Has Anyone Ever Used Grade 5 Bolts As Head Bolts. Any Success?

fords2live · Jun 16, 2013

I can't use my tty bolts again obviously and the parts store only had one side on hand and I had to make a car show so i just grabbed some bolts from the hardware store. A guy told me that they wont hold. Does that mean they're gunna stretch? Arent tty bolts ment to stretch with the head anyways?

mikestang63 · Jun 16, 2013

IMO you need to replace all of those grade 5 bolts with a quality set of head bolts- at least grade 8, preferably ARP. I would never use those on my car.

http://www.rockcrawler.com/techreports/fasteners/index.asp

srtthis · Jun 16, 2013

Not something I'd even risk... To much to lose nothing to gain. Even if it holds when you go to replace them your out another set of head gaskets another set of intake gaskets another set of header gaskets. Not to mention the time...

85_SS_302_Coupe · Jun 16, 2013

I have parts store replacements on mine right now and one random 1/2 grade 8 because the prick I bought my block from failed to mention that one of the head bolts was stripped out from the block so I had to drill and tap it a size larger. I haven't had any issues yet.

7991LXnSHO · Jun 16, 2013

Grade 5 just risks too much. You are holding in an explosion and spinning parts under a lot of force. TTY bolts only are measured to stretch as an alternative to just torque. If you have to be cheap, a used TTY would be better than grade 5 hardware. But how you measure yield and torque the second time is beyond me and experts, hence the one time only rating. ARP has earned its reputation.

Gearbanger 101 · Jun 16, 2013

srtthis said:
Not something I'd even risk... To much to lose nothing to gain. Even if it holds when you go to replace them your out another set of head gaskets another set of intake gaskets another set of header gaskets. Not to mention the time...

If he pulls the cheaper bolts out one at a time starting in the center and torques the new ones in their place in steps, he should be fine afterwards. As long as he's not pulling the head off the block, disturbing the gaskets, they shouldn't' distort.

srtthis · Jun 16, 2013

Gearbanger 101 said:
If he pulls the cheaper bolts out one at a time starting in the center and torques the new ones in their place in steps, he should be fine afterwards. As long as he's not pulling the head off the block, disturbing the gaskets, they shouldn't' distort.

buddy of mine did that with his truck to put head studs in. im just not sure try that one.

Gearbanger 101 · Jun 16, 2013

srtthis said:
buddy of mine did that with his truck to put head studs in. im just not sure try that one.

I've seen engines that had run for years, only to find out during their eventual rebuild time that one or more of the head bolts had broke or let go at some undetermined time prior, without the owner being the wiser. Didn't even use antifreeze. Same goes for intake bolts. lol

These old 302's are pretty robust as long as you're not throwing a lot of boost or spray at them.

mikestang63 · Jun 16, 2013

Gearbanger 101 said:
I've seen engines that had run for years, only to find out during their eventual rebuild time that one or more of the head bolts had broke or let go at some undetermined time prior, without the owner being the wiser. Didn't even use antifreeze. Same goes for intake bolts. lol

These old 302's are pretty robust as long as you're not throwing a lot of boost or spray at them.

Who knows if he even got accurate torque reading using those bolts, as their stretch point is pretty much done before the grade 8 even starts. Did the OP use oil, assembly lube, thread sealant on the threads and what did he torque them to? What kind of head gasket did you use?

I also think that if he only drove it a few miles, he can try and pull the bolts out one at a time and replace them. Hopefully he won't disturb the head or gasket. The only problem is you'll always be wondering when the head is going to lift. He needs to keep an eye on the temp, coolant, oil, etc. for any telltale signs.

Bryan83taco · Jun 16, 2013

That's a lot riding on cheap hardware store bolts. I wouldn't do it. Spend the extra cash on ARP bolts and have some piece of mind.

Shakerhood · Jun 16, 2013

I would not take a chance.

clement · Jun 16, 2013

considering oreily has felpro 302 headbolts for $23, and Mr Gasket bolts for $32, I don't know why you would run hardware store stuff. my buddy has a set of pro comp head studs (against my advisement) on his 410 with 14:1 compression. I know people have had issues with those, but he has been lucky. and those are only $40.

90lxcoupe · Jun 17, 2013

Dont be a hack, put the right ARP bolts in it, or use studs.

jadigen · Jun 17, 2013

fords2live said:
I can't use my tty bolts again obviously and the parts store only had one side on hand and I had to make a car show so i just grabbed some bolts from the hardware store. A guy told me that they wont hold. Does that mean they're gunna stretch? Arent tty bolts ment to stretch with the head anyways?

making a car show isn't worth the risk of a catastrophic failure. call summit or jegs and buy the proper head bolts for it and do it right the first time..

Has Anyone Ever Used Grade 5 Bolts As Head Bolts. Any Success?

fords2live

Member

mikestang63

srtthis

the guy doing it does every local racers rear end

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

7991LXnSHO

wanna catch the space herp

Gearbanger 101

Straight Outta Locash

srtthis

the guy doing it does every local racers rear end

Gearbanger 101

Straight Outta Locash

mikestang63

Bryan83taco

Active Member

Shakerhood

clement

90lxcoupe

jadigen

Member

Similar threads

Has Anyone Ever Used Grade 5 Bolts As Head Bolts. Any Success?

Member

the guy doing it does every local racers rear end

it sucks (I know) to be on the receiving end

wanna catch the space herp

Straight Outta Locash

the guy doing it does every local racers rear end

Straight Outta Locash

Active Member

Member

Similar threads

Privacy & Transparency

Privacy & Transparency