Generation III Internal Engine - Bulk ARP bolts torque spec

Do you guys use ARP specs or GM?

I'm using the bulk fasteners for the oil pump mounting, cam timing gear, and plate. I plan on using loctite for this application.

ARP's 24 ftlbs or GMs 18 ftlbs?

(Threading into the Aluminum block just scares me lol..)

I'd use GM's numbers. The ARP numbers don't take into account the material you'll be threading into, they'll assume iron/steel, not softer aluminum.

(Threading into the Aluminum block just scares me lol..)

Stud them!! lolz...

Do you guys use ARP specs or GM?

I'm using the bulk fasteners for the oil pump mounting, cam timing gear, and plate. I plan on using loctite for this application.

ARP's 24 ftlbs or GMs 18 ftlbs?

(Threading into the Aluminum block just scares me lol..)

For that stuff I would stick with GM specs. ARP called for 75 ft lb on the head bolts so I went with that.

I'd use GM's numbers. The ARP numbers don't take into account the material you'll be threading into, they'll assume iron/steel, not softer aluminum.



Stud them!! lolz...

I've got to disagree here. Bolts (or studs) need to be in tension with a predetermined amount of stretch in order to do their job. You will only get the correct number from the bolt manufacturer. Another reason to never use a bolt when a stud is available!

Interesting,

Is anyone smart on the affect torque if I omit Ultra Torque lube in place of loctite? Or no difference?

No way would you torque an 8mm bolt to 24 ft lbs into aluminum! You will strip the threads out of the block. Follow GM's 18 ft lbs spec on the oil pump & 24 ft lbs on the cam gear.

Russ Kemp

No way would you torque an 8mm bolt to 24 ft lbs into aluminum! You will strip the threads out of the block. Follow GM's 18 ft lbs spec on the oil pump & 24 ft lbs on the cam gear.

Russ Kemp

The bolts have an 8mm head but are actually 6mm bolts & youre right theres no way I would put that much torque on them.

The bolts have an 8mm head but are actually 6mm bolts & youre right theres no way I would put that much torque on them.

No, they are 8mm X 1.25 bolts. The head is 10mm

Perhaps these (ARP) bolts will achieve the ARP spec if turned into an iron block. This is why GM lists the torque for these bolts into an aluminum block at less.

I doubt you'd reach the "correct" fastener stretch on these small bolts threaded into an aluminum block-as also stated by Russ.

On such a small thread at these low tension levels, I don't think using locktite instead of thread lube will make any difference. Not a bad idea to use locktite-you'll sleep better.

Follow GM's numbers.

Yea I would sleep alot better knowing the cam retaining plate and cam sprocket are not going to jiggle loose. ;)

No way would you torque an 8mm bolt to 24 ft lbs into aluminum! You will strip the threads out of the block. Follow GM's 18 ft lbs spec on the oil pump & 24 ft lbs on the cam gear.

Russ Kemp

Actually just found out that the countersunk cam retainer plate bolts should only go 12ft/lbs. Latest spec from a subscription service the machine shop I use pays for.

Interesting,

Is anyone smart on the affect torque if I omit Ultra Torque lube in place of loctite? Or no difference?

The bolt preload is determined by the applied torque, the bolt parameters (size, thread, fit class, etc.) and the friction. Friction is the only parameter you can "attempt" to control and it is usually done with lube. That's why ARP spent so much time developing their new lube. As to the friction differences between their lube and Loctite, only ARP would have that data and I would go straight to them.

However, you can spend a lot of time chasing these parameters but if you don't have an accurate torque wrench it is all in vain.

When i ordered and installed my arp bolts, i ordered the ones made for the ls1 engine, so when arp developed the specs, it was for the aluminum engine. Cleaning the holes is the part i always worry about. Clean, chase clean, paper towels to poke in the holes and clean again, so theres no extra resistance when threading in a bolt

The bolt preload is determined by the applied torque, the bolt parameters (size, thread, fit class, etc.) and the friction. Friction is the only parameter you can "attempt" to control and it is usually done with lube. That's why ARP spent so much time developing their new lube. As to the friction differences between their lube and Loctite, only ARP would have that data and I would go straight to them.

However, you can spend a lot of time chasing these parameters but if you don't have an accurate torque wrench it is all in vain.

I don't know...I have their LS1 cam retaining plate and cam bolts and neither have instructions. ARP doesnt list the instructions for these on their website.

Get this....

ARP gets a BIG thumbs down!!! I tried to get the torque spec from them and they said 24-28ftlbs for the 8mm bolts. I asked them if that tq was safe for an aluminum engine, I get "That is the torque for those bolts"! ARG! I may not even use them now. The won't even give a straight answer.

Get this....

ARP gets a BIG thumbs down!!! I tried to get the torque spec from them and they said 24-28ftlbs for the 8mm bolts. I asked them if that tq was safe for an aluminum engine, I get "That is the torque for those bolts"! ARG! I may not even use them now. The won't even give a straight answer.

Once again, the whole point of torquing a fastener is to apply the correct amount of stretch (preload) to it. "It" being the fastener. Any lesser value will risk the fastener coming loose, any greater value will risk breaking the fastener. The material you are threading it into does NOT come into play here. If you are worried about pulling the threads, I'd suggest you get a heli-coil kit and get after it...

Once again, the whole point of torquing a fastener is to apply the correct amount of stretch (preload) to it. "It" being the fastener. Any lesser value will risk the fastener coming loose, any greater value will risk breaking the fastener. The material you are threading it into does NOT come into play here. If you are worried about pulling the threads, I'd suggest you get a heli-coil kit and get after it...

You may be right in this context, which involves the threads in an LS bock, but there is no engineeering/physical rule that says that the bolt will always stretch, give, or break before the threads of whatever it is tightened into.

