Bolts vs studs

Lt_Bongwater

Active member
Hi,

While trying to install the CI Alum head using ARP studs, this happened:



Basically the block cracked while I was torquing the studs, I respected the assembly order as well as the torque specs. I don`t think I applied too much torque, I tend to believe it`s metal fatigue combined with the way the studs are built, they are thicker on the upper part which I assume makes them prone to eating inside the lower part due to increased friction.

I wanted to check if anybody else experienced something like this before, and what is your advice?

I got another engine block and will start working on it soon, however now I`m super reluctant to using studs again. I`m thinking of going for bolts, anybody has any experience with a similar install?

Thanks in advance,

Cristian
 
Studs are not torqued into the block, they are installed just short of bottoming out in the hole.
The nut is torqued onto the stud.

It looks like the cylinder adjacent to the crack has a liner installed.
If so, the block may be repairable once disassembled. Check with your machinist.
 
Its not uncommon for sleeves to split the deck like this when installed with too much interference fit. It was probably already cracked and you just didn't know it and torqing the head just finished it off.
 
CNC-Dude":1riros02 said:
Its not uncommon for sleeves to split the deck like this when installed with too much interference fit. It was probably already cracked and you just didn't know it and torqing the head just finished it off.

I am with CNC-Dude on this one, I have seen it happen more then once on a sleeved block. I had zero issues using studs, and as they put less stress on the block when torqued then bolts...
 
G R E A T thread.
Thanks for the share (esp pic!) ! frm our neighbor frm acc the big pond.
Thanks 2 ALL who've commented.
Good luck w/the work around with this set back.
I'm rootin for ya !
 
Thanks guys for all the comments and support. My new block has arrived, it`s at the machine shop now, which gives me some more time to do some more research.

Any tips on installing the ARP studs (on the Alum head), so that I avoid this? Is there any kind of specialty lube I should be using? I`ve seen a tutorial where some guys are building a performance engine and their torquing the studs three times, each time unscrewing it completely and oiling it, they didn`t say what they were using however.

On another note, if I were to use bolts instead of studs (i`m a bit paranoid :)), does anybody knw what I should get that would fit on the Alum head? The standard bolts are no good, the`re too short.

Thanks, will keep you guys posted with the progress.

Cristian
 
No 'exspirit' here so just a quick check in.

The studs don't need the tq/re-tq. The nuts'n washers R where the clamping force IS. Put them on last/later after studs R 'set'.

Where ur head cracked can B caused by the lip below (water pump area) when the stud hits that it pressures up the upper portion & breaks it.
Some use a soft set heat resistant thread lock on bottom of stud. Gotta make sure U don't Bottom Out the studs. Mark the stud to where U can see u r not going too deep. (This aids later to C if they've loosened after break in or some time/miles'n heat cycles).

Keep talkin (& enjoyin all the beautiful scenery ur county has 2 offer!)
 
Maybe chase/tap the threads of the new block, no matter if using bolts or studs. Even if new, you can get false torque readings if the threads are messed up. An inexpensive tap will do the job in short time.

And I'm sure I'll hear different opinions, but if you're not running high compression, you don't need studs. My pops was a Ford mechanic for 25 years and a drag racer. He built many many race engines and never used studs. He could be (and is) old school... but that's what he told me building my engine.

Good luck!
 
i like em due to repeated head swaps, changes, upgrades ( 3 - 4 each ) & clampin force.

"... what I should get that would fit on the Alum head…"
Ck in w/Matt @ VintageInlines.com (phone or on-line)
 
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