This is the head for my SC300. If running OEM GTE pistons and rods, this is what needs to be done to a GE VVTI head to run a GTE headgasket while keeping quench within spec and yields 9.2-9.3:1 compression.
i am also one of those who don't get it.. just get taller pistons, they don't cost that much. 2gr-fxs is one example - its from toyota, same quench pads that is lower than the deck, also has one pad missing cuz there needs to be space for DI. Still manages to get 13:1 compression ratio.
only part I did get was this was for a OEM GTE piston so he didn't have to get a piston. But, agreed, if I am changing stuff it would have been the piston.
Wouldn't have been easier to weld over the quench pads and then mill? Or, was this person specifically interested in lowering the combustion chamber volume as well?
Mind blown - and now more confused than ever. I've not cc'd GE-VVTi parts before, but from internet sleuthing, the best numbers I've found are 42cc chamber and 8cc dish in the piston. Based on that, the 86mm x 86mm bore and stroke, 0.005" deck clearance and a head gasket thickness of 0.015" - you come real close to the 10.5:1 compression that Toyota claims. If you use 46cc for the chamber - calculated compression goes down to 9.8:1 To get back to 10.5:1, you have to decrease piston dish to 4cc... again I've not cc'd one of those - but they sure LOOK like they have more than 4cc dish. What gives? I trust Dave, here - but I'm obviously missing something.
this is the first time I have CC the chamber on a VVTI head, so I honestly couldn't say who is right or wrong lol. Maybe I am wrong. idk. I agree like the tech you wrote down here. Maybe in a few weeks I will CC another stock one and see if it checks out. But, rememer that this one is valve jobbed, and has a different valve. Is that worth 4cc? I don't think so. But, we can play with that.
Nice way to get it similar to get it gte gasket quench, but now he has no room for future deacking. Im consider taking about .015 off mine, somewhere in the middle to get it right, but leave some meat for a couple rebuilds/decking before the head is too far gone. Any opinion on that?
@davidparker9676 lol the amount of time it would take to reshape a combustion chamber would never be worth it... Eapecially when you can get ge he heads for dirt cheap. It also adds different metals which effect the cooling of the cylinder head and introduce hot spots. So no, lol that would be the worst advice ever. The only time you weld is to repair a damaged spot and usually only makes sense when its a small spot and budget in mind. Nobody is doing that to redesign abd reshape all 6 to change quench lol.
i did it. welded up all the quench pads. you still have to machine down the head a bit, because the weld sinks in on the edges. i did it to keep the compression as low as possible. i had 41.5cc with stock valves and stock chambers on a vvti. after welding, resurfacing and reshaping the chamber i had 42.5cc, which gives me 8.7:1 with 8.3:1 pistons and GTE HG. im just curious how they got 46cc. i measured with a 0.01g precision scale.@@josesupra
This engine / head package is intended to last a very long time. I don’t intend on ever rebuilding or needing to. It’s just a new GTE shortblock and a fully built head, GTE headgasket and ARP studs. Streetable, reliable, 700~hp
something is off here. milling 0.75mm should only remove 4.35cc. pi x 4.3^2 x 0.075. i measured my chamber 41.5cc. it was resurfaced once before by 0.1mm, so stock cc should be 42cc.
We do have a porting vid of the GE head ruclips.net/video/1Kynu5RySu4/видео.htmlfeature=shared ruclips.net/video/mpjzeYF0ROs/видео.htmlfeature=shared ruclips.net/video/NFuYdakiT8A/видео.htmlfeature=shared
@@headgames thanks! I wasn’t planning on it, for some reason it reminded me of a b16 head and the end result looks more like that of a gsr. Since I cought your eye, thoughts on the gsc 6mm stem exhaust valves ? For b16/8
Why would you/would you not want to do this? And why would you compensate with a thicker head gasket? Doesn’t the thicker head gasket defeat the purpose of doing this?
I think the goal is to have as close to GTE combustion chamber properties as possible- so you can have GTE-like properties when using the 5-layer MLS OEM head gasket. If you are using a GE head with the quench pads, you end up with a larger combustion chamber volume than with the GTE head which reduces the compression ratio and increases quench area beyond what is considered "optimal". You can do some math to try to offset that with custom pistons that place it closer to the top of the block's deck but in general when using off-the-shelf forged pistons or OEM GTE pistons, the GE head and GTE head gasket places the combustion chamber a bit too far up. Too wide of a quench area can sometimes affect the engine's natural detonation suppression. You absolutely don't want to use the factory composite GE head gasket with a turbo setup for longevity. I like this mod in that it allows you to run off-the-shelf pistons for GTE motors and the 5-layer OEM MLS head gasket, and aside from the head's flow characteristics (which I think the GE head is the superior head to the GTE anyway) you'll get GTE-like predictability with what compression and behavior to expect. I'm thinking of doing the same with my GE-VVTi build.
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This is the head for my SC300. If running OEM GTE pistons and rods, this is what needs to be done to a GE VVTI head to run a GTE headgasket while keeping quench within spec and yields 9.2-9.3:1 compression.
You have better eyes than I, Dave! I need color in my burette to be able to read it. LOL
I will probably get there when I get older lol
Make sure you hit that like button just how you hit the gas pedal.
i am also one of those who don't get it.. just get taller pistons, they don't cost that much.
