Treyvs

I am looking at an ARP Ring Compressor for a 3.780 (5.3L) bore. My block has been bored to 3.784 to allow for nitrous and boost. Will this compressor still be able to be used to install the 3.780 pistons? The compressors come in size increments of .010, so I am thinking that it shouldn't be an issue since it is once 4 thousandths. Any help is appreciated.

KCS

iTrader: (20)

Your block is 3.784"? What pistons are you using?

chrisfrost

iTrader: (8)

Why not buy an adjustable ring compressor 2"-5"?

Treyvs

Tried the adjustable one and it likes to not stay tight, or square on the piston. I had to have the block bored and the rings opened up a bit to accommodate the heat from the nitrous. The pistons are 3.780 Wiseco -2.2cc Flat Top's with valve reliefs, and they fit snug in the bore still. The rings are 3.785. Watched a couple of videos on those ARP Compressors and they seem quite legit.

KCS

iTrader: (20)

Have you measured your piston to wall clearance? The problem I'm seeing is that piston companies don't usually sell you a 3.780" piston, they sell you a piston for a 3.780" bore and the piston will actually measure somewhere in the neighborhood of 3.777" so that the recommended clearance is already "built in". Wiseco I know is like this. So if you're using PN K474M96, you're going to have something like .006-.007" piston to wall clearance with the bores sitting at 3.784". That's pretty excessive.

The ARP ring compressor should still work though, regardless.

Treyvs

My machine shop checked all the clearances with a Wiseco representative, so I know that they hammered out the details, so I am not sure of the exact clearance. They would have been fine with the stock 3.780 bore if I was not going to use power adders down the road. Since I am, additional clearance is needed for the more heat generated with the power adders. I leave the math to the pros, as I always liked history. Lol

chrisfrost

iTrader: (8)

Lm7 factory bore is 3.779 ! Are You're pistons forged? Because I know They do increase the clearance a little for forged stuff but power adders if done the best way have intercoolers and meth and/or water injection to keep things cool to allow 4 the most ignition timing advance which equates to alot more power and to help engine longevity . With the adjustable ring compressors You just use plenty of oil and crank the compressor fairly tight and You should'nt ever have any issues,,,,,,,pretty straight forward but it's You're decision .

high n dry

iTrader: (18)

the ARP piston ring compressors r very good! i have one i used for my stock ls1 build... 3.900" works great. PM me if this one will work for u.

Treyvs

Yes, they are forged. The videos I have seen on the ARP Compressors got me sold on them instantly.

RezinTexas

I used a 3.900" ARP ring compressor on my 3.903" bore motor and it worked perfect.

You're only going over by an additional 0.001", you'll be fine.

niscur29

I got my arp "style" compressor off eBay for about 20 bucks. Worked prefect for my lq9.

jszklany

iTrader: (1)

ebay compressor for me too, worked great! cheap too!

Treyvs

For everyone who is still curious, my compressor came in today and helped me in getting the shortblock done in just under 3 hours. Photos attached.

LS1MCSS

iTrader: (18)

You should have spent more time on it. You have at least one main cap backward.

http://www.gmhightechperformance.com.../photo_24.html

Treyvs

Well spotted. Was looking through my photos and noticed it. Good thing all that was needed was to take it off and turn it around and re-torque it to spec.

I usually get in a rush when I am passionate about things. Good thing for photos or I would have missed it.