Lessons in head gasket matters.
09-14-2010, 10:43 PM
#1
Tech Contributor
Thread Starter
Lessons in head gasket matters.
Well, I had a guide come loose in my old patriot heads last year and I replaced them with a set of AFR's. AFR said to use a LS7 head gasket and so I did it without questioning them (mistake 
). Ever since then, my car has spiked in coolant temps after a romp and run a bit higher than usual in temps. As many of you know, I worked on lowering the temps with a Dewitts radiator, shroud, fans, giant oil cooler, and Meziere water pump. I tackled the temps and made it to where I could drive in temperatures well over 100 degrees with the A/C on. I also noticed that ever since I put the AFR heads on it would spit coolant out of the reservoir if I got the boost all the way up. Once it spit out a little, it would stop doing it, but the coolant level was a bit low. That didn't matter so much in the winter months though. I decided to pull the heads off and see what was going on. I had trails of carbon in at least 4 cylinders where the heads lifted and spit combustion past the head gasket and in some places, into the coolant system. I also noticed the steam holes were blocked. 
After some research, I read where a LS1Tech member, Vee8 had the same issue. The deal is you cannot (or should not) use a LS7 gasket with a Iron block unless you are willing to punch out those steam holes. Changing to the LS9, 7-layer gasket fixed it for him and that's what I already bought along with some ARP2000 studs. I also resurfaced the heads. I like a smooth finish on the heads and the machine they used, the Storm Vulcan didn't cut it for me. I had them run it over a surface plate to lighten the machine grooves on them. I will have the car back on the road by Friday and will follow up with the results after some driving.
). Ever since then, my car has spiked in coolant temps after a romp and run a bit higher than usual in temps. As many of you know, I worked on lowering the temps with a Dewitts radiator, shroud, fans, giant oil cooler, and Meziere water pump. I tackled the temps and made it to where I could drive in temperatures well over 100 degrees with the A/C on. I also noticed that ever since I put the AFR heads on it would spit coolant out of the reservoir if I got the boost all the way up. Once it spit out a little, it would stop doing it, but the coolant level was a bit low. That didn't matter so much in the winter months though. I decided to pull the heads off and see what was going on. I had trails of carbon in at least 4 cylinders where the heads lifted and spit combustion past the head gasket and in some places, into the coolant system. I also noticed the steam holes were blocked. After some research, I read where a LS1Tech member, Vee8 had the same issue. The deal is you cannot (or should not) use a LS7 gasket with a Iron block unless you are willing to punch out those steam holes. Changing to the LS9, 7-layer gasket fixed it for him and that's what I already bought along with some ARP2000 studs. I also resurfaced the heads. I like a smooth finish on the heads and the machine they used, the Storm Vulcan didn't cut it for me. I had them run it over a surface plate to lighten the machine grooves on them. I will have the car back on the road by Friday and will follow up with the results after some driving.
09-14-2010, 10:44 PM
#2
Tech Contributor
Thread Starter
Here's a quote with pics from the original post that I found.
Well I pulled the heads to swap in the LS9 head gaskets, and I did confirm that the LS7 gasket, does not match the coolant ports on a 6.0L iron block. This obviously is not good, and may have contributed quite a lot to the fact that I pushed water every time it has been on the dyno. Even with a mild tune.
LS7 gasket on 02 LQ9 block....
Old 6.0L gasket fits much nicer....
LS7 gasket, note the black area on the bottom where it was pushing water,
The new gaskets will be here tomorrow, and I will compare the LS9 gaskets.
LS7 gasket on 02 LQ9 block....
Old 6.0L gasket fits much nicer....
LS7 gasket, note the black area on the bottom where it was pushing water,
The new gaskets will be here tomorrow, and I will compare the LS9 gaskets.
09-14-2010, 11:01 PM
#3
Le Mans Master
Cool beans. Hopefully your parts come in soon...would hate to see you on the DNQ list. 
I can see how the temps would spike because of this but I'm having a hard time understanding why partially/mostly covering those holes would cause it to lift the head enough to push boost out into the water jackets. Especially considering how the marks in that last pic are directly opposite where the problem is.
