Head Stud depth

[jlpst94]

I'm installing heads studs in my 1.6TD.  Should all of the head studs be at the same height once they are tightened in the block?  I have two in the front center that are about 1/2" higher that the others.  Im afraid the threads might be too high once I put the head over them.   I've checked the holes in the block and there doesn't seem to be anything stopping those two studs from going in further.  Just seems strange that two of them are that much taller than the rest.   

[ToddA1]

I can't see it being an issue. The studs would need to be a lot higher than they are to interfere with the valve cover.

-Todd

[TylerDurden]

I'd check how many threads are engaged. Last I checked (with bolts), only 19mm of threads are actually engaged in the block... take away 12mm and there isn't much left holding on.

New bolt length = 110.4mm (Tip to washer)

Block-Hole depth = 43.5mm
Head-hole depth = 78.8
Gasket = 1mm
Combined hole depth = 123.3mm

Block recess before threads begin = 13mm
Thread engaged during fastening = 19mm
Remaining open threads in block after threading head and bolts = 11mm

[libbydiesel]

I've installed several sets of head studs and they have always all been installed to a similar depth.  I would chase the threads in the holes that are not as deep and see if it is an issue with buildup in the block threads.

[745 turbogreasel]

That, and you don't really want them tight in the  block, but  like 1/4 turn shy or so.

[RunninWild]

I've done that twice but have had the studs bottom themselves out on the 2nd pass at 125lbs the two times I have changed the head. Next time I'm going to just tighten them by hand until they stop spinning. Its a scary feeling when your double checking your torque and you end up getting an extra 1/4 turn on a few of the studs.

[libbydiesel]

ARP instructions say to screw them into the block "Hand tight only".  To me that means bottomed in the hole and assumes clean threads in the block.  They do not say to keep them from bottoming by 1/4 turn. 

[745 turbogreasel]

relooked at my Raceware instructions

---tap and clean holes
---clean stud threads (they come in a protective coating)
---light coat in teflon sealant on  stud-block threads(keeps em from turning)
---thread by hand to bottom
---thread back up any amount  needed to allow  full  thread engagement of the nut with  hardened washer, may be a few turns.


Bad memory, I guess it's been  some years since they gave me any trouble.

[fatmobile]

I think they are supposed to get backed off from bottoming out  because the studs expand at a different rate than the block and it could cause some stress on the threads.
 At least that's why I've been doing it.