What power level do Gen 3 block start to lift heads?
12-05-2015, 08:25 PM
#3
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It's all, like he said in the tune, head and gaskets, specially powerband, evo guys are making 800 per 4 holes but are spinning 9k rpm, LQs are making 800 tq at 5500 in some cases, hard to keep a head down with just 4 studs per hole
12-06-2015, 12:20 AM
#4
Surely this is more related to the peak torque than power? And it's cylinder pressure that really causes the heads to lift. Dept. WILL cause it to happen also as the peak pressure with dept. get ridiculous!
12-06-2015, 10:23 AM
#5
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The block doesn't really determine when the heads lift, so you're asking the wrong question.
Thick deck heads with ARP custom aged studs on a 4.8 that moved the power up high, they might not start to lift until 1300+ HP. Maybe more if the block is retapped for bigger studs.
Larger cubic inches, huge amounts of mid range boost and torque, OEM castings, even with studs they might lift before you make 4 digits.
Thick deck heads with ARP custom aged studs on a 4.8 that moved the power up high, they might not start to lift until 1300+ HP. Maybe more if the block is retapped for bigger studs.
Larger cubic inches, huge amounts of mid range boost and torque, OEM castings, even with studs they might lift before you make 4 digits.
12-07-2015, 01:33 PM
#7
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The blocks themselves weren't changed much between gen 3 and 4. One won't keep the heads pinned better than the other.
Good studs, retapped for 1/2" studs, thick deck heads, good head gaskets, etc all keep heads down. Keep down peak pressures, etc. The actual setup is far more responsible than the block itself for a head lifting.
Good studs, retapped for 1/2" studs, thick deck heads, good head gaskets, etc all keep heads down. Keep down peak pressures, etc. The actual setup is far more responsible than the block itself for a head lifting.
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12-07-2015, 02:22 PM
#8
Power doesn’t lift heads, cylinder pressure does. Usually spikes in cylinder pressure from detonation.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
12-07-2015, 02:32 PM
#9
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Power doesn’t lift heads, cylinder pressure does. Usually spikes in cylinder pressure from detonation.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
12-08-2015, 03:03 AM
#11
Power doesn’t lift heads, cylinder pressure does. Usually spikes in cylinder pressure from detonation.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
An 8:1 engine can make the same HP as a 10:1 engine with less cylinder pressure. Meaning a lower base compression engine is less likely to lift a head at “X” HP level than a higher base compression engine.
Just don't want anyone to be confused and blame detonation for head lifting. The ls community has gotten to such insane power levels with these now that you can just simply over power the strength of the casting, not the clamping force of the head studs/bolts.
12-08-2015, 06:47 AM
#12
I did say "usually" caused by detonation. Sure, some may make enough to lift the head without detonation spikes, but thats not usually the case.
That's why some are able to push 1400 crank hp and keep the heads down, and some can't. I've seen a stock block trap 182+ at 3300lbs with a standard arp studs and L92 heads @ 30+psi. Didn't have head gasket issues all season. I've seen guys claim to blow HG's out on power alone at well under 900hp too. In reality...its almost always detonation.
That's why some are able to push 1400 crank hp and keep the heads down, and some can't. I've seen a stock block trap 182+ at 3300lbs with a standard arp studs and L92 heads @ 30+psi. Didn't have head gasket issues all season. I've seen guys claim to blow HG's out on power alone at well under 900hp too. In reality...its almost always detonation.
12-09-2015, 07:17 AM
#14
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Just asking.. I know some say (which I haven't looked for myself) that the gen 4 block has a little extra webbing.
Have you tried or known anyone that has tried to push a gen 3 block that hard with or without pushing water?
12-09-2015, 09:26 AM
#15
I've been curious of this as well. I plan to push 4 digits through my gen 3 5.3 in my Subaru and i would rather not be ripping the heads off all the time. I was originally planning 243 heads/ls9 gaskets/arp studs, but this thread has me worried that I should say no to 243's and go with an aftermarket head and 1/2" studs.
