6speediroc

iTrader: (5)

I have a 2006 LQ4 I plan to boost to 8-12psi, intercooled, maybe with meth as well. The 317 heads have never been off this motor..it has 75,000miles on the clock. It's in the car running NA right now with a 2002 LS6 cam..

1. Do I need to tear this thing down and re-gap the rings before boosting to these levels?

2. How much boost can I safely run without re-gapping?

3. How much boost can I safely run before needing to install head studs (like these http://www.alpermotorsports.com/inde..._detail&p=2434) with the GM LS9 12622033 gaskets?

JRENIGAR

iTrader: (37)

1) No, Im running an 07 stock shortblock @ 12#'s with no problems.

2 & 3 D/K

JoeNova

1. No.
2. A lot, if you keep temps down.
3. Same as #2

8-12 PSI is very safe on a stock ring gap.
Heat makes the rings expand. Run low timing and water/meth injection to keep combustion temps down and the rings and cast pistons will last a very long time.
Same thing goes for studs. Keeping the heat down will reduce the chances of detonation and spikes in cylinder pressure.

You could always get head studs, remove the stock head bolts one a time in the proper torque sequence and replace them with studs, then you won't have to remove heads or replace gaskets.

Forcefed86

iTrader: (4)

1.) Impossible for us to predict what your gaps will be at. I've seen a hole as tight as .016 when the others were .020 on the same engine. I think .016 is too tight. .019-.024 is the norm for high mileage top rings I've seen. Also every motor I've pulled apart had A TON of carbon build up in the ring lands. Always good to clean the carbon out and check the gaps on any build IMO.

2.) See #1 no way for us to tell you this.

3.) Those studs are only marginally better than the OEM bolts strength wise. Boost doesn't lift heads, cylinder pressure does. Cylinder pressure on one setup at 20lbs may be much higher on another at 20lbs. To many variables for us to tell you this either. I've seen 800+whp on factory head gaskets/bolts. I've also seen people pop them under 600whp. If you get into detonation you can lift at head at any boost level.

6speediroc

iTrader: (5)

Thanks, that makes sense about the detonation being the real issue..

69-chvl

iTrader: (11)

I had a 04 LQ9 with 74k on the clock and IIRC some gaps were like .015, some like .019. Kinda tight if your pushing it. But with good gas, easy timing and low boost you should be OK. Just put another 50k miles on it before really hammering it lol!!!

alocker

iTrader: (10)

Per Forcefed's post, I think the carbon buildup is worth the effort to pull the pistons. Even my 39K mile LY6 had a lot of build up and the chance to clean them was worth it. They all had .014 rings too. Everything else to me is worth it if you are taking the time to boost a motor. I get the sloppy method but I have less time than money (don't really have money either) and swapping junkyard shortblocks is not in the cards for me. To me cleaned and gapped rings, ARP head studs, and LS9 gaskets are excellent insurance.

JoeNova

This may sound ridiculous, but I filled my methanol tank with Seafoam and put my Hobbs switch on 1 PSI back when I was running on the 5 PSI wastegate. Did a pretty good job of cleaning up the cylinders and rings but my oil looked pretty nasty afterwards.

I agree with Forcefed86 about removing them to clean up carbon from the rings, but as a general statement I've taken a nasty sludge filled junkyard engine over 12 PSI without adjusting the ring gaps. When I finally took it apart they were only at .017". Yes, its possible to make it live with a tight gap for a very long time, if this is your first turbo build I wouldn't recommend it.

ablakez28

iTrader: (9)

I like to regap and do studs on any motor im going to boost. It really isnt 100% needed but I like o have a look at everything inside and inspect bearing, hone, etc. Also I have had a few motors that really had huge variations in ring gap. Last motor was from .014 to .032. Once found a spun bearing. Once found a cracked ring. So on junkyard motors to me its worth the day to do a refresh.

6speediroc

iTrader: (5)

Thanks guys, so not absolutely necessary to clean & regap for 12ish psi, but highly recommended.. head gaskets should be good to go as they are, but obviously upgrade if tearing apart.

69-chvl

iTrader: (11)

My current lq9 with 120k was treated to head-studs only...I took the factory bolts out and replaced with the China studs, one at a time. Typical boost setting is 14psi and all has been well. I have a self-imposed limit of 16psi at this point.

I figure once I take the heads off and upgrade the head gaskets, you might as well change lifters also. There about $100.00 to replace. This is the one thing I'm more concerned about - putting stiffer dual springs and a more aggressive cam on lifters that have some time on them.