Starting on page 12 of this link is a discussion what happens when the tensile strength of the bolt is too high relative to the nut to which is to be attached.

http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

So, it is theoretically possible to have a bolt that will destroy the female threads into which it is tighened before it achieves a certain torque specification (based on yield strength which is what ARP uses).

Using the GM specifications will provide the same bolt preload. However, if you lubricate the bolt where the GM specification does not require it (this includes loctite), then you are putting more preload into the bolt due to a reduction in friction and hence into the aluminum threads. This is one reason I always cringe when I see guys adding loctite/lube where GM doesn't require it as they run the risk of internal thread damage especially since most are using lessor cost and likely less accurate torque wrenches.

Using the GM specifications will provide the same bolt preload. However, if you lubricate the bolt where the GM specification does not require it (this includes loctite), then you are putting more preload into the bolt due to a reduction in friction and hence into the aluminum threads. This is one reason I always cringe when I see guys adding loctite/lube where GM doesn't require it as they run the risk of internal thread damage especially since most are using lessor cost and likely less accurate torque wrenches.

Are suggesting less than 18ftlbs when using loctite?

Do you have the part number for these bolts?

Do you have the part number for these bolts?

ARP 661-1002 8mm x 1.25 (Plan was to use them for Oil pump mounting) and
ARP 134-1002 8mm x 1.25 (Cam retaining bolts)

I use arp and i havent had a problem with them.
From my experience arp hasn't let me down .... yet... lol

On page 24 of this PDF from ARP, they have a fastener torque chart. In your case 20 ft lbs with their lube, and 25 ft lbs using 30 weight motor oil. Now like said earlier, follow the specs from the maker of the fasterner. I used ARP head bolts a couple weeks ago for my ls1 heads. This torque value is much higher than the torque valve your looking to use. Worked out fine for me, I would use a 2 pass method, 11 ft lbs the first pas, 20 the second pass using ARP moly lube. With an aluminum block its all in the prep, chase the threads, use a can of compressed air ( like for computers) clean the threads, use paper towels if water could be in there and use a small vacuum to vacuum holes also. My friends always think I'm going over board, but I've never stripped a thread or broke a bolt. On the cam, cam plate and oil pump, I have reused the stock bolts with loctite also, with no issues. Here's the link.

http://www.google.com/url?sa=t&rct=j&q=arp%20661-1002%20torque%20specs&source=web&cd=2&ved=0CGgQFjAB&url=http%3A%2F%2Fwww.rs-motorsinc.com%2Fcatalogs%2FARP-Catalog.pdf&ei=oYmpT7zkD-maiAKQ0YilCw&usg=AFQjCNF4cCct82Cs-nTY6-bcOv9SDmQd4A

Guys, look at it this way:

ARP makes fasteners that are rated to a specific stretch which they've determined and published torque specifications for. These numbers are for a best case scenario, with the fastener threaded into a fixture or nut equaling the strength of the fastener through what the material is or thread depth engagement.

Those are their numbers and they're gonna stick to them.

Now, if you're dealing with an aluminum block with a limited thread depth engagement, it would be wise to go with the maker's torque spec, in this case GM. Otherwise, attempting to torque them to ARP's specified stretch numbers will in all likely hood result in you pulling the threads out of the block.

I'd also say that there's too much being made here about these smaller fasteners. Use the better ARP bolts. Torque to the GM specs. Use locktite to be sure nothing loosens up unless you want it to.

After Many conversations with ARP....I went a head and trusted them. I torqued the cam retaining bolts to 24 ft lbs. Seem to have held up fine. I had the heads lubed with ultra torque with Blue loctite on the threads. Went slow, in a circular pattern in increments of 10-15-20-24.


Now I feel sick about it lol...Thermal heat expansion and a bolt some day popping out has me losing sleep :zzz:

While I certainly hope this all goes well for you, I think you're making a mistake.

GM specs these bolts (even for iron blocks) at 18 ft lbs.

As you have an aluminum block, I would worry that with heat cycles, the threads in the block may fail. Aluminum and steel/iron expand and contract at different rates with heat so I think the GM specified numbers is more important in an aluminum block.

If you had an iron block, the higher torque numbers of the better (ARP) fasteners would be OK.

While I certainly hope this all goes well for you, I think you're making a mistake.

GM specs these bolts (even for iron blocks) at 18 ft lbs.

As you have an aluminum block, I would worry that with heat cycles, the threads in the block may fail. Aluminum and steel/iron expand and contract at different rates with heat so I think the GM specified numbers is more important in an aluminum block.

If you had an iron block, the higher torque numbers of the better (ARP) fasteners would be OK.

Ahh....Man....

What about all the other specs? Say, the head bolts? Are you saying ARP specs will fails me even if the bolts are holding now?

Looks to me, your F-'d if you do or you dont!

You don't torque to ARP spec, they will not have the clamping (Spring) force they were designed for.

You do torque, and now thermal expansion will fail the thread!

I may just throw the stockers back in!! What a freakin headache

The bolts you're using are their "bulk" bolts, not designated for a specific application. Head bolts are.

I'd bet that if ARP made a bolt specifically for what you're using them for, they'd be closed to the GM numbers.

These little bolts don't really rely on a stretch for fastening. They just hold things in place and get screwed in tight enough to prevent them from coming out.

Head bolts, main bolts, crank bolts, yes, they need a certain stretch as they're a clamping something critical.

I say keep the nicer ARP bolts but go back to the GM torque numbers.

I say keep the nicer ARP bolts but go back to the GM torque numbers.

Cam plate retaining bolts were LS1 specific. Thats why it drove me insane that ARP would put the stiff arm and say 24ftlbs and not address my concern with the aluminum block. The only fasteners I'm using in "bulk" is the Oil pump mounting.