What about the different thermal expansion properties of SS and aluminum? After alot of heat cycles and such close tolernces and stress put on the timeserts or helicoils couldnt the block crack or the insert deform?

 

I honestly believe that because the block is not solid it is the culprit here. Under a heavy (FI) load that thing probably "torques" all over the place and what you all are seeing is the end of a "domino effect". Sort like looking at a glacier, in that 90% percent of it's mass is hidden yet all you see is that little 10% bit that's visible. Are the guys with sleeved blocks having the same issues?? Would it be feasible to concentrate on strengthening the block more ie. with a heavier girdle??

I'm still learning so don't blast me too hard..

 

I think that a billet girdle would help alot. Im not sure if Performance Motorsport has them on their racing motor or not.

 

Yeah, something like this that's used on the GNTType V6 would be nice and strengthen the block considerably..

 

There are cases where guys with sleeved blocks have suffered head gasket failure. However, I'm not sure what kind of head gaskets were involved (oe vs Cometic) and what the head studs were torqued to. I believe that because this is a semi-new issue that these likely had the oe head gaskets and the studs torqued to 65 or so lbs (really just hoping this is the case ). Once the head lift issue started to come up is when (I think anyway) the better head gaskets started to be more heavily favored over the oe ones. Some have said that a sleeved block with the upgraded studs and head gasgets are good for 725, plus or minus 25.

 

Why dont we just used 1 inch studs and hammer them into the block instead of using heli coils or timeserts? that should hold right? if not just put some JB weld in there before we hammer them in......hmmmm.... yup thats what im going to do.

 

I'm with XBS on this one.

 

you guys are getting so close, the answer is almost touching you, lol. first off, the VQ35 already has a pretty good main stud girdle stock. i don't think i billet one is going to give ya much advantage.
i strongly feel that it is simply the head flexing. the leaks that have been found (in the cases i have seen and heard) on the opposite axises of the head studs, not directly in line with the head studs. now while i still feel bigger head studs will definately help, if stretching head studs were the only prob, you would see leaks inline with the head studs also. what this means is that the head itself is flexing and lifting under the pressure. not completely because of the head studs, but the structural design of the head.
part one of a 3 part head strengthening saga will be ready tomorrow, finally!!

 

Do you think the new Cosworth head has more structural integrity, making it less prone to deflect under boost...?

 

i have not researched much behind the cosworth head. if it is still a factory casting, then the problems would be the same.

 

like scott said, it is a factory reworked head

 

OK then, hear me out and try to keep an open mind about what i'm going to say. If the problem is the fact that the head is indeed flexing, surely the cheapest and simplest way to fix this, wolud be to fabricate some sort of bracket that cross braces over the top of each cylinder, so that you effectively have an even clamping force all across the cylinder head, as opposed to just where the bolts are? It could be a bit far fetched, but maybe? Does anybody understand what i'm trying to say?
Another thing, (whilst i'm on my wild thought process), the fact that the VQ35 has an open deck design, people say it makes it alot more prone to flexing under high boost, which is why people then resort to sleeving, essentially ridding itself of the open deck design, but has nobody thought that maybe, a revolutionary head gasket, with potrusions that sit perfectly within the cooling water channels have a similar effect, not as much as sleeving, but still give the upper end of the combustion chamber a bit more support, by leanind on the outer wall?

 

of course you could always try to improve flow out of the heads also...this would ? relieve some the the pressure causing the lift

 

all really good ideas you have layed out here. i have already been through this point though. as far as a bracket going across the cylinders or in my case i was looking at some sort of bar that a seat could be machined into the head across the head bolts to distribute the load better. first off, pretty much impossible to do due to the follower bucket bridging. even if it was possible, you have the intake and exhaust runners you would be running across, and it would not help anything at all.
as far as a channeled head gasket, every block is going to have very slight variations in the castings, and you would not be able to keep a consistent spacing from block to block. now i have a block mod that really simplifies the idea behind this. you can drill holes around the top of the cylinders, centerlined on the coolant passage, (3/8" diaX1/4" deep) and then fill them with 3/8" alum rod. heliarch them in, then a resurface and you are golden. if you do this, be sure to not block the coolant passages in the head gasket though. this ties the deck surface together for a fraction of the price of sleeves. this is a subby trick. their blocks are way worse than ours as far as the open deck is concerned.

 

hey jim, the pressure is already gone by the time you are getting the exhaust gases out. if you vented the actual power stroke, will i'm sure you see how that is counter productive.
now one thing that comes to mind along these lines though is heat. is the extra heat generated actually deforming the heads and this is why it takes awhile for the initial "head lifting" symptoms to pop up. if that is the case, ceramic coating the combustion chamber and bottom of the valves and exhaust runners will greatly reduce the heat that would normally convect to the head. i will find out when i completely rip my motor apart to do all the engine mods and tricks we come up with.

 

Come on dude ... spill the beans

 

lol, will be back in a few hours with pics and everything.

 

I am so glad this thread has progressed past the point of clamping force and 1/2" studs. Although I am sure this will "help" I am still fairly confident that there is some degree of distortion in the head when torqued and exposed to multiple heat cycles. How do you address this? I know Scott's idea is new and "outside the Box", but is anyone else trying to address the clamping force or seal betwwen the culinders where the head studs to not generate equal or adequate force?

How about the guys with sleeves? I know Philthy has sleed 2 blocks, one with Dartons, one with liners. Any comment to the boost levels you are seeing lift with sleeves?

 

Come on Scott! It's been a more than a few hours!!!!!

 

ok ok, lol. gunna start another thread. pics are loading now.