Hey guys, do i need to put thread sealant on the rocker arm studs protruding into the intake ports. The 289 high performance v8 was a screamer, but never had enough cylinder head to pour on the torque at high rpm. Many engines come from the factory with pressfit rocker arm studs. Back at the race in long beach of 09, it happened and pat repaired the 2 studs with a time sert. Use feulingarp rocker arm shaft studs and nuts to help relieve stress on the milwaukee. They include a carbidetipped bit and an arbor pilot for accurate machining. Tighten the rocker arm nuts to between 17 and 23 footpounds of torque if the engine. Apr 12, 2012 how to machine stud bosses on sbc camel hump heads.
Use to replace worn or damaged studs on oe iron bbc heads. These comp cams stud boss cutting tools are designed to machine down the cylinder head in order to mount a screwin rocker arm stud. Comp cams rocker arm stud puller and tap guide provides a convenient method to remove pressedin rocker arm studs. Check the rocker arm shafts for nicks, cracks, wear and damaged threads. The car was just normally going down the road when a bang was heard. Although torque specifications are generally thought of as important when installing the engines main components, a number of other components are also assigned torque specifications on the 351w, including the spark plugs, the flywheel bolts, the rocker arm cover bolts and the vibration dampers single bolt. Vortec l31 cylinder head crankshaft coalition wiki. Analysis of a failed rocker arm shaft of a passenger car. Sep 30, 2014 hey guys, do i need to put thread sealant on the rocker arm studs protruding into the intake ports. You need to find the correct torque required for the stud and found in the service manual and re torque it. Rocker studs, standard length for big block chevy alexs. Did not think twice about buying my second cutter since the first one had worked so well. I did the same thing, your push rod is bent and or rocker arm is cracked. Rocker stud holes are not blind as they go into the water jacket.
The magnum blocks feed oil to the rocker arms and heads through the lifters and pushrods. If the original holes werent deep enough and were tapped only to the bottom of those holes without drilling them additionally, theres a possibility that the only thread that is seeing the total torque is the one at the very cornerbottom of the each hole. If you check the oil and the ticking sound persists, then chances are you are having an issue with one or more of the rocker arms, and you need to replace the ones that are having an issue. Remove the stock rocker arm pedestal assemblies, pedestal guide channels and pushrods. Just be warned, lots of those blocks have cracked the main webs at one of. Jan 04, 2018 after the rocker arm stud boss is flycut for screw in studs, how much crack is left. Aug 14, 2015 not claiming this to be the best method, im just saying with luck its easy. On my ford 302 heads, i wish that the fine threads on the rocker side. The stud needs something to tighten against or it will never torque to spec. No need to pull the rocker arm studs before machining the pad. The text book way to do this is to machine the stud boss down square and tap it for screw in studs. You have to remove the nut from the stud or remove the head bolt that is holding down the rocker arm.
Nov 16, 2019 the stud needs something to tighten against or it will never torque to spec. Sturdy stand holds cylinder heads safely and securely while you repair cracks, grind seats, clean. They found that a fatigue crack in rocker arm shaft was initiated at through hole and subsequently propagated along its sidewall. Ticking lifters, broken rocker studs hot rod magazine. Removing pressed in rocker studs on small block chevy vortec heads using kd tools no 705 stud puller. One stud broke near the top where the nut hits the rocker under normal, freewaycruise speeds 7075 mph with.
The boss 302 was an excellent racing engine, but it was a real dog on the street because its huge ports didnt deliver good lowend torque. The raised area on the side of the stud will contact the top of the boss as a stop but the torque spec required to seat the threads is enough to crack the top of the boss. Repair of external freeze cracks, bolt holes, rocker stud bosses, etc. Vortec heads have gotten a reputation for cracking easily. We are not comfortable with putting a stud that size in a boss that small. I did notice some small nicks on the rockers where it looks like the edges of the stud nut is hitting the aluminum rocker arm but they appear to be real minimal. Cracks may also occur on the rocker box or in the rocker bosses. Make sure the rocker does not bottom on the rocker stud radius. Anyway, you will not be able to just tap the hole, however, you will need to machine down the boss the stud is in, or the new stud will be too high. This comes up so frequently that i would like to explain 2 easy fixes that exist for this situation.
