WARNING! Apex Headstud Failures!

[WildHorse]

OP said manufacturer said they tested fine on return.

Yep, manufactures never, ever blame their product

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[Mad1186]

Another member (@Mad1186) and I have had apex torque head stud failures! The headstuds are loosening over time, this is not due to power. If you have apex head studs please read this carefully!

Both were gen3 coyote head stud kits. Both were running gen3 shortblocks with gen 2 heads (the heads shouldn't really affect this but it is interesting).

My head stud kit was part of the batch shipped beginning of October 2022. Unsure of when the other person's was produced.

My car had them on for about 5k miles before the engine broke due to unrelated issues. During engine teardown, I discovered 2 loose bolts and one backed-out stud. Several studs/bolts I could tell were not close to torque spec, some were even just hand-tight.

I sent the headstuds back to Apex to check out and they said they didn't see anything wrong with them. I held off on making a post because I thought there was a possibility I did something wrong, but with another failure, it is enough confirmation for me that there is a serious problem.

Technical Stuff:
I now have arp head studs, neither arp nor apex mentions retorquing head studs. As I understand some head studs require this but since the coyote ones are such a pain to access they are made so they shouldn't have to be retorqued.

Apex Torque Specs:
Step 1: 74 lb/ft
Step 2: 92 lb/ft

ARP Torque Specs:
Step 1: 40 lb/ft
Step 2: 80 lb/ft
Step 3: 125 lb/ft

ARP uses lube on the contacting washer and nut surface, as well as the nut threads.
Apex only uses lube on the contacting washer and nut surface.

Both headstuds are reusable, you can disassemble the motor, clean them up, and reuse them as they are not torque to yield.

ARP Part #: 256-4702
Apex Torque Part #: CM-HSK-12M

Other members (@Mad1186) post regarding his headstud and engine failure: https://www.mustang6g.com/forums/threads/engine-failure.189694/post-3813981

Definitely happened to me as well, i ordered my Apex headstuds around February this year and with about 8k miles, car blew a head gasket. On tear down studs backed out, nuts were loose and either some were super tight or super loose. Very frustrating to find this was the problem. And I’m relieved to hear i am not the only person who had this problem, i ordered ARP headstuds as well, just waiting for them to come in!

 

[K4fxd]

I feel like Apex would have noticed if they stretched though. I specifically marked at least 1 stud and bolt that was loose.

You should have measured the set for length before sending them back.

Yep, manufactures never, ever blame their product

I agree here.

 

[tdstuart]

You should have measured the set for length before sending them back.

Ya, I didn't think of it, I should have.

 

[tdstuart]

Definitely happened to me as well, i ordered my Apex headstuds around February this year and with about 8k miles, car blew a head gasket. On tear down studs backed out, nuts were loose and either some were super tight or super loose. Very frustrating to find this was the problem. And I’m relieved to hear i am not the only person who had this problem, i ordered ARP headstuds as well, just waiting for them to come in!

Who did you buy them from? I sent mine back to Apex and got a warranty claim, they refunded me all my money and I used that to help buy the ARP ones. I purchased through beefcake btw.

 

[Mad1186]

Who did you buy them from? I sent mine back to Apex and got a warranty claim, they refunded me all my money and I used that to help buy the ARP ones. I purchased through beefcake btw.

I bought mine from lethal performance, I’m definitely gonna have to do that. I don’t have the box or anything though. Did you just send them in any ole box? I most definitely want a refund.

 

[tdstuart]

I bought mine from lethal performance, I’m definitely gonna have to do that. I don’t have the box or anything though. Did you just send them in any ole box? I most definitely want a refund.

I don't think the box matters, I just used a random box.

I would call up lethal performance and ask them to start the process of doing the warranty refund. You should be able to get store credit and can use that to help pay for the arp ones.

 

[tdstuart]

I updated the initial post to include Apex's response on their findings with my headstuds and also a runout issue that they mentioned when emailing me.

 

[Mad1186]

I don't think the box matters, I just used a random box.

I would call up lethal performance and ask them to start the process of doing the warranty refund. You should be able to get store credit and can use that to help pay for the arp ones.

I bought ARP ones the minute i saw that the Apex ones were backed out! Haha I’ll definitely call them though.

 

[tdstuart]

I bought ARP ones the minute i saw that the Apex ones were backed out! Haha I’ll definitely call them though.

Well you will hopefully get some money back to spend on more parts haha

 

[zero_chance]

Ah, this is excellent! Also had Apex studs from a gen 3 that had two shear off five minutes after they were torqued, impaling my arm in the process. Had client contact Travis and he said they were overtorqued (74#'s) even though I got the spec from a website that sold their product and listed the same torque and sequence listed above. When confronted with that Travis had the website pull it from their page and said "Oh that's only for certain batches and that shouldn't be public knowledge." I used way back machine to snip a copy of the page before they had it removed. Travis also threatened to sue me for defamation even though everything I said is true. Searches will reveal other folks that have the studs randomly launching after install also. And strangely enough, their coyote line is "out of stock" so I messaged and they confirmed they're all being redesigned. Will find the pics.

 

[zero_chance]

 

[zero_chance]

Not over torqued, material defect. Note, this occurred in January of this year.

 

[tdstuart]

Ah, this is excellent! Also had Apex studs from a gen 3 that had two shear off five minutes after they were torqued, impaling my arm in the process. Had client contact Travis and he said they were overtorqued (74#'s) even though I got the spec from a website that sold their product and listed the same torque and sequence listed above. When confronted with that Travis had the website pull it from their page and said "Oh that's only for certain batches and that shouldn't be public knowledge." I used way back machine to snip a copy of the page before they had it removed. Travis also threatened to sue me for defamation even though everything I said is true. Searches will reveal other folks that have the studs randomly launching after install also. And strangely enough, their coyote line is "out of stock" so I messaged and they confirmed they're all being redesigned. Will find the pics.

That is crazy!

I wish vendors would look at these things more seriously. I messaged beefcake about this thread and heard nothing.

I hope people find this thread and stay away from apex. Worth it to spend the extra for the arp headstuds.

Where have you found other people having issues?

 

[zero_chance]

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