I've just been doing some research about my future engine build up and I found most people recommend arp head studs and rod bolts, but why leave the main bolts stock OEM?


Is there a reason why no one recommends using ARP Main studs? I mean the bottem end can only be as strong as it's weak part right...

 

i asked the same question before and got no help so im gonna bump for ya

 

id like to know as well

 

The stock main bolts are fine until you get into the high hp numbers.Nothing wrong with using them,its just not necessary.
Glenn

 

The stock bolts hold it all together just fine, and they are good on 700whp turbo car setups.. I think arp recomends their studs to be torqued to 70ft/lb which is quite a bit higher than the stock torque specs, so I'm sure the block would try to maybe move or "twist" a little and possibly cause the line hone to be out of wack.

I'm pretty sure this is what happens but someone please correct me if I'm wrong.

 

I could see them really only being necessary in the most strenuous of builds. Like 10,000+ rpm race motors. Everyone rocks stock main bolts without problem including me.

 

what about LS/b20 builds that dont have a girdle

fixed for spelling


Modified by JCushing at 12:08 PM 2/12/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JCushing &raquo;</TD></TR><TR><TD CLASS="quote">what about LS/b20 builds that done have a girdle</TD></TR></TABLE>
If its a stock girdle conversion then the stock gsr main bolts work fine.Some of the aftermarket girdles require different lengths and use studs.
Glenn

 

Like someone just mentioned, the ARP main-studs require more torque so I would think you might get a different main-bearing clearance with them. I have heard something about how the main-studs "twist" the girdle. But I have no proof. Never had a problem with stock main bolts.

 

its the same with the rods, more tq means you need to have the main caps resized. now is it worth the effort? it is for the rod bolts but how bout the main studs?

 

Thanks

 

just torque them down to Honda spec then. But I can't find any for the ls/b20 anyway. Unless you can use the B18C ones? Eather way ARP is just a better safe then sorry kinda thing. I just wish I could find the LS ARP mains.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CBURKE &raquo;</TD></TR><TR><TD CLASS="quote">just torque them down to Honda spec then. But I can't find any for the ls/b20 anyway. Unless you can use the B18C ones? Eather way ARP is just a better safe then sorry kinda thing. I just wish I could find the LS ARP mains.</TD></TR></TABLE>

Arp recomends 70 ft/lb, not stock spec. Do you torqe your arp head studs to the stock spec, I don't think so.

 

Ok, but I have seen many engine builders do this because of the torque specs being much higher then the stock.


Modified by CBURKE at 2:51 PM 2/16/2006

 

It could be a problem. For any given fastener to work properly in needs required amount of preload.

For ARP this is higher, needing more TQ in the end, but providing more clamping force and so on...

One can play with this to certain extent, but there is that fine line, when fastener can back out on you if it does not have enough preload...

I do agree though that quite a few Honda builders go with 64-65TQ on head studs. Also I do know of one case where 70TQ shifted cyl bore and ruined the engine. (block was decked and head milled).

Anyway just to muddy the waters some more...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Adi Radoncic &raquo;</TD></TR><TR><TD CLASS="quote">Arp recomends 70 ft/lb, not stock spec. Do you torqe your arp head studs to the stock spec, I don't think so.</TD></TR></TABLE>

here are some good questions: does ARP test bore distortion with their tq spec? i doubt it. do they recommend that you measure it using their studs and specs and bore/hone accordingly? no such directions were included with mine- head or main. will ARP reimburse you if you ruin your engine by using their specs instead of Honda's? are you willing to find out the hard way?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slofu &raquo;</TD></TR><TR><TD CLASS="quote">

here are some good questions: does ARP test bore distortion with their tq spec? i doubt it. do they recommend that you measure it using their studs and specs and bore/hone accordingly? no such directions were included with mine- head or main. will ARP reimburse you if you ruin your engine by using their specs instead of Honda's? are you willing to find out the hard way?</TD></TR></TABLE>

I doubt they check for distortion at all or measure it, and again i seriously doubt they will replace anything becuase of their bolts.

The way to do it would be to torque them to 70 ft/lb, and line hone the block, after that mic the crank and the cap bores and see where your at. Get the correct bearings and go on with your build.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Adi Radoncic &raquo;</TD></TR><TR><TD CLASS="quote">The way to do it would be to torque them to 70 ft/lb, and line hone the block, after that mic the crank and the cap bores and see where your at. Get the correct bearings and go on with your build.</TD></TR></TABLE>
You can also use a dial bore inside the tunnel and measure the bore as you increase the torque on the cap. If you can get each stud to 70lbs without distortion, you are good to go. But this is a real pain in the *** and you would not see any benefits until around the 800-900 whp range, is my guess.

 

my guess is that their recommendation comes from not only the material strength and thickness of the studs, but that stockers are tq-to-yield type bolts and ARPs aren't. they can handle more tq and will clamp better, and, as mentioned, they require a preload (typically on the order of a few "/#s), but tq'ing them more than necessary just makes for more work to do it properly.