odd exhaust stud

[grimreaper]

All of my exhaust threads have been helicoiled but i noitced after a few heat cycles one or two would be a 1/4-1/8 of a turn loose. They torque right back down and feel secure and able to go further except i noticed the whole stud/nut moves and not just the nut on the stud. I was under the impression this is not how a stud is supposed to work. Am i correct in re tqing even though the stud itself is now turning?

 

[tlo86]

i never liked helicoils... always went to a larger stud

 

[jdub]

Grim - are you using the stock nuts? Were they previously used?

I'm using ARP 12 pt nuts on stock studs...the head was helicoiled. A proper helicoil is stronger than the threads in aluminum...regardless of stud size.

The studs should be seated finger tight against the head before the nut is screwed on/torqued.

 

[grimreaper]

Grim - are you using the stock nuts? Were they previously used?

I'm using ARP 12 pt nuts on stock studs...the head was helicoiled. A proper helicoil is stronger than the threads in aluminum...regardless of stud size.

The studs should be seated finger tight against the head before the nut is screwed on/torqued.

reused the stock nuts and studs.

you sir have some nice $5 nuts, i actually called arp today hoping for some good knowledge on studs and what i should expect. They didnt care to much once i told them they weren't arp studs.

all were finger tight before torquing.

Little info to make the picture more detailed: After the 1st 50 miles, all needed a little torquing (1/8-1/4 turn MAX). Checked them again after another 50 miles or so and a few needed less then 1/8 turn except last one on the back of the head (#7?). It needed a good 1/8 of a turn. Checked them again and all are good except that damn #7, another 1/8 turn or so.

****pulled it out, helicoil and threads are perfect, hopefully new hardware will solve it****

 

[jdub]

Yeah...those babies are a bit pricey. Got the ARP washers too.
Next motor has a set of ARP studs for the exhaust

The castle locking nuts Toyota uses are not high on my list. I've seen them loosen more than once...almost sounds like yours is gripping the stud, causing the stud to loosen.

I'd switch them out too.

 

[suprarx7nut]

FWIW, the castle nuts on my exhaust manifold->front exhaust section flange kept loosening. I got new toyota castle nuts and they stopped loosening. Could just use a dab of loctite, perhaps, but I wasn't sure about the heat affecting it and I worked at toyota so the nuts were very easy to get.

 

[grimreaper]

Next motor has a set of ARP studs for the exhaust

they told me they dont make studs for the stock hole size whos this hook up of yours??
unless:
a) bigger studs
b)different motor:naughty:

almost sounds like yours is gripping the stud, causing the stud to loosen.
new bolts should solve it,

bingo

Ill try new hardware after work tomorrow

 

[jdub]

One out of two isn't bad
(not bigger studs)

 

[grimreaper]

FWIW, the castle nuts on my exhaust manifold->front exhaust section flange kept loosening. I got new toyota castle nuts and they stopped loosening. Could just use a dab of loctite, perhaps, but I wasn't sure about the heat affecting it and I worked at toyota so the nuts were very easy to get.

im not aware of any loctite that will handle such extreme temps. is there any?

not exactly the best way to fix a loose bolt on the exhaust manifold

 

[grimreaper]

One out of two isn't bad
(not bigger studs)

what treachery of a motor are you sticking in the 7m's place?

 

[jdub]

LOL...it's a 7M, just a different motor than the one in the car now.
(sorry for the confusion)

 

[pln]

they told me they dont make studs for the stock hole size whos this hook up of yours??
unless:
a) bigger studs
b)different motor:naughty:



bingo

Ill try new hardware after work tomorrow

Put in bigger studs. I have m12 (12mm). The threads in the head were so worn out that i didnt even have to drill. Made new threads directley (dont know the english word for the tool) without drilling. It has worked fine one year now. Its a operation many do. Check that your exhaust manifold hasn´t been deformed before putting it back.