be the impression. As for the threads being damaged, good point although it would take a lot of mineral build-up and rust on the end of the bolt to actually damage the threads. There is a clearance and the threads in the block should be well protected with a good sealant. I've never, and I do mean never, had any trouble getting head bolts out of a chevy small block and various other motors. Once they break free it doesn't take much effort to get them to the point of finger loose.
As for the 22 ft-lb's and degrees, I don't believe they use 2 motors for tightening the bolts. I'm pretty sure it's just 1 machine and the reason for the degrees is to eliminate the friction induced error (between head/bolt washer and threads) as torque increases. It's just a way of increasing the accuracy of the bolt stretch. I used to rebuild motorcycle engines the same way because it took the type of thread sealant/lock out of the equation.
Could you explain your 2nd reason because I'm a little confused by it.

88TPI406GTA

I believe they ARE TTY bolts.

I know from my time as a part time auto parts guy that the aftermarket basic SBC bolts from Fel-Pro are TTY...

The old bolts didn't used to be TTY...but a lot of the newer ones are...simply to help the engine keep the head gasket seal. Also, remember that TTY bolts, like rod bolts, are much stronger when properly torqued due to the nature of the design of the bolt. Even if there isn't thread damage, that isn't really the point.

I don't think that you are going to get a confirmed answer on this for GM bolts...but I would replace them with a new set.

I think people would be surprised at how many TTY bolts are in use on vehicles made in the Thirdgen era and newer...including drivetrain and chassis bolts.

HTH...

3.8TransAM

Heres what I have always used as a guideline.

On Chevy smallblock heads. It was acceptable to use them twice.
(cant swear it on years with vortec heads however, so i wont)

I have only done this when I can verify where and when the bolts were from. If I had done it with new ones prior or was assembled by someone who I could trust to verify. Than and only if everything else was acceptable would I ever resue them, menaing no overheating to a nuclear status or other types of catastrophic failure. Even then the amount fo time I have reused a headbolt, would amount to less than my fingers on one hand.

The premise behind the whole torque to yield scenario is some of what has been posted. The other large part of it is the style and composition of newer head gaskets. The other big part is if everyone on this post compared torque wrences no matter how nice or how fancy(and yes i own nice fancy $$$$ ones and craftsmen ones) they would all come up different.

When u think about it the torque to yield will give you more consistent results, but in a car is a real PIA to do for those who have done it :-) But the additional torque over the conventional method is where they make up for it. Put an torque angle head on a breaker bar in the car at an angle sitting in the engine bay and tell me how accurate you get 76degrees on all the head bolts lol.

I have reused headbolts on my own engine with vortec heads and never had a head sealing issue. This was stock bolts once and ARP bolts once.(done for reasons other than losing head gaskets).

Realistically I would think you would be better off following the torque to yield route as far as clamping capability was concerned, however if going this route I would definitely confirm that you can indeed do it with the bolts you are planning on using.

Either way u go, I would 99-1 replace the bolts and not worry about it

later
Jeremy

Supervisor42

Not that they can't tell, just that at $85 per hour cleaning off the sealant and inspecting the bolts is not cost effective and the penalty for rework is too steep for a dealer.
I was basically saying the same thing by saying this: "Allowance for torque resistance during torqueing." with the emphasis on the resistance of the threads. The dealer techs aren't allowed enough time to run a tap thru each hole in the block. When the engine is reassembled there will still be leftover sealant in the holes which affects the torque.
I'll try to get a picture of the machine that installs the head bolts at the factory. It's a lot different than you would expect.

83ho86tpi

blah, blah, blah
my .02$

I was taught at school that headbolts can be re-used twice then should be replaced and TTY can only be used once.

and when in doubt, replace them

SSC

Well when I used the L30 short block in my now sisters camaro guess what I used with the older 416 heads? Yep the head bolts from the L30, They look cooler.

