Lifting the heads!!!
 

Had another gasket leak on the heads. It was getting bad like last time where it was burning coolant on a cold start. Anyways, I pulled the heads and noticed that BOTH sides are lifting and blowing past on the outside of the motor, only one side was burning coolant.

WHat head gaskets are the bigger power motors using and having success with? I've been using GM MLS 6.0 gaskets. This is the 3rd set fixing to go on, and I don't really wanna do this again.

Pics to come later. :)

I think that besides making a gasket choice, you might want to check your heads for straightness and maybe your cylinder decks too. This will require an engine straight edge and feeler gages. If your heads are warped significantly, head gaskets won't solve the problem. Also, why are you using 6.0 L gaskets designed for a 4.000" bore when your 5.3 L has a 3.779" bore? This alone might be causing significant head gasket sealing problems.


Steve

Might be time to look into some Cometics. I see more and more LS1 guys using them. Down side is they are pretty expensive. Are your heads studded??

I guess I should have given a little more info, it's a 5.3 with 6.0 heads on it. That's the reason for the 6.0 gaskets. I thnk I'm gonna try using some lube and a little different torqueing process that someone mentioned on the heads. ;)

Yes, they are studded.

The heads aren't warped, if that were the case, I would think it would be one or 2 cylinders, not all 4 on both sides on the outside edges. You can see the charred gasket on the head side on all 4 on one side and the back 3 on the other side, and one cylinder on the one that was leaking coolant on the block side. The last time this happened it was on the opposite side from the one that's now leaking. The heads were not swapped from last time either.

Since I already have the MLS gaskets, I'm gonna give them a shot again using a little more torque, 85 instead of 75. I also have to have this done by tomorrow, early Fri evening at the absolute latest.

That's wild bro. I was using the stock 6.0L gaskets and didn't have any problems at 14psi. You're just a savage! :)

Are there any problems running the 6.0 heads on a 5.3? I could buy a set for cheap, but I'm thinking different bore size.... :confused:

No problems here. Worked great for me and Flyer. :)

The performance is awsome, for boosted apps, but I've had problems with head gaskets though. I do spin my up pretty high for a stock motor though. 6600 shift points and 6900 rev limiter.

I'm using MLS gaskets too. Did you over-torque your heads? Studs or bolts?

You have a detonation problem? as this is the only reason you should be lifting your heads if you are.

I had some tip in KR, but I think most of it was headers banging around. I see ~1-2* of KR at most and that's very intermittant after a header change, before the header change, 5-7*.

They were torqued to 70 the 1st time and 75 the 2nd. The 2nd time around there was a LOT more attention to detail when I torqued them down.

Flyer, I'm not sure what you have for fasteners, but I got some ARP L19 studs and torqued them to 100 on the mains, and 26 on the pinch studs.

On the mustang 5.0 i am used to if you over torque your intake bolts it will lift or make it easier for them to lift sound like that the case here go 5lbs less on the intake bolts.

Quit messin around and get a set of AFR or Allpro head
They thicker deck surface will help out
or A set of cometics that's what's going on my next motor
you have head studs right if ya don't invest in a set

I use the MLS gaskets and torque them to 80 ft/lbs.If they are lifting it is a good chance there is too much timing in the tune.

Do not need too. Stock heads, bolts adn gaskets are good for 1000fwhp or better. If you are lifting with less then that there is another problem lurking. There is a handful of cars well into the 8's with stock heads and gaskets with studs too.

My truck has stock bolts and stock mls gaskets. My boost has been as high as 22psi on the engine dyno. The engine now has 24,000 miles on the original gaskets. Best et is still 11.81@114.49 at 5500 pounds. Leaving today for Power tour.


Kurt

Just an update on things ... dead in the water!

I went to torque down the final head the last time and ended up messing up one of the nuts on the stud. It pulled the threads out of the nut, but didn't do anything to the stud itself. Thunder is gonna hook me up on a new nut.

I was torqueing them to 85 lb/ft.

Turbo, where did you get the L19 studs and how much. You can PM me if you'd rather. :)

I hope this is the last time this happens. If I go through this again, I'm gonnaput the 5.3 heads back on. I think I remember when this happened, I was at the track and was running pretty hard. It may have gotten a little to hot, coolant and IAT's. The ambient temp out was something like 80-85 that night. It felt like it just sat down up top and took forever to get to the shift point from about 6000rpm.

i spit out a couple of head gaskets on my old motor. finialy i got serious about doing it right.

i had the heads surfaced, something like 005, head studs, stock 6.0 mls gaskets, motor oil for stud lube and 15 ft/lb's over what ever it said. i think i went to 90 ft/lbs with them. i got the block real clean but never checked it for warpage.

with that set up i had no more problems. i didn't see any more or any less KR after this so i dont think it was knock that was taking them out. i think it was either in imperfect head surface or the studs not being tight enough. i probably ran for 6months with that set up, lots of dyno runs and track runs. got my 640rwhp and 10.91 with that set up too.

I'm thinking it's the studs. When I was talking with Thunder, they mentioned that it's not to terribly uncommon for them to back off after a couple of heat cycles. It makes sense too with the aluminum heads expanding and contracting. I'm hitting them with 85 ft/lbs this time, I think ARP mentioned 70.

I did spray some Tri-Foam on the studs for lube. It's like Liquid Wrench, but better. :)

I got my L19s through APE before they got into the screwing people business. I think they were are $400, but I got them explicitly for the boost and the ability to over torque 'em.

Also, I torqued the heads down, then ran it and got it hot, pulled all the top end crap off again and retorqued everything.