2gr-fxs is one example - its from toyota, same quench pads that is lower than the deck, also has one pad missing cuz there needs to be space for DI. Still manages to get 13:1 compression ratio.
only part I did get was this was for a OEM GTE piston so he didn't have to get a piston. But, agreed, if I am changing stuff it would have been the piston.
Wouldn't have been easier to weld over the quench pads and then mill? Or, was this person specifically interested in lowering the combustion chamber volume as well?
it was a specific request. And, you would be adding many hours to this task, along with a seat install.
Mind blown - and now more confused than ever. I've not cc'd GE-VVTi parts before, but from internet sleuthing, the best numbers I've found are 42cc chamber and 8cc dish in the piston.
Based on that, the 86mm x 86mm bore and stroke, 0.005" deck clearance and a head gasket thickness of 0.015" - you come real close to the 10.5:1 compression that Toyota claims.
If you use 46cc for the chamber - calculated compression goes down to 9.8:1
To get back to 10.5:1, you have to decrease piston dish to 4cc...
again I've not cc'd one of those - but they sure LOOK like they have more than 4cc dish.
What gives? I trust Dave, here - but I'm obviously missing something.
Love the logical thinking and quick math you included. I'm curious myself now
this is the first time I have CC the chamber on a VVTI head, so I honestly couldn't say who is right or wrong lol. Maybe I am wrong. idk. I agree like the tech you wrote down here. Maybe in a few weeks I will CC another stock one and see if it checks out. But, rememer that this one is valve jobbed, and has a different valve. Is that worth 4cc? I don't think so. But, we can play with that.
@@headgames It'd be awesome if you checked another VVTi head and let us know what you find!
Nice...
Nice way to get it similar to get it gte gasket quench, but now he has no room for future deacking. Im consider taking about .015 off mine, somewhere in the middle to get it right, but leave some meat for a couple rebuilds/decking before the head is too far gone. Any opinion on that?
Weld the chambers instead. Make it look however you want.
@davidparker9676 lol the amount of time it would take to reshape a combustion chamber would never be worth it... Eapecially when you can get ge he heads for dirt cheap. It also adds different metals which effect the cooling of the cylinder head and introduce hot spots. So no, lol that would be the worst advice ever. The only time you weld is to repair a damaged spot and usually only makes sense when its a small spot and budget in mind. Nobody is doing that to redesign abd reshape all 6 to change quench lol.
i did it. welded up all the quench pads. you still have to machine down the head a bit, because the weld sinks in on the edges. i did it to keep the compression as low as possible. i had 41.5cc with stock valves and stock chambers on a vvti. after welding, resurfacing and reshaping the chamber i had 42.5cc, which gives me 8.7:1 with 8.3:1 pistons and GTE HG. im just curious how they got 46cc. i measured with a 0.01g precision scale.@@josesupra
This engine / head package is intended to last a very long time. I don’t intend on ever rebuilding or needing to. It’s just a new GTE shortblock and a fully built head, GTE headgasket and ARP studs. Streetable, reliable, 700~hp
Roughly .006" for every cc on a LS head.
something is off here. milling 0.75mm should only remove 4.35cc. pi x 4.3^2 x 0.075. i measured my chamber 41.5cc. it was resurfaced once before by 0.1mm, so stock cc should be 42cc.
Wont adding a thicker head gasket just put the quench pads back in?
Do you have any porting videos on a 2jz ge vvti head?
no sir, but maybe in the future!
We do have a porting vid of the GE head
ruclips.net/video/1Kynu5RySu4/видео.htmlfeature=shared
ruclips.net/video/mpjzeYF0ROs/видео.htmlfeature=shared
ruclips.net/video/NFuYdakiT8A/видео.htmlfeature=shared
Can this be done to a b16 cyl head?
@@badboyracing5391 I wouldn’t suggest that
@@headgames thanks! I wasn’t planning on it, for some reason it reminded me of a b16 head and the end result looks more like that of a gsr. Since I cought your eye, thoughts on the gsc 6mm stem exhaust valves ? For b16/8
@@badboyracing5391 if you’re making 1000+whp that valve would be great! Any other manufacturer, it’s a custom valve. We use them in sfwd applications.
Why would you/would you not want to do this? And why would you compensate with a thicker head gasket? Doesn’t the thicker head gasket defeat the purpose of doing this?
I think the goal is to have as close to GTE combustion chamber properties as possible- so you can have GTE-like properties when using the 5-layer MLS OEM head gasket. If you are using a GE head with the quench pads, you end up with a larger combustion chamber volume than with the GTE head which reduces the compression ratio and increases quench area beyond what is considered "optimal".
You can do some math to try to offset that with custom pistons that place it closer to the top of the block's deck but in general when using off-the-shelf forged pistons or OEM GTE pistons, the GE head and GTE head gasket places the combustion chamber a bit too far up. Too wide of a quench area can sometimes affect the engine's natural detonation suppression. You absolutely don't want to use the factory composite GE head gasket with a turbo setup for longevity.
I like this mod in that it allows you to run off-the-shelf pistons for GTE motors and the 5-layer OEM MLS head gasket, and aside from the head's flow characteristics (which I think the GE head is the superior head to the GTE anyway) you'll get GTE-like predictability with what compression and behavior to expect.
I'm thinking of doing the same with my GE-VVTi build.
A high boost 2jz is not a small block Chevy. Quench pads are useless