Seriously GM does not list them as TTY bolts but if you feel you must replace them go for it. Azone lists the bolts as the same part number since they are replacment parts that cross over.

scuzz

I've built 4 96-99 vortec 350 engines and have inspected and re-used the same head bolts if they look okay. I've not had the first problem. My mechanic buddy at the Chevy dealer that gets me my core motors says that's cool as long as they inspect okay. He says they are not torque to yeild.

chevymec

iTrader: (5)

Ok, i see that alot of people are getting info from different places. But it seems that all are correct. I have vortec heads on my motor. I bought new head bolts when I got them. I have taken the heads off atleast 2 times and reused the bolts I just make sure to clean them off and apply teflon sealer to the threads. These specs are straight from GM

Cylinder Head Bolt (Preferred Method)

All Bolts First Pass in Sequence
30N·m
22Lb Ft

--

Long Bolt Final Pass in Sequence
75 degrees

Medium Bolt Final Pass in Sequence
65 degrees

Short Bolt Final Pass in Sequence
55 degrees

Cylinder Head Bolt (Optional On-Vehicle Strategy)

First Pass in Sequence
35N·m
26Lb Ft

--

Second Pass in Sequence
60N·m
44Lb Ft

--

Final Pass in Sequence
90N·m
66Lb Ft

--

I have never nor has anybody that work at the dealer with me TTY on that style head bolt. The LS1 style motors require it. Use the standard in car method and be done with it. If you are leary about re-using the head bolts, got to the dealership and buy a new set. They are cheap, $20 or so I think.

JPrevost

chevymec, thank you, that's exactly what I thought!

chevymec

iTrader: (5)

No problem I voted no on the poll and them looked up the info. It was a first on me.

chevymad

If they are tty bolts they'll all be stretched. Measure them to see if they're longer then new ones. Every time you reuse a tty bolt it'll stretch a bit more. Even if they are tty bolts you can reuse them once. It's usually not done, who wants a come back? Besides a mechanic won't know how many times the bolt has actually been used. Now on your own rig you know and can make the decision yourself.

Also you could use either bolt, but you should follow the torque procedure for the type of bolt you have. The head doesnt make the difference its the fastener. TTY bolts give at a certain tension, hence why they stretch. Regular bolts will stretch a bit at their rated tq but return when released.

The boat store

Well this was what just happened at 65lbs torque on used bolt!

lucky I was able to tap out, broke 1/8" below deck. Was almost done too, second to last bolt left to torque.

Fast355

iTrader: (2)

I know this is an ancient thread but might just help a few people from getting burned.

^^^Against my own advice years ago in this very post I attempted to re-use the bolts on the L30 (305 Vortec) in my brothers 80 C10 truck. He was almost flat broke financially at the time and had popped the head gasket. Snapped off one of the last bolts on the last pass at 65 ft/lbs. Luckily mine snapped well above the deck surface and I was able to easily remove it with a pair of vice grips after removing the head. I would NEVER attempt to reuse them again. If it was brittle enough to snap it was not delivering its full clamping force. I buy good reuseable bolts from ARP now and avoid the GM/Felpro garbage ones.

Looking back....He had a stuck thermostat and badly overheated the engine. Did not hurt the block or heads. I think when it overheated, the expansion of the heads and block stretched the bolts, then it smoked the head gasket on the next startup and run. When I reused the stretched bolts, one gave way. GM has also had TTY fastners since the late 70s in some engines. Most of the Oldsmobile diesel head gasket failures can be attributed to TTY bolt failure. Then the mechanic not knowing better would reuse the already stretched bolts making the head gasket repair. Then shortly after it would pop the gaskets again. I have since seen a GM 350 industrial engine manual (think it was Kohler) that shows Vortec head bolts to be throw away items when removed.

Working in a Nissan dealer parts department, I saw a stubborn mechanic from an independent shop who bought parts from us that would not buy head bolts replace the head gasket 3 times on a 2.5L in a Nissan Altima within a couple of months. Each time I would suggest head bolts and each time he would say NOPE. He raised hell that we had defective parts after the 2nd head gasket failure. Even after explaining to him why he needed to replace the bolts he said he was going to get a Felpro gasket and be done with the car. Car came back a few days latter. Car ended up in our service department after a long drawn out ordeal with Nissan consumer affairs. One of our master techs changed the head gasket and head bolts after straight edging the head and block and the customer never had an issue again that I know of.

I have also seen main cap bolts and rod bolts reused on a LS 5.3 with catastrophic failure at 2,000 rpm on the highway. Lets just say 2 main caps and 3 rods ended up in the pan with gapping holes in the block.