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Stud Advice Please

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I'm thinking about upgrading my after market head bolts to ARP studs.

Can someone tell me what the advantage is to having the "uncut" stud version and if there is really any advantage to having 12 point nuts.





studs put less stress & wear on the block deck threads, and provide more consistant clamp loads, the 12 point, stud nuts and washers tend to have less clearance issues in tight areas, than the head on a 6 point bolt, and are less likely to round off as the tq is applied, but be aware that getting the heads up and out in a confined engine compartment is generally a P.I.T.A. over studs that extend up several inches past the block when fenders and brake boosters, etc. are in the way







bits of useful info here



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I was doing some reading about studs as well.... and while I hope Grump can elaborate further, I think that an undercut stud has better elasticity, meaning that it can conform to the cyclical stresses that each cylinder's combustion process applies to it with less chance of failure. From what I was reading though, it seems that it is commonly used or suggested in cases where there are studs of varying length, because the shorter studs of the normal un-cut variety will not conform to the stresses in the same manner as the longer ones will. The longer ones allow more stretching of the stud. It also seems that undercut studs should be used in conjunction with dowels or pins, as the thinner shank area of the undercut studs can not handle shear loads as well.

That is my understanding of it, now perhaps Grump will shed more light or correct me = )

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I should also add the reason behind this post is that I ran too much NOS (210HP) into a SBC (which BTW grumpy had advised me not too in a previous post) anyway I think i lifted the head, overheated the engine, melted the strap of a spark plug and broke of a rocker arm stud all on the same run trying to better my newest personal best ET of 9.88. I'd like to change from

a FEL PPO precompressed 1003 head gasket to a multi layer gasket but i'm not sure if i can do this as there's a slight ridge on the heads from the previous gaskets. I'm trying to make the motor strong enough for 250HP NOS


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I thought you guys might like this overly-studly BMW S-52 engine. Honestly it's NA with 220,000 miles on it and the only thing done was to repair a crack in the head.






Here is the repaired cracked area in the head




I had to use a Degree wrench for this job.






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thanks grump can you tell me anything about "Undercut" studs are they worth the extra $$$

that depends on the application thier used in, the under cut studs maintain thier clamp force, more consistantly over a longer stretch distance, let me explain that a bit

if you use the standard , studs on a cylinder head the heads get torqued in place at standard temps, when the engine heats up the metals expand, and the clamp loads tend to increase a bit,when it cools the metals contract,and the clamp loads tend to return to original levels, this cycles the stress and clamp loads, on an iron block with iron heads and even with aluminum heads the standard non-under cut studs are fine in most applications,because BOTH the studs and the head gaskets are designed to work with this repetitive cycle, if you have an all aluminum block and heads your probably better off with the under cut studs due to the greater dimensional shifts as the engine changes temp.

either design will tend to keep the clamp forces in a useable and predictable range, but the non-undercut studs are less likely to maintain the same exact clamp forces over the temp shifts the engine sees between running and cooling cycles.

short answer, on a iron block engine ID just sellect the standard ARP studs and follow the installation info posted earier in the thread, keep in mind aluminum thread strength fatigues far faster than iron or steel and it requires about 2.5-3 times the thread dia. to depth ratio to equal the resistance to stripping threads in aluminum vs about 1.7-2 times the thread dia. to depth ratio to equal the resistance to stripping threads in steel or iron

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I think anyone considering head studs on a SBC should read this:



I went back to studs only after I went to a Dart (Sportsman) block - which has blind head bolt holes that don't go into the water jacket - i.e., no coolant leaks from studs.

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guys! Ive YET to have a single stud or bolt leak!


its simple! run a tap thru the threads, test screw the clean/dry stud by hand to verify no clearance or binding then ,clean them and dry the threads on the block and studs,before you start the assembly, and just dip the total threaded surface on the lower studs course thread end of the stud that screws into the block into the correct sealant. spin it in your fingers slowly as you move the stud to the hole in the block to keep from dripping sealant on the deck,

thread it into the block full depth , back it out a 1/2 turn and let it set up for a few minutes before assembling the head gaskets and heads,but assemble the heads while the sealants still fresh/liquid, torque too spec and let the engine set for a few hours (preferably over night)




the stuff works far more relieably than most thread pastes or thread sealants, it cleans ,off fingers with a scotchbrite pad and gas or alcohol,....provided you have not let it set up on your skin very long, once its started too dry ...good luck


YES it works on BOLTS ALSO





I can,t believe the stuff I see at times..in the car mags that are SUPPOSED to be articles composed by guys who know what they are doing!!!!!!!

I picked up a copy of one of the more comon, chevy based magazines and theres PICTURES of a guy dipping head bolts in yellow weather strip adhesive to be used as a thread sealant on the bolt threads (its not designed to come in direct contact with oil and/or high heat coolant),and its not going to give the correct tq readings either, and on the next page the guys gooping, GOBS of clear silicone like youll use to seal aquariums or bathroom fixtures 1/4 thick on/around the intake manifold ports, NEITHER SEALANT is DESIGNED FOR or is LIKELY to perform correctly IN EITHER APPLICATION, and WHERE does this guy think all that excess silicone will go once the intakes torqued down????

theres only two high probabilitys, it will flow into the port where it will eventually harden and get sucked into the cylinders or it may hang there causing a restriction in the port, or if it flows down, it gets into the lifter gallery where its eventually going to get into the oil pump pick up screen, restricting or blocking oil flow

i would not let these guys fix a flat tire let alone work on MY ENGINES all I can do is shake my head and wonder who if ANYONE screens these articles


always use the manufacturers suggested installation instructions, as some applications or gasket types REQUIRE differant lubes or sealants but heres a rought guide



head bolts #5, dip clean dry thread in



or this




then insert and tq heads in place



head gaskets #3

main bolts #2

rod bolts #2

oil pump stud and nut #4

oil pan bolts #5

oil pan gasket #6

cam spocket bolts #4

timing cover gasket #6

timing cover bolts #1

intake bolts #1

intake gasket #6

thermostat housing bolts #5

thermostat housing gasket (also do you really need it) usually yes #6

Exhaust manifold/header bolts #1

Exhaust manifold/header gaskets #3

Water pump bolts #5

water pump gaskets #6

fuel pump #6

crank/damper bolt #1

Torque converter bolts #4

flywheel/flexplate bolts #4

bellhousing bolts #2


1 antiseize

2 oil or ARP thread lube

3 copper coat spray gasket sealer or apply dry in some cases (see manufactures suggestions)

4 loctite (red or blue depends on application ,read the lables)

5 http://www.devcon.com/devconfamilyproduct.cfm?familyid=386&catid=69

6 black high temp RTV


use the correct stuff for the application, AND READ & FOLLOW THE DIRRECTIONS it prevents PROBLEMS

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