i've heard you have to do this. just wondering what people thought and what they did. not really wanting to get into the machining. may just re use the main bolts. not producing ALOT of horsepower, just figured i'd use them since i had them. thanks.

 

yes you will need a align hone b/c the arp's change how the caps are being held down.

 

The Internet "kneejerk" answer is always yes to this question (from what I've seen in a few threads related to this) but IMO it's not mandatory if you properly check all your clearances after the install of the studs using a micrometer and a dial bore gauge thats accurate to four decimal places (.0001). The use of the ARP studs will slightly effect the bearing clearance because it will slightly reduce the vertical height of the cap by about .0003 to .0004 based on what I have measured. So technically you will have slightly less vertical clearance when you install the same bearing shells (note we are discussing less than half a thou here).

If your super **** and have the money to maximize everything its certainly not a bad idea if done properly but a bad hone could potentially be alot worse then the few tenths out of round the fasteners produce. If you size the bearing properly using the ARP hardware obviously, the chance of an issue is very slim. Think about how many guys just throw aftermarket rod bolts in their factory LS engines....that would distort that hole of that rod bore alot worse than a huge/thick six bolt steel main cap IMO.

Make sure your machine shop is good and make sure you check their work should you opt to do so would be my advice.

Hope this helps...

-Tony

PS....The other issue I find with the line hone situation is most of the GM blocks I have worked with all come on the high side of tolerance right out of the box. The saddles are usually already 2.7509- 2.7510.....the spec calls out 2.7500 - 2.7510. If someone align hones it too big now you don't have enough bearing crush which can cause more issues than the few tenths out of round from the stud install. Lots of stuff to consider here

 

Thanks alot Tony, I respect your word and appreciate your response! I think i'll just stick with the factory bolts and check my clearances there. I don't NEEED the studs so I think the bolts will suit me just fine. Thanks!

 

My 383 uses the arp's without a hone, but we checked it all out first. It's been running for 3 years now and making 500+ at the wheels. Also did a track day last Friday with oil temps up to 301 running 5w40 Rotella synthetic and all is well. Check things over then decide what needs to or doesn't need to be done

 

We do about 250 Gen III blocks a year and line hone almost all of them and on some it is like Tony says and they really don't move that much especially on like LSX or iron with ARP main studs. Some of the older aluminum blocks we have seen will not turn over with .0015 measured clearance when not line honed! Some do though as well.

The cranks that don't spin that people bring in from their home rebuilds we line hone and at the same .0015-.0020 now they spin just fine. Also the side bolts have a big effect on clearance and so does having the caps in front of and behind the main cap you are measuring torqued correctly as well. Otherwise you will see some results keep changing as you bolt caps down.

Old aluminum blocks I have seen sag and don't just go out of round maybe like the cap getting egg shaped but the holes themselves are no longer all concentric because when installing new bearing in place of old the crank feels bad and with the old ones back in it will spin again! Again we cut the caps .0020 lower and line hone right back out and the crank spins like a top even with the new bearings that are not worn to the wear and tear and "sag" of the block. This is mostly on very old blocks with some real miles on them.

I used to put the OEM stuff back together after we pulled the cranks and rods off just to see in the old days quite a lot to see what GM was doing especially on the new engines we got in. It is sometimes surprising especially ring gaps! All clearances were bigger than I thought but the mains on the aluminum blocks were usually fairly tight.

 

I was surprised how tight my OEM short was when I pulled it apart after 50K of "spirited" use, literally 400 confirmed chassis dyno runs, and countless trips to 7K with the new AFR heads and cam package. Even the rods were tight which surprised me because they didn't have to account for the aluminum expansion.

It's no wonder some of the aftermarket builds out there have such low oil pressure....I see alot of these guys running loose clearance even for a Gen I engine!

You still owe me a phone call btw!

 

TONY

You constantly amaze me with your UNIQUE knowledge!!!!!: thumbs: Well Done!

BC

 

The shootout always destroys the last and this month. I will call you soon Tony and am very interested in the new stuff you guys have for sure as we have so many big engines that can always use more airflow! AFR as a rule for us has always been a good company and we always seem to make more power than we should with your stuff Tony!

On the bearings we always err on the side of safety and clearance if there is a question so our stuff has somewhat larger clearances but not huge. If I see too much pressure especially from a stock pump engine I know something is setup wrong and it probably won't last long! Of course we do a lot of crazy build here.