ARP head studs NOT a good solution?

[AFM744]

ARRRG. I'm being informed (too late) on the Engine Building Forum that the ARP head studs are not a good solution on the Turbo. Yet many of you proudly list them in your mods.

Did I miss the Memo?

[NathanUK]

I'm sure the Supertec ones are better but I too thought ARP & Raceware were good.

[Turboo934]

I had a raceware head stud fail at 40K,on my 76 Turbo.Replaced them with Supertec studs.

[sand_man]

I bought my ARPs from a very reputable builder (Imagine Auto) and had them inspected by another Porsche engine master (Neil Harvey - Performance Developments) when he had all of my parts for machining and test fitting. Neil even sells his own head studs (probably the ultimate head studs) and he had only positive things to say about ARP. So many people have their preferences...nothing is gospel! I ain't worried!

[DonE]

Originally Posted by AFM744

ARRRG. I'm being informed (too late) on the Engine Building Forum that the ARP head studs are not a good solution on the Turbo. Yet many of you proudly list them in your mods.

Did I miss the Memo?

Ignore those threads - it's like debating who makes the best oil.....

You'll be just fine. One day a supertec stud will fail and someone like you will stay up all night worrying about their quality.

[bcoats]

well said and so true DonE

Originally Posted by DonE

Ignore those threads - it's like debating who makes the best oil.....

You'll be just fine. One day a supertec stud will fail and someone like you will stay up all night worrying about their quality.

[AFM744]

Thank you for the sanity-check guys. I was telling a friend that thanks to the innArWub there IS such thing as too much information. Thousands of Turbo owners blissfully drive their cars unaware of the impending doom of their Dilavars because they have better things to do than obsess over PelicanParts.
They probably enjoy their cars more NOT knowing what we know!!!

I'm splitting the cases tonight to put in the rod bolts and fix the case seam leak. I will mic the cylinders, pistons, journal and rod bearings for peace of mind, but it is evident in the honing marks in the cylinder walls, machining grooves in the piston skirts, etc that this motor (at 90k) is in great shape, and I shouldn't've worried about all the other horror stories about broken rings, cracked lands, etc.

[sand_man]

Originally Posted by AFM744

Thank you for the sanity-check guys. I was telling a friend that thanks to the innArWub there IS such thing as too much information. Thousands of Turbo owners blissfully drive their cars unaware of the impending doom of their Dilavars because they have better things to do than obsess over PelicanParts.
They probably enjoy their cars more NOT knowing what we know!!!

I agree. I'm by no means discounting what Steve at Rennsport has to say....he's a serious guru/authority on these engines. It's just...I dunno, maybe what DonE said about debating this stuff to death.

[sand_man]

Advice on Head Studs for 930

[WERK I]

I think the debate on the ARP head studs revolved around the metallurgical characteristics of the studs. As you know these engines are modular in design and the thermal expansion rates are significant. Porsche spent a lot of time in designing studs that had close the same expansion rates as their corresponding counterparts. The debate around the ARP's was the studs losing their clamping force due to the heat cycling that takes place. This in turn, would require more diligence by the owners' part to routinely check torque settings on the heads. I don't know if I buy into that argument..... I'm no metallurgist.

We do know the delivar head studs were prone to snapping, but I've been running the 993tt studs now for 5 years with no problems.

I don't think you can go wrong with either product. Rod bolts are another matter all together........

[sand_man]

Originally Posted by WERK-I

I think the debate on the ARP head studs revolved around the metallurgical characteristics of the studs. As you know these engines are modular in design and the thermal expansion rates are significant. Porsche spent a lot of time in designing studs that had close the same expansion rates as their corresponding counterparts. The debate around the ARP's was the studs losing their clamping force due to the heat cycling that takes place. This in turn, would require more diligence by the owners' part to routinely check torque settings on the heads. I don't know if I buy into that argument..... I'm no metallurgist.

That's my understanding of the "argument" as well. However, what's weird is that neither the Supertec nor the Performance Developments head studs (both often regarded as some of the best studs, even for turbo engines) come in the Dilivar material, so commonly known to have these expansion/contraction properties.

[juan ruiz]

Originally Posted by DonE

Ignore those threads - it's like debating who makes the best oil.....

You'll be just fine. One day a supertec stud will fail and someone like you will stay up all night worrying about their quality.

LOL

[NathanUK]

What do you run on your 3.2 Juan? Also, what rod bolts?

TIA

[juan ruiz]

ARP Did 610rwhp with stock rods and stock bolts, but for peace of mind changed them to Pauter rods, mains also have ARP

[strokher racing]

No problems so far at high hp with my ARP stuff

[930gt-40r]

mine are great as well, the thermal expansion bug didnt bite me.

[AFM744]

Thanks again for everyone's input.
I spent the weekend (almost) finishing the teardown. Good news is the bottom end looks excellent, looked like new journal and big-end bearings. Bad news is, the exhaust valve guides are worn to hell (visibly oblong) and this took a toll on the valve seats. So the heads have to be sent out... so the whileyerintheritis hits full stride...

Mwwaaaahhaaaahhhaaa!