It has run fine to this point and i have readjusted the lash twice to make sure it was okthe rotate the pushrod till it stops then give another half turn method. Analysis of a failed rocker arm shaft of a passenger car engine. This boss cutter uses the stud as a pilot, allowing better lineup and providing. For use on mark iv big block chevy engines with 716 threads. Buy online for free next day delivery or same day pickup at a store near you. I know of a number of peeps who have accually cracked the stud boss off on one side. Look at the boss for the exhaust studs, even the reinforced ones on the rt heads.
Trick flow rocker arm studs are ideal for street or competition use. Sometimes the force of gm shooting them in so hard, they get so hot it accually welds itself in. Hi randy, one area to check here is the thread depth in the head and the depth at the bottom of the stud. Check with the manufacturer for these dimensions if need be, otherwise the stud and guide plate can be measured with a caliper. Once you start making performance modifications, and the open pressure of your valve springs rises over 280 lbs. Engine is a 302 with an edelbrock rpm power package with the roller cam and lifters. Comp cams stud boss cutting tools 4729 free shipping on. Rocker arm stud pulled looseany ideas for fi 091703 03. Some lug or boss failures have been attributed to improper ndt processes during overhaul which has failed to detect fatigue cracks developed. We have the best rocker arm kit for the right price.
Broken rocker stud chevy message forum restoration and. A tool kit for drilling and pinning a press in type rocker arm stud in the stud mounting boss bore of the mounting boss of an engine head, said tool kit comprising an alignment block having a vertical stud receiving bore for receiving the rocker arm stud, a nut threaded onto the stud to lock the alignment block to the stud upon the mounting boss, said block having a. Ticking lifters, broken rocker studs hot rod magazine hot rod. Here is an old school fix for problematic pressin rocker studs. We have the best rocker arm stud for the right price. Jan 12, 2010 how serious is a broken rocker arm shaft.
This kit is designed to allow stud mounted, adjustable rocker arms to be installed on ford 302351w engines and dodge 318 5. Note that the rocker arm specification also varies depending on the year of the engine. Installation instructions rocker arm stud conversion kit. Pulled 1516 perfect 1 barely cracked the boss at the top. This chapter deals with the cam side of the valvetrain, including the rocker arm. The mechanic working at the time said it could be the cold weather and to drive it for a few days to see if the problem persists. They are pressed or threaded into the top of the cylinder head, and the rocker arms are attached to the top. Step by step the smallblock ford has never been blessed with particularly good cylinder heads in its halfcentury service life. The heads must be removed and the oe pressed in studs removed. Gm rocker arm thread damage 2 easy fixes southeast.
Cast iron or cast aluminum cracked or broken, bell housing repair, tail shaft housings. Miscellaneous head tools redlands reconditioning supplies. Different brand studs have different machining specifications. These are best for cast iron heads, as this design may crack the bosses on aluminum heads. This is especially true when long pushrods and valves are employed you should raise the installed height of the rocker arm. The directions with my arp rocker studs calls for it, along with moly lube. The new a460 heads do have the proper length exhaust stud boss threaded hole and the new studs with the 1. If youve ever broken a exhaust stud boss or stripped the spark plug threads, you might want to invest the repair cost into purchasing amc heads because these repairs can be expensive. So yesterday i made a post about the noise problem i was having in my car.
Remove the nut from the stud and remove the rocker arm inspect for cracks. These rocker arm studs resist the valve train flexing generated by higher horsepower. We have encountered so many people who try to fix these stripped bolt holes themselves and wind up not solving the problem. Heating the stud boss a little bit really allows the studs to slide out easier. Sbc rocker stud pins screwin studs discussion in the hokey. How to pull oem pressin rocker arm studs and replace them with screw in studs on small block chevy cylinder heads. One of the rocker studs was pulling out of the head, so i made a guide to tap the hole for a screw in stud. Important tech note it is highly advisable to determine what the optimum rocker arm stud length is for your particular application. Auto engine blocks, cylinder heads, manifold repair, welding. Removing pressed in rocker studs on chevy vortec heads. This is especially true when long pushrods and valves are employed you should raise the installed height of the rocker arm to compensate for the longerthanstock components. The first was a tool that cut the boss using the original stud as a guide. The rocker arms exhibited no signs of binding, brinelling, cracking, or general distress.
