arp head studs

[ginglesturbo]

is it true that you have to take the block ou to put in arp head studs?? i am changing the hg now...i was going with a hks 1.2 mm bead and arp studs.... the head and block are still in the car ... here are some pics

here is my car

 

[jdub]

Nope...not true. But you will have to put the studs in after you place the head on the block and use the pilot pins to align the block/MHG/head...or, you can put a couple of studs in along the side to make it easier to align. Don't put studs in the rear holes or you will have trouble getting the head to drop on.

Make sure:
1) You put the washers on the head before the stud goes in or you may not have the clearance for the washers to seat all the way down.
2) The studs go in finger tight
3) You torque to ARP spec (80 ft/lbs w/ moly for lube) using the TSRM torque pattern in 10-15 ft/lb increments. I would torque to spec, loosen (per the pattern), tighten again....3 cycles. This produces the most accurate torque according to ARP.
4) If the MHG is new, do not use any spray sealer on it.
5) I'm a believer in doing a re-torque after at least 5 heat/cool down cycles.

 

[ginglesturbo]

if i have top put the head on first before the syuds then what is the point of using studs??? should i just get arp head bolts instead?? studs are made so they can go on first so you can be sure the head is alligned perfect....so if you cant even do that with them then whats the point of them?? do they realy hold the head to the block better?

 

[starscream5000]

The point is a more even load distribution from the studs and less stress on the threads in the block, not to mention a more accurate torque measurement.

 

[ginglesturbo]

so i should stick with the studs.....i figured if i used studs this time...next time it will be easier to get the head off also...but if i gotta do all that to get them on ...i guess it is still worth it..im not planning on blowing another one for a while so i wanna do it right this time

 

[jdub]

The point is a more even load distribution from the studs and less stress on the threads in the block, not to mention a more accurate torque measurement.

^^^ To expand on this, there is not the torsional "twist" on studs you get on a bolt shaft when torquing it down. Again, more accurate torque readings. Studs are superior to bolts in both clamping force and accurate torque. You can use bolts with no problem, but the point of studs is not to make it easier to align the head to block

 

[ginglesturbo]

right so if i wanna do it the best way i can i need to use the studs...correct?....

 

[jdub]

I would use studs

 

[ginglesturbo]

studs it is....with the hks 1.2 bead hg

 

[jdub]

Are you having the head decked? MHG's require a very smooth surface...the HKS is around 25-30 RA (roughness average). It is also VERY important the block/head surfaces are flat...the TSRM has the allowance.

The RA spec for a MHG also applies to the block...you might get away with it depending on the condition of the block surface, but it will need to be very clean. Don't be tempted to sand it...that will induce high/low points on the block deck.

The thickness of the MHG depends on how much material is removed from the head when having it decked...also the block if it is decked. Using a thinner/thicker MHG will affect compression ratio.

If you can't have the head/block decked, you will be better off using a stock composite HG.

 

[ginglesturbo]

im gonna clean the block myself and have the head done at a shop since the block is staying in the car....should i just use a toyota hg? are they copper mesh from the factory??

 

[jdub]

It's going to depend on the condition of the block, but if you are not getting the block decked, I would use a Toyota HG. Give Champion Toyota a call and order the complete head gasket kit. In addition to the HG, it has all the gaskets/seals you will need...manifolds, cam seals, valve seals, valve covers, etc. You might as well have a valve job done on the head while it's at the machine shop...use the seals out of the above kit.

The stock HG are composite material...they get a bad rep because they blow. The TSRM torque spec is too low, that plus guys raising boost and going lean (detonation) is what causes the problem. If you use ARP studs and install per above, you will be good for boost in the mid-teens all day.

The surfaces still need to be flat...VERY important. I would use a spray sealer on a composite HG...Permatex copper...the problem with the spray on a MHG is it reacts with the viton coating. Not a problem on a composite HG. Also, read the TSRM on doing this...one gotcha is the application of silicone sealer at two points where the head rests on the forward timing plate. Miss this one and you got an oil leak.

 

[j3pz]

what jdub is saying is when you use a mhg, the block needs extra care, it needs an extremely smooth surface for the mhg to seal right. if not done properly, you are more prone to bhg again.

this may not be a problem for you though, you maybe able to check the RA yourself.

 

[ginglesturbo]

o ok well i will use the toyota hg kit and stick with taking the head to a machine shop and cleaniung the block myself...thanks