Im doing so work to the car and I dont really like the small nuts that come with the arp's for the 2.4 I just think they're to small 1/2 inch.So I called DCR and he said they had the same problem so he had some upgraded nuts made which will spread the clamping force a little better.These nuts are 3/4 inch they should keep the head from floating at high boost plus they're a lot less likely to strip when removing.The way I look at it the more you can spread the clamping force the better.
Looks like a good idea.
Dave Tekampe
Director SDAC National
VP SDAC-Chicago
85 GLH-Turbo (DC intercooled)
86 GLHS #107
87 GLHS #148
87 CSX #161, #608, #674
88 CSX-T #529, #541
89 Shadow Competition Package and lots more...
Are they the same thread style as the old school 11MM studs?
I was thinking the same thing,my buddy has a set of 8 valve studs I will check them tonight and let you know.Originally Posted by 8valves
Just a thought here:
To save time when pulling the 16v head a lot of people simply
removed the nuts or head bolts without pulling the cam's. The
small 12point nut does make this task pretty easy. The boss
area of the head (were the nut/washer meet the head) is
pretty thick if you ever saw a DOHC apart, not sure there
would be any gains in a larger nut, cant hurt though.
Yup the 2.0/2.4 blocks are 11mm like the 86+ 2.2/2.5's.
Are they the same length aswell?
-Rich
Never even attempted to remove head without pulling the cams,that looks like a good way to gouge the hell out of the cams.As far as gains it all depends on how much boost you wanna run I believe dcr said they run 67psi on there race car.My opinion is the small nuts suck the threads started to tear up and Ive only removed them twice.
No the 2.0/2.4 arp's are an inch longer than the 8 valver's.Are they the same length aswell?
The 8v head bolts are longer but if you cut them so 15/16"
hangs below the deck of the DOHC head they work. Spin
a matching 11mm nut over the head bolt, quickly cut with
a cutoff wheel and cool with oil. polish the threads that were
just cut prior to removing the 11mm chaser nut and you are
done.
If you measure and look at your 8v block you will also find
that matching 15/16" depth. Thats pretty shallow even for
a factory setup, thats another plus of buying the studs.
I ran the ) modified(and used) 8v headbolts every day with no
coolant leaks with the MLS but that setup was never pushed
much beyond 300hp.
Hey russ is the thread pitch the same going into the 2.4 block as the 2.2?It looked a little different when I seen my buddies arp's.The real trick is if you're using a mls gasket is to make sure,if you have the block and head cut IT HAS TO BE BABY SMOOTHI just finally
after you install the ARP washer with the ARP 12 point nut, are you gaining anything with the DCR stuff. It honestly doesnt look like your spreading it much more than the ARP hardware does. It may be a different story on the DCR car which was in excess of 45 PSI, but i can almost guarentee he didnt use ARP hardware.
From reading on srt4forums.com it seems with high power numbers the pressure under the washers was causing them to embed into the aluminum in the head and then the head would lift. So by going with a larger washer you have less pressure.
The ARP washers have a surface area of .366"^2 with an OD of .814" and ID of .444". Not knowing the actual size of the DCR washers I would say from the picture they are over 1" when comparing to the ARP washers. If you said they were 1" with the same ID then they would have a surface area of .631"^2. That is about 72.5% more surface area and thus 42% less pressure under the washer. Sounds good to me.
89Shelby2.4.......what is DCR charging for the washer/nut combo? If you have some calipers lying around could you let me know what the actual OD/ID of the washer is?
Also I compared the 8V ARP washers to the 16V ones I have and they are the same size so there would be no advantage in using them.
DJ
Its $60
Let me get this straight, you compared the 8v to 16v both are arp correct?? Or 8v to stock 16v washers? Basically I was thinking that the arp washers are smaller than stock washers, but this may not be?
I compared the washers with the 8V ARP studs to the washers with the 16V 1.8L ARP studs and they are both the same. They are also the largest washer for a 7/16" bolt that ARP lists on their site (7/8" OD). I'm pretty sure the washers on the 1.8 set and the SRT4 set are the same. The only possible difference was the length.
I don't think I have any of the stock 16V washers around to compare to but the DCR ones are definately bigger than the ARP and the need to fit in the stock counter bore so if the stock washers fill the counter bore then they are probably bigger. Long enough sentence for yaNot that it would be real hard to measure the stock washer though I would be hesitant in using it if it is possibly softer than the ARP hardware.
DJ
The washers are close to 1 inch I didnt measure them,but the nut is 3/4 inch.You're right about the washers embedding into the head from being to small they did it slightly to mine.For the money it is a very good upgrade in my opinion.
I grabbed a stock 8V head bolt washer from the 11mm Mopar kit today and it has a larger OD of .925" but also a larger ID of .475". This gives it a surface area of .495"^2 which is still 35% larger than the ARP head stud washer. I don't know how to find out if it is as hard as the ARP short of doing a hardness test but besides that it would be an upgrade since there would still be 26% less pressure under the washer. It is also something that most people probably have sitting in their garage.
DJ
OK, here's my thought on the whole subject that I hope someone can add too.
I measured the ARP stud to have a diameter of .432". Metal, or in this case a stud, will start to permanantly deform once it passes it's yield strength at which point the stud will be permanently longer. The ARP200 material studs have a yield of 180,000 psi which means they must see a force of 27,849 lbs before they will yield. The surface are under the nut of the ARP stud (the part that is in contact with the washer) is 0.233"^2. This meas at the point of yield in the bolt there will be 119,697 psi of pressure on the washer. So the washer under the nut must be able to withstand 119,697 psi of pressure without yielding or it will deform like the head does with the small washers. Grade 8 hardware has a yield of 120,000 which to me means any washer grade 8 or higher would be fine. My bet is the stock washers at least equivalent if not stronger than grade 8. (I wish I knew for sure) This is all at the point of yield which is an absulute worst case. I believe (I can't find it right now) that the torque spec is around 75% of yield which is idealy never surpassed but of course is sometimes.
Any thoughts? I guess I'm looking for an alternative to paying 60US plus another 40US in shipping to the cold country just for some nuts and washers.
DJ
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