We noticed a rattling sound coming from the engine when we test drove it. I have a broken rocker arm stud while i was driving today being very easy on the motor. It might be possible at that point to weld up the crack using what ever process necessary, tap it out deeper, and use a stud with a deeper threaded portion. The installation procedure for both engines is the. Comp cams ultra pro magnum rocker arms ford v8 boss 302. Engine wiring harness bracket nut to intake manifold stud. We carry a large array of cylinder head parts including balance shift eliminators, valve adjustment discs, stud boss cutters, and head holders. How to machine stud bosses on sbc camel hump heads. The text book way to do this is to machine the stud boss down. How to machine stud bosses on sbc camel hump heads youtube.
Not claiming this to be the best method, im just saying with luck its easy. Inspect the rocker arm bushing for correct size by sliding the shaft into the bushings to check. Suddenly during the startup of a passenger car engine, a high abnormal noise accompanied by a jerky vibration of the engine had been manifested. Jegs ls series rocker arms with upgraded trunnion kit with offset intake rockers for gm ls3, ls9, l92, and l76. Simply slide the tool over two sidebyside studs and crank down on the retaining nut to force out the stud. Ive been having problems with rocker studs ripping out of my aluminum heads. Piston engine rocker shaft boss failures civil aviation authority of. Rocker arm studs keep coming loose 348 and 409 engines.
A cracked boss isnt the end of the world, gently torque a bolt in that boss, trough out the crack, and weld it up. Its a 327 with new afr heads that only have about 200300 miles on them. The stud girdle can be used with the 516 bottom stud setup too because it is 38 on top. Jul 22, 2007 hi randy, one area to check here is the thread depth in the head and the depth at the bottom of the stud. The rocker arm nuts keep backing off after i drive it about 20 miles. Unlike the cylinder head bolts, the rocker arm nuts may be tightened to their final torque specification individually. Valve cover was pulled to see a broken stud and some damaged to the rocker arm slot. Install the new roller rocker arms for number 1 cylinder with the flat area on the trunnion shaft up. A common upgrade at this stage is to tap the cylinder heads and switch to threaded rocker arm studs. After dismantling, the local dealer service found that the rocker arm is broken near the middle as shown in fig. The main consideration is that the rocker arm trunnion if a roller rocker or the rocker slotpivot ball if stamped steel rocker doesnt bottom out on the stud radius. Oct 23, 20 how to replace rocker arm studs,mine are press in. Oil the pushrod, rocker stud threads, rocker arm and nut.
Although a 38x38 rocker stud would allow higher spring pressures to be used, there have been numerous reports of cylinder head stud boss cracking when. Competition cams 4729 stud boss cutter this is the second cutter that ive bought and got 4 sets of heads out of the first cutter and it still works but want the best cut i can get and am retiring my first one just for a backup if needed. Jun 27, 2009 so yesterday i made a post about the noise problem i was having in my car. If the studs protrude into the intake port or water jacket. These studs are made from 8740 chromoly steel and are included with trick flow assembled heads. It does not take very ling to replace a rocker arm and you can complete the project in your driveway. Modifying a chevy 350 vortec head to accept thread in. If youre looking for plus length bbc studs, we carry those also. Studmounted rocker arms are the middle option between pedestalmounted fine for stock applications and shaftmounted a hardcore racing option for vehicles operating at over 7,000 rpm rocker arms. A wire feed will do the trick here, weld maybe a second or two at a time then cool off with compressed air, grind down some of the excess weld, and be sure to seal the stud when you install it for the last time. If the rocker arm is loose there could be two reasons.
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