12-10-2015, 02:38 AM
#16
I did say "usually" caused by detonation. Sure, some may make enough to lift the head without detonation spikes, but thats not usually the case.
That's why some are able to push 1400 crank hp and keep the heads down, and some can't. I've seen a stock block trap 182+ at 3300lbs with a standard arp studs and L92 heads @ 30+psi. Didn't have head gasket issues all season. I've seen guys claim to blow HG's out on power alone at well under 900hp too. In reality...its almost always detonation.
That's why some are able to push 1400 crank hp and keep the heads down, and some can't. I've seen a stock block trap 182+ at 3300lbs with a standard arp studs and L92 heads @ 30+psi. Didn't have head gasket issues all season. I've seen guys claim to blow HG's out on power alone at well under 900hp too. In reality...its almost always detonation.
The pin bushings where perfect (typical first sign of detonation), as where the rod bearings.
12-10-2015, 07:43 AM
#17
I agree with what you're saying. The problem is, and what has me confused, is that there where zero signs of detonation in my short block pieces yet the gaskets where trashed on like 7 holes.
The pin bushings where perfect (typical first sign of detonation), as where the rod bearings.
The pin bushings where perfect (typical first sign of detonation), as where the rod bearings.
Alcohol and alcohol based fuels generally don’t show clear signs of detonation. You usually skip straight into pre-ignition and instant sky high cylinder pressures. I also had perfect looking plugs/bearings last time I lifted a head and torched the deck. Hammered pins/bearings and speckled plugs are pump/race gas stuff. Ask any top alcohol engine guys about “signs of detonation” and they will just look at you like your crazy. You’d have to have cylinder pressure transducers to get the real scoop and prove anything, but that’s the shared theory from the alcohol guys I’ve talked to anyway.
12-10-2015, 09:50 AM
#18
Thing is, 4 bolt block above 1000hp you have a lot more to worry about then just lifting heads.
Let's ASSUME, you got the heads to stay put with custom aged 1/2 studs and a really thick head surface. Now you will need to worry about the following -
- Dragonslayer or better crank to avoid flexing and taking out a main.
- Dowled or pinned mains even with better crank to minimize flex
- Filled block to keep cylinders stable
The amount of machine work required to make a 4 bolt motor live multiple seasons above, I'll say 1200WHP is cost prohibitive and a stubborn cause. Just invest the first time in a 6 bolt per cylinder set up and enjoy your power making capabilities and growth for additional power capabilities for years to come.
Let's ASSUME, you got the heads to stay put with custom aged 1/2 studs and a really thick head surface. Now you will need to worry about the following -
- Dragonslayer or better crank to avoid flexing and taking out a main.
- Dowled or pinned mains even with better crank to minimize flex
- Filled block to keep cylinders stable
The amount of machine work required to make a 4 bolt motor live multiple seasons above, I'll say 1200WHP is cost prohibitive and a stubborn cause. Just invest the first time in a 6 bolt per cylinder set up and enjoy your power making capabilities and growth for additional power capabilities for years to come.
12-10-2015, 10:45 AM
#19
I agree. If you want more than 1200 crank hp, go with an aftermarket block.
If you have been following the new beryllium (sp?) head gasket technology guys are keeping the OEM heads/block sealed on 4 bolt heads at 1500+ hp using standard (not aged, not ˝ “) ARP pro studs. Trapping 184 @ 3300lbs. That’s using an unfilled OEM block and L92 Head.
http://www.yellowbullet.com/forum/sh....php?t=1332810
If you have been following the new beryllium (sp?) head gasket technology guys are keeping the OEM heads/block sealed on 4 bolt heads at 1500+ hp using standard (not aged, not ˝ “) ARP pro studs. Trapping 184 @ 3300lbs. That’s using an unfilled OEM block and L92 Head.
http://www.yellowbullet.com/forum/sh....php?t=1332810
12-10-2015, 10:25 PM
#20
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Cant tell you how many 4 bangers I have seen torch a head and a block when the tune looked perfect! No knock-good fuel...and she gon'!