I can see how the temps would spike because of this but I'm having a hard time understanding why partially/mostly covering those holes would cause it to lift the head enough to push boost out into the water jackets. Especially considering how the marks in that last pic are directly opposite where the problem is.
09-14-2010, 11:31 PM
#4
Tech Contributor
Thread Starter
Cool beans. Hopefully your parts come in soon...would hate to see you on the DNQ list.
I can see how the temps would spike because of this but I'm having a hard time understanding why partially/mostly covering those holes would cause it to lift the head enough to push boost out into the water jackets. Especially considering how the marks in that last pic are directly opposite where the problem is.
I can see how the temps would spike because of this but I'm having a hard time understanding why partially/mostly covering those holes would cause it to lift the head enough to push boost out into the water jackets. Especially considering how the marks in that last pic are directly opposite where the problem is.
I would hate to see me on the DNQ list as well. Especially since I've stayed off the track in anticipation of this event. 
09-15-2010, 08:21 PM
#10
Tech Contributor
Thread Starter
09-15-2010, 10:19 PM
#12
Team Owner
Nice heads-up -
I will be looking forward to your results, sriving and the temps
Thanks,Matt
I will be looking forward to your results, sriving and the temps
Thanks,Matt
09-16-2010, 12:02 PM
#13
Race Director
09-16-2010, 07:08 PM
#15
Former Vendor
11-25-2011, 10:51 PM
#17
Instructor
You just take words out of my mouth. My car did the same thing, I just order a zr1 ls9 mls 7 layers metal gasket for my lq9 block. The mls 3 layers don't hold high boost and start to push water. That's a good advice. Thanks for sharing. 
Last edited by mcantuaria23; 11-25-2011 at 10:56 PM.
11-26-2011, 08:56 PM
#18
Melting Slicks
I'll add 1 more wrench to this. AFR recommends nothing less than a 4.125" bore gasket on their 225 big bore heads. I opted away from ls7's b/c of issues like these and ended up buying cometics. Anything smaller like a ls9 gasket will stick into the combustion chamber of the heads just a hair and isn't 100% optimal. This is regardless of bore. I'm running a 3.905" bore.
That said, lots of people do it without issues. I'd rather not do it when pushing serious boost.
That said, lots of people do it without issues. I'd rather not do it when pushing serious boost.
11-26-2011, 09:52 PM
#19
Former Vendor
FWIW, I think the LS7 gasket is a POS.
On the AFR 225 head I tested, the LS9 gasket fit fine, so we used it.
The car never popped gaskets again, the LS7 would leak on every cylinder.
On my own car-I used the LS9 gaskets-even though they slightly did overhang in the chamber-well, 160 mph quarter mile passes later there still in there with no signs of leakage.
The LS7 gaskets on other hand leaked after a few quarter mile passes with a soft tune.
LS9 for the win.
On the AFR 225 head I tested, the LS9 gasket fit fine, so we used it.
The car never popped gaskets again, the LS7 would leak on every cylinder.
On my own car-I used the LS9 gaskets-even though they slightly did overhang in the chamber-well, 160 mph quarter mile passes later there still in there with no signs of leakage.
The LS7 gaskets on other hand leaked after a few quarter mile passes with a soft tune.
LS9 for the win.
11-26-2011, 10:11 PM
#20
Melting Slicks
Have you had any experience with cosmetic?
FWIW, I think the LS7 gasket is a POS.
On the AFR 225 head I tested, the LS9 gasket fit fine, so we used it.
The car never popped gaskets again, the LS7 would leak on every cylinder.
On my own car-I used the LS9 gaskets-even though they slightly did overhang in the chamber-well, 160 mph quarter mile passes later there still in there with no signs of leakage.
The LS7 gaskets on other hand leaked after a few quarter mile passes with a soft tune.
LS9 for the win.
On the AFR 225 head I tested, the LS9 gasket fit fine, so we used it.
The car never popped gaskets again, the LS7 would leak on every cylinder.
On my own car-I used the LS9 gaskets-even though they slightly did overhang in the chamber-well, 160 mph quarter mile passes later there still in there with no signs of leakage.
The LS7 gaskets on other hand leaked after a few quarter mile passes with a soft tune.
LS9 for the win.
