ARP Studs - Don't Fit in LS1?
12-21-2016, 09:53 AM
#1
ARP Studs - Don't Fit in LS1? Per my build thread (https://ls1tech.com/forums/conversio...ion-wagon.html) this happened yesterday:
If anyone has any ideas of why this happened it would be appreciated; and if anyone has an ARP M11x2.0 stud sitting around and can measure its OD that would be awesome.
The fun really began when I went to put the heads on and the 11mm (.4331" diameter ) ARP studs wouldn't thread (M11x2.0) into the block without binding/galling - whereby the stock bolts go in without issue. Yes, the threads were chased (6 times per hole) and blown out (with compressed air and solvent). Measured the stock bolts (.423") and the ARP studs (.430") to find a .007" difference. The basic pitch matches in both the bolt and stud, and each measures out at 2.0 with a gauge. ARP's tech line basically said they aspire to a "higher class of bolt" (let's say a Class 3) which may be causing the problem where a regular production class threaded hole (let's say a Class 2), thus the variance in tolerance from one to the next is the root issue of the interference fit. Another possibility is the block is sitting around 10-13*C (~50-55*F) causing the tolerances to close up - but that is a bit of a stretch (bolt pun fully intended).
Thread class article:
https://www.fastenal.com/content/fed...s%20Design.pdf
Rather than mope - I just cleaned the orange sealant/thread-locker goop off the threads of a set of new GM bolts, coated them with ARP Ultralube, and torqued them down. A pretty easy process by comparison - except that I am out $200+ on the ARP studs. Using this process these bolts were good enough to hold the heads down on my Procharged LS2, and they will hold this thing together.
Thread class article:
https://www.fastenal.com/content/fed...s%20Design.pdf
Rather than mope - I just cleaned the orange sealant/thread-locker goop off the threads of a set of new GM bolts, coated them with ARP Ultralube, and torqued them down. A pretty easy process by comparison - except that I am out $200+ on the ARP studs. Using this process these bolts were good enough to hold the heads down on my Procharged LS2, and they will hold this thing together.
12-21-2016, 10:58 AM
#2
TECH Junkie
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did you buy the thread chasers to clean out the holes. I have a 99 formula and last winter i did arp headstuds and got the thread chasers and so much crap comes out .
12-21-2016, 11:05 AM
#3
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Head Stud Installation Method This case was also found by my use in the "early days" before I had my own studs created.
I do have some very early ARP's, somewhere, I will have a look.
I am sure they would not be the same "batch".
Lance
I do have some very early ARP's, somewhere, I will have a look.
I am sure they would not be the same "batch".
Lance
12-21-2016, 11:31 AM
#4
http://www.tapmatic.com/tapping_ques..._h_limits.ydev
Like I told the folks at ARP: You over-engineered the fastener.
My brother is a production engineer and even he said there is no justifiable reason to create such a high Class (close tolerance) bolt to go into a production (loose tolerance) engine.
The best part was when the ARP tech line even suggested that I could see the same issue installing their crank bolt. I am going to crack that open today to see if it too will be an issue.