Ugh: One bad SBC block head thread

[NewbVetteGuy]

The "Newb" part of my forum name is there for a reason.

I finished the bottom-end rebuild of my SBC last weekend and yesterday I cleaned up my new head studs, added ARP thread sealant to the bottom threads and started installing them. Everything went "by-the-book" except for one thread that started to get pretty tight after screwing it in 3/4s of the way, I used the alan-head to tighten it in all the way thinking that tightening it in all the way and then pulling it back out might pushout whatever leftover crud was in the bottom. (Bad idea, I now know).

The stud REALLY didn't want to back out and the alan head of the stud got rounded off- then I attached my vice grips to the center of the stud to try and get it out of the block (the only tool I had that I could use).

Now I need to locate 1 new short stud, AND I need to figure out what to do with the messed up threads in the block: Anyone think that a simple thread chaser is going to work here or should I just go straight to a tap? (What specs for the chaser / tap?)

Is ARP thread sealant still likely to seal it once I'm done with the thread chaser/ tap or do I need to go with something more "heavy duty" for this stud?



Adam

[mag2555]

Basic rule of Thumb with head bolts or studs or the same with main cap hardware is that they need to go in with finger force only, especially if your using bolts and want to get correct torque levels!
if this can not take place with new hardware that has good threads then it time to get hold of the needed size bottom tap.
Before you use the tap you need to roll over the end of the cutting edges a tad do you just clean out the threads , not cut what's there bigger.

[ClassAct]

The "Newb" part of my forum name is there for a reason.

I finished the bottom-end rebuild of my SBC last weekend and yesterday I cleaned up my new head studs, added ARP thread sealant to the bottom threads and started installing them. Everything went "by-the-book" except for one thread that started to get pretty tight after screwing it in 3/4s of the way, I used the alan-head to tighten it in all the way thinking that tightening it in all the way and then pulling it back out might pushout whatever leftover crud was in the bottom. (Bad idea, I now know).

The stud REALLY didn't want to back out and the alan head of the stud got rounded off- then I attached my vice grips to the center of the stud to try and get it out of the block (the only tool I had that I could use).

Now I need to locate 1 new short stud, AND I need to figure out what to do with the messed up threads in the block: Anyone think that a simple thread chaser is going to work here or should I just go straight to a tap? (What specs for the chaser / tap?)

Is ARP thread sealant still likely to seal it once I'm done with the thread chaser/ tap or do I need to go with something more "heavy duty" for this stud?



Adam

Use a QUALITY bottom tap and make sure you blow all the crap out of the bottom of the hole. You really need a nozzle that will go to the bottom of the hole to do it right.

[NewbVetteGuy]

The "Newb" part of my forum name is there for a reason.

I finished the bottom-end rebuild of my SBC last weekend and yesterday I cleaned up my new head studs, added ARP thread sealant to the bottom threads and started installing them. Everything went "by-the-book" except for one thread that started to get pretty tight after screwing it in 3/4s of the way, I used the alan-head to tighten it in all the way thinking that tightening it in all the way and then pulling it back out might pushout whatever leftover crud was in the bottom. (Bad idea, I now know).

The stud REALLY didn't want to back out and the alan head of the stud got rounded off- then I attached my vice grips to the center of the stud to try and get it out of the block (the only tool I had that I could use).

Now I need to locate 1 new short stud, AND I need to figure out what to do with the messed up threads in the block: Anyone think that a simple thread chaser is going to work here or should I just go straight to a tap? (What specs for the chaser / tap?)

Is ARP thread sealant still likely to seal it once I'm done with the thread chaser/ tap or do I need to go with something more "heavy duty" for this stud?



Adam

Use a QUALITY bottom tap and make sure you blow all the crap out of the bottom of the hole. You really need a nozzle that will go to the bottom of the hole to do it right.

I bought ARP's 7/ 16 -14 tap this morning.

My understanding is that all of the head bolt holes in an SBC 350 go into the water jacket. I've already got all the freeze plugs installed but after running the tap through it I can rotate the block upside down in the engine stand and blow it out real good through the holes in the top of the block...

Adam

[ClassAct]

The "Newb" part of my forum name is there for a reason.

I finished the bottom-end rebuild of my SBC last weekend and yesterday I cleaned up my new head studs, added ARP thread sealant to the bottom threads and started installing them. Everything went "by-the-book" except for one thread that started to get pretty tight after screwing it in 3/4s of the way, I used the alan-head to tighten it in all the way thinking that tightening it in all the way and then pulling it back out might pushout whatever leftover crud was in the bottom. (Bad idea, I now know).

The stud REALLY didn't want to back out and the alan head of the stud got rounded off- then I attached my vice grips to the center of the stud to try and get it out of the block (the only tool I had that I could use).

Now I need to locate 1 new short stud, AND I need to figure out what to do with the messed up threads in the block: Anyone think that a simple thread chaser is going to work here or should I just go straight to a tap? (What specs for the chaser / tap?)

Is ARP thread sealant still likely to seal it once I'm done with the thread chaser/ tap or do I need to go with something more "heavy duty" for this stud?



Adam

Use a QUALITY bottom tap and make sure you blow all the crap out of the bottom of the hole. You really need a nozzle that will go to the bottom of the hole to do it right.

I bought ARP's 7/ 16 -14 tap this morning.

My understanding is that all of the head bolt holes in an SBC 350 go into the water jacket. I've already got all the freeze plugs installed but after running the tap through it I can rotate the block upside down in the engine stand and blow it out real good through the holes in the top of the block...

Adam

You are correct. For some reason I decided, in my head you had an aftermarket block which would have blind head bolt holes.

You can catch most of the crap that you are removing with the tap if you put some grease in the flutes of the tap.mthat will reduce the junk falling into the bloc by probably 95%.

This is why even psychologists don't want to look inside my head. I make shit up that seems right to me!

[Schurkey]

The Vortec block I assembled a few months ago (GM "880" casting) had blind head bolt holes for the top row of four bolts on each deck.

I used sealer on those threads too--just to keep the lubricity the same on all head bolts.

[NewbVetteGuy]

The Vortec block I assembled a few months ago (GM "880" casting) had blind head bolt holes for the top row of four bolts on each deck.

I used sealer on those threads too--just to keep the lubricity the same on all head bolts.

Awesome. I was expecting that some holes were blind and was planning on doing the same. Then I checked and realized that they ALL go into the water jacket.


Adam

[houser45]

Just helicoil it and be done with it. Make a jig out of a thick piece of steel for the tap drill to stay straight. 1 1/2” or so thick. Then drill the jig block out to keep the helicoil tap straight.

[tresi]

In this situation or any other Clean and tap all holes as you are cleaning the block. Whenever a thread gets tight before it should stop and fix it then. Don't continue on and try to make up for it later. If you ran a tap through sealer consider the sealer ineffective. Clean the goop off the tap, retap with some type of solvent on the tap and reclean the tap again. If there is 1 thing more than anything else that people screw up is that they will not stop when they hit a problem.

[ProPower engines]

Ain't that the truth

Thoses of us that do this stuff all day for a living see our fair share and in some areas more then our fair share of dumb mistakes cause guys are in a hurry or just do not know any better.
There has been more screwed up bolt holes from guys installing head studs and since ARP has added a hex drive in their studs guys just ram then in the holes without giving them a 2nd thought.

I have an import block here that is hard to locate and pricey as well but the owner thought he would just put the studs in himself. he oiled the threads in the block and the threads of the stud as well and ramed them in cracking 4 of the 10
holes in the block from hydraulic pressure trying to squeeze the oil past the threads.

Ya can't fix stupid ............but you can invoice for it