head gasket question

[grimkiller]

a simple qiestion i hope. as i get into the bigger mods will have to look at getting a different head gasket to deal with the higher preassures that will be produced with high boost and what not??

 

[DieselTrap]

I don't know if you guys get around to Oring the head or even fire ring the motor and head, with a new head gasket. It helps my Cummins hold together.

 

[mojogoes]

Yes my 1z motor has been oringed.

 

[Sootman]

My understanding that any change in the head gasket (thicker/thinner) to change the compression ratio is quickly thwarted by the computer. It will just reconfigure for the changes in pressure.

I am interested in the oring/firering info. That sounds interesting.

 

[jasonTDI]

Unless you are doing 180+ HP just get ARP studs.

 

[Satiro]

What's ORING and FIRERING?

 

[Sootman]

Unless you are doing 180+ HP just get ARP studs.

APR headstuds are not as strong as the stock ones which are a class 2 I understand. I put APR's in my car only to learn this info later. Save yourself $100+ bucks.

 

[DieselTrap]

O-ringing can be in the head or block which people usally use a stainless wire in a grove made in the head or block, the fire ring is more of a ring joining the head and block which taks a little more machining but is the strongest I know of. But I can't belive the ARP studs are weaker than stock bolts, I know with the CTD you can buy your studs in 12mm or 14mm which you would have to drill and tap for. I think Piers offers something for studs too?

 

[Sootman]

Apparently the stock studs are a class 2 and the APR's something else. Difficult to describe but the stock studs have a greater contact area on the surface(the sprial) than the ARP's. Ask a mechanical engineer, they'll know. That's how I found out.

 

[Sootman]

It was pointed out to me that the old classification system that I'm used to using is no longer in force. SAE now uses a different standard, therefore "class 2" is inaccurate.

Regardless the bottom line is that the APR head studs aren't as strong as the stock studs.

Getting old sucks!

 

[rjr311]

Stock Febi head bolts are 10.9 - they have a nominal tensile strength of 10 * 100 Newtons per square millimeter ... 1000 N/mm^2 which translates _roughly_ to 145 Kpsi.

Arp 8740 Studs are rated at between 180K psi and 210K psi ( these number appear in different places with different values such as here -
http://www.centuryperformance.com/fastenermaterials.asp.

There may be some fudge factoring but from the numbers the ARPs are stronger.

 

[TDIJetta99]

There's a reason that the ARP's are $100 and the stock bolts are $30.... Go ahead and try to torque a stock VW head bolt to 100ft/lbs, then try the same thing with the ARP's.. You won't get much past about 75-80 before the stock bolt stretches and breaks.. The ARP's won't bust till almost 170... You can try this in a vise with a big stack of washers and some nuts if you wish...
The ARP's are quite a bit stronger than the stock bolts in most applications...

 

[jasonTDI]

APR headstuds are not as strong as the stock ones which are a class 2 I understand. I put APR's in my car only to learn this info later. Save yourself $100+ bucks.

Where's the documentation? According to metalurgy that should not be the case.

 

[jasonTDI]

never mind.....

 

[hatemi]

And the ARP studs have finer thread in the top so the same twisting torque results in more preasure. The OEM 10.9 bolts arent that strong...