Grade 12.9 bolts in place of ARP studs.

[paolomarks]

How did it work out using generic bolts?  What did you use?  Mcmaster?  Part no.s?  A question for TheMan53,  you say that you sell some bolts, where can I get them.  I need headbolts for my AAZ.  Thanks, Paolo.

[R.O.R-2.0]

How did it work out using generic bolts?  What did you use?  Mcmaster?  Part no.s?  A question for TheMan53,  you say that you sell some bolts, where can I get them.  I need headbolts for my AAZ.  Thanks, Paolo.

you can get factory bolts for $0.99 at the parts store.

[clarkrep]

An update on my buddies '84 I mentioned earlier
the head gasket failed to hold combustion chamber gasses where they belong.  
He had about 3,000 miles on it and was running 18-20 psi max, I put his new pump on from Giles thats set up for 30 psi and 5,500rpm....
it was foolish of me to not dial the boost back since its running factory manifolds. anyway it lasted about a day...

Pulled the head off and couldn't find where it had been leaking(normally it pretty obvious in my experience) I actually wrote down the length this time around and i torqued them to 125ftlbs with 15w-40. Im gonna limit boost to 20 psi and report back when he's got some miles on it.

They are Holo-Krome 12.9 socket head cap screws 12mmX1.75 and measure 4.71in under the head. That comes to 119.63mm. Washer thickness is .125in.
Measured an original stretch bolt and it was 4.53in under the head 115.06mm.

I consider it a success regardless of whether the head gasket went. I think with higher power levels ARP headstuds are definitely the way to go and have used them in the past with good results. Hope this helps.
Aaron

P.S.
Thanks to theman53 for makin me go back and look at my shop notes. I had the length wrong. Hope it didn't mess anyone up. It's updated with the new length.

[RunninWild]

Any more info on this from people? I'm getting ready to drop the $250 on some arp studs but I can't help but thinking there has to be a cheaper way. Plan on running 25+psi so stretch bolts arnt the answer... Would love to hear if anyone was able to run standard high grade bolts long term without issue?

[theman53]

Summit has them for under 200 and 10 shipping, I don't know if these are the ones or not...
http://www.summitracing.com/parts/arp-204-4706/overview/

I used unbrako bolts in the bottom end of my build and so far so good. I wouldn't use bolts on the head if I was going to go for big gains, I would used studs and there is no cheap route there.

[VW Smokr]

Personally used head studs from Raceware; very nice units.    http://raceware-fasteners.com/  They are very specific about what fits, however, I don't know their current prices.

[libbydiesel]

http://www.amazon.com/ARP-2044706-Diesel-Volkswagen-Engine/dp/B007FH8WNS

[southernman]

Guys, I agree with those in favor of the ARP (or any) stud over a bolt - in any application - and every engine I build gets studs. Never had a head gasket failure with the studs. Can't say the same for bolts...

Even NA builds I perform get studs because they're so reliable and consistent.

Bolts are fasteners (provide force/retention from one direction).

Studs are clamps (providing clamping force/retention from two directions).

Just by nature of their design, you can run the highest grade bolt you can find, and never approach the clamping forces of a lower grade stud. It's simple physics.

The only pitfall I can share is the studs DO require re-torqueing at intervals to properly "set" them. After the 3rd re-torque of my ARP studs, they retain >98% of their torque values, which means they vary by <2% across all studs - for the entire life-cycle of that engine. Every studded engine where I've observed head gasket failures was the result of the builder/owner ignoring the re-torqueing requirements from the mfg and failure to 'set' the studs as recommended.

They're more pricey, but bolt performance will NEVER match stud performance, and you truly pay for what you get - or don't get...

If you're after max power, or just plain max reliability and consistency, you can't beat studs.

Just my 2 cents.

Southernman

[theman53]

The retorque is something I do differently as I use and old gasket and torque them 3 times. Then I go in with the new gasket and do the real torque. After machining most all metals need this, unless you can cryo treat them.

Raceware has had some issues. Rabbit Jockey had some and IIRC so did crazy andy where the stud stripped. I think they used to be great, but now might have some bad batches.

[libbydiesel]

Just by nature of their design, you can run the highest grade bolt you can find, and never approach the clamping forces of a lower grade stud. It's simple physics.

I'm a big fan of studs, but that's not physics.

[southernman]

Just by nature of their design, you can run the highest grade bolt you can find, and never approach the clamping forces of a lower grade stud. It's simple physics.

I'm a big fan of studs, but that's not physics.

And your point is...?

[libbydiesel]

A bolt can maintain the same amount of clamping force of a stud.  The idea that it can't is superstition or imagination, not physics.

The benefits of the head studs are that they are reusable, cause less stress on the block threads, and have a fine thread on the outside and so apply a greater clamping force for a given twisting force.  The greater clamping force is from the finer thread pitch, not the fact that they are studs